5种改性淀粉吸附Cu2+性能及动力学研究

摘要

具有一定功能基团的改性淀粉可提高对重金属离子的吸附能力,分别以阳离子淀粉、磷酸酯淀粉、磷酸酯双淀粉、氧化淀粉和尿素淀粉5种改性淀粉为吸附剂,以紫外分光光度法测量吸附后的Cu2+质量浓度,考察了改性淀粉对Cu2+的吸附动力学,并对比了不同改性淀粉的吸附效果.结果表明,在改性淀粉用量为0.1 g、铜离子初始浓度为2 g/L、溶液体积为100 mL的条件下饱和吸附,其中磷酸酯淀粉吸附量最大,达50.7 mg/g.吸附动力学研究表明5种改性淀粉的吸附等温数据均符合Freundlich模型.阳离子淀粉吸附数据符合准二级动力学模型,其余4种改性淀粉吸附数据更符合准一级动力学模型.%Modified starch with specific functional groups can increase the adsorption capacity of heavy metal ions.Cationic starch, phosphate starch, distarch phosphate, oxidized starch and urea starch were used as adsorbent respectively, and the ultraviolet spectrophotometry was used to measure the concentration of Cu2+.What's more, the adsorption effect and kinetics of above modified starches on Cu2+ were investigated.The results show that phosphate starch has the maximum saturated adsorption of Cu2+ in the five kinds of starches, which can reach 50.7 mg/g under the conditions when the dosage of modified starch was 0.1 g, the initial concentration of Cu2+ was 2 g/L and the volume of solution was 100 mL.Adsorption kinetic studies showed that the adsorption isotherm data of these modified starches match with the Freundlich isotherm model.The data of cationic starch is in accord with pseudo-second order kinetic model, and the others' adsorption data more coincide with pseudo-first order kinetic model.