The SBA-15 (a mesoporous SiO2 material) decorated with 10% aluminum (Al-10-SBA-15) was found to be an excellent adsorbent to remove As(V) from water. The highly dispersed aluminum species have been obtained over the well-ordered mesoporous Al-10-SBA-15 adsorbent and act as the active adsorption sites for arsenic(V) removal instead of SiO2. The adsorption behavior of As(V) onto Al-10-SBA-15 was investigated in aqueous solution using various experimental parameters. The adsorption data of As(V) could be fitted more successfully by the Langmuir isotherm than the Freundlich isotherm model, and the pseudo-second-order equation described this entire adsorption process well. It is found from the analysis of kinetic data with the intraparticle diffusion mode that both the boundary layer (film) diffusion and intraparticle diffusion may contribute to the rate-limiting steps. Importantly, Al-10-SBA-15 exhibits high arsenic(V) removal in the wide pH range of 2.0-8.2 and can remove As(V) from water containing arsenate of <= 2.235 mg.L-1 to reach levels in accordance with the regulations for drinking water purposes (<10 mu g.L-1). Consequently, Al-10-SBA-15 is believed to be an effective adsorbent for treating arsenate contaminated wastewater.