改性化合物对聚酰胺膜材料亲水性及抗污染性能影响的分子力学计算与实验研究

Effects of modification chemical on hydrophilic and antifouling properties of polyamide membranes:molecular mechanics calculation and experimental investigation

以反渗透技术应用于海水淡化为背景,采用分子力学方法计算聚酰胺反渗透膜材料PA及3种改性化合物(PEGMA、SPM、AMPS)与水分子、典型有机污染物海藻酸AA形成各种氢键复合物的相互作用能、生成概率与平均相互作用能,以此为基础选择适宜的膜改性化合物,增加膜表面亲水性,降低海藻酸污染。分子力学计算表明,PA及3种改性化合物与水分子结合的强弱顺序为:PEGMA>PA>SPM>AMPS;它们与海藻酸AA分子结合的强弱顺序为:AMPS>PA>SPM>PEGMA。将PEGA'链接'到聚酰胺膜SW30表面,制得改性聚酰胺膜MSW30。实验表明,改性聚酰胺膜MSW30的亲水性能及抗污染性能均较原膜SW30有显著提高,实验结果与分子力学计算结果一致。

The molecular mechanics method was introduced in the context of seawater reverse osmosis desalination process to investigate the interaction between membrane materials and water or alginic acid in terms of interaction energy,probability,and mean interaction energy of the H-bond complexes,thus providing theoretical information on the selection of chemicals for membrane modification to promote hydrophilic and antifouling properties.According to molecular mechanics calculation,the order of mean interaction energy between membrane materials and water was PEGMAPASPMAMPS,and that between these materials and alginic acid was AMPSPASPMPEGMA,so PEGMA was considered as the best modification chemical among the three chemicals.Using the click chemistry method,a new modified membrane MSW30 was prepared by coating 2-bilayer PEGA onto the polyamide membrane SW30.It was confirmed by contact angle measurements and fouling experiments that the modified membrane MSW30 was more hydrophilic and showed better resistance to fouling by alginic acid than the unmodified membrane SW30,which was also in agreement with the molecular mechanics calculation.