PROCESS-DEVELOPMENT FOR REMOVAL AND RECOVERY OF PHOSPHORUS FROM WASTE-WATER BY A NEW ADSORBENT .1. PREPARATION METHOD AND ADSORPTION CAPABILITY OF A NEW ADSORBENT

Alophene and activated alumina can adsorb phosphate ion, and their adsorption capacities have been increased by adding aluminum sulfate or iron sulfate, respectively, to form complex salts on their surfaces. In particular, activated alumina combined with 2.0 x 10(-4) mol of aluminum sulfate/g has a large adsorption capacity and good characteristics. This new adsorbent adsorbs various inorganic phosphorus species in a pH range from 4 to 7. Coexistence of various inorganic and organic anions does not disturb the adsorption of phosphate ion, but coexistence nitrate and sulfate ions disturb the adsorption slightly. Phosphate is adsorbed in the early stage by the reaction with the complex salt Al4(OH)6(SO4)3, which was formed by the reaction of aluminum sulfate and aluminum hydroxide on the surface of activated alumina, and in the delay time by the reaction with the aluminum hydroxide.