NGO/PDA-DAG改性膜制备及抗污染性能研究

以多巴胺（DA）、1，3-二氨基胍盐酸盐（DAG）、氨基化氧化石墨烯（NGO）为改性剂，将氧化沉积和表面接枝法联用于聚偏氟乙烯（PVDF）原膜表面改性，得到NGO/PDA-DAG改性膜，研究改性膜的制备条件及其抗污染性能.结果表明：①改性膜最佳制备条件为DA浓度1.5mg/mL，DA氧化沉积时间4h，DAG质量浓度1wt%，NGO浓度2mg/mL，NGO接枝时间1h；②改性膜的亲水性能改善明显.改性剂向膜面引入了-NH₂、C=N、-OH、C=O等亲水性官能团，使静态接触角由68.7°（原膜）下降到38.7°（改性膜）；③改性膜比原膜具有更高的机械强度.改性层改善了原膜表面应力传递盲区，使改性膜表面粗糙度由原膜的46.5nm下降到18.3nm.改性膜的拉伸强度和杨氏模量分别为22.83和376.25Mpa，比原膜提高了39.72%和13.57%；④改性膜的选择透过性和抗有机污染性能显著提高.与原膜相比，改性膜对牛血清白蛋白（BSA）的截留率提高18.64%、纯水通量恢复率提高34.08%、膜总污染率下降20.67%（可逆污染率提高13.41%、不可逆污染率下降34.08%）；⑤改性膜抗菌性能强，且抗菌效果稳定持久.改性膜连续4次抗菌测试（38℃下接触2h）的平均抗菌率分别为92.3%、88.5%、87.9%、85.6%，能有效防止生物膜污染发生，而原膜无任何抗菌特性.

Study on the preparation of NGO/PDA-DAG modified membrane and its anti-fouling performance

The NGO/PDA-DAG modified membrane was prepared with PVDF membrane as the raw material, the chemicals dopamine (DA), 1,3-diaminoguanidine hydrochloride (DAG) and aminated graphene oxide (NGO) as modifiers, the oxidative deposition method combined with surface grafting way as the modification technology. The preparation conditions of the modified membrane and its anti-fouling performance were investigated. The results were shown as below:①The optimal preparation conditions of the modified membrane were DA 1.5mg/mL, oxidation deposition time of DA 4hour, DAG 1wt%, NGO 2mg/mL and grafting time of NGO 1hour;②The hydrophilicity of the modified membrane were improved significantly. The modifiers introduced hydrophilic functional groups such as -NH₂, C=N, -OH and C=O to the membrane surface, which reduced the static contact angle from 68.7° (the original membrane) to 38.7° (the modified one);③The modified membrane showed a higher mechanical strength than that of the original membrane. The modification layer improved the stress transferring dead zone on the surface of the original membrane, thus the surface roughness of the modified membrane dropped from 46.5nm to 18.3nm. The tensile strength and Young's modulus of the modified membrane were 22.83 and 376.25Mpa respectively, which were 39.72% and 13.57% higher than those of the original membrane;④The selective permeability and anti-organic fouling performance of the modified membrane were enhanced markedly. Compared with the original membrane, the modified membrane's interception rate of BSA and the pure water flux recovery rate increased by 18.64% and 34.08% separately, its total fouling rate decreased by 20.67% (where, reversible fouling rate increased by 13.41%, and irreversible fouling rate decreased by 34.08%);⑤The modified membrane has possessed strong antibacterial performance, and the antibacterial effect was stable and lasting. The antibacterial rate of the modified membrane under four consecutive antibacterial tests (contacting conditions:38℃, 2hour) was 92.3%, 88.5%, 87.9%, 85.6%, respectively, which can effectively prevent the modified membrane from biofilm fouling, and the original membrane did not have any antibacterial properties.