聚酰胺表面结构及其对复合膜分离性能的影响

SURFACE STRUCTURE OF POLYAMIDE LAYER AND ITS EFFECT ON COMPOSITE MEMBRANE PERFORMANCE

以杂萘联苯聚芳醚超滤膜为支撑层,通过间苯二胺(MPD)、哌嗪(PIP)与均苯三甲酰氯(TMC)的界面聚合制备复合膜.用红外光谱和X射线衍射分别分析了超薄功能层的化学结构与聚集态,用原子力显微镜观察了膜表面形貌,并用统计学方法计算了膜表面的平均粗糙度等特性参数,研究了MPD/PIP比例对膜表层化学结构、形貌和分离性能的影响.结果表明,随着二胺单体MPD/PIP比例从0/100提高到100/0,功能层聚酰胺的聚集态具有从无定形向部分结晶转变的趋势,复合膜表面平均粗糙度由17.8nm提高到71.9nm,膜对NaCl的截留率由26%提高到99%,而通量则由130L.m-2.h-1降低到12L.m-2.h-1.复合膜具有良好的稳定性,温度由25℃提高到80℃,通量提高了2倍左右,而对NaCl的截留率基本不变.

Thermal stable composite membranes were prepared through the interfacial polymerization of mphenylene diamine （ MPD ）, piperazine （PIP） and trimesoyl chloride （ TMC ） on poly （ phthalazinone ether） ultrafihration membrane. The effect of the proportion of PIP and MPD in aqueous phase on the chemical structure of the active layer polymer, surface morphology and separation properties of the composite membranes was studied. The results showed that the average roughness of the surface of the composite membranes increased from 17.8 nm to 71.9 nm, the rejection for NaCl solution increased from 26 % to 99 %, while the flux decreased from 130 L·m^-2·h^-1 to 12 L·m^-2·h^-1, as the proportion of the monomers MPD/PIP increased from 0/100 to 100/0. The flux of the membranes trebled as the operating temperature increased from 25 ℃ to 80 ℃, while the rejection kept constant, which testified the good thermal stability of the membranes.