the influence of organic cement additives on radionuclide mobility

P O S I V A O Y

FI -27160 OLKILUOTO F INLAND

Tel +358-2-8372 31

Fax +358-2-8372 3709

Mart t i HakanenHe in i E rvanne

February 2006

Work ing Repor t 2006 -06

The Influence of Organic Cement Additiveson Radionuclide Mobility

A Literature Survey

Mart t i Hakanen

He in i E rvanne

Labo ra to ry o f Rad iochem is t r y

Depa r tmen t o f Chem is t r y

Un i ve rs i t y o f He l s i nk i



A Literature Survey

Working Reports contain information on work in progress

or pending completion

The conclusions and viewpoints presented in the report

are those of author(s) and do not necessarily

coincide with those of Posiva

February 2006

THE INFLUENCE OF ORGANIC CEMENT ADDITIVES ON RADIONUCLIDE MOBILITY

A LITERATURE SURVEY

ABSTRACT

This review evaluates the influence of organic cement additives on radionuclide mobility The work outlines evaluations under cement conditions where report drafts were available and an evaluation under groundwater conditions (non-cement conditions) based on the chemical structures of the main components in polyelectrolyte additives and on recent results of metal-humic bounding Literature of effects of plasticizers on copper and bentonite are reviewed

This work was done under contract 975503EJOH and 977005PJJ to Posiva Oy

Keywords cement organic additives radionuclide mobility groundwater copper bentonite

SEMENTIN ORGAANISTEN LISAumlAINEIDEN VAIKUTUS RADIONUKLIDIEN KULKEUTUMISEEN

KIRJALLISUUSSELVITYS

TIIVISTELMAuml

Kirjallisuusselvitys arvioi sementin orgaanisten lisaumlaineiden vaikutuksia radio-nuklidien kulkeutumiseen Kulkeutumista kaumlsitellaumlaumln sementtivesi-olosuhteissa ja pohjavesiolosuhteissa Arvioinnin pohjana olivat orgaanisten lisaumlaineiden paumlauml-komponettien kemialliset rakenteet ja todennaumlkoumlinen metalli-humussitouminen uusimpien tietojen valossa Lisaumlksi kaumlsitellaumlaumln lisaumlaineiden vaikutuksia kupariin ja bentoniittiin

Tyouml tehtiin Helsingin yliopiston ja Posiva Oyn vaumllisellauml sopimuksella 975503EJOH and 977005PJJ

Avainsanat orgaaniset lisaumlaineet sementti bentoniitti kupari pohjavesi radionuklidien kulkeutuminen

1

TABLE OF CONTENTS

Abstract

Tiivistelmauml

1 ORGANIC CEMENT ADDITIVES 2 2 SORPTION OF RADIONUCLIDES UNDER CEMENT CONDITIONS 3 21 Effects of plasticizers on radionuclide solubility in cement

conditions 4 22 Cement-superplasticizer interactions 4

23 Leaching from concrete 6 24 Degradation of additives 8 3 SORPTION OF Ni Eu AND Th ON CEMENTS 10 31 Sorption on cement in artificial cement water (ACW) 10 32 Sorption of Eu on additive-containing cement 13 33 Degradation of polymeric cement additives 13 4 SORPTION OF Eu ON CEMENT AND TITANIUM

DIOXIDE AT pH 123 14 41 Summary of the results for DMA experiments 17 42 Sorption of Eu on cement in presence of well-known complexants 18

5 SUMMARY OF RESULTS IN CEMENT CONDITIONS 20

51 Experiments at PSI 20 52 Experiments at Linkoumlping University 20

6 BEDROCK CONDITIONS 22 61 Complex forming groups in organic cement additives 22 62 Radionuclide complexation by organic substances 23 63 Sorption of carboxylic acids and NOM on minerals 24 64 Radionuclide sorption in organics-containing solutions 24

65 Sorption and binding to natural organics in NOM-containing solutions 24

7 EFFECTS OF PLASTICIZERS ON COPPER 27 8 INTERACTION OF PLASTICIZERS WITH BENTONITE 28 9 CONCLUSIONS 29 91 Effect of organic cement additives in cementitious conditions 29 92 Effect of organic additives in groundwater conditions 29

REFERENCES 31

ABBREVIATIONS 38

2

1 ORGANIC CEMENT ADDITIVES

The characteristics of concrete or cementitious injection grouts are influenced by the mass ratio of water to cement materials used in the mixture Reducing the proportion of water increases the cement paste density this results in higher paste quality An increase in paste quality will yield concrete with higher compressive and flexural strength lower permeability increased resistance to weathering and improves the bonding of concrete and reinforcement reduces the volume change from drying and wetting and reduces shrinkage cracking tendencies Reducing the water content in a mixture may result in a stiffer mixture which reduces the workability and increases potential placement problems

Water reducers (WRA) retarders and superplasticizers (SP) (ASTM C494 2004) are admixtures for concrete which are added to reduce the water content in a mixture or to slow the setting rate of the concrete while retaining the flowing properties of a concrete mixture

Commonly used WRA are lignosulphonates and hydrocarboxylic (HC) acids A retarder can be composed of organic and inorganic material The organic material may consist of unrefined Ca Na NH4 salts of lignosulphonic acids hydroxycarboxylic acids and carbohydrates

Superplasticizers are soluble macromolecules that are hundreds of times larger than a water molecule The interaction mechanism of the superplasticizers is known to be adsorption by C3A (tricalcium aluminate) which prevents agglomeration by repulsion of same charges and releases entrapped water The adsorption mechanism of superplasticizers is partially different from that of WRA The difference relates to the compatibility between Portland Cement and superplasticizers It is necessary to ensure that the superplasticizers do not become permanently fixed with C3A in a cement particle which would cause a reduction in concrete workability

The typical portions of superplasticizers used to increase the workability of concrete range from 1 to 3 litres per cubic meter of concrete when liquid superplasticizers contain about 40 of active material To reduce the water cement ratio higher proportions of superplasticizers are used that is from 5 to 20 litres per cubic meter of concrete

There are four types of superplasticizers sulphonated melamine sulphonated naphthalene modified lignosulphonates and combinations of high proportions of water reducing and accelerating admixtures In the last group belong the polycarboxylates and polyacrylates The most commonly used are melamine-based and naphthalene-based superplasticizers

3

2 SORPTION OF RADIONUCLIDES UNDER CEMENT CONDITIONS The organic additives studied by PSI (Glaus and Van Loon 2004) and SKB (Dario et al 2003) can be classified according to their main chemical component (Table 2-1) The additives are commercial products of fairly ill-defined composition and may contain also components other than those indicated in the product safety sheets The cement admixtures are often combinations of lignosulphonate to reduce water surface tension naphthalene to increase the negative surface charge on cement particles so that they repel each other and melamine to form a lubricating film on particle surface (Malbye and Garshol 2000) Table 2-1 Cement additives surveyed for sorption effects of radionuclides on cement The main chemical component a trade name concentration in solution and reference to the report are indicated Melamine sulphonate formaldehyde polycondensate (PMS)

Melment F10 100 (solid) PSI Melment F 317 100 (solid) PSI Peramin F 35 (dry content) DMA Sikament-320 40 PSI Sikament-300 40 PSI Napthalenesulphonic acid polymer with formaldehyde (PNS) Sikament 210 40 DMA Cementa Melcrete 30-60 DMA Mighty 150 30-60 DMA Rheobuild 1000 40 PSI Vinyl maleic acid copolymer (VC) Sikament 10 20 DMA Polyether polycarboxylate (PC) Peramin Conpac 30 27-33 DMA XA 3060 M317 60 PSI Modified polycarboxylic ether (PC) Glenium 51 35 DMA Gluconic acid sodium salt (GL)

Na-Gluconate tech 45 PSI Lignosulphonate (LS) 242 Zewa EF 5 45 PSI Carbohydrate (PP) PSI plasticizer 50 PSI DMA = Dario et al 2003 PSI= Glaus and Van Loon 2004

4

21 Effects of plasticizers on radionuclide solubility in cement conditions

Effects on solubility of Tc(IV) U(IV) Pu(IV) and Am(III) by a PNS-lignosulphonate (HS-100) and a polycarboxylic acid polymer (HS-700) in cement equilibrated water (pH 120 ndash 124) were determined by Greenfield et al (1998) 3 and 03 concentrations of the additives were used The results given Table 2-2 a and b indicate high increases in solubilities especially for Pu and Am The speciation modelling suggested that the dominating form of Pu was Pu(IV) but the authors could not exclude that Pu(V) was present Modelling of the results using stability constants of model compounds for the radionuclides indicated no increase in solubility of the elements A complexation model applied earlier to NOM natural organic materials)-complexation (Maes et al 1994) gave the trends reasonably However the authors conclude that the model is not as such applicable to cement pore water conditions Am(III) is a chemical analogue for Eu(III) and Pu(IV) and U(IV) for Th(IV) used in studies (Glaus and Van Loon 2004 Dario et al 2003) for evaluation of additives for effects on sorption of radionuclides on cement Table 2-2 a Uranium and technetium solubility determinations Solution Additivewater Eh (mV) U (M) Tc ( M) Concrete w - -500 lt 2x 10 -7 7 x 10 -9 HS-100 30 gkg -480 5 x 10-5 5 x 10-6 HS-100 3 gkg -490 5 x 10-6 2 x 10-8 HS-700 30 gkg -480 7 x 10-5 9 x 10-8 HS-700 3 gkg -490 4 x 10-6 3 x 10-8 b Plutonium and americium solubility determinations Solution Additivewater Eh Pu (M) Am (M) Concrtete w - +180-+200 2 x 10-10 5 x 10-11 HS-100 30 gkg +170 4 x 10-6 5 x 10-6 HS-100 3 gkg +210 4 x 10-9 3 x 10-7 HS-700 30 gkg +190 6 x 10-6 8 x 10-6 HS-700 3 gkg +200 2 x 10-8 1 x 10-8

22 Cement-superplasticizer interactions

The mechanisms of superplasticizer-cement interaction have been reviewed by Mollah et al (2000) The role of calcium cations as charge neutralisers by providing a positively charged site for sorption of negatively charged polyelectrolytes was postulated This model can account for the retardation in hydration and the rapid increase in negative zeta potential owing to interaction of cement with polyelectrolytes with no hydrophobic tail The reactions decrease the amount of free calcium and affect the hydration of cement temporarily Sorption of additives on cement is high and there are indications that desorption of polyelectrolyte additives (PNS sulphonated naphthalene and LS lignosulphonate) from hardened cement is very

5

slow (Glaus and Van Loon 2004 Iriya et al 2001) Out leaching of only the pore solution fraction was noticed (Onofrei et al 1991) The distribution of SP can be divided into three portions polymers in the pore water adsorbed polymers incorporated polymers Mannonen (1996) determined the amount of free and bound PNS for simultaneous addition of PNS and water and addition of PNS one minute after water Delayed addition was followed by a decrease in the amount of bound PNS to a half or even to a third of that of simultaneous addition The amount of the free PNS in the water phase governs the admixture amount which is adsorbed on the binder particles After initial increase the amount of bound PNS decreases in rate depending of the cement When dosage of PNS was increased from 05 to 3 (of dry cement) the amount of free PNS varied between 0 to 1-2 of cement (dry weight) in simultaneous addition while in delayed the amount of free PNS increased to 25 (of dry cement) The adsorption on the cement particles in the delayed addition of PNS is similar for all cement types However the distribution of PNS between hydration products and adsorbed phase on cement particles in the simultaneous addition is different The adsorption of admixture into the hydration products of cement was high for extra rapid cements and almost non-existent for low heat cement Bonen and Shankar (1995) also observed that the most important factor of cement for SP adsorption was the specific area of tricalcium aluminate (C3A) According to Aitcin et al (1987) the particle size distribution of cement also has an influence on the retardation effect of PNS Onefrei and Grey (1989) have studied the adsorption of PNS in hardened cement pastes Using labelled sulphur (32S) in Na-PNS they showed that after hardening PNS was strongly bound and immobilized within hydrated phases of the cement (principally CSH and CAH phases) Greisser (2002) studied adsorption on cement components for three kind of SPs PNS (1000-2000 gmol) PMS (10 000 gmol) and PC (20 000 gmol) Pore water analyses showed that the amount of adsorbed and incorporated SP strongly increases with the amount C3A in the cement For the PC the sorption was lowest whereas for the PNS it was highest Andersen et al (1987 1988) found that PNS having lowest molecular weight had the highest adsorption on cement The length of carbon chains was explained to be the reason for different adsorption Bonen and Sakar (1995) found that in OPC cement paste the monomer dimer and probably other low molecular weights PNS molecules are more likely to remain differentially in the pore solution whereas higher molecular weight polymers are adsorbed on the cement particles The PMS and PNS have a higher affinity to C3A than PC type of SP Depending on the cement type and amount of SP used several authors found relative adsorption values ranging from 51 to 94 wt- of the total amount added (Nawa et al 1989 Bonen and Sarkar 1995) It has been measured for PC-type SP having carboxylic ionic groups that the adsorption increases with the charged group density in a macromolecule (Ushikawa et al 1997) For PC-type OPC cements the adsorption of SP molecules is less influenced by timing of addition (Ushikawa 1995) This implies that PC-type SPs get less incorporated in the hydration products

6

SPs adsorption behaviour is influenced by the content of sulphates ions in the pore water Greisser (2002) The addition of Na2SO4 to the mixing water increased the fraction which was not adsorbed or incorporated The result confirmed previous studies for PNS-type SP (Nawa et al 1989 Nawa and Eguchi 1992 Andersen et al 1986 Kim et al 2000) Free SO3 originating from PNS and sulphate ions present in the pore water compete with PNS-polymers for the same reactive sites on the hydrating surface particularly C3A Yamada et al (2000 2001) discovered that this result can also applied to PC-type SPs during dormant period Additionally the adsorption mechanism of PC was found to be reversible Temperature increase has a pronounced effect on the hydration kinetics of cement and increases the adsorption of SPs on cement

23 Leaching from concrete

Herterich et al (2003 2004) extractedleached cement mortar and concrete samples with PNS and PC in alkaline solutions with different organic solvents and aqueous solutions at high temperature Pure water and dichloromethane as solvents were sufficient for the determination of characteristic mobile compounds Their results were that organic impurities formiate and acetate were leached to water More than 70 of the added admixture is irreversible bound into the concrete matrix This value is higher than previously reported by other authors (Herb et al 2001 Spanka and Thielen 1995 Ruckstuhl 2002) by a factor of approx 2 The sample geometry can be one reason for this It can also be attributed to higher temperature and longer leaching times Herterich et al (2003 2004) noticed that increase of the dosage of the admixture correlated with an increase of the mobilized amounts This is in accordance with studies made by Mannonen (1996) where he observed that when the dosage increased the portion of free PNS increased For PNS-based admixtures the PNS-species determined in aqueous extracts of cement bound building materials were modified compared to the PNS of the initial products In studies by Herterich et al (2003 2004) the leached amounts of the water soluble part of the active component of PC (polyethylene glycol(derivate)p-toluenesulphonic acid) correlated positively with the measured TOC emissions Compared to the original product there was strong depletion of the active component (polyethylene glycol(derivate)p-toluenesulphonic acid) in all leachates investigated On the other hand this may be due to the much stronger adsorption of the active component than the alcoholic fraction on cement grain on the other hand due to its large molecular size the active component presumably shows the smallest diffusion coefficient retarding its leaching The leached amount of active component after 56 days was 03-19 of the added amount The leached amount was smallest for lowest wc ratio and highest for highest ratio For large polyethylene glycol molecules deviation from diffusion control was pronounced In the course of hydration the concrete matrix gets more and more dense making transportation of large molecules (eg active component) increasingly difficult This means that after an initial wash-off of surface bound species there was almost no further emission of the active component to the ground water Identified compounds in the leachates were polyethylene glycol and p-toluenesulphonic acid no polycarboxylate backbone was observed Glaus and van Loon (2004) measured the desorption of PNS from crushed hardened cement paste (HCP) They showed that a large part of PNS do not desorb within the

7

time span investigated (~2 weeks) They were not able to decide from the experiments whether it was due to irreversible sorption or to very slow desorption kinetics Also experiments with for 4 and 20 months cured PNS- and LS-containing HCP-material (hardened cement paste) were done The exact determination of the concentration of PNS in the pore water based on UV-VIS measurements could not be obtained but they assumed that the order of magnitude was correct They have an indication that PNS remain in a stable state after the first few months The total amount of PNS removed from HCP during the four desorption steps was about 7 of the initial content of PNS UV-spectra from LS-sample leachants suggested production of vanillin owing to hydrolysis of LS Ruckstuhlrsquos (2003) findings in field tests were in agreement with laboratory test results of Herb et al (2000) for hardened cement paste Ruckstuhl (2003) concluded that polar chemicals are primarily leached from fresh cement to the ground water Herb et al (2000) performed 2 month leaching tests with water simulant at room temperature Only 2-NS and 26-NDS were observed in the leachates They suggested that the elution was diffusion controlled and comparable to the elution behaviour of lithium Palmer and Fairhall (1993) studied the pore water of grouts They determined the concentrations of PNS and PMS after 90 days storage The concentration of PMS in solution increased by a factor of two to three when dosage level increased from 075 to 15 (vv) whereas the concentration in the PNS system remained fairly constant Pojana et al (2003) performed standard leaching tests (24 hours) on crushed concrete samples added with PMS admixture Oligomer-by-oligomer separations of leaching solutions permitted to reveal that only shorter oligomers of PMS are released from concrete as reported for PNS while longer oligomers and isomers were strongly retained into concrete matrix This was a short-term study lacking details In studies by Spanka and Thilen (1995) PMS retained in concrete but monomers of PNS were possible to eluate from concrete In three days 04 was leached to solution In the first 24 hours there was rapid elution which decreased to a stable level in 3 days From PNS there are leached monomers to the solution They have a 28 days old cement cylinder which contained 1-2 of PNS Dransfield (2005) review leaching tests made by cement producers to establish that their concrete constructions would not pollute drinking water For UK Drinking Water Inspectorate (DWI) PNS PMS and PC admixtures were tested according to EN 206-12000 (European Standard for concrete production and admixture use) The test dosages were 33 (PMS) 22 (PNS) 11 (PC) and the TOC was measured in 3 days intervals up to 45-48 days The rate of leaching falled off quickly and was generally less than 500microgL after the third 3 days interval The highest leaching was found for PMS Level of PMS however dropped back close to the level of others at the end of test the TOC being then below 05 mgL In the German leaching tests PMS leached highest but after the third 3 days interval leveled again TOC for PMS was still 8 times higher than that of PNS or PC Onefrei and Grey (1989) have studied the leachability of PNS on hardened cement pastes According to them the PNS can be leached from grouts but the cumulatively

8

released quantity over 30-day period were low ~10-12 kgm2 in comparison to the loading in the solid phase (10-13 to 10-12 kgm2) The high-performance grout was leached with three different groundwaters of different salinity The release rate increased with increasing temperature and salinity of the groundwater All the pore water and leaching studies performed have been short-term tests and so far long-term test have not been carried out However long-term experiments are required if far reaching decisions are made of the behavior of these superplasticizers

24 Degradation of additives

Degradation of additives has not been conclusively shown under cement conditions Comparison with humic substances suggests that the aromatic parts of additives are not degraded under groundwater conditions Simple aliphatic additives citrate and gluconate are most easily degraded by microbial activity Microbial degradation of citrate is common under aerobic conditions (Leckie and Redden 1997) Microbial activity was suggested to decrease concentration of PNS monomers like 1-NS 2-NS16-NDS and 17-NDS Oligomers 27-NDS and 15-NDS were not degraded within 195 days (Ruckstuhl et al 2002) Gascoyne (2002) has reviewed Canadian studies (Haveman et al 1996) on biodegradation of PNS type SP (Disal ) Biodegradation of naphthalene by the genus Pseudomonas bacteria is well documented (Rosello-Mora et al 1994 Sanseverino et al 1993 Yen and Serdour 1988) Pseudomonas are common in subsurface bacteria They are not able to degrade polymers into monomers and need some other microbe to destruct the PNS polymers Results for aerobic incubation conditions did not indicate degradation of Disal over the 7-weeks experimental time Under anaerobic conditions in nitrate-added solutions the bacteria population increased by an order of magnitude suggesting that Disal could stimulate growth of the bacteria under denitrifying conditions These preliminary studies suggest that destruction of PNS by Pseudomonas may need cooperation with some other microbe to fully use polymers as a food source The degradation of polyacrylate ethers is due to the labile ester bond that binds the chains of PEG to the main chain This bond is labile in a wide pH range The more the pH of the solution differs from neutral the fasters the bond is hydrolyzed The reactions are slower for low molecular weight molecules The hydrolysis of polyacrylate ether produces polymetacrylate and polyethylene glycol monomethyl ether molecules The polymetacrylate is a very stable polymer The hydrocarbon chain is very resistant to chemical attacks whereas the carboxylate group is reactive and can undergo decarboxylation In the long run decarboxylation will occur and more probably in the extreme pH and at higher temperature The PEG and its monomethyl ether are also very stable polymers The degradation requires probably harder conditions than those prevailing in a concrete repository (Boreacuten 2004) Low molecular weight oligomers of polymetacrylate have been shown to be biologically degradable (Suzuki et al 1993 Kawai 1995) The PEG with molecular weight under 20 000 Da can be degraded under aerobic and unaerobic conditions (Kawai 2003 Huang et al 2005) Under aerobic conditions the terminal hydroxyl

9

group is oxidized to an aldehyde and then to a carboxylic acid Finally glyoxylate is eliminated leaving the polymer This can continue until the whole polymer is degraded The anaerobic degradation proceeds through isomerisation followed by hydrolysis The product is acetaldehyde and PEG with one glycol unit shorter (Kawai 2003)

10

3 SORPTION OF Ni Eu AND Th ON CEMENTS

31 Sorption on cement in artificial cement water (ACW)

This section summarises the work done by PSIGlaus and Van Loon (2004) Sorption of Eu and Th on crushed hardened Portland cement (025g cement 1000mL) was measured in ACW (artificial cement water pH 133) containing 2wt (aged 4 months) of cement additives (Figures 3-1 and 3-2) The solutions were typical to fresh cement conditions The sorption of Eu and Th was nearly the same for these nuclides under the influences of the different additives The log Rd values of Eu for PNS PC SI300 and PMS decreased from 25 m3kg to 06-2 m3kg The LS SI320 and GL decreased log Rd values to about 10-1 m3kg Sorption of Eu in PP-added solution was too low to be measurable Diluting the additive concentrations by a factor of 10 resulted in Rd values for Eu and Th in PNS PC SI300 and PMS increasing to values found in non-additive systems The increases of Eu and Th Rd values in LS SI320 GL and PP solutions were only 05 log units For PC the Rd values of Eu and Th in the diluted solutions were lower than in the original 2 solutions Figure 3-1 Sorption of europium on crushed cement in solution containing selected organic cement additives (Table 2-1) In the text the Rd values are expressed in m3kg (Fig 45 in Glaus and Van Loon 2004)(PNS=NS PMS=MS)

11

Figure 3-2 Sorption of thorium on crushed cement in ACW solution containing selected organic cement additives (Table 2-1) In the text the Rd values are expressed in m3kg (Fig 47 in Glaus and Van Loon 2004) (PNS=NS PMS=MS) Figure 3-3 Sorption of europium on crushed cement in 14 months aged ACW solution containing selected organic cement additives (Table 2-1) In the text the Rd values are expressed in m3kg(Fig 46 in Glaus and Van Loon 2004) (PNS=NS PMS=MS)

12

Sorption of Eu was also measured in solutions aged for 14 months Figure 3-3 illustrates how increasing the ageing time from 4 to 14 months did not affect the Rd values Dilution of the additive concentration (LS SI320 GL PP) by a factor of 100 and 1000 was followed successively by a 05 log unit increase in Rd values for a 10ndashfold dilution Sorption of Ni in a 10ndashmonth aged ACW (Figure 3-4) clearly decreased for PC SI300 LS GL and PP when the additive concentration was 2 in water PNS PMS and SI320 did not affect the sorption of Ni A 10ndashtimes dilution of the additive concentration was followed by an increase of the Rd values to no-additive ACW values for all the additives Figure 3-4 Sorption of nickel on crushed cement in 10ndashmonth aged ACW containing selected organic cement additives (Table 2-1) In the text the Rd values are as m3kg (Fig 48 in Glaus and Van Loon 2004)(PNS=NS PMS=MS) The mass ratios of the cementwateradditive were about 1400040 (assuming 50 of the additive reagent in the commercial solution) in the PSI experiments with water containing 2 additive In a grout the ratios are approximately 110005ndash005 The additives are sorbed strongly on cement and it is possible that this has different consequences depending on the attachment mechanism of the additive on the solid In real systems it is obvious that the pore solution additive concentrations are lower than in the additive-containing water used for preparation of grout The sorption behaviour of Eu and Th was about the same and the authors concluded that it is sufficient to use only Eu to evaluate the influence of additives on sorption to cement This conclusion is reasonable when taking into account the similarities in order of complexation constants for Eu and Th as presented by Hummel et al (2003) Lignosulphonate Na-gluconate PSI-carbohydrate and one of the PMS-type additives (SI320) decreased sorption of Eu and Th more than the other additives

13

32 Sorption of Eu on additive-containing cement

Sorption of Eu Th and Ni on hardened cement containing PNS PZ (PP in text) and LS was the same as on cement without the additives (Figure 3-5) The experiments were again performed with a 025 g1000 mL solid to solution ratio The relevance of these conditions was justified on the assumption that the additives are not desorbed from the cement (Only about 5ndash10 of the additive used in preparation of cement was desorbed from crushed cement during the approximately one year experiment) The sorption of Eu Th and Ni was about the same as for cement without additives Figure 3-5 Sorption of Eu Th and Ni on hardened cement pastes containing PNS LS and PZ (=PP) additives and on non-additive containing cement (Blank) (Fig 614 in Glaus and Van Loon 2004) (PNS=NS)

33 Degradation of polymeric cement additives

Degradation of the additives studied by Glaus and Van Loon (2004) under cement conditions was not detected during the experiments The authors concluded that the additives should be regarded stable under the cement conditions Some changes in UV-VIS absorption spectra during the additive sorption studies on cement were observed However the authors suggested that this could have been due to differences in sorption of the different compounds in the additives as molecular weight fractionation of humic substances by adsorption onto minerals is a known phenomenon (Hur and Schlautman 2003)

14

4 SORPTION OF Eu ON CEMENT AND TITANIUM OXIDE AT pH 125 This section summarises the work performed by Dario et al (2003) They have performed experiments on the sorption of Eu on crushed hardened cement and TiO2 The solution was 03 M NaCl for cement and TiO2 For TiO2 also a NaCl + 0002 M CaCl2 solution ([NaCl]+[CaCl2] = 03M) was used The pH of solutions was about 125 The solution analyses showed that after the experiment with cement the water contained 2ndash4 mM Ca indicating dissolution of Ca from the solid This may have effected the composition of the sorbent cement The chemical conditions were representative of altered cement The cement additives were added to water in proportions of 10-6ndash10-1 LL (volumevolume) (proportions of NaCl solution for the additives in solution form given as L in the figures) and well-defined organic acid complexants in 10-6ndash10-1 M concentrations Notice that in the figures from Dario et al (2003) the L is expressed in molar concentration (M) for well-defined compounds and as volume fraction of liquid phase (flp) for cement admixture solutions With a mean of 50 solid concentrations L-values of 410-2 correspond to 2 solid (weightvolume) as used by Glaus and Van Loon (2004) The solid (cement TiO2) to solution ratio was 1g1000 mL Selected sorption results derived from Figures 4-1 ndash 4-8 are given in Table 4-1 Fulvic acid (Figure 4-8) was used as a reference to synthetic additives Figure 4-1 Sorption of Eu on cement and Figure 4-2 Sorption of Eu on cement and TiO2 in NaCl and NaCl+Ca (pH 125) TiO2 in NaCl and NaCl+Ca (pH 125) solutions containing Sikament 10 (Fig 4-12 solutions containing Sikament 210 (Fig in Galus and Van Loon 2004) 4-13 in Glaus and Van Loon 2004)

15

Figure 4-3 Sorption of Eu on cement and Figure 4-4 Sorption of Eu on cement and TiO2 in NaCl and NaCl+Ca (pH 125) TiO2 in NaCl and NaCl+Ca (pH 125) solutions containing Peramin Conpac 30 solutions containing Peramin F (Fig (Fig 4-14 in Dario et al 2003) 4-15 in Dario et al 2003) Figure 4-5 Sorption of Eu on cement and Figure 4-6 Sorption of Eu on cement and TiO2 in NaCl and NaCl+Ca (pH 125) TiO2 in NaCl and NaCl+Ca (pH 125) solutions containing Glenium 51 (Fig 4-16 solutions containing Cementa Melcrete in Dario et al 2003) (Fig 4-17 in Dario et al 2003)

16

Figure 4-7 Sorption of Eu on cement and Figure 4-8 Sorption of Eu on cement and TiO2 in NaCl and NaCl+Ca (pH 125) TiO2 in NaCl and NaCl+Ca (pH 125) (pH 123) solutions containing Mighty solutions containing fulvic acid (Fig 150 (Fig 4-18 in Dario et al 2003) 4-8 in Dario et al 2003) Table 4-1 Selected Eu sorption results for the cement TiO2 in NaCl and TiO2 in Ca-added NaCl solution (Dario et al 2003) Notice the L is expressed in molar concentration (M) or volume fraction of liquid phase (flp) logLL = lower limit of additive concentrationproportion inducing reduced sorption -3 = log Kd (m3kg) at 10-3 M (for citric acid) or proportion of additive

concentration (for cement additives) -2 = log Kd (m3kg) at 10-2 M (for citric acid) or proportion of additive

concentration (for cement additives) additive cement TiO2+NaCl TiO2+NaCl+Ca logLL -3 -2 logLL -3 -2 logLL -3 -2 Sikament 10 -5 05 nd -45 24 14 -6 13 nd Sikament 210 -5 -1 nd -5 12 02 -7 05 -04 Peramin Conpac 30 -5 0 nd -9 08 06 -10 08 nd Peramin F -5 075 nd -32 4 18 -7 18 10 Glenium 51 -5 05 nd -5 25 12 -7 20 16 Cementa Melcrete -45 05 nd -5 05 - -5 10 nd Mighty 150 -5 01 nd -5 09 0 -6 10 nd citric acid -35 30 10 -5 25 18 -5 25 18 fulvic acid -25 26 -48 27 18 -30 40 10 nd=not determined

17

41 Summary of the results for DMA experiments

Sikament 10 and Mighty 150 have the same behaviour for cement and TiO2+Ca systems Sikament 10 Sorption on TiO2 less affected than by Mighty 150 Sikament 210 Sorption on cement very much reduced due to the additive sorption on TiO2 and TiO2+Ca the same as for Sikament10 Peramin Conpac 30 Sorption on all solids much reduced by the additive Much scattering of sorption values Peramin F Sorption on cement is the same as for Sikament 10 and Mighty 150 sorption on TiO2+Ca is the same as for Sikament 10 and Glenium 51 sorption on TiO2 less reduced than by the other additives but about the same as by fulvic and citric (and ISA) acids Glenium 51 Almost the same as for Sikament 10 Cementa Melcrete Sorption on cement TiO2 and TiO2+Ca nearly the same for all conditions Results for cement the same as for fulvic acid and all results the same as for ISA Sorption on cement Sikament 210 and Peramin Conpac 30 reduce sorption more than the other additives In summary the differences between the additives for the most part are not large taking into account the uncertainties owing to that the additive concentration was volume parts of commercial additive solution in the experimental solutions Comparison of results for Glenium 51 (Dario et al 2003) and PC (Glaus and Van Loon 2004) Sorption of Eu and Th in 02 (wv) PCACW was lower than in 2 ACW Rd-value for Eu in 02 PC in ACW were about the same as for L = 04 Glenium 51 in 03 M NaCl (pH 125) It remains unresolved if this is just a singular coincident or a point on a general trend Sorption of Eu and Th on cement showed that sorption was more reduced on altered cement at pH 125 than on fresh cement at pH 133 The results show that at cement-to-additive mass ratios relevant for grouting there are no effects on the sorption of Eu on cement attributable to the additives However the sorption mechanisms in the study conditions remain unclear and the behaviour of the alternative additives should be surveyed before selections are made The sorption results for the melamine formaldehyde polycondensate-based additives did not show any feature in sorption performance to favour its use as an additive

18

Fulvic acid Reduction of sorption is slightly smaller than that caused by the synthetic polyelectrolyte additives but the trends are the same These results suggest that the effects of the synthetic additives are at a first approximation the same as that of fulvic acid

42 Sorption of Eu on cement in the presence of well-known complexants

The report of Dario et al (2003) also contained results from experiments with hydrocarboxylic acids citric acid (Figure 4-9) D-gluconic acid (Figure 4-10) oxalic acid aminopolycarboxylates EDTA (ethylenediaminetetraacetic acid) DTPA (diethylenetriaminepentaacetic acid) and NTA (nitrilotriacetic acid) common An(IV) complexants TTA (thenoyl-tri- fluoro-acetone) and AcAc (acetylacetone) and ISA (isosaccarinic acid) a compound formed during cellulose degradation under cement conditions It was shown that only DTPA and ISA reduce the sorption of Eu on TiO2 and cement at much lower complexant mass concentrations than the cement additives The Eu sorption on TiO2 experiments for EDTA DTPA NTA gluconic acid and citric acid were modelled on the assumption that the complexants do not sorb (as verified by experiments) The fitted complex formation factors were in agreement with the literature values only for ISA The authors concluded that even taking into account the uncertainties in Eu speciation this result could not be easily explained The possible explanations are that hydrolysed Eu-species may also form complexes or that complexes other than EuL-form (n=1) are formed Figure 4-9 Sorption of Eu on cement and Figure 4-10 Sorption of Eu on cement and TiO2 in NaCl and NaCl+Ca (pH 125) TiO2 in NaCl and NaCl+Ca (pH 125) solutions containing citric acid (Fig 4-5 solutions containing gluconic acid (Fig in Dario et al 2003) 4-6 in Dario et al 2003) The results for citric acid and gluconic acid are summarised as follows

19

Citric acid Sorption on cement and on TiO2+(NaCl)+Ca less reduced at high (molar) concentrations than for other cement additives Sorption on TiO2 less reduced than for fulvic acid Gluconic acid Reduction in sorption starts at about the same molar concentration as for citric acid At higher concentrations reduction in sorption is much greater than for citric acid and at 10-4 M sorption is lower than for the polymeric additives at 10-4 proportion in solution Neither of these acids reduce sorption at organic-to-cement mass ratios found in grout or cement

20

5 SUMMARY OF RESULTS IN CEMENT CONDITIONS This literature review focussed on three different kinds of radionuclides Eu (III) Th (IV) and Ni (II) and their behaviour was evaluated in detail

51 Experiments at Paul Scherrer Institute (PSI)

The sorption results of Eu Th and Ni for hardened cement in ACW at pH 133 show that at high additive-to-cement (surface) ratios some additives in solution (PNS PC SI300 PMS) reduce the sorption only slightly and are unproblematic for sorption on cement form waste and in cement environments Results also show that the melamine-based additives may have very different effects on sorption At additive-to-cement surface ratios expected for waste cement only GL and PP reduce sorption of Eu and Th (Glaus and Van Loon 2004) Sorption on additive-loaded hardened cement was the same as on unloaded cement The desorption of GL and PNS from hardened cement was very slow and the results for additive-loaded cement are most probably valid It should be pointed out that the experimenters did not intend to determine the sorption mechanisms of the nuclides Thus it remains unsolved whether the nuclides sorbed on cement or complexed with the sorbing additives Enhanced sorption of some metals on iron oxides owing to carboxylic acid in solution has been detected The Eu and Th sorption Rd values in ACW containing 2 (dry weightvolume) of PNS PC SI300 or PMS are much higher than for any additives studied by Dario et al (2003)

52 Experiments at Linkoumlping University

The sorption experiments of Dario et al (2003) were performed at pH 125 using 03 M NaCl and 2 mM Ca-added to 03 M NaCl containing cement additives at 10-6 to 10-1 parts per solution Some well-known carboxylic acid and nitrilocarboxylic acid complexants were also surveyed for effects on sorption As a reference also fulvic acid was used as an additive in the solutions The use of the simple electrolyte solutions resulted in the dissolution of some calcium from the cements This was found for all additives but was not expected to influence the comparative effects of the additives on Eu sorption Comparison with Rd-values in Glaus and Van Loon (2004) is only speculative The experimental conditions in Dario et al (2003) are closer to those of altered cement environments For all the additives studied the lower level of proportion (LL) in the solution showing reduction in sorption was roughly 10-5ndash10-45 The additives that least affected the sorption of Eu on cement were Peramin F Cementa Melcrete Glenium 51 and Sikament 10 At high additive-to-cement ratios Sikament 210 and Mighty 150 reduced the sorption to a level lower than the other additives

21

The influence of fulvic acid on Eu sorption had very much the same characteristics as the synthetic polyelectrolytes Citric acid reduced sorption at the high molar concentrations much less than the polyelectrolyte additives Citric acid has three carboxylic groups per mole (MW = 192) The number of carboxylate groups per carbon atoms in citric acid and carboxylate polyelectrolytes is within an order of magnitude Comparison of their influences on sorption should be made on a mass basis Taking this into account the reducing effect of citric acid on sorption is not greater than that of carboxylate polyelectrolytes Both the results from Glaus and Van Loon (2004) and Dario et al (2003) suggest that the studied additives do not affect sorption of Eu Th and Ni in high-pH cements at the cement-additive ratios normally used in practical applications

22

6 BEDROCK CONDITIONS No studies on the effects of cement additives on radionuclide sorption under non-cement conditions are available The effects must therefore be estimated from results for organic polycarboxylates and hydoxycarboxylates and natural organic materials (NOM)

61 Complex forming groups in organic cement additives

The approximate order of decreasing affinity of organic functional groupings in NOM for metal ions under groundwater conditions is -O- gt -NH2gt -N=N- gt =N gt -COO- gt -O- gt C=O enolate amine azo ring N carboxylate ether carbonyl Functional groups in cement additives and their potential for metal complexation and cation exchange PMS several ring N (135-carbons form bonds between N and C in melamine) substituted amino groups anionic sulfonate groups PNS anionic sulphonate groups in napthalene PPPC anionic carboxylate groups in aliphatic skeleton ether substituted carboxylate PPS like PP with some substitution by sulphonic groups containing aliphatic or

aromatic anionic sulphonate group in place of a carboxylic group LS anionic sulphonate groups phenolic groups GL sodium salt of gluconic acid (C6H12O7) CIT citric acid (2-hydroxy-123-propanetricarboxylic acid (C6H8O7) (For chemical structures of the additives see Fjaumlllberg and Lagerblad 2003 Dario et al 2003 Glaus and Van Loon 2004) The potentially high-affinity nitrogen-containing groups are mainly in the melamine (PMS) based additives The -NH-CH-OH functional group of melamine-formaldehyde resin is assumed to be responsible for the sorption of Fe(III) and Al(III) at pH 5 while cations of Mg Ca Ni Co Zn Cu Cd Pb and Cr(III) are only slightly sorbed (Filik et al 1997) The sulphonate groups are anions of a strong acid and are deprotonated in groundwater and cement waters The sulphonate-containing additives are often in a Na salt form in the additives The sulphonic group in lignosulphonates (LS) attach to

23

cations and form compounds that do not sorb on silicate minerals (Wold 2003 Wold and Eriksen 2003) It is to be expected that the other sulphonic groups have similar behaviour in groundwater conditions Naphthalene sulphonic (PNS) based additives show low complexation affinities but formation of soluble non-sorbing PNS compounds is possible The order of decreasing ability of metal ions to chelate in groundwater is approximately Fe(III) Al(III) gt Cu(II) gt Ni(II) Co(II) gt Fe(II) gt Mn(II) It is known that trivalent metals such as lanthanoids and actinoids have a very high affinity to NOM This is why Eu is often used to survey the effects of organics on RN (radionuclide) behaviour in natural systems

62 Radionuclide complexation by organic substances

The molecular structures of organic additives prepared by polycondensation are not well defined and only the main structural units are known The order of affinity for complex formation above suggests that the nitrogen-containing additives (melamine-based and N-vinyl maleic acid derivatives) form stronger complexes than hydrocarbons Eu complex formation preferences nitrogen and oxygen donors than sulphur donors in several aliphatic and aromatic dicarboxylic acids in neutral to slightly basic waters (Lis et al 1995a Lis et al 2002) These findings also suggest that the nitrogen-containing additives should be evaluated more narrowly before their use in proximity to a radioactive waste repository The polyelectrolyte cement additives have carboxylic groups and so formation of multidentate complexes is possible The simpler aliphatic organic acids are able to form strong complexes with divalent and trivalent metal ions The structures of the aromatic additives are rigid and there are also steric hindrances for multidentate complexation Complexation of Eu with polyacrylic acids (MW 6000 ndash 4 000 000 Daltons) at pH lt 10 was interpreted to be that three carboxylates function as monodentate ligands At pH gt 10 the hydrolysed complex is probably Eu3+(COO-)3middot 2H2O(OH-)2 (Lis and Choppin 1995b) In general the binding properties of polyacrylates to lanthanide ions are pH dependent since increasing the pH increases the ionisation of functional groups of polyelectrolytes (Choppin et al 1998) The binding is primarily site binding (97) but there is probably also a small fraction binding non-site specifically (condensation) Anionic Eu complexes are formed at pH 10 in reactions with cyclohexylpolycarboxylic acids (Choppin and Radko 2003) The carboxylic and phenolic parts in additives are common also in NOM The compositions of NOM are to some extent site-specific The aromatic nature of NOM for groundwater increases typically from surface to deeper waters (Frimmel and Abbt-Braun 1999) In the fulvic acids there can be one acidic group per 4ndash8 carbon atoms

24

63 Sorption of carboxylic acids and NOM on minerals

Aromatic acid sorption to goethite (pH lt 93) has been modelled by surface complexation between Fe(III) in goethite and the functional groups in acids (Evanko and Dzombak 1999) The sorption equilibrium constants were highest for compounds having adjacent carboxylic groups lower for compounds with adjacent phenolic groups and lowest for compounds with phenolic groups in the ortho position relative to the carboxylic group Sorption of carboxylate ions on iron oxides with positive surface charge at pH lt 93 in low ionic strength Na-salt solutions has been shown in many studies (Edwards et al 1996) By application of the general properties of fulvic acid and goethite the sorption model indicated that hydroxylic groups are more important than deprotonated carboxylic groups in the sorption on goethite in groundwater pH conditions (pH 7) (Filius et al 2003) At lower pH the carboxylic groups are more important in fulvic acid sorption on goethite The natural polyelectrolytes have electrostatic repulsion between different segments From this it follows that the polyelectrolytes sorbed on mineral surfaces tend to form thin layers An increase in ionic strength may screen the electrostatic forces owing to an increased attachment of cations to the polyelectrolyte This behaviour is common to all NOM (Stumm and Morgan 1996 Stumm 1992)

64 Radionuclide sorption in solutions containing organics

Aromatic carboxylic acids and citric acid increase the sorption of divalent transition metal ions on iron oxides at lower pH (3ndash7) The increase is directly proportional to the strength in complexation with the acid (Angove et al 1999 Marcussen et al 2003) Sorption of Th on hematite at 10-6 M citrate was not affected but at 10-3M citrate the sorption showed a great decrease between pH 25 and pH 8 (Lenhart et al 1999) The authors suggested that the local low sorption is due to formation of a soluble Th-citric complex Citrate (10-6 M) complexation of uranyl enhances sorption of U on hematite especially at higher pH regions (Leckie and Redden 1997 Redden et al 2001) Citrate complexation decreases sorption of divalent cations on montmorillonite and Al2O3 (Marcussen et al 2003 Yamaguchi et al 2002) Effects on sorption to kaolinite and iron oxides were minor (Angove et al 1999 Marcussen et al 2003) The calcium or magnesium concentration in solution has a decisive role in soluble DOC concentration Ca or Mg cations sorb on negatively charged surfaces and enable sorption of DOC A decrease in DOC has been shown to reduce soluble Cu concentration Ca-DOC complexation formation factors indicate that DOC in Ca-containing groundwaters (pH 7) is in Ca-form (Roumlmkens et al 1996) In seawater 99 of citrate and 94 of oxydiacetate are complexed to seawater cations in agreement with the single cation complexation constants (De Stefano et al 1999)

65 Sorption and binding to natural organics in NOM-containing solutions

The effects on sorption of metal ions on geologic material have been studied recently under high pH conditions The effects of polyelectrolytes on metal sorption on NOM depend on pH metal concentration and NOM concentration The ionic strength effects are minor but competition by other ions mainly by Ca should be taken into account (Lenhart et al 1999)

25

Takahashi et al (1999) made multitracer sorption experiments on kaolinite and amorphous silica The experiments were conducted with 2 g kaolinite or 0012 g silica 003 g humic material1000 mL of 002 M Na-perchlorate solutions In these conditions competitive effects were not expected Only the kaolinite results are referred to here because dissolution and colloid formation in silica in high pH systems is not commented on by the authors In brief the results for the rare earth elements and lanthanoids show that in the middle pH region (pH 5ndash9) sorption is only about 10 in the humic containing samples but without the humics the sorption was complete and had a maximum at pH 5ndash8 The effects of humics on the sorption decreased with increasing pH and at high pH the sorption reduction by humics was low Hummel et al (2000) reported a very comprehensive evaluation of binding of some nuclear waste nuclides to humics and an estimation of a conservative roof (= maximum humic concentration that does not have a diminishing effect on nuclide speciationinorganic sorption) The data for extending the modelling up to pH 10 and to ionic strength between 002 and 02 was produced using a complex addition method and preventing the tracers to form hydroxy complexes (Glaus et al 2000) The conservative roof approach excluded the effects that possibly reduce binding to humics and it did not consider whether the humate was sorbed or not The calculated results for Wellenberg water (low-salinity water in equilibrium with atmospheric CO2 pH 83) (Figure 6-1) showed that 50 of Eu Ni U(VI) Ca Th and Np(V) is bound to humate at concentrations 10-7 10-55 10-42 10-2 10-17 and 10-12 g humateL respectively (Hummel et al 2000) An increase in ionic strength decreases the NOM-bound amount for Eu between pH 7 and 85 by about a factor of 5 Binding of Eu to humate rapidly decreases with increasing pH From pH 84 to 95 the same degree of binding needs three orders of magnitude more humate (Figure 6-2) The behaviour of humates in nuclide binding is indicated of the trends for the interaction of cement additives with carboxylic and phenolic groups with nuclides

26

Figure 6-1 Modelled humate binding of Eu Ni U(VI) Ca Th and Np(V) in Wellenberg groundwater (Fig 29 in Hummel et al 2000) Figure 6-2 Modelled Eu-humate complexation at various ionic strengths and pH The shaded area indicates Swiss groundwater conditions (Fig 28 in Hummel et al 2000)

27

7 EFFECTS OF PLASTICIZERS ON COPPER No reference to studies on the interaction or complexation between copper and PNS PMS or PC plasticizers was found Because it is assumed that polycarboxylic ester (ether) types of SP will undergo hydrolysis and further degradation to carboxylic acids literature on effects on binding of Cu with carboxylic acids was surveyed Under reducing conditions Cu is likely to be present in the form of Cu(I) which is more weakly hydrolysed than Cu(II) No complexation constants for Cu(I) with relevant carboxylic acid were found during the literature research Carboxylic acid-copper interactions Polyacrylic acids Sorption of Ni Cu(II) and Pb on linear hydrosoluble poly(acrylic acids) has been studied in 01ndash10 M NaNO3 at pH 4ndash6 (Morlay et al 1998 1999 Perret et al 2000 Morlay et al 2000) and on crosslinked poly(acrylic acid) ( Morlay et al 2001) The order of increasing sorption is Ni lt Cu(II) lt Pb The results showed that metal ions can be trapped on these materials The sorption properties of linear hydrosoluble and crosslinked forms were about the same Stability of Cu(II)-poly(acrylic) acid is greater than those of acetic or glutaric acid Cu complexes (Morlay et al 1998) Polyacrylic acids (PA) at pH 75ndash95 are precipitated as Ca-salts in 310-3 M Ca solutions at PA concentrations smaller than 100 ppm the limiting value depending on the nature of the PA (Amjad et al 2003) Higher pH and higher temperature favour formation of the precipitate These results suggest that Cu-complex forming behaviour of PC degradation products should be studied in more detail Monocarboxylic acids Under humic oxygen-containing atmosphere formic acids (carboxylic acids) may cause pitch corrosion (ant-nest corrosion) of metallic copper (Corbett 2000) The relevance of these findings to solution conditions at canister-bentonite interface is uncertain Dicarboxylic acids Complexation of dicarboxylic acids as possible degradation products of PC was calculated using the Hydraql program as a preliminary effort to evaluate effects of PC on copper Scoping calculations of Cu (II)-malonate complexation were made for saline (10-9 M Cu(II) 10-3 M Ca 10-3 and 10-2 M Mal (Malonate) pH 6ndash11) groundwaters Minteq DB was used for hydrolysis of Cu (II) and data compilation by King et al (2002) for Cu (II) carbonates Cu(II)-malonate and Ca-malonate stability constants were from Prapaipong et al (1999) These calculations showed that malonate complexation of Cu dominates over hydrolysis at pH lt 72 for 10-3 M Mal and pH lt 74 for 10-2 M Mal The main malonate complexation was with Ca for the whole pH range

28

8 INTERACTION OF PLASTICIZERS WITH BENTONITE No references on the effects of cement plasticizers on bentonite were found in the literature Bentonite is used to make cement more elastic The adsorption of plasticizers on cement particles in cementitious environments suggest that plasticizers are adsorbed on bentonite (clay) surfaces as well and have potential to disperse clay particles in water

29

9 CONCLUSIONS The commercial cement additives are most probably mixtures of a number of different chemical substances The main components only are given in product safety data sheets It follows that the compositions of candidate products should be better known before use when more certainty about their behaviour is needed

91 Effect of organic cement additives in cementitious conditions

The publications surveyed in this review contain results for fresh and altered cement conditions as artificial cement water (pH 133) and high pH (125) NaCl solutions were used As a first approximation the additives that at high solution concentrations induce less reduction in sorption are less problematic (Figures 3-1 to 3-5) It should be noted that sorption of Eu in NaCl on Ca-deficient cement was low for all the studied additives at high additive concentrations (Figures 4-1 to 4-8) The differences in experimental conditions make it difficult to compare the results in the two reviewed reports A few additives induced great decreases in the sorption of Eu Th and Ni from ACW on cement Their use should be avoided without more specific knowledge of their behavioureffects in relevant solidsolution conditions The experiments with additive-containing waters were performed under very large solution-to-solid ratios (025ndash05 gL) and this may have influenced the experimental Rd (Kd) values At cement-to-additive mass ratios relevant to grouts the reduction in sorption was small for all the additives (Figures 3-3 and 3-4) On the other hand sorption of Eu Th and Ni from ACW on hydrated cements containing these additives was the same as that for cements in no-additive conditions (Figure 4-1) This result is in good agreement with the findings that complexation of radionuclides by NOM is low at the pH range typical of cement environments Solubility of U Pu and Am may be orders of magnitude higher in solutions containing PNS-lignosulphonate and carboxylic acid polymer No results were found of impacts of increased solubility on sorption behaviour of these nuclides Citric acid showed the same trends in reduction of Eu sorption on cement polyelectrolyte additives even when taking into account the uncertainties in initial solution concentrations The results for cement environments suggest that at organic additive-to-cement mass ratios relevant for grouting the studied additives do not affect the sorption of Ni Eu and Th on cement

92 Effect of organic additives in groundwater conditions

Evaluation of the effects of non-degraded additives on sorption under groundwater conditions were based on their chemical structures and a general knowledge of complex formation affinities on the chemical grouping in the additives The polyelectrolytes especially those containing carboxyl and phenol groups affect radionuclide sorption under cement conditions (pH 12ndash13) in a similar degree as fulvic acid (Dario et al 2003) The sorption properties and effects on metal ion sorption of carboxylic acids show similarities with the effects of natural organic

30

materials on radionuclide sorption It follows that the effect of the polyelectrolyte cement additives on radionuclide sorption under groundwater conditions can be evaluated only approximately Melamine-based additives contain groups with a potential for strong complex formation In the studies evaluated here they did not show any advantages over the other additives In one case this type of additive contained some other compound that reduced substantially the sorption of Eu and Th on cement Melamine structure is very different from what is known of NOM in groundwater Melamine-based of additives should be studied in more detail before use in the vicinity of radioactive waste Naphthalene sulphonate-based additives form strong ionic compounds but their complex formation potential is low The possibility of formation of non-sorbing compounds with nuclide cations needs to be studied Otherwise these additives seem to be non-problematic The structure of these compounds are most probably very stable in groundwater Lignosulphonate is known to form stable non-sorbing compounds with groundwater cations This type of additive should be studied in more detail before use in the vicinity of radioactive waste The carbohydratecarboxylate polyelectrolyte-based additives most probably bind nuclides in the same fashion as the humates (NOM) In non-cement conditions tri-valent Ln(III) and An(III) nuclides and at lower pH also An(IV) are effectively bound to NOM Their similarities in behaviour to NOM in groundwater give a good basis for estimating the behaviour of radionuclides in waters containing organic cement additives In the absence of experimental results the organic cement additives should be evaluated to behave like NOM in the complexation of radionuclides in groundwater Recent results confirm that trivalent elements may be especially bound to NOM at low organic concentrations This suggests that organic cement additives may enhance especially the mobility of Ln(III) and An(III) radionuclides and care should be taken in their use near radioactive waste repositories Effects of SP agents on copper could only be estimated from soluble Cu(II) ion complexation by carboxylic acids that are possible degradation products of PC type plasticizers under cementitous high-pH conditions Simplified calculations show that under low-pH groundwater conditions there is a risk for Cu(II) complexation with carboxylic acids Effects on copper by SP agents should studied further

31

REFERENCES Aitcin PC Sakar SL Regourd M Volant D 1987 Retardation effect of superplasticizers on different cement fractions Cement and Concrete research 17 (6) 995 Amjad Z Zuhl R Zibrida JF 2003 Factors influencing the precipitation of calcium-inhibitor salts in industrial water systems Association of water technologies Inc 2003 Annual Convention Phoenix AZ Andersen PJ Kumar A Roy DM Wolfe-Confer D 1986 The effect of calcium sulphate concentration on the adsorption of a superplasticizer on a cement methods zeta potential and adsorption studies Cement and Concrete research 16 (2) 255 Andersen PJ Roy DM Gaidis JM 1987 The effects of adsorption of superplasticizer on the surface of cement Cement and Concrete research 17 (5) 805 Andersen PJ Roy DM Gaidis JM 1988 The effect of superplasticizers molecular weight on its adsorption on and dispersion of cement Cement and Concrete research 18 (6) 980 Angove MJ Wells JD Johnson BB 1999 Adsorption of cadmium(II) onto goethite and kaolinite in the presence of benzene carboxylic acids Colloids and surfaces A physicochemical and engineering aspects 146 (1-3) 243-251 ASTM C494 2004 Standard specification for chemical admixtures for concrete American Society for Testing and Materials

Bonen D and Shankar SL 1995 The superplasticizers adsorption capacity of cement pastes pore solution composition and parameters affecting flow loss Cement and Concrete research 25 (7) 1423 Boreacuten H 2004 Degradation of polycarboxylate ethers in a concrete repository A commented literature survey Choppin G R Redko M Y 2003 Comparison of structural effects on Eu(III) complexes with cyclohexyl and benzene polycarboxylic acids Journal of solid state chemistry 171 44-50 Choppin GR Stout BE Pages M 1998 Complexation of NPO2+ by aromatic polycarboxylates J Alloys and Comp 271-273 774-777

Corbett RA 2000 Formicary corrosion Corrosion testing laboratories Inc httpwwwcorrosionlabcompapersformicary_corrosion-2000paperhtm Dario M Molera M Allard B 2003 Effect of organic ligands on the sorption of europium on TiO2 and cement at high pH Draft

32

De Stefano C Gianguzza A Piazzese D Sammartaus S 1999 Speciation of low molecular weight carboxylic ligands in natural fluids protonation constants and association with major components of seawater of oxyacetics and citric acids Anal Chim Acta 398103-110

Dransfield JM Leaching of organic admixtures from concrete Cement Admixtures Assosiation Homepage 050705 httpwwwadmixturesorgukdownloadsxIS20Leaching20of20Admixtures20from20Concretepd Edwards M Benjamin M M Ryan J N 1996 Role of organic acidity in sorption of natural organic matter (NOM) to oxide surfaces Colloids and Surfaces A Physicochemical and Engineering Aspects 107 (20) 297 - 307 Evanko CR Dzombak DA 1999 Surface complexation modelling of organic acid sorption to goethite Journal of colloid and interface science 214 189-206

Filik H Oumlzturk B Dogutan M Gumus G Apak R 1997 Separation and preconcentration of iron (II) and iron (III) from natural water on a melamine- formaldehyde resin Talanta 44 pp 877-884

Filius JD Meeussen JCL Lumsdon DG Hiemstra T Riemsdijk von WH 2003 Modeling the binding of fulvic acid by goethite The speciation of adsorbed FA molecules Geochim Cosmochim Acta 67 (8) 1463-1474

Fjaumlllberg L Lagerblad B 2003 Flyttisatsmedels funktion doseringsbehov och kemiska uppbyggnad rapport gjort av uppdrag av SKB

Frimmel FH Abbt-Braun G 1999 Basic characterization of reference NOM from central Europe - similarities and differences Environment international 25 191-207

Gascoyne M 2002 Influence of grout and cement on groundwater composition Posiva Working Report 2002-07 44p

Glaus MA Hummel W Van Loon LR 2000 Trace metal-humate interactions I Experimental determination of conditional stability constants Applied Geochemistry 15 953-973

Glaus MA Van Loon LR 2004 A generic procedure for the assessment of the effect of concrete admixtures on the retention behaviour of cement for radionuclides Concept and case studies PSI Bericht 04-02 (Draft)

Greenfield BF Hett DJ Ito M McCrohon R Heath TG Tweed CJ Williams SJ Yui M 1998 The effect of cement additives on radionuclide solubilities Radiochim Acta 82 27-32 Greisser A 2002 Cement-Superplasticizer Interactions at Ambient Temperature Dissertation Swiss Federal Institute of Technology Haveman SA Stroes-Gascoyne S Hamon CJ 1996 Biodegrasation of a sodium suphonated naphthalene formaldehyde condensate by bacteria naturally present in

33

granitic groundwater Atomic Energy of Canada Limited technical Record TR-721 COG-95-547 Herb H 2001 Zur Mobilisierung von sulfonhaltigen Betonzusatzmitteln aus Zementstein Dissertation Universitaumlt Karlsruhe Herb H Koumlster R Houmlll WH 2000 Elution von sulfonhaltigen Betonzusatzmitteln aus Zementstein Vom Wasser 95 205 Herterich UVolland G Krause G Hansen D 2003 Determination of concrete admixtures in concrete by NMR spectroscopy Otto-Graf-Journal 14 101 Herterich UVolland GWustholz T Stegmaier M 2004 Leaching properties of self compacting concrete (SCC) Otto-Graf-Journal 15 153 Huang Y-L Li Q-B Deng X Lu Y-H Liao X-K Hong M-Y Wang Y 2005 Aerobic and anaerobic biodegradation of polyethylene glycols using sludge microbes Process Biochem 41 (1) 207 Hummel W Glaus MA Van Loon LR 2000 Trace metal-humate interactions II The conservative roof model and its application Applied Geochemistry 15 (7) 975-1001 Hur J Schlautman M A 2003 Molecular weight fractionation of humic substances by adsorption onto minerals J Colloid Interface Science 264 313-321 Iriya K Kubo H Kato T Fujita H 2001 Study on evolution of disposal environment due to alteration of cement Summary report JNC-TJ-8400-2001-035 (in Japan Abstract INIS ATOMINDEX)

Kawai F 1995 Proposed mechanism for microbial degradation of polyacrylate JMacromolecular Sci-Pure ApplChem A 32 (4) 835 Kawai F 2003 In Biopolymers vol 9 Matsumura S and Steinbuumlchel (eds) Miscellanwous Biopolymers and Biodegradation of Synthetic Polymers pp272-281 Wiley Weinheim Kim B-G Jinag SP Aitcin PC 2000 Slump improvement mechanism of alkalies in PNS superplasticizerd cement paste Materilas and Structures 33 363 King F Ahonen L Taxen C Vuorinen U Werme L 2002 Copper corrosion under expected conditions in a deep geologic repository Report POSIVA 2002-01 Posiva Oy Helsinki Leckie J and Redden G 1997 Sorption of Heavy Metals and radionuclides on Mineral Surfaces in the presence of Organic CO-Contaminants Progress Report DE FG07-96ER14698 Department Of Civil and Environmental Engineering Standford University Standford California

34

Lenhart J J Murphy R J Saenton S Honeyman B D 1999 The Effect of Citric Acid on the Sorption of Thorium and Uranium on Hematite Interfacial and Colloidal Phenomena in Aquatic Environments Anaheim California March 21 - 25 1999 Preprints of Extended Abstracts 39 366-368

Lis S and Choppin G R 1995b Luminiscence study of europium (III) complexes with several dicarboxylic acids in aqueous solution J Alloys and Comp 225 257-260

Lis S Hnatejko Z Barzynski P Elbannowski M 2002 Luminicence studies of Eu(III) mixed ligand complexes J Alloys and Comp 344 70-74

Lis S Wang Z Choppin GR 1995a Spectroscopic study of ion binding in synthetic polyelectrolytes using lanthanide ions Inorg Chim Acta 239 139-143

Maes A Dierckx AFM Vancluysen J 1994 The Formation of Mixed Complexes between Metals Humic Acids and Small Organic and Inoreganic Ligands in Binding Models Concerning Natural Organic Substances in Performance Assessment Proceedings of NEA Workshop Bad Zurzach Switzerland OECD

Mannonen R 1996 Effects of addition time of sulphonated naphthalene-based superplasticizers on the properties of concrete Dissertation Helsinki University of Technology Marcussen H Holm PE Hansen HCB 2003 Nickel sorption to goethite and Na-montmorillonite in presence of citrate Oral presentation at 7th International Conference on Biochemistry of Trace Elements Uppsala Sweden 15-19 June 2003 httpwwweomsluseICOBEADDITIONAL SP5ORMARCUSSENPDF MelbyeT and Garshol KF 2000 in httpwwwMBTCOMrocksupprocksupp_CH3_ENPDF

Mollah MYA Adams WJ Schennach R Cocke DL 2000 A review of cement-superplasticizer interactions and their models Advances in cement research 12 153-161

Morlay C Cromer Y Mouginot Y Vittori O 1998 Potentiometric study of Cu(II) and Ni(II) complexation with two high molecular weight poly(acrylic acids) Talanta 45 1177-1188 Morlay C Cromer Y Mouginot Y Vittori O 1999 Potentiometric study of Cu(II) and Ni(II) complexation with two high molecular weight poly(acrylic acids)comparison with Cu(II) and Ni(II) Talanta 48 1159-1166 Morlay C Cromer Y Mouginot Y Vittori O 2000 The removal of copper (II) and nickel (II) from dilute aqueous solution by a synthetic flocculant A polarographic study of the complexation with a high molecular weight poly(acrylic acid) for different pH values Water Res 34 455-462

35

Morlay C Cromer Y Mouginot Y Vittori O 2001 Determination of the complexation properties of a crosslinked poly(acrylic acid) gel with copper (II) nickel (II) and lead (II) in dilute aqueous solution Can J Chem 79 370-376 Nawa T and Eguchi H 1992 Effect of cement characteristics on the fluidity of cement paste containing an organic admixture in 9th International Congress on Cement Chemistry New Delhi pp579-603 Nawa T Eguchi H Fukaya Y 1989 Effect of alkali sulfate on the rheological behaviour of cement paste containing a superplastizicer In 3rd International Conference on Superplasticizers and other chemical admixtures in concrete Ottawa pp405-424 Onofrei MN and Gray MN 1989 Adsorption studies of 35S-labelled superplasticizer in cement-based grout in Superplasticizers and Other Chemical Admixtures in Concrete In Proceedings Third Int Conf Ottawa Canada 1989 (VM Malhotra ed) American Concrete Institute Detroit pp 645-660 Onofrei M Gray MN Roe LH 1991 Superplasticizer function and sorption in high performance cement based grouts Stripa Project TR-91-21 Stockholm Sweden Palmer JD and Fairhall GA 1993 The radiation stability of ground granulated blast furnace slagordinary portland cement grouts containing organic admixtures MRS XVI 285 Perret S Morlay C Cromer Y Vittori O 2000 Polarographic study of the removal of cadmium (II) and lead (II) from dilute aqueous solution by a synthetic flocculant Comparison with copper (II) and nickel (II) Water Res 34 3614-3620 Pojana G Carrer C Cammarata F Marcomini A Crescenzi C 2003 HPLC determination of sulphonated melamines-formaldehyde condensates (SMFC) and lignosulphonates (LS) in drinking and ground waters Intern J Environ Anal Chem 831 51 Prapaipong P Shock E L Koretsky CM 1999 Metal-organic complexes in geochemical processes Temperature dependence of the standard thermodynamic properties of aqueous complexation between metal cations and dicarboxylic ligands Geochim Cosmochim Acta 63 vol 17 pp 2542-2577 Redden G Bargar J Bencheikh-Latmani R 2001 Citrate enhanced uranyl adsorption on goethite An EXAFS analysis J Colloid Interf Science 244 211-219

Rosello-Mora RA Lalucat J Garcia-Valdez E 1994 Comparative biochemical and genetic analysis of naphthalene degradation among Pseudomonas stutzeri strains Applied Environmental Microbiology 60 977-972 Ruckstuhl S 2001 Environmental Exposure Assessment of Sulfonated Naphthalene Formaldehyde Condensates and Sulfonated Naphthalenes Applied as Concrete Superplasticizers Dissertation University of Zurich

36

Ruckstuhl S Suter MJ-F Giger W 2003 Sorption and mass fluxes of sulfonated naphthalene formaldehyde condensates in aquifers J Cont Hydrol 67 1 Ruckstuhl S Suter MJ-F Kohler H-PEGiger W 2002 Leaching and primary biodegradation of sulfonated naphthalenes and their formaldehyde condensates from concrete superplasticizers in groundwater affected by tunnel construction EnvSciTechn 36 3284 Roumlmkens PF Bril J Salomons W 1996 Interaction between Ca2+ and dissolved organic carbon implications for metal mobilization Applied Geochemistry 11 109-115

Sanseverino J Applegate BM King JMH Sayler GS 1993 Plasmid mediated mineralization of naphthalene phenantracene and antracene Applied Environmental Microbiology 59 1931-1937 Spanka G and Thielen G 1995 Untersuchungen zum Nachweis von verluumlssigenden Betonzusatzmitteln und zu deren Sorptions- und Elutionsverhalten Beton 45 H5 320 Stumm W 1992 Chemistry of the Solid-Water Interface John Wiley and Sons New York pp-114-125 Stumm W Morgan JJ 1996 3rd edition Aquatic Chemistry John Wiley and Sons New York Suzuki T Hukushima K Suzuki S 1993 Effect of ozone treatment upon biodegradability of water-soluble polymers EnvironSciTechnol 12 1180 Takahashi Y Minai Y Ambe S Makide Y Ambe F 1999 Comparison of adsorption behavior of multiple inorganic ions on kaolinite and silica in the presence of humic using the multitracer technique Geochim Cosmochim Acta 63 815-836 Uchikawa H Sawaki D Hanehara S 1995 Influence of kind and added timing of organic admixture on the composition structure and property of frech cement paste Cement and Concrete research 25 (2) 353 Uchikawa H Hanehara S Sawaki D 1997 The role of steric repulsive force in the dispersion of cement particles in fresh paste prepared with organic admixture Cement and Concrete research 27 (1) 37 Wold S 2003 On diffusion of organic colloids in compacted bentonite Doctoral thesis Royal Institute of Technology Stockholm Sweden

Wold S Eriksen TE 2003 Diffusion of lignosulfate colloids in compacted bentonite Applied Clay Science 23 43 - 50

Yamada K Takahashi T Hanehara S Matsuhisa M 2000 Effects of the chemical structure on the properties of polycarboxylate-type superplasticizers by

37

sulphate ion concentration in aqueous phase Cement and Concrete research 30 197-207 Yamada K and Hanehara S 2001 Interaction mechanism of cement and superplasticizers - The roles of polymer adsorption and ionic conditions of aqueous phase Concrete Science and Engineering Vol 3 no 11 135-145 Yamaguchi NU Scheinost AC Sparks DL 2002 Influence of gibbsite surface area and citrate on Ni sorption mechanisms at pH 75 Clays and Clay Minerals 50784-790 Yen KM Serdour CM 1988 Genetics of naphthalene catabolism in Pseudomonads Critical Reviews in microbiology 15 247-268

38

ABBREVIATIONS AcAc acetylacetone ACW artificial cement water C3A tricalcium aluminate CIT citric acid DOC dissolved organic carbon DTPA diethylenetriaminepentaacetic acid DWI UK Drinking Water Inspectorate EDTA ethylenediaminetetraacetic acid GL gluconic acid sodium salt HC hydrocarboxylic acid HCP hardened cement paste ISA isosaccarinic acid Kd distribution ratio in equilibrium (used by Dario et al 2003) LS lignosulphonate Mal malonate NOM natural organic materials NTA nitrilotriacetic acid OPC ordinary Portland cement PA polyacrylic acids PC polyether polycarboxylate PEG poly(ethylene glycol) PMS melamine sulphonate formaldehyde polycondensate PNS napthalenesulphonic acid polymer with formaldehyde PP carbohydrate =PZ Rd distribution coefficient (used by Glaus and Van Loon 2004) RN radionuclide SP superplasticizers TOC total organic carbon TTA thenoyl-tri- fluoro-acetone UV-VIS ultra violet and visible light detection VC vinyl maleic acid copolymer WRA water reducers

Mart t i Hakanen

He in i E rvanne

Labo ra to ry o f Rad iochem is t r y

Depa r tmen t o f Chem is t r y

Un i ve rs i t y o f He l s i nk i



A Literature Survey

Working Reports contain information on work in progress

or pending completion

The conclusions and viewpoints presented in the report

are those of author(s) and do not necessarily

coincide with those of Posiva

February 2006


A LITERATURE SURVEY

ABSTRACT






TIIVISTELMAuml




1

TABLE OF CONTENTS

Abstract

Tiivistelmauml










REFERENCES 31

ABBREVIATIONS 38

2








3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38



A LITERATURE SURVEY

ABSTRACT






TIIVISTELMAuml




1

TABLE OF CONTENTS

Abstract

Tiivistelmauml










REFERENCES 31

ABBREVIATIONS 38

2








3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38




TIIVISTELMAuml




1

TABLE OF CONTENTS

Abstract

Tiivistelmauml










REFERENCES 31

ABBREVIATIONS 38

2








3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


1

TABLE OF CONTENTS

Abstract

Tiivistelmauml










REFERENCES 31

ABBREVIATIONS 38

2








3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


2








3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


3




4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


4





5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


5


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


6




7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


7


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


8




9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


9


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


10




11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


11


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


12


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


13





14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


14


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


15


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


16




17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


17



18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


18




19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


19


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


20






21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


21


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


22





23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


23




24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


24







25


26


27


28


29






30


31




32











33



34









35



36





37


38


25


26


27


28


29






30


31




32











33



34









35



36





37


38


26


27


28


29






30


31




32











33



34









35



36





37


38


27


28


29






30


31




32











33



34









35



36





37


38


28


29






30


31




32











33



34









35



36





37


38


29






30


31




32











33



34









35



36





37


38


30


31




32











33



34









35



36





37


38


31




32











33



34









35



36





37


38


32











33



34









35



36





37


38


33



34









35



36





37


38


34









35



36





37


38


35



36





37


38


36





37


38


37


38


38


the influence of organic cement additives on radionuclide mobility

Documents