氧化剂高碘酸钠诱发多巴胺自聚合在MBfR膜表面改性中的应用

Sodium periodate oxidant-induced dopamine polymerization for membrane surface modification in a membrane biofilm reactor (MBfR)

针对膜生物膜反应器(Membrane Biofilm Reactor,MBfR)研究中疏水性微孔膜氧传质性能不佳等问题,采用自聚合法(多巴胺为单体)对自制疏水性聚偏氟乙烯(PVDF)中空纤维膜进行表面改性,并选用高碘酸钠(Sodium Periodate,SP)为氧化剂,研究氧化剂SP投加对于多巴胺自聚合过程、改性膜性能及稳定性的影响.研究结果表明,与未投加SP相比,投加SP能够通过加速多巴胺的自聚合及聚多巴胺在膜表面的沉积,大大缩短多巴胺表面改性时间(自24h降至6h),同时获得适用于MBfR技术的机械性能、亲水性能、氧传质性能良好的多巴胺改性膜,改性膜接触角自原膜76.5°降低至33.4°,氧总转移系数自原膜0.78×10^(-2) min^(-1)提高为1.58×10^(-2) min^(-1)(原膜的2.03倍).此外SP的投加还可以提高改性膜在极性溶液、强酸、强碱中的稳定性,投加SP改性膜在丙酮、0.1mol/L HCl及0.1mol/L NaOH中的稳定性较未投加SP改性膜分别提高了96.5%,85.1%与48.8%.

In an effort to overcome the shortcomings of hydrophobic poly（vinylidene fluoride）（PVDF）hollow fiber microporous membranes-such as insufficient oxygen supply capacity and poor antifouling properties-a surface-modified composite membrane has been prepared using a self-made hydrophobic PVDF hollow fiber membrane and self-polymerization of dopamine.Sodium periodate（SP）was selected as an oxidant and its influence on dopamine polymerization,and the performance and stability of the resulting modified composite membrane were investigated.The results showed that the addition of SP could significantly shorten the time needed for dopamine surface modification（from 24 h to 6 h）by accelerating the polymerization of dopamine and the deposition of polydopamine on the membrane surface.The modified membrane prepared with SP addition showed good mechanical properties,hydrophilicity and oxygen mass transfer performance for applicationin a membrane biofilm reactor（MBfR）.After addition of SP,the surface hydrophilicity of the resulting modified membrane was enhanced（the contact angle decreased from 76.5°to 33.4°）,and its oxygen transfer coefficient improved by a factor of two,from 0.78×10^（-2） min^（-1） to 1.58×10^（-2） min^（-1）.Furthermore,the addition of SP could improve the stability of the resulting modified membrane in polar solvents,and in acid and alkali media;compared with the modified membrane prepared without SP addition,the stabilities of the modified membrane prepared with SP increased by 96.5%,85.1% and 48.8% in acetone,0.1 mol/L HCl and 0.1 mol/L NaOH respectively.