YU Rongtai 1, FENG Jie 2, MA Xiang 1, LU Huang 1, WAN Yawei 1, XIE Zhipeng 3, WANG Changan 3
(1. School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China; 2. China Kaolin Clay Company, Suzhou 215006, Jiangsu, China; 3. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China)
Abstract: Phosphate adsorption removal by alkaline dry/wet modification and ammonium removal by thermal modification were investigated. The effects of modification methods, pH and dosage on the removal rate of phosphate/ammonium by modified attapulgite were studied, and the mechanism of attapulgite adsorption of phosphate and ammonium was discussed. The results showed that, the removal rate of ammonium by thermal modification of attapulgite was 57% at 500 °C for 2 h; the removal rate of phosphate by dry modification was about 92% at the mole ratio of NaOH:attapulgite of 1:1; the best pH was 4 for phosphate adsorption, and the removal rate of phosphate was about 92%; when the dosage was 1.0 g/100 ml and 0.5 g/100 ml, the ammonium removal and phosphate adsorption ratio were above 58% and 83%,respectively. The results of FTIR and XRD showed that, the crystal structure of attapulgite was damaged by alkaline modification, while the adsorbed water by mineral, zeolite-water and interlayer water of attapulgite were stripped by thermal modification.
Key words: thermal modification; alkaline dry/wet modification; ammonium; phosphate; attapulgite