P(N-MAAm)水凝胶吸附剂的制备及其对亚甲基蓝染料吸附性能的研究

Preparation of P(N⁃MAAm)hydrogel adsorbent and study on its adsorption performance for methylene blue dye

将N-羟甲基丙烯酰胺引入聚丙烯酸-丙烯酰胺体系,采用“一锅煮”法合成了P(N-MAAm)水凝胶。结果显示,当n(AM)∶n(AA)为1∶4、中和度为60%、交联剂用量为0.4%、n(AM)∶n(N-MA)=9.5∶0.5时,P(N-MAAm)对亚甲基蓝(MB)的实测最大吸附量可达1603.77 mg/g;降低环境温度、盐度,提高pH有利于P(N-MAAm)水凝胶吸附MB;吸附动力学曲线符合准一级动力学模型(R_(1)>0.999),吸附等温线更符合Langmuir模型(R_(L)>0.981),P(N-MAAm)水凝胶对MB的吸附过程更倾向于是物理吸附,并且可能是多分子层吸附。P(N-MAAm)水凝胶通过Langmuir模型拟合计算得到理论最大吸附量为3170.27 mg/g;具有良好的可重复利用性能,5次吸附-解吸循环后对MB的去除率仍高于95%。

By adding N⁃methylolacrylamide into polyacrylic acid⁃polyacrylamide system,P(N⁃MAAm)hydrogel is synthesized through the“one⁃pot”method.Results show that the maximum adsorption capacity of P(N⁃MAAm)hydrogel to methyl blue can reach 1603.77 mg·g^(-1)when the ratio of acrylamide to acrylic acid is 1∶4,the neutralization degree is 60%,the crosslinker dosage is 0.4%,and the ratio of acrylamide to N⁃methylolacrylamide is 9.5∶0.5.Lower environmental temperature,lower salinity,and higher pH favor the adsorption of methylene blue by P(N⁃MAAm)hydrogel.The adsorption kinetics curve conforms to the pseudo⁃first⁃order kinetic model(R_(1)>0.999),and the adsorption isotherm can be better described by Langmuir model(R_(L)>0.981).The adsorption process of methylene blue by P(N⁃MAAm)hydrogel tends to be physical adsorption,furthermore possibly multilayer adsorption.According to Langmuir model fitting,the theoretical maximum adsorption capacity of P(N⁃MAAm)hydrogel is 3170.27 mg·g^(-1).P(N⁃MAAm)hydrogel also demonstrates excellent reusability,delivering an above 95%removal rate to methylene blue after five adsorption⁃desorption cycles.