Electrospun polyphenylquinoxaline fibrous membrane: a versatile filtering medium for separation of highly alkaline aqueo
- PDF / 1,379,354 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 29 Downloads / 179 Views
ORIGINAL PAPER
Electrospun polyphenylquinoxaline fibrous membrane: a versatile filtering medium for separation of highly alkaline aqueous red mud pollutant Lu‑meng Yin1 · Chen‑yu Guo1 · Lin Qi1 · Xin‑ke Wang1 · Na Zhang1 · Lin Wu1 · Jin‑gang Liu1 Received: 21 May 2020 / Accepted: 3 September 2020 / Published online: 2 October 2020 © The Polymer Society, Taipei 2020
Abstract 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. Keywords Electrospinning · Polyphenylquinoxaline · red mud · filtration · membrane · alkalinity
Introduction Red mud (RM) represents a class of hazardous by-products produced in the process of alumina smelting, either by the conventional sintering process or by the widely used Bayer’s procedure [1]. With the decreasing contents of worldwide bauxite ores for the alumina smelting, the produced amount of RM by-products by smelting alumina can reach two tons or even more when producing one ton of fine alumina [2–4]. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10965-020-02281-4) contains supplementary material, which is available to authorized users. * Jin‑gang Liu [email protected] 1
Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
As a result, the produced RM has increased year by year and billions of tons of RM have been stored in the world [5]. RM is usually composed of a mixture of metal oxides and hydroxides, including F e2O3, TiO2,
Data Loading...
