Copper Sequestration Using Local Waste Products

Jim IppolitoResearch Soil Scientist

USDA-ARSKimberly, ID

Presentation Outline• Why worry about Cu in Idaho?• Waste materials

– Beneficial use

• Laboratory solution sorption studies• Greenhouse soil sorption studies• Conclusions

Why Worry About Cu in Idaho?

(nass.usda.gov/QuickStats/)

Idaho Dairy Cow Population

Year

1900 1920 1940 1960 1980 2000 2020

Dai

ry C

ows

(in th

ousa

nds)

0

100

200

300

400

500

600

Local Wastes• Can we beneficially reuse

Amalgamated Sugar Co:• Spent Lime Waste?

– 274,000 tons/year

• Coal Ash?– 19,000 tons/year

• Goal is to sequester Cu

Laboratory Solution Sorption Study• Fly ash or Lime waste

– 1g into 50mL centrifuge tubes

• Add 50mL of increasing Cu solutions in pH buffers– Rates equivalent to 2500, 5000, 12500, 25000, 75000,

100000 mg Cu/kg– pH: 6, 7, 8, 9

• Shake for 1 month and analyze solution for Cu

• Replicated 3 times

Fly Ash Copper Adsorptionvs pH

(1 month shaking)

Cu Added (mg kg-1)

0 5000 10000 15000 20000 25000

Cu

Adso

rbed

(mg

kg-1

)

0

5000

10000

15000

20000

25000 pH 6pH 7 pH 8 pH 9 1:1 Cu Adsorption

Fly Ash Copper AdsorptionpH 6

(1 month shaking period)

Cu Added (mg kg-1)

0 20000 40000 60000 80000 100000

Cu

Adso

rbed

(mg

kg-1

)

0

20000

40000

60000

80000

100000Observed Cu AdsorptionPredicted Cu Adsorption1:1 Cu Adsorption

Fly Ash Cu Adsorption = 26,060[1-e(-4.29e-5*Cu Added)]R2 = 0.86

Lime Waste Copper Adsorptionvs pH

(1 month shaking)

Cu Added (mg kg-1)

0 5000 10000 15000 20000 25000

Cu

Adso

rbed

(mg

kg-1

)

0

5000

10000

15000

20000

25000 pH 6pH 7 pH 8 pH 9 1:1 Cu Adsorption

Lime Waste Copper AdsorptionpH 6

(1 month shaking period)

Cu Added (mg kg-1)

0 20000 40000 60000 80000 100000

Cu

Adso

rbed

(mg

kg-1

)

0

20000

40000

60000

80000

100000Observed Cu AdsorptionPredicted Cu Adsorption1:1 Cu Adsorption

Lime Waste Cu Adsorption = 44,640[1-e(-2.33e-5*Cu Added)]R2 = 0.96

Next Question

• Can lime waste sorb excess soil Cu?

Healthy Alfalfa Cu-Affected Alfalfa

Greenhouse Soil Cu Sorption

• Soil received:– 0, 250, 500, 1000 mg Cu/kg– Incubated for ~9 mo

• Lime waste– 0, 0.5, 1.0, 2.0% by weight (0,10,20,40 tons/ac)– Incubated for 3 months

• Alfalfa– 15 seeds/pot– 2.5 months of growth

Greenhouse Soil Cu Sorption• Measured:

– Plant yield– Plant Cu content– DTPA extractable soil Cu– Soil phases that Cu could be associated with:

• Soluble species/carbonates/cation exchange sites• Fe/Mn (hydr)oxides• Organics• Residuals

0% Lime Waste

0 250 500 1000

0.5% Lime Waste

0 250 500 1000

1% Lime Waste

0 250 500 1000

2% Lime Waste

0 250 500 1000

Soil pH = 7.9; biochar pH = 8.5

Cu added = 0, 250, 500, 1000 mg kg-1

Lime Waste added = 0, 0.5, 1, 2% by wt

Alfalfa Yield vs Cu Added

Cu Added (mg kg-1)

0 100 200 300 400 500

Alfa

lfa Y

ield

(g)

0.0

0.5

1.0

1.5

2.0

0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: NSCu Rate: p < 0.001Lime x Cu Rate: NS

Alfalfa Cu Content vs Cu Added

Cu Added (mg kg-1)

0 100 200 300 400 500

Plan

t Cu

Con

cent

ratio

n (m

g kg

-1)

0

2

4

6

8

10

12

14

16

18

20

22

0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: p <0.001Cu Rate: p = 0.003Lime x Cu Rate: p = 0.045

DTPA Extractable Soil Cu vs Cu Added

Cu Added (mg kg-1)

0 200 400 600 800 1000

DTP

A Ex

trac

tabl

e C

u (m

g kg

-1)

0

100

200

3000% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: NSCu Rate: p < 0.001Lime x Cu Rate: NS

Sequential Soil Cu ExtractionSoluble, Carbonate, Cation Exchange Associated Cu

Cu Added (mg kg-1)

0 200 400 600 800 1000

Solu

ble,

Car

bona

te, C

atio

n Ex

chan

ge S

ite C

u (m

g kg

-1)

0

50

100

150

200

250

300

0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: p = 0.018Cu Rate: p < 0.001Lime x Cu Rate: p = 0.003

Iron and Manganese (Hydr)oxide Associated Cu

Cu Added (mg kg-1)

0 200 400 600 800 1000

Fe/M

n (H

ydr)

oxid

e C

u (m

g kg

-1)

0

20

40

60

80

100

120

140

160 0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: p = 0.043Cu Rate: p < 0.001Lime x Cu Rate: p = 0.002

Organic and Sulfide Associated Cu

Cu Added (mg kg-1)

0 200 400 600 800 1000

Org

anic

and

Sul

fide

Cu

(mg

kg-1

)

0

20

40

60

80

100

120

0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: p <0.001Cu Rate: p < 0.001Lime x Cu Rate: p = 0.019

Residual Cu

Cu Added (mg kg-1)

0 200 400 600 800 1000

Res

idua

l Cu

(mg

kg-1

)

0

20

40

60

80

100

120

140

0% Lime Waste 0.5% Lime Waste1% Lime Waste 2% Lime Waste

Lime Waste Rate: NS Cu Rate: p < 0.001Lime x Cu Rate: NS

Conclusions• Lime waste and fly ash sorb solution Cu

– Decreasing pH increases sorption– Fly Ash: ~26,000 mg Cu/kg– Lime Waste: ~45,000 mg Cu/kg

• Lime waste addition to Cu-laden soil– No improvement in alfalfa yield

• Decreased alfalfa Cu content– No effect on extractable (i.e. DTPA) soil Cu– No major discernable differences in soil Cu phases

Conclusions• The use of lime waste:

– Appears to be a viable option for sequestering solution copper.

– Would not be recommended for alkaline soils containing excess copper.

Thank you

Questions?

Jim Ippolito, Ph.D.Research Soil Scientist

USDA-Agricultural Research ServiceNorthwest Irrigation and Soils Research Laboratory

Kimberly, IdahoEmail: jim.ippolito@ars.usda.gov

Phone: (208)423-6524