¹Department of Civil Engineering and ²Department of Agronomy, Kansas State University, Manhattan, KS, 66506
Organic ligands may affect the adsorption of heavy metals to soil by the formation of complexes. Batch adsorption experiments were conducted to determine the effect of citrate on the adsorption of zinc to soil. At concentrations ranging from 0 to 1500 µmol L-1, the adsorption of zinc by a soil under constant pH was measured in the presence of citrate of 0 to 10000 µmol L-1. It was found that the adsorption of citrate by soil was independent of zinc concentration, but the adsorption of zinc by soil was dependent on citrate concentration. Zinc adsorption increased with increasing citrate concentration up to 3000 µmol L-1; zinc adsorption decreased with increasing citrate concentration beyond 3000 µmol L-1. The adsorption of the zinc-citrate complex was ligand-like at this pH, and the increase or decrease of zinc adsorption was due to the formation of the zinc-citrate complex.
adsorption, heavy metal, organic ligand, ligand-like complex
This paper is from the Proceedings of the 10th Annual Conference on Hazardous Waste Research 1995, published in hard copy and on the Web by the Great Plains/Rocky Mountain Hazardous Substance Research Center.