Ca-Al-Cl型层状双金属氢氧化物用于强碱性溶液中六价硒的去除（英文）

Selenium(Ⅵ) removal from caustic solution by synthetic Ca-Al-Cl layered double hydroxides

为提取铜阳极泥强碱性浸出液中的六价硒,通过三种共沉淀方法得到分子式为Ca2Al(OH)6Cl·2H2O的Ca-Al-Cl层状双氢氧化物(Ca-Al-Cl-LDHs)。综合FESEM、XRD、FTIR、BET和XPS分析发现,所得Ca-Al-Cl层状双氢氧化物具有片状形态、六方晶体结构以及典型矿物相和官能团。其中,正向进料方式得到的样品具有最佳的硒吸附能力。因素实验表明:低温、低氢氧化钠浓度和高吸附剂用量有利于六价硒的吸附。通过对吸附所得数据进行热力学及动力学拟合,发现吸附过程符合Langmuir吸附模型及准二级动力学模型。在50℃时,Ca-Al-Cl-LDHs对六价硒的最大吸附量达到188.6 mg/g。

To extract selenium(Ⅵ)from the highly caustic leachate of copper anode slime,the Ca-Al-Cl layered double hydroxides(Ca-Al-Cl-LDHs)with a formula of Ca2 Al(OH)6 Cl·2 H2 O by three co-precipitation methods were synthesized.A plate-like morphology and hexagonal crystal structure with typical mineral phases and functional groups were identified by the FESEM,XRD,FTIR,BET and XPS analysis.The forward feeding sample exhibits the best adsorption capacity of Se(Ⅵ).The factor experiments then reveal a favorable adsorption process with low temperature,low NaOH concentration and high adsorbent dosage.Furthermore,the adsorption kinetics and isotherm parameters can be well described by the Langmuir isotherm and the pseudo-second-order models,respectively.Accordingly,the maximum adsorption amount of Se(Ⅵ)onto Ca-Al-Cl-LDHs reaches188.6 mg/g at 50 ℃.