基于天然生物材料制备可降解水凝胶去除水中Cu(Ⅱ)和Cr(Ⅵ)研究

Preparation of degradable hydrogel based on natural biological materials for the removal of Cu(Ⅱ) and Cr(Ⅵ) from water

以腐植酸钾(KHA)、壳聚糖(CTS)、蒙脱土(MMT)为原料合成了一种KHA/CTS/AA-MMT水凝胶材料,用于去除重金属Cu(Ⅱ)和Cr(Ⅵ)。采用SEM、FT-IR、XPS对水凝胶材料结构进行表征,证实水凝胶的空间网络结构。对水凝胶材料的吸水倍率,以及在不同pH条件进行测试,发现在弱酸性至碱性吸水溶胀性能优良,溶胀率可达80g/g。研究结果表明,在298K时,水凝胶材料对Cu(Ⅱ)和Cr(Ⅵ)的吸附量分别可达249.45和212.81mg/g;通过热力学分析可知,水凝胶对Cu(Ⅱ)、Cr(Ⅵ)的吸附是放热过程,主要是化学吸附且为自发过程。通过XPS与吸附过程理论拟合得知,吸附Cu(Ⅱ)、Cr(Ⅵ)主要是羰基的螯合与氨基的配位作用,该材料在重金属去除方面具有广阔的应用前景。

A KHA/CTS/AA-MMT hydrogel material was synthesized using potassium humate(KHA),chitosan(CTS)and montmorillonite(MMT)as raw materials for the removal of heavy metals Cu(Ⅱ)and Cr(Ⅵ).SEM,FT-IR,and XPS were used to characterize the structure of the hydrogel material,and the spatial network structure of the hydrogel was confirmed.The water absorption rate of the hydrogel material was tested under different pH conditions,and it was found that it had excellent water absorption and swelling performance from weak acidic to alkaline conditions,with a swelling rate of up to 80g/g.The research results showed that:at 298K,the adsorption capacity could reach 249.45mg/g and 212.81mg/g,respectively.The thermodynamic analysis showed that the adsorption of Cu(Ⅱ)and Cr(Ⅵ)by hydrogel was an exothermic process,mainly chemical adsorption and spontaneous process.According to XPS analysis and theoretical fitting of the adsorption process,the adsorption of Cu(Ⅱ)and Cr(Ⅵ)was mainly achieved by the coordination of the carbonyl group and the amino group.This material has broad application prospects in the removal of heavy metals.