Abstract
The uptake of trivalent arsenic from aqueous solutions onto indium-doped ZnO (IZO) nanopowder was studied. The nanopowder was fabricated using a modified sol-gel method under supercritical drying conditions of ethanol. X-ray diffraction and nitrogen adsorption techniques were employed to characterize the IZO nanopowder. The N-2 adsorption isotherms reveal that pure and doped ZnO nanopowders were mesoporous materials. Removal of arsenite ions from the solutions by IZO nanopowder was conducted in a batch-mode reactor. The impact of initial concentration, indium-doping dose, temperature and pH were considered. Arsenite removal was pH sensitive scoring its maximum elimination capacity at pH 3 and 7. The adsorption equilibrium was well delineated by Langmuir isotherm. Data were further found to comply with the pseudosecond-order kinetic law, and the process was spontaneous endothermic physisorption.