壳聚糖/改性平菇复合吸附剂对Cr(VI)的吸附特性

以壳聚糖和经酒石酸改性的平菇粉末为材料，通过戊二醛进行交联反应，制得壳聚糖-改性平菇凝胶小球（CMPOD）复合生物吸附剂，用于水溶液中Cr（VI）的吸附去除.结果表明，在实验所测pH值（2~10）范围内，复合吸附剂对Cr（VI）的吸附量随着pH值上升而降低；随着Cr（VI）初始浓度或温度的提高，吸附剂对Cr（VI）的吸附量均相应增加，当Cr（VI）初始浓度为600mg/L，温度为50℃，Cr（VI）吸附量可达190mg/g以上；Cr（VI）的吸附符合准二级动力学方程及Freundlich等温吸附模型；热力学分析表明，吸附剂对Cr（VI）的吸附过程为自发的吸热反应.扫描电镜（SEM）分析显示，吸附剂具有发达的网状结构，吸附Cr（VI）后网状孔隙被填充，且能谱分析（EDS）出现明显的Cr（VI）吸收峰；傅立叶红外光谱分析（FTIR）表明，壳聚糖中的氨基成功引入复合吸附剂中，在Cr（VI）吸附中为主要作用官能团.

Characteristics of Cr(VI) removal by cross-linked chitosan/tartaric acid modified Pleurotus ostreatus composite adsorbent

Chitosan-Pleurotus ostreatus composite adsorbent (CMPOD) was prepared by using chitosan and tartaric acid modified Pleurotus ostreatus, and applied for Cr(VI) removal from solutions. The results showed that Cr(VI) adsorption capacity decreased with the increase of pH value in the pH range of 2~10. Cr(VI) adsorption capacity increased with the increase of initial Cr(VI) concentration and temperature. The adsorption capacity reached over 190mg/g for 600mg/L Cr(VI) at 50℃. The adsorption process followed the pseudo-second-order kinetic model and Freundlich isotherm. Thermodynamic analysis showed that the adsorption process was spontaneous and endothermic. An abundant web structure was observed in the adsorbent by SEM. The pores in the web structure were filled and Cr(VI) peak appeared in EDS spectra after Cr(VI) adsorption. FTIR spectra demonstrated that amino group in chitosan was introduced into the adsorbent and was the dominant group for Cr(VI) adsorption.