聚酰胺表面结构及其对复合膜分离性能的影响

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.

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

Thermal stable composite membranes were prepared through the interfacia l polymerization of m-phenylene diamine (MPD),piperazine (PIP) and trimesoy l ch loride (TMC) on poly(phthalazinone ether) ultrafiltration membrane.The effect o f the proportion of PIP and MPD in aqueous phase on the chemical structure of th e active layer polymer,surface morphology and separation properties of the comp osite membranes was studied.The results showed that the average roughness of th e surface of the composite membranes increased from 17.8 nm to 71.9 nm,the re je ction 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 proportio n of the monomers MPD/PIP in creased 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,whic h testified the good thermal stability of the membranes.