Hongying Tang,Kang Geng,Jinkai Hao,Xiaojuan Zhang,Zhigang Shao,Nanwen Li
Quaternized poly(sulfone)s based on trimethylamine (PSf-TMA-x) and triethylamine (PSf-TEA-x) are developed to form quaternary ammonium (QA)-biphosphate ion pairs as promising high temperature proton exchange membrane (HT-PEM) in H 2 /O 2 fuel cells. The strong QA-biphosphate ion-pair interaction results in high acid absorption and thus high proton conductivity of 78.1 mS cm −1 for PSf-TEA-110/PA membrane at 160 °C in spite of its lower degree of functionalization. Thus, the peak power density of more than 400 mW cm −2 is achieved at 160 °C for the quaternized PSf membranes in H 2 /O 2 fuel cell, which is higher than that of the poly(benzeimidazole) ( m -PBI) membrane (370 mW cm −2 ). Subsequently, the degradation mechanism of the PSf membranes is demonstrated using NMR technique to be occurred in both the polymer backbone and the QA groups. The stability investigation of model compounds further confirms that the degradation of the membranes resulted from the scission of ether linkage and isopropylidene group and the SN2 nucleophilic substitution of QA at operating conditions. Therefore, the significant performance decrease is observed and the lifetime is only less than 30 h at 200 mA cm −2 which is much lower than that of m -PBI membrane (>40 h).
Xibin Wu,Zhimei Wei,Jie Yang,Gang Zhang,Shengru Long,Xiaojun Wang
The purification of dye wastewater plays a critical role in water pollution treatment. Adsorption is a cheap and effective separation technology but is limited by the reuse of adsorption materials. Ultrafiltration membranes have a relatively high flux but their pores are too large to reject small dye molecules. In this study, negatively charged oxidized poly (arylene sulfide sulfone) (O-PASS) membrane, NMP pretreatment oxidized O-PASS (N-O-PASS) membrane, and O-PASS@UiO-66-NH 2 /O-PASS composite membranes were fabricated to retain cationic methylene blue (MB) from wastewater by combining ultrafiltration and adsorption techniques. The increased porosity of the N-O-PASS membrane provides more available adsorption sites for an equilibrium MB adsorption amount of 22.5 (mg g −1 ) and 100% rejection in the first 10 min during ultrafiltration with a pure water flux of 162.32 (L m −2 h −1 bar −1 ). Due to the enhanced hydrophilicity and separating property by deposited UiO-66-NH 2 particles and PASS resin, O-PASS@UiO-66-NH 2 /O-PASS composite membrane shows a flux of 170.32 (L m −2 h −1 bar −1 ) and a 100% MB rejection in 60 min with great reusability. The O-PASS@UiO-66-NH 2 /O-PASS composite membrane is a new promising membrane for the removal of dyes from wastewater. Meanwhile, the superior solvent resistance endows it great adaptability in wide applications, especially in harsh conditions.
危险品化学品经营许可证（带存储）