壳聚糖-生物炭复合材料对U(Ⅵ)的吸附性能试验研究

以壳聚糖（CTS）和生物炭（AC）为原料，采用原位沉淀法制备了壳聚糖-生物炭（CTS-AC）复合材料，研究了吸附时间、铀初始浓度、初始pH值、温度和干扰离子等因素对CTS-AC吸附U(Ⅵ)的影响，探讨了CTS-AC对U(Ⅵ)的吸附动力学、等温线，采用傅里叶红外光谱（FT-IR）、X射线衍射（XRD）、扫描电镜（SEM-EDS）及比表面积分析（BET）等手段进行了相关机理分析。实验结果表明，CTS-AC吸附U(Ⅵ)的最佳条件为：pH=4、CTS-AC投加量0.8～1 g/L、吸附时间240 min，在此条件下，最大吸附率可达94.85%。CTS-AC对U(Ⅵ)的吸附等温线模型符合Langmuir模型，U(Ⅵ)的吸附动力学符合准二级模型；高浓度Cu²⁺对CTS-AC吸附U(Ⅵ)的抑制作用明显；FT-IR、XRD和EDS结果表明，CTS的负载未改变AC的原结构，仅增大了其孔径、增加了结合位点。CTS-AC对U(Ⅵ)的吸附机制为配位作用以及离子交换。

Experimental Investigation on Adsorption of U(Ⅵ) by Chitosan-biochar Composite

Chitosan-biochar (CTS-AC) composites were prepared by using chitosan (CTS) and biochar (AC) as raw materials. The effect of initial U(Ⅵ) concentration, reaction time, initial pH, reaction temperature and interference ion on the adsorption of U(Ⅵ) by CTS-AC was investigated, and the adsorption behavior of U(Ⅵ) by CTS-AC was characterized by FT-IR, XRD, SEM-EDS and specific surface area analysis (BET). The results show that the optimum conditions for the adsorption of U(Ⅵ) by CTS-AC are pH=4, dosage of CTS-AC 0.8-1 g/L and adsorption time 240 min. Under these conditions, the maximum adsorption rate can reach 94.85%. The isothermal thermodynamic data of the adsorption of U(Ⅵ) by CTS-AC accord with the Langmuir model, and the adsorption kinetics is in accordance with the quasi-second-order kinetic model. The inhibiting effect of high concentration of Cu²⁺ on the adsorption of U(Ⅵ) by CTS-AC is obvious. The results of FT-IR, XRD and EDS show that adding CTS dose not change the original structure of AC, but the pore size and the binding sites increase. The adsorption mechanisms are coordination and ion exchange.