稀土学报(英文版)
稀土學報(英文版)
희토학보(영문판)
JOURNAL OF RARE EARTHS
2014年
5期
458-466
,共9页
张艺%徐莹%崔昊%刘炳杰%高翔%汪东风%梁鹏
張藝%徐瑩%崔昊%劉炳傑%高翔%汪東風%樑鵬
장예%서형%최호%류병걸%고상%왕동풍%량붕
La(III)%bentonite%chitosan beads%defluoridation%adsorption%fluoride%rare earths
Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad-sorbent, La(III)-loaded bentonite/chitosan beads (La-BCB) was prepared for defluoridation from aqueous solution. The effects of various parameters such as dosage of La(III), pH, temperature, contact time, initial fluoride concentration and presence of co-existing anions were investigated to examine the defluoridation behavior. The maximum defluoridation capacity of La-BCB was 2.87 mg/g at pH 5, 30 °C. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and Fourier transform infrared spectros-copy (FTIR) were employed to analyze the characteristics of La-BCB. The equilibrium fluoride adsorption data fitted well with both Langmuir and Freundlich isotherm models. TheRL value revealed that the defluoridation process using La-BCB was favorable. The adsorption kinetics followed pseudo-second order kinetic as well as particle and intraparticle diffusion models. The presence of car-bonate and bicarbonate reduced defluoridation capacity of La-BCB while sulphate, nitrate and chloride showed slight effect. The ex-hausted La-BCB was regenerated using sodium hydroxide with only 17% loss. The reasonable defluoridation mechanism could be interpreted as adsorption and ion exchange.