以半纤维素(木聚糖)为原料,以丙烯酸(AA)、N-异丙基丙烯酰胺(NIPAm)单体,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,在光引发剂安息香二甲醚(DMPA)紫外引发下,通过接枝聚合,制备水凝胶吸附剂,利用红外光谱(FT-IR)、扫描电镜(SEM)分析水凝胶和水凝胶吸附金属离子前后的结构,并研究pH、金属离子初始浓度、吸附时间对Cd²⁺、Zn²⁺吸附性能的影响。结果表明:吸附平衡时间约为240min,对Cd²⁺和Zn²⁺的最大吸附量分别为520mg/g和337mg/g。水凝胶对金属离子的吸附为离子交换机制,吸附行为符合动力学准二级模型和Langmuir方程,半纤维素基水凝胶对重金属废水具有显著的吸附效果,可作为重金属废水处理用的生物质吸附剂。

biomass hydrogel was prepared as bioadsorbent by the crosslinking copolymerization of hemicellulose(xylan) with acrylic acid(AA) and N-isopropylacrylamide (NIPAm) using N,N′-methylenebis-acrylamide (MBA) as crosslinker and 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photoinitiator through UV irradiation.The chemical microstructure,interaction between the hydrogel and the metal ions,and porous structure of the hemicellulose hydrogel were determined by FTIR and SEM.The effects of pH value,the initial concentration of the metal ions,and contacting time on adsorption capacities were studied.The results shown that the adsorption equilibrium time was about 240 min from the adsorption kinetics study,the maximum adsorption capacity of Cd²⁺ and Zn²⁺ were 520mg/g and 337mg/g,respectively.The adsorption process was an ionexchange mechanism.The equilibrium data were well fitted to the Langmuir isotherm.The kinetic data were found to be well represented by the pseudo-second-order kinetic model.The hemicellulose-based hydrogel adsorption had good adsorption performance for the Cd²⁺ and Zn²⁺,and can be used as biomass adsorbent to treat the heavy metal ions in wastewater.