无机添加剂对磺化杂环共聚醚砜复合膜性能的影响

Effect of Inorganic Additives on the Performance of Sulfonated Heterocyclic Copoly(ether sulfone) Composite Membranes

以磺化联苯型杂萘联苯共聚醚砜(SPPBES)为涂层材料,分别加入LiCl、NaCl、KCl作为无机添加剂配制浸涂稀溶液,在联苯型杂萘联苯共聚醚砜(PPBES)超滤底膜上,采用涂覆方法制备磺化杂萘联苯共聚醚砜复合纳滤膜(SPPBES-LiCl、SPPBESNaCl和SPPBES-KCl)。考察了无机添加剂对复合膜的分离性能的影响,复合膜对不同无机盐的脱盐率顺序均为Na_2SO_4>NaCl>Mg SO_4>MgCl_2,表现出荷负电纳滤膜的分离特征,以LiCl为添加剂所制备的SPPBES-LiCl复合纳滤膜的脱盐率最高,通量最小。研究了复合膜的耐热性能和耐氧化性能,当操作温度从20℃升至95℃时,SPPBES-LiCl复合膜的通量由46 L·m^(-2)·h^(-1)增加到130 L·m^(-2)·h^(-1),而脱除率下降约3%,相比于SPPBES-NaCl和SPPBES-KCl,SPPBES-LiCl复合膜分离性能随操作温度升高变化最小。在0.2 g·L^(-1)的NaCl O溶液中浸泡8 d,SPPBES-LiCl复合膜通量增大2%左右,而SPPBES-NaCl与SPPBES-KCl的通量增幅小于8%;相比于SPPBES-NaCl和SPPBES-KCl膜,SPPBES-LiCl复合膜具有更好的耐氧化稳定性。此外,3种磺化杂萘联苯共聚醚砜复合纳滤膜均表现出了较好的耐酸碱稳定性。

Sulfonated copoly （phthalazinone biphenyl ether sulfone ） （SPPBES） coating solutions were prepared with SPPBES as material and LiCl, NaCl as well as KCl as inorganic salt additives. SPPBES composite nanofiltration membranes were prepared with copoly（phthalazinonc biphenyl ether sulfone）（PPBES） as ultrafiltration support membranes via dip coating method. The composite nanofiltration membranes prepared with LiCl, NaCl and KCl as inorganic salt additives were named as SPPBES-LiCl, SPPBES-NaCl and SPPBES-KCl, respectively. The effect of inorganic salt additives on the performance of composite nanofihration membrane was studied. The composite nanofiltration membranes showed the rejection of inorganic salt in the order of Na2SO4 〉 NaCl 〉 MgSO4 〉 MgCl2, exhibiting the characteristic of negatively charged nanofiltration membranes. SPPBES-LiCl composite membrane showed highest salt removing rate while SPPBES-KCl composite membrane exhibited highest flux among the three membranes. The thermal stability, oxidative stability and chemical stability of composite membranes were investigated in detail. When the operating temperature increased from 20 to 95 ℃ , the flux of SPPBES-LiCl membrane increased from 46 to 130 L·m^-2·h^-1 while the salt removing rate decreased by 3%. Compared to SPPBES-NaCl and SPPBES-KCl membrane, SPPBES-LiCI membrane showed the least change on membrane performance with the increasing temperature. After composite membranes were immersed into 0. 2 g · L^- 1 NaClO solution for 8 days, the flux of SPPBES- LiCl composite membrane increased by 2% while the flux of SPPBES-NaCl membrane and SPPBES-KCl membrane increased about 8%. Besides, SPPBES-LiCl composite nanofiltration membrane showed better oxidative stability than SPPBES-NaCl membrane and SPPBES-KCl membrane. It was found that SPPBES composite membranes showed good high temperature resistance, excellent chemical stability and oxidation resistance.