Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface structure of the materials was investigated with X-ray diffraction (XRD), a N2 adsorption-desorption technique, Fourier transform-infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) to understand the effect of surface properties on the adsorption behavior of phosphate. The mesoporous materials were loaded with Al components by reaction with surface silanol groups. In the adsorption test, the Al-impregnated mesoporous materials showed fast adsorption kinetics as well as high adsorption capacities, compared with activated alumina. The uniform mesopores of the Al-impregnated mesoporous materials caused the diffusion rate in the adsorption process to increase, which in turn caused the fast adsorption kinetics. High phosphate adsorption capacities of the Al-impregnated mesoporous materials were attributed to not only the increase of surface hydroxyl density on Al oxide due to well-dispersed impregnation of Al components but also the decrease in stoichiometry of surface hydroxyl ions to phosphate by the formation of monodentate surface complexes.

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 2 /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 SBA-15 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. Al 10 SBA-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 Al 10 SBA-15 for POE/POU application due to its rapid and high adsorption capacity.