Environmental International Vot. 2, pp. 61-62, Pergamon Press Ltd. 1979. Printed in Great Britain.

Water and Soil Pollution by Spent Lubricating Oils

Latif H. All, Hikmat S. Alsalim and Rafil A. Bashir Chemistry Department, College of Science, University of Mosul, Mosul, Iraq

This paper shows that spent lubricating oils from automobile engines generate carboxylic acids on environmental exposure. Samples of exposed oils, isolated from polluted river water and shore muds obtained from various locations, showed a direct proportionality between carboxylic acid content and time of exposure. Carboxylic acids were isolated by solvent extraction and studied by infrared spectroscopy.

Introduction Experimental

During a previous work on the separation of oil from tar sand by the hot water flotation process, it was found that exposure to the environment had a detrimental effect on processibility (Ali, 75) and that the process conditions induce the formation of surfactants including carboxylic acid (Ali, 78). It was suggested that the ease of formation of surfactants under the relatively mild thermal and weathering conditions of the hot water process (ca. 80°C) may throw a light on some of the effects expected from oil pollution as a result of tankage breaking, industrial effluents etc.

In the city of Mosul, Iraq (population 500,000), there is no control on effluents from car washing and lubrication facilities. Spent lubrication oil is thrown directly into the sewage lines and ends up directly in the Tigris river water, since no sewage treatment facilities exist. Besides the ugliness created on the shores for many miles down-stream, the effects are also devastating because of the agricultural importance of the thousands of square miles of flat shore land which are deluged during the high-water season. In addition to this, and according to our present findings, some significant changes are taking place in the chemical nature of the lubricating oil, rendering part of the oil walter soluble. This adds more danger to the aquatic life in the river which is shown by the complete disappearance of shells for many miles down-stream. Synergestic effects of oil pollution and that caused by dairy, tanning, sugar, and textiles industries existing in the city may also account for the occasional mass killing of fish for several miles down-stream. The damaging effects of oil pollution of the sea were studied by several workers (Hepple, 68; Smith, 68).

61

Separation of spent lubricating oil from samples To a 100 ml (or g) of the polluted water or mud

samples, a 2 × 20 ml of benzene was added and the mixture was vigorously shaken. The benzene layer was separated, dried with anhydrous sodium sulphate, filtered and the benzene evaporated.

Infrared measurement Oil samples obtained in the above procedure were

dissolved in CCI 4 and i.r. spectra were obtained using 0.1 mm NaC1 cells and a Unicam SP 200 spectrophotometer.

Isolation of carboxylic acids A sample of an exposed spent lubricating oil (1.462 g)

obtained according to the above mentioned separation procedure was dissolved in 50 ml CCI 4. The latter solution was extracted with 3 x 20 ml of 2°70 aqueous NaOH solution. Extracts were combined, neutralized with dilute HCI, then extraxted with 3 × 20 ml diethylether. The combined etherial layers were dried with anhydrous sodium sulphate, filtered, then the ether was completely evaporated.

Results and discussion

Polluted water and mud samples were taken from different locations starting in a polluted sewage line opening, and as far down-river as 20 km. The specifications of the sampling sites and i.r. spectroscopic measurements are given in Table 1. Figure 1 illustrates the trends in the formation of carboxylic acids as a function of exposure time, and also gives a

62 L.H. Ali, H.S. Aisalim and R.A. Bashir

E

I--

Fresh unexposed somple

R e f e r e n c e to peak oss ingmenf

vC-H I I / / I I I I I

3500 2500 [700 1500 1300

cm-~

Fig. 1. Formation of carboxylic acids on exposure of spent lubricating oils to environmental conditions.

spec t rum o f ca rboxyl ic acids ex t rac ted f rom Sample No . 4 (see Table 1). No te the g radua l f o r m a t i o n o f the acidic ( O - - H ) s t re tching v ib ra t ion ( p 2400-3600 cm-1, and the ca rboxy l ic (C = O) s t re tching v ib ra t ion ( v 1703 cm-l) .

The m e t h o d o f ca lcula t ing the re la t ive increase in ca rboxy l ic ac id content as a func t ion o f exposure t ime

was car r ied out in a way to give a unit less, no rma l i s ed n u m b e r showing the jus t s ta ted re la t ionsh ip . This m e t h o d o f c o m p u t a t i o n , which excluded the concen t r a t i on effects , was based on the a s sumpt ion tha t the a b s o r b t i o n value in the region v 1470 cm -1 for the C - - H bending , in the least a f fec ted sample (Sample No. 1), to be equal to 1.00.

To check whether or not the t he rma l cond i t ions in the car engine induce ca rboxy l ic acids f o r m a t i o n , spent oils f rom an o ld car (Dodge , 55) and tha t f rom a new mode l (Toyo ta , 77) were examined by i .r . spec t roscopy . The spec t ra o b t a i n e d were s imi lar to tha t o f a pure fresh lubr ica t ing oil sample and con ta ined no carboxyl ic acid a b s o r p t i o n .

Quan t i t a t ive ly , the weight o f ca rboxyl ic acids i so la ted f rom Sample No. 4 was 4 .2% o f the to ta l weight o f the exposed lubr ica t ing oil sample . A thin f i lm o f f loa t ing oil was obse rvab le on the r iver wi th a dep th o f 10-20 m on the water sur face and ex tend ing for m a n y k i lometers down-s t r eam. Th inn ing o f spent lubr ica t ing oil was resul t ing f rom the use o f keros ine in engine cleaning. Black s ta ined, po l lu t ed shores extend for a cons iderab le d is tance and are increas ing rap id ly .

In o rde r to be t te r u n d e r s t a n d the na tu re o f i so la ted ca rboxy l ic acid samples , m o r e de ta i led studies are cur ren t ly being conduc ted while the effects o f ar t i f ic ia l i r r ad i a t i on o f s imula ted samples are also being s tudied to de te rmine the role o f pho toc he mic a l ox ida t ion in the ac id fo rma t ion .

Refe rences

Ali, L.H. (1975) Studies on the aging phenomenon in tar sand, Fuel 54, 223. Ali, L.H. (1978) Surface active agents in the aqueous phase of the hot water flotation process for oil sands, Fuel 57, 357. Hepple, P. (1968) Scientific aspects of pollution of the sea by oil, Proc. Symp. held on 2 October, 1968, The Institute of Petroleum, London. Smith, J.E. (1968) Torrey Canyon Pollution and Marine Life, Marine Biological Association of the United Kingdom.

Table 1. Effects of exposure on the formation of carboxylic acids from spent lubricating oils.

Sample Sampling site Absorbance values Normalized values No. specifications 1470 cm -1 1703 cm -I 1470 cm q 1703 cm -t

1" Water sample directly where sewage line pours into river 0.155 0.010 1.00 l

2* Watei" sample 20 km down-stream 0.733 0.094 4.73 2 3* Dry polluted mud sample 20 km

down-stream; 1 month exposure 0.554 0.112 3.57 3 4* As sample No. 3; 3 month exposure 0.904 0.330 5.85 6 5* As sample No. 3; 4 month exposure 0.203 0.105 ! .30 8 6 As sample No. 3; 4.5 month old 0.405 0.234 2.61 9 7 As sample No 3, 4 - 5 month old 0.298 0.153 1.92 8 8 Dry polluted mud sample in the area

where sewage line pours into river 0.655 0.195 4.23 5 9 Thick oily layer floating on stagnant

water near area where sewage line pours into river 0.675 0.255 4.35 6

(*) The relevant parts of the spectra of these samples are shown in the figure.