Removal of vanadate anion by calcined Mg/Al-CO_3 layered double hydroxide in aqueous solution  

煅烧烧型Mg/Al-CO_3双金属氧化物对水溶液中钒酸根离子的脱除(英文)

作　　者：宋海磊 焦飞鹏[1] 蒋新宇[1] 于金刚[1] 陈晓青[1] 杜邵龙[1] 

机构地区：[1]中南大学化学化工学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2013年第11期3337-3345,共9页中国有色金属学报（英文版）

基　　金：Projects(21176263,21175155)supported by the National Natural Science Foundation of China

摘　　要：Mg/Al-CO3 layered double hydroxide （LDH2） with Mg（II）：Al（III） molar ratio of 2：1 was synthesized by co-precipitation method and its calcined product Mg2Al-CLDH（CLDH2） was prepared by heating Mg2Al-LDH at 773 K for 6 h. Removal of vanadate anion （ 3-4VO ） from aqueous solution on CLDH2 was studied. Batch studies were carried out to address various experimental parameters such as Mg/Al molar ratio, adsorbent dosage, initial concentration of solution, contact time and temperature. Vanadate was removed effectively at the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-first-order model. Isotherms for adsorption vanadate by CLDH2 at different solution temperatures were well described using the Langmuir and Freundlich equations, and the isotherm parameters were calculated using linear regression analysis. The adsorption data fitted the langmuir model with good values of the correlation coefficient （R2〉0.999）. The negative value ofΔGΘand the positive value ofΔHΘindicate that the adsorption processes are spontaneous endothermic in nature. The mechanism of adsorption suggests that the surface adsorption is the main process.采用共沉淀法合成Mg/Al摩尔比为2:1的层状双金属氢氧化物Mg/Al-LDH,并在500℃下煅烧6 h得到煅烧双金属氢氧化物Mg/Al-CLDH。研究Mg/Al-CLDH对钒酸根的吸附性能,探讨镁铝摩尔比、吸附剂用量、溶液初始浓度、时间和温度等因素对吸附效果的影响,并对其吸附过程的动力学和热力学过程进行研究。研究表明:Mg/Al-CLDH对钒酸根的吸附效果很好。该吸附过程符合准一级动力学方程,平衡吸附等温线很好地符合Langmuir方程,并且Langmuir方程拟合常数高达0.999。通过热力学计算发现ΔGΘ为负值,ΔHΘ为正值,表明此吸附本质上是吸热自发过程。吸附机理研究表明此吸附主要是表面吸附。

关 键 词：layered double hydroxide VANADATE adsorption KINETICS THERMODYNAMICS 

分 类 号：X703[环境科学与工程—环境工程]