Microbial composite for Cr(III) remediation from effluents

Abstract

Chromium (III) in the industrial effluents is considered hazardous due to oxidation and therefore its remediation by alternate methodology such as biosorption has recently gained importance. Though sorption of Cr(III) on algae and fungi have been studied, their applications as fungal-clay composite is not much investigated. Growth of A.niger with bentonite showed release of spores and development of full cells in <72h facilitating good metal uptake. In this study, Aspergillus niger and bentonite have been used to develop a composite sorbent and removal of Cr(III) from a model effluent solution of 100ppm Cr(III) was investigated. A maximum sorption of 85% Cr(III) was achieved with 1%(w/v) composite (1:6 ratio of biomass to bentonite) of <50μm size within a contact time of 5 min at 2.5pH and 35oC temperature. Increasing the pH up to 4.0 caused elevation in the degree of sorption. The composite was thus found to be effective sorbent to treat chromium (III) containing waste solutions.