Copper Adsorption by KOH Activated Pecan-Shell Biochar.

Dairy operations in the Pacific Northwest USA often use a copper sulfate (CuSO4) foot bath to minimize hoof diseases.  When finished, the spent CuSO4 solution is frequently disposed into lagoons with lagoon effluent later sprayed onto fields as a fertilizer.  Unfortunately, repeated application of Cu-enriched lagoon effluent is resulting in topsoil Cu-accumulation.  Because Cu is a plant micronutrient, concern has arisen if this practice will result in a soil Cu plant nutrient imbalance.  To sequester Cu and reduce the like hood of soil imbalances, we studied the ability of KOH-activated pecan-shell based biochar to adsorb Cu from solution.  In a series of laboratory incubation experiments, this biochar type was capable of adsorbing at least 25,000 mg Cu/kg biochar.  Our next goal is to determine biochar’s ability to adsorb Cu from Cu-fortified soils and to quantify concentrations of bioavailable soil Cu.  It is anticipated that this biochar type should be capable of sorbing available soil Cu and could potentially be used on Idaho soils receiving Cu-enriched dairy waste effluent as a best management practice.