Article

Effects of pH on Cr-Fe interaction during Cr(VI) removal by metallic iron.

Regional Research Laboratory, Council of Scientific and Industrial Research, Bhopal-462 026, India.
Environmental Technology (impact factor: 1.41). 09/2003; 24(8):1041-7. DOI:10.1080/09593330309385643 pp.1041-7
Source: PubMed

ABSTRACT In the present investigation, the effect of pH on Cr-Fe interactions has been studied by carrying out Cr(VI) removal utilising metallic iron from the dichromate solutions of pH 2 to 7 by batch shaking process. Since the presence of ferrous iron in the solution is mainly responsible for Cr(VI) reduction, solubility of iron from the metallic iron was also measured. The maximum Cr(VI) removal efficiency was found at pH 2 but pH 3 was considered to be a suitable solution condition for Cr(VI) removal due to the occurrence of a minimum level of iron in the treated solution. Chemical analysis of Cr(VI)-reacted iron and treated dichromate solutions has indicated the reduction of Cr(VI) to Cr(III) at the metal surface itself at pH 2 and 3 and in the solution at pH 4 and above. A considerable decrease in chromium concentration on the iron surface in the pH range 4 - 7 as compared to pH 2 and 3 was also observed by EDXA analysis. These studies confirmed that after reduction, involvement of Cr(III) with Fe takes place at the metallic iron surface itself at pH 2 and 3 while it reduces with the rise of pH.

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Keywords

Chemical analysis
 
chromium concentration
 
considerable decrease
 
Cr(VI)-reacted iron
 
Cr-Fe interactions
 
dichromate solutions
 
ferrous iron
 
iron surface
 
metal surface
 
metallic iron
 
metallic iron surface
 
minimum level
 
pH range 4
 
present investigation
 
solubility
 
suitable solution condition
 
treated solution
 

I B Singh