Electrospun polyphenylquinoxaline (PPQ) ultrafine non-woven fibrous membrane (UFM) has been successfully used as the filtering medium for the separation of highly alkaline aqueous red mud (RM) slurry (pH = 13.0 at 21.5 °C), known as the industrial waste during production of alumina. For this purpose, the PPQ solution was prepared by dissolving the PPQ resin derived from 1,4-bis(4-benzilyloxy)benzene (DBOB) and 3,3′,4,4′-tetraaminodiphenylether (TADPE) in N-methyl-2-pyrrolidone (NMP) at a solid content of 8 wt%. Then, the PPQ UFM was fabricated by a one-step ES procedure. For comparison, the polyimide (PI) UFM, poly(pyromellitic dianhydride-co-4,4′-oxydianiline) (PMDA-ODA, PI-ref) was made by a two-step ES procedure. The obtained flexible and tough PPQ UFM was used as the filter for the separation of highly alkaline aqueous RM slurry. During the separation process, the PPQ UFM exhibited excellent stability in the aqueous alkaline environments of RM slurry either at room temperature (pH = 13.0 at 21.5 °C) or at higher processing temperature (pH = 12.1 at 60.5 °C). RM powder was efficiently separated from the slurry via the PPQ UFM and easily stripped from the membrane. Water contact angle (WCA) measurements revealed the hydrophobic nature of the PPQ UFM (WCA = 113.4° for pure water and WCA = 128.4° for aqueous sodium hydroxide solution at a solid content of 20 wt%). Comparatively, PI-ref (PMDA-ODA) UFM exhibited poor stability in the high-temperature alkaline environment.

电纺聚苯基喹喔啉（PPQ）超细非织造纤维膜（UFM）已成功用作过滤介质，用于分离高碱性含水赤泥（RM）浆料（在21.5°C下pH = 13.0），被称为工业废料在氧化铝生产过程中。为此，通过将衍生自1,4-双（4-苯甲酰氧基）苯（DBOB）和3,3'，4,4'-四氨基二苯醚（TADPE）的PPQ树脂溶解在N-甲基-固含量为8 wt％的2-吡咯烷酮（NMP）。然后，通过单步ES程序制造PPQ UFM。为了进行比较，聚酰亚胺（PI）UFM，聚（均苯四dianhydride-共通过两步ES方法制得-4，4′-氧二苯胺（PMDA-ODA，PI-ref）。将获得的柔韧性强的PPQ UFM用作分离高碱性RM水性浆液的过滤器。在分离过程中，PPQ UFM在室温下（在21.5°C下，pH = 13.0）或在更高的处理温度下（在60.5°C下，pH = 12.1）在RM浆料的碱性水溶液中均表现出出色的稳定性。RM粉末通过PPQ UFM有效地从浆液中分离出来，并且很容易从膜上剥离。水接触角（WCA）测量揭示了PPQ UFM的疏水性（固体含量为20 wt％时，纯水的WCA = 113.4°，氢氧化钠水溶液的WCA = 128.4°）。相比之下，PI-ref（PMDA-ODA）UFM在高温碱性环境下显示出较差的稳定性。