Mechanism of Cr (VI) biosorption by neem sawdust.

Abstract: The mechanism of Cr (VI) uptake by neem sawdust was investigated using different chemical and instrumental techniques. Batch biosorption studies after the removal of the components viz. lignin and cellulose of the biosorbent revealed that lignocellulosic moieties play a predominant role in the biosorption of Cr (VI). FTIR analysis showed that the bonded-OH groups, C=O groups, SO stretching, C-O stretching and-CN3 stretching were involved in Cr (VI) biosorption. The biosorbent was analyzed for its elemental composition using EDAX. The oxidation state of chromium in neem sawdust after Cr (VI) adsorption from aqueous solution was investigated using electron spin resonance (ESR). ESR experiments confirmed that Cr (VI) was reduced to Cr (III) on lignin component of neem sawdust. The mechanism involved in biosorption of Cr (VI) was found to be adsorption coupled reduction. Key words: Biosorbent Chromium (VI) Chromium (III) Mechanism INTRODUCTION mechanism of Cr (VI) sorption by neem sawdust using Chromium, a priority metal pollutant is widely used and instrumental analysis. by various modern industries like electroplating, tanning, textile, etc. resulting in discharge and accumulation in METHODS large quantities into the environment (Sharma, 2003).