Arsenic removal from an aqueous solution by modified A-niger biomass:: Batch kinetic and isotherm studies

Batch studies were conducted to examine the adsorption kinetics and adsorption capacity of iron oxide-coated biomass (IOCB) for As(III) and As(V). The optimum pH for As(V) and As(III) removal was found to be 6. The equilibrium time for removal of arsenic was found to be approximately 7 h. The adsorption of As(V) on IOCB was rapid compared to that of As(III) adsorption. An increase in temperature (from 5 to 30 degrees C) was found to increase As(III) removal, whereas in the case of As(V), the removal increased with temperature from 5 to 10 degrees C, but remained relatively constant thereafter up to 30 degrees C. The pseudo-second order rate equation was found to describe better the kinetics of arsenic adsorption than other equations. The isotherm data for As(V) removal fitted better with the Langmuir equation compared with other tested models and the isotherm data for As(III) removal fitted better with Redlich-Peterson equation than other tested models. Iron oxide-coated fungal biomass (A. niger) was found to be efficient in removing arsenic from an aqueous solution. (c) 2007 Elsevier B.V. All rights reserved.