Interference Studies for Multi- Metal Binding by Medicago Sativa (al- Falfa)

Previous studies have shown that alfalfa shoot biomass has the ability to bind a significant amount of various individual metals from aqueous solutions. Since most heavy metal-contaminated waters contain more than one heavy metal, it was necessary to determine the binding abilities of the alfalfa biomass with multi-metal solutions. Multi-metal binding capacity experiments resulted in the following order of affinity for the multi-metal binding by the alfalfa biomass: 42.1mg/g for lead(II), 11.4 mg/g for chromium(III), 6.5 mg/g for copper(II), 4.4 mg/g for cadmium(II), 4.3 mg/g for zinc(II), and 0.5 mg/g for nickel(II). In order to better understand how this system may behave with hard cations such as magnesium and calcium which are found in contaminated waters, batch laboratory interference studies were performed with various calcium and magnesium concentrations (0.1mM 1M). In general, the alfalfa biomass seems to have a high selectivity to bind copper, lead, and chromium in the presence of high concentrations of calcium and magnesium from a multi-metal-containing solution. The information obtained will be useful for the future development of an innovative technology to remove heavy metal contaminants from polluted groundwaters