Phosphate Removal In Wastewater by Functionalized Mesoporous SBA-15

Abundant phosphorous (P) in water causes eutrophication which threatens human health. As the regulation to control the level of phosphate in wastewater becomes much stricter, more efficient phosphate removal method should be developed. Existing phosphate removal methods such as biological, physical and chemical treatments are limited to remove phosphate efficiently. For this reason, mesoporous silica (SBA-15) was applied to remove phosphate in wastewater. SBA-15 has large surface, abundant reactive ionized surface, the simplicity to control their pore size, highly uniformed pores and application of functional groups. However, due to its low affinity for phosphate itself, SBA-15 was modified with several functional groups. These functional groups were chosen by their affinities for phosphate. Amine, aluminum, titanium, and thiol groups were adopted as the phosphate affinitive functional groups. Functionalized SBA-15 samples were synthesized by the post-synthesis method and analyzed with XRD, TEM, EDX and BET. To determine their adsorption capacities, equilibrium and kinetic tests were conducted and their adsorption capacities were determined by time and concentration. Each sample was analyzed by ion chromatography. According to each data, all samples were synthesized well. From the adsorption capacity tests, amino-functionalized SBA-15 showed the best adsorption capacity (66.57 mg/g) and possibility of its practical applications to real wastewater among these functionalized samples. Also Al-functionalized SBA-15 also had good adsorption capacity for phosphate (39.60 mg/g). Based on this study, it is proven that functionalized SBA-15 is a promising adsorbent for phosphate effectively than existing treatment methods.