La(Ⅲ)-loaded bentonite/chitosan beads for defluoridation from aqueous solution  

作　　者：张艺 徐莹 崔昊 刘炳杰 高翔 汪东风 梁鹏 

机构地区：[1]College of Food Science and Engineering,Ocean University of China [2]Ocean and Fishery Bureau of Lianyungang City [3]College of Food Science and Technology,Fujian Agriculture and Forestry University

出　　处：《Journal of Rare Earths》2014年第5期458-466,共9页稀土学报（英文版）

基　　金：Project supported by National Special Fund for Scientific Research on Public Causes(201005020);China Postdoctoral Science Foundation(2013M531652);National Natural Science Foundation of China(31302162)

摘　　要：Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La（IlI）-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 ℃. 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. The RL 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.Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La（IlI）-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 ℃. 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. The RL 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.

关 键 词：La（III） BENTONITE chitosan beads DEFLUORIDATION adsorption FLUORIDE rare earths 

分 类 号：TQ085.4[化学工程]