Biosorption of copper(II) from aqueous solutions by Aspergillus niger-treated rice straw

Abstract

The biosorption of copper(II) from aqueous solutions by rice straw treated with Aspergillus niger, namely fermented rice straw, was investigated to identify the metal removal efficiency of biosorbents, and, for the first time, proximate analysis of raw rice straw was performed. Fermented rice straw exhibited a short biosorption equilibrium time of 30min, high biosorption capacity (23.8mg/g) and high removal efficiency at a pH range of 4.0–6.0. The biosorption capacity of fermented rice straw was better than that of raw rice straw under the identical conditions can be ascribed to the enzyme system secreted by Aspergillus niger which changed the surface properties of raw rice straw. In addition, the biosorption mechanism was involved in chelation with functional groups such as −OH, CO, CO and CC, and the biosorption data obtained were well described by the pseudo-second order and the fredunlich isotherm model. The obtained data suggesting that the microbiologically-treated rice straw could become a promising biosorbent.