『Abstract
　Three novel composite adsorbents, sulfate-coated zeolite (SCZ), hydrotalcite (SCH), and activated alumina (SCAA), were characterized and employed for the removal of phosphate from aqueous solution using equilibrium and kinetic batch experiments. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction spectrum were used to study the surface characteristics of the coated layer. Equilibrium tests showed that the adsorption of phosphate followed both Langmuir and Freundlich isotherms. The powder-type SCZ was better for phosphate removal (maximum binding energy, β=11.49 mg g^-1) compared to hydrotalcite and activated alumina. The adsorption of phosphate was considered to take place mainly by ion exchange. The kinetic data followed a pseudo-second-order kinetic model. The initial adsorption of phosphate onto the sulfate-coated adsorbents was fast, indicating that the sulfate-coated materials developed in this study can be used as promising adsorbents for the removal of phosphate from wastewater or sewage.

Keywords: Sulfate coated; Zeolite; Hydrotalcite; Activated alumina; Phosphate』

1. Introduction
2. Materials and methods
　2.1. Preparation of adsorbents
　2.2. Adsorption batch experiments
　2.3. Modeling of adsorption isotherm
　2.4. Analytical methods
3. Results and discussion
　3.1. Characteristics of the sulfate-coated and noncoated adsorbents (SEM, XRD, FTIR)
　3.2. Equilibrium adsorption
　3.3. Kinetic adsorption
　3.4. Phosphate removal efficiency by the surface-modified adsorbents
4. Conclusions
Acknowledgments
References