Yaxu Guan,Shao-Lu Li,Zhenxing Fu,Yiwen Qin,Juntao Wang,Genghao Gong,Yunxia Hu
In this work, we synthesized a zwitterionic polymer PEI-CA for the first time and then grafted it onto the surface of polyamide RO membrane via layer-by-layer interfacial polymerization (LbL-IP). XPS and ATR-FTIR techniques were used to verify the successful modification with PEI-CA. The zwitterionic hyperbranched polymer PEI-CA endowed the modified membrane with much improved surface hydrophilicity and decreased surface negative charge. The tailored M-PEICA exhibited a high water permeance up to 3.92 L m −2 h −1 bar −1 (increased by 62 %) while holding a good NaCl rejection (98.93 %). The dynamic fouling experiments proved that grafting of PEI-CA can help to effectively elevate its antifouling performance against most organic foulants except small molecular negatively charged surfactant SDS. Therefore, we further employed the mixed reagents modification strategy with arginine and PEI-CA, the resulting RO membrane M-mixed presented obviously improved antifouling performance towards SDS, the overall antifouling performances are even better than the well-known RO membrane CR100 of DOW FILMTEC™, that well illustrated multiple reagents modification strategy could be an efficient way that can meet all critical standards. Overall, the novel polymer PEI-CA and as-fabricated RO membranes with outstanding antifouling performances in this study have vast application potential in field of water treatment .
Shao-Lu Li,Yaxu Guan,Yiwen Qin,Youcai Chen,Dandan Cheng,Genghao Gong,Yunxia Hu
In this study, a novel antifouling loose nanofiltration (LNF) membrane was prepared by the cross-linking and grafting of hydrolyzed polyacrylonitrile ultrafiltration (HPAN UF) substrate with a polyethylenimine (PEI) based zwitterionic polymer PEI-CA through the covalent amide bond. The successful introduction of PEI-CA was verified by various techniques. The tailored membrane HPAN-PEICA exhibited ultra-high water permeance (73.5 L m −2 h −1 bar −1 ) and meanwhile maintained excellent rejection (~99.9 %) for dye Brilliant Blue R (BBR), Methyl Blue (MB), Congo red (CR) and Chrome Black T (CBT). In addition, it exhibited ultralow rejection (below ~6 %) towards the inorganic salts (NaCl, Na 2 SO 4 , MgCl 2 and MgSO 4 ), with excellent dye/salt selectivity of ~65. The as-fabricated membrane HPAN-PEICA was proved having good long-term operation stability and pressure resistance properties. Dynamic fouling experiments confirmed that the membrane HPAN-PEICA presented excellent antifouling performance towards four typical model foulants (LYZ, SA , HA and BSA). Over all, we believed that the tailored LNF membrane HPAN-PEICA having great application prospects in textile effluent treatment.
The yield stress and zeta potential of washed spherical α-Al2O3 suspensions with two to four layers of critic acid(CA) and polyethyleneimine(PEI_Mw1.8and 70 kDa) adsorbed sequentially were characterized. With CA adsorbed as the first layer, pHξ=0 was shifted to a lower pH and the maximum yield stress (τymax) was reduced. With PEI adsorbed as the first layer, the pHξ=0 was moved slightly higher. With the introduction of the second layer, the CA/PEI additive was formed which functioned as a bridging agent. The pH range of yield stress was broadened significantly and increased with the number of layers. This pH ranged from 2.5 to 11. The CA/PEI multilayer additive loses its positive charge at pH >11. There was less adsorption in layer3 and layer4 when lower Mw PEI is applied to the suspension. The CA/PEI multilayer additive formed by PEI of Mw70000 and CA was larger in size than that formed by PEI of Mw 1800 and CA. Lower Mw PEI produced a stronger flocculated network or higher τymax suspension due to a higher concentration of multilayer additive. CA/PEI multilayer additive was participating in bridging and particle bridging interaction was not affected by the adsorption order of CA and PEI.GRAPHICAL
危险品化学品经营许可证（带存储）