Use of X-ray absorption spectroscopy and esterification to investigate Cr(III) and Ni(II) ligands in alfalfa biomass
- Univ. of Texas, El Paso, TX (United States). Dept. of Chemistry
- Brookhaven National Lab., Upton, NY (United States)
Previously performed studies have shown that alfalfa shoot biomass can bind an appreciable amount of nickel(II) and chromium(III) ions from aqueous solution. Direct and indirect approaches were applied to study the possible mechanisms involved in metal binding by the alfalfa biomass. The direct approach involves investigations of the metal-bound alfalfa shoot biomass by X-ray absorption spectroscopic analysis (XANES and EXAFS). Results from these studies suggest that nickel(II) and chromium(III) binding mostly occurs through coordination with oxygen ligands. Indirect approaches consist of chemical modification of carboxylate groups that have been shown to play an important role in metal binding to the alfalfa biomass. An appreciable decrease in metal binding resulted after acidic methanol esterification of the biomass, indicating that carboxyl groups are entailed in the metal binding by the alfalfa biomass. In addition, base hydrolysis of the alfalfa biomass increased the binding of these metals, which further indicates that carboxyl groups play an important role in the binding of these metal ions from solution. Therefore, by combining two different techniques, their results indicate that carboxylate groups are the major ligands responsible for the binding of nickel(II) and chromium(III) by alfalfa biomass.
- OSTI ID:
- 298244
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 1 Vol. 33; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Biosorption of cadmium, chromium, lead, and zinc by biomass of Medicago sativa (alfalfa)
Calcium and magnesium interference studies for the binding of heavy metal ions in solution by Medicago sativa (alfalfa)