Phosphate Adsorption on Aluminum-Impregnated Mesoporous Silicates:  Surface Structure and Behavior of Adsorbents

• Published in: Environmental science & technology Vol. 38; no. 3; pp. 912 - 917
• Main Authors: Shin, Eun Woo, Han, James S., Jang, Min, Min, Soo-Hong, Park, Jae Kwang, Rowell, Roger M.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-02-2004
• Subjects: Adsorbents; Adsorption; Aluminum; Aluminum - chemistry; Applied sciences; Continental surface waters; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Fertilizers; Fourier transforms; Kinetics; Materials Testing; Natural water pollution; phosphates; Phosphates - chemistry; Phosphates - isolation & purification; phosphorus; Phosphorus removal; Pollution; Pollution, environment geology; Porosity; Silica; silicates; Silicates - chemistry; Studies; surface properties; Water pollution; Water Purification - methods; Water treatment and pollution; Phosphates; Detergent; Liquid solid adsorption; Adsorption capacity; Phosphorus; Aluminium; Inorganic adsorbent; Phosphate fertilizer; Silicates; Porous material; Surface structure; Decontamination; Impregnated material; Surface water; Lakes; Stream; Water pollution; Kinetics; Porosity; Surface area
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es030488e

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.