混合单体对等离子体法改性PTFE膜微生物亲和性能的影响

膜材料氧传质性能和微生物亲和性对MABR（膜曝气生物膜反应器）的稳定运行及处理效果有重要影响，为探究混合单体对等离子体法改性PTFE（聚四氟乙烯）膜微生物亲和性能的影响，采用两步等离子体法分别在PTFE膜表面接枝聚合DOPA（左旋多巴）/GMA（甲基丙烯酸缩水甘油酯）、Lys（赖氨酸）/GMA、BA（苯胺）/GMA和DEA（乙二胺）/GMA四种混合单体，测定改性前、后PTFE膜的微生物亲和性，并进一步确定最佳混合单体改性PTFE膜的氧传质性能.结果表明:与未改性PTFE膜和仅接枝聚合GMA单体改性复合膜相比，DOPA/GMA、Lys/GMA、BA/GMA和DEA/GMA混合单体改性复合膜表面的微生物亲和性均有提高；Lys/GMA混合单体改性复合膜表面的微生物亲和性最佳，显著高于未改性PTFE膜，膜表面的生物量用ρ（DNA）和ρ（TOC）表示，分别为9.67 ng/μL和103.44 mg/L，比未改性PTFE膜高出34.7%和286.0%，同时其膜表面的生物量增加速度最快；DOPA/GMA和DEA/GMA混合单体改性膜表面的微生物亲和性相近，且高于BA/GMA混合单体改性膜；Lys/GMA混合单体改性复合膜的最大氧传质系数为1.17 m/d（操作压力为35 kPa），显著高于未改性PTFE膜的0.48 m/d（操作压力为11 kPa）.研究显示，两步等离子体法接枝聚合的混合单体改性能够同时改善PTFE膜的微生物亲和性和氧传质性能，更适合于制备MABR复合膜，可为开发MABR专用膜材料提供理论基础和技术支持. 

Effect of Mixed Monomer on Microbial Affinity of PTFE Membrane with Plasma Surface Modification

Oxygen mass transfer and microbial affinity of membrane material have a significant impact on stable operation and pollutant removal of an MABR (membrane-aerated biofilm reactor). In order to explore the effects of mixed monomers on the microbial affinity of plasma-modified PTFE (polytetrafluoroethylene) membranes, a two-step plasma modification method was used to graft and polymerize L-poly-cyclopentene on the surface of PTFE membrane. Four kinds of mixed monomers, DOPA (levodopa)/GMA (glycidyl methacrylate), Lys (lysine)/GMA, BA (aniline)/GMA, and DEA (ethylenediamine)/GMA, were used to modify the PTFE membrane surface. Microbial affinity was quantified by the increase in biomass on the membrane surface after seven days of cultivation. Biomass was expressed by ρ(DNA) and TOC. The results showed that the affinity of microbes for all the surface-modified PTFE membranes was higher than that for the unmodified PTFE membrane. The membrane modified with Lys/GMA mixed monomers showed the highest affinity:the membrane surface biomass ρ(DNA) and TOC were 9.67 ng/μL and 103.44 mg/L, respectively, which were 34.7% and 286.0% higher than those for the unmodified PTFE membrane. The maximum oxygen mass transfer coefficient of Lys/GMA-modified PTFE membrane was 1.17 m/d, which is significantly higher than 0.48 m/d of the unmodified PTFE membrane. The results indicate that the two-step plasma surface modification with mixed-monomer polymerization can significantly improve microbial affinity and the oxygen mass transfer coefficient of PTFE membrane. Thus, this paper provides a theoretical basis and technical support for developing new membrane materials for MABR.