Biochars impact on soil moisture storage in an Ultisol and two Aridisols

Ippolito, J.A. and Strawn, D.G. and Scheckel, K.G. and Novak M, J and Ahmedna, M. and Niandou, M.A.S. (2011) Biochars impact on soil moisture storage in an Ultisol and two Aridisols. Journal of Environmental Quality. 35(6):2333-2341.

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Abstract

Excessive copper concentrations in water systems can negatively impact biological systems. Because copper can form strong associations with organic functional groups, we examined the ability of biochar (a carbon-enriched organic bioenergy by-product) to sorb copper from solution. In a batch experiment, potassium hydroxide-steam activated pecan shell biochar was shaken for 24 hours in pH 6, 7, 8, or 9 buffered solutions containing various copper concentrations to identify effect of pH on biochar copper sorption. Afterwards, all biochar solids from the 24 hours shaking period were air-dried and then analyzed using X-ray absorption fine structure spectroscopy to determine solid-phase copper speciation. In a separate batch experiment, biochar was shaken for 30 days in pH 6 buffered solution containing increasing copper concentrations; the copper sorption maximum was calculated based on the exponential rise to a maximum equation. Biochar sorbed increasing amounts of copper as the solution pH decreased from 9 to 6. The X-ray absorption fine structure results revealed that copper was predominantly sorbed onto a biochar organic phase at pH 6 in a molecular structure similar to copper adsorbed on humic acid. The X-ray absorption fine structure spectra at pH 7, 8, and 9 suggested that copper was associated with the biochar as three phases: 1) a complex adsorbed on organic ligands similar to copper on humic acid; 2) carbonate phases similar to azurite; and 3) a copper oxide phase like tenorite. The exponential rise equation fit to the incubated samples predicted a copper sorption maximum of 42,300 mg/kg copper. The results showed that potassium hydroxide-steam activated pecan shell biochar could be utilized as a material for sorbing excess copper from water systems, potentially reducing the negative effects of copper in the environment.

Item Type: Article
NWISRL Publication Number: 1483
Subjects: Soil > Soil quality
Depositing User: Michelle Wayment
Date Deposited: 03 Mar 2014 21:56
Last Modified: 03 Mar 2014 21:57
Item ID: 1521
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1521

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