Facile synthesis of mesoporous Ce-Fe bimetal oxide and its enhanced adsorption of arsenate from aqueous solutions.

The mesoporous Ce-Fe bimetal oxide (MCFO) was synthesized through a soft-template method and first applied in the adsorption of arsenate in aqueous solutions. The synthesized MCFO was characterized with BET surface area, X-ray diffraction (XRD), zeta potential, scanning electron microscope (SEM), and Fourier transform infrared (FTIR) analysis. The mesoporous structure of the MCFO was determined according to the characterization result. The adsorption efficiency of arsenate ions on the MCFO was studied as a function of initial As(V) concentration, contact time, pH, and coexistent anions. It was found that the adsorption isotherms could be well described by Langmuir model, and the calculated maximum adsorption capacity of MCFO-1 for As(V) was 91.74 mg g(-1), which was significantly greater than that of ordinary Ce-Fe bimetal oxide (CFO). The results showed that the adsorption kinetic data obeyed the pseudo-second order model. Lower pH was favorable for As(V) adsorption on the MCFO. Coexistent phosphate ions exhibited an obvious interference on As(V) adsorption, followed by silicate and fluoride ions. The analysis of BET and FTIR indicated that the high efficiency of As(V) adsorption on this Ce-Fe bimetal oxide (MCFO) was closely related to its uniform mesoporous structure and abundant surface hydroxyl groups.