Mucor biosorbent for chromium removal from tanning effluent

Waste industrial Mucor meihi biomass was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. Sorption levels of 1.15 and 0.7 mmol/g were observed at pH 4 and 2 respectively while precipitation effects augmented these values at higher pH ranges. Acid elution of biosorbed chromium increased with decreasing eluant pH to a maximium value of ca. 30% at approximately zero pH. Successive elution stages with increasingly strong acids resulted in a cumulative chromium recovery of in excess of 80%. Both acid and base treatments eluted biosorbed chromium and successive acid/base and base/acid treatments resulted in recovery values approaching 100% at low metal loadings. These values decreased to 80 to 60% at higher biomass metal loadings. In comparative studies with ion exchange resins, the Mucor biomass demonstrated chromium biosorption levels that correspond closely to those of commercial strongly acidic exchange resin while the pH behaviour mirrored that of the weakly acidic resins in solution. The chromium elution characteristics from the Mucor biomass were similar to those of both the weakly and strongly acid resins.