Use of vetiver (Vetiveria zizanoides) in remediation of cyanide soil contamination

Abstract

"The purpose of this greenhouse study was to assess the vetiver (Vetiveria zizanoides) in terms of the capacity to tolerate and accumulate cyanide (KCN) from contaminated soils of varying physicochemical properties. The toxicity of potassium cyanide (KCN) to grass vetiver (Vetiveria zizonioides) was tested. At the end of test, almost all cyanides had vanished from soils. Also, the in vivo capacity of Vetiveria zizonioides to remove cyanide was evaluated. For cyanide adsorption onto Vetiveria zizonioides, various parameters, affecting the removal rate, such as pH (6-8), and contact time (3-9months) were evaluated. The effect of pH on cyanide complex ion uptake rate and capacity of Vetiveria zizonioides was studied at 4-8 mg kg-1 initial cyanide concentration. Cyanide adsorption was increased with increasing soil pH, water content and contact time. At an optimum pH of 8, over 85% removal of 8 mg kg-1 cyanide was obtained for Vetiveria zizonioides after 9 months of contact time. Data from the experiment were analyzed with statistical software SPSS. The removal of cyanide by vetiver might be useful in cleanup of soil from gold and silver mining."