In this study, novel polymers of intrinsic microporosity (PIMs)-based hollow fiber structured packings were prepared by a facile pour-coating method and successfully applied as structured packings for isopropanol (IPA)/water distillation. The design of an ultrathin PIM-1 layer on the inner surface of hollow fibers effectively protected the membrane from mechanical damage, especially when assembled into the module. Based on the material properties and specific polymer chain structures, the hydrophobic PIM-1 layer made composite membranes to not only have a strong affinity for alcohols and moisture resistance but also possess a large surface area and excellent stability, which effectively decreased the membrane resistance and promoted the fast membrane transfer rate during the distillation process. The prepared PIM-1/PAN hollow fiber structured packings with a controllable defect-free PIM-1 layer down to 34 nm can be easily operated far beyond the normal flooding limit and achieve a very low height of a mass transfer unit (HTU) of 4.0 cm.
Jiawen Fu,Haowei Pan,Mingzhe An,Zihao Li,Hong Wang,Xinping He,Chunhai Yi
Polyvinyl alcohol (PVA) is a promising membrane material for pervaporation (PV) desalination. However, the adjustment and control of the cross-linking structure is still a challenge for PVA membrane. In this study, a novel pH-resistant PVA-based composite membrane for efficient pervaporation desalination was developed by precisely adjusting the cross-linking behavior. Vinyl alcohol-vinylamine copolymer (VA-co-VAm) containing both hydroxyl and amino groups was synthesized. Cross-linking reaction was carried out based on the Schiff base reaction between amino groups (in VAm moiety) and glutaraldehyde (GA) under alkaline conditions. Cross-linking degree of PVA selective layer was carefully controlled by adjusting the amino group content in copolymer. Results showed that membrane prepared with VA-co-VAm that containing 5 wt% N-vinylformamide (NVF) displayed superior hydrophilicity and the largest free volume fraction. Pervaporation test indicated that the modified cross-linking membrane showed good stability under extreme pH conditions. Specifically, under strong acid conditions (pH ~ 1) and alkaline conditions (pH ~ 14), the membrane showed excellent desalination performance with water flux over 12 kg/(m 2 h), and the salt rejection higher than 99.95%. Based on the above results, the prepared membrane offers a promising platform for desalination under extreme pH conditions, which shows great potential in industrial wastewater treatment.
危险品化学品经营许可证（带存储）