Removal of Arsenic Using Mesoporous Silicate Media

The highly ordered mesoporous silica SBA-15 was successfully synthesized and incorporated with iron, aluminum, and zinc oxides by use of an incipient wetness impregnation technique. Aluminum 10% impregnation was safely incorporated by an incipient wetness impregnation technique for SBA-15, which had 638.75 m/g of BET surface area and 48 Å of pore diameter, without producing clogging of pore structures. The adsorption capacities of these materials were evaluated with adsorption isotherm and kinetic studies under different batch conditions. Aluminum was the best incorporation metal compound and impregnation of aluminum 10% for SBA15 had greater than 2 times higher arsenate adsorption capacity and 15 times higher rate than activated alumina under the condition of 0.133 mmol/L arsenate initial concentration and 0.333 g/L of solids concentration. Al10SBA-15 showed about 2.2 ~ 2.4 times higher arsenate adsorption capacities than activated alumina in a broad range of arsenate initial concentrations, in which the Freundlich isotherm model was fitted very well. The ratecontrolling step of arsenate adsorption for all adsorbents appeared to be explained by both the exchange reaction and diffusion reaction. These results showed great advantages of Al10SBA-15 for POE/POU application due to its rapid and high adsorption capacity.