Column studies were conducted, using iron oxide-coated Aspergillus niger biomass, to examine the removal of arsenic [As(III) and As(V)] from an aqueous solution. The Thomas and Yan models were examined to predict the breakthrough curves. The Yan Model described the data better (based on the R-2 values) when compared with the Thomas Model. The adsorption capacity of the iron oxide-coated biomass estimated by the Thomas Model {1070 mu g/g for As(V) and 700 mu g/g for As(111)} was comparable to the calculated value of its adsorption capacity {1080 mu g/g for As(V) and 880 mu g/g for As(III)}. (c) 2007 Elsevier Ltd. All rights reserved.