羧乙基壳聚糖蒙脱石吸附养殖水体中Cu^2+的应用

Adsorption of Cu^2+ in aquaculture water using carboxyethyl chitosan(CEC)/montmorillonite adsorbent

为了寻求性能良好、环保吸附剂,用于去除养殖水体中重金属Cu^2+,作者利用蒙脱石负载羧乙基壳聚糖制备成复合吸附剂,并利用IR、SEM、XRD等手段分析其表面性能,将其用于处理Cu^2+溶液,考察了环境因子对其吸附性能的影响,并从吸附动力学和吸附热力学角度分析吸附剂对Cu^2+的吸附机理,最后考察其再生利用效果。结果表明:羧乙基壳聚糖成功进入到蒙脱石层间;在羧乙基壳聚糖与蒙脱石质量比为1︰25、40℃恒温水浴搅拌60min、pH=6.0、最佳投加量为4.0g/L、处理浓度不超过30 mg/L Cu^2+溶液时,复合吸附剂对Cu^2+去除率可以达到96.23%,将其用于淡水养殖鱼塘水体中, Cu^2+去除后可达到《渔业水质标准》规定;吸附剂对Cu^2+吸附热力学实验结果表明,符合Langmuir模型,反应过程为自发、吸热反应;吸附动力学结果表明该吸附符合准二级动力学方程,反应属于化学吸附;再生实验中NaOH的再生效果优于HCl。

A carboxyethyl chitosan(CEC)/montmorillonite composite adsorbent was synthesized with CEC and montmorillonite, and its surface structure was analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The adsorption-affecting conditions of Cu^2+ treatment from the aqueous solution to the composite were investigated. The adsorption course of the adsorbents was investigated on the basis of the adsorption kinetics and thermodynamics. Finally, the effect of regeneration was investigated. Results showed that CEC was successfully coated onto montmorillonite. The adsorption efficiency of Cu^2+ reached 96.23% under the following conditions: CEC-to-montmorillonite mass ratio of 1︰25, pH of 6, temperature of 40℃, time of 60 min, adsorbent dosage of 4.0 g/L, and initial Cu^2+ concentration of 30 mg/L. The adsorption kinetics and isotherm of Cu^2+ on the composite followed the pseudo-second-order and Langmuir models, respectively. The thermodynamic and kinetic parameter studies indicated that adsorption was a spontaneous, endothermic, and chemical process. The regeneration effect of NaOH was better than that of HCl.