氧化石墨相氮化碳掺杂聚醚酰亚胺混合基质膜的制备及分离与抗污性能

Preparation, Separation, and Anti fouling Performance of Graphene Oxide Phase Nitrogen doped Polyetherimide Mixed Matrix Membrane

摘要:

为克服聚醚酰亚胺（PEI）超滤膜因疏水性强（水接触角>80°）易吸附污染物的劣势，解决现有改性剂改性PEI膜分散性和界面相容性差的问题，首先，以三聚氰胺为原料，采用过氧化氢一步水热法制备氧化石墨相氮化碳（OGCN），然后通过掺杂改性PEI膜制备了OGCN掺杂 PEI混合基质膜（MMM），采用FTIR、XRD、XPS、SEM、AFM和接触角测试仪对MMM的结构组成、微观形貌和水接触角进行表征和测试，考察了铸膜液中OGCN质量分数（0.3%~0.9%）对MMM纯水通量和牛血清蛋白（BSA）截留率的影响，系统探讨了其在高效分离和抗污染中的协同机制。结果表明，OGCN通过羟基与PEI酰胺基团形成氢键网络，显著提高了MMM表面的亲水性，水接触角从PEI膜的79.05°降至67.34° ~70.32°。当OGCN质量分数为0.5%时，制备的MMM膜（M2）的纯水通量为990.85 L/(m2·h)，较PEI膜提升了35% ，BSA截留率为98.47%。在不同pH（pH＝2、12）和高温（80 ℃）条件下，M2膜表现出卓越的化学和热稳定性，纯水通量波动率<5%， 并且在高温下仍能保持>93%的BSA截留率，在耐污染实验中纯水通量恢复率（FRR）达到94% 。M2膜的表面粗糙度降低至4.65 nm，结合其增强的亲水性，从而有效抑制了BSA的吸附。

Abstract:

To overcome the disadvantage of polyetherimide (PEI) ultrafiltration membranes, which are prone to adsorbing contaminants due to their strong hydrophobicity (water contact angle >80°), and to address the poor dispersibility and interfacial compatibility issues of PEI membranes modified with existing modifiers, firstly, oxidized graphite phase nitrogenized carbon (OGCN) was prepared using hydrogen peroxide via a one-step hydrothermal method using melamine as the raw material. Subsequently, OGCN-doped PEI mixed matrix membranes (MMM) were prepared by doping the modified PEI membrane. The structural composition, microstructure, and water contact angle of the MMM were characterized and tested using FTIR, XRD, XPS, SEM, AFM, and a contact angle tester. The influence of the OGCN mass fraction (0.3%–0.9%) in the casting solution on the pure water flux and bovine serum albumin (BSA) retention rate of the MMM was investigated, and the synergistic mechanism in efficient separation and anti-fouling was systematically explored. The results showed that OGCN formed a hydrogen bonding network with the amide groups of PEI through hydroxyl groups, significantly improving the hydrophilicity of the MMM surface, with the water contact angle decreasing from 79.05° for the PEI membrane to 67.34°–70.32°. When the OGCN mass fraction was 0.5%, the pure water flux of the prepared MMM membrane (M2) was 990.85 L/(m2·h), an improvement of 35% compared to the PEI membrane, and the BSA retention rate was 98.47%. Under different pH conditions (pH =2,12) and high temperatures (80°C), the M2 membrane exhibited excellent chemical and thermal stability, with a pure water flux fluctuation rate of <5%, and maintained a BSA retention rate of >93% even at high temperatures. In the anti-fouling experiment, the pure water flux recovery rate (FRR) reached 94%. The surface roughness of the M2 membrane decreased to 4.65 nm, which, combined with its enhanced hydrophilicity, effectively inhibited the adsorption of BSA.