Industrial processes often produce large amounts of alkaline wastes. Alkaline treatment processes need to be resistant to high concentration, and are complex and low concentration. Membrane technology has the benefits of high performance and energy conservation. However, the current polymeric membrane materials are not strong enough in severely alkaline areas. To address this issue, Prof. Li Pei from Beijing University of Chemical Technology and Dr. Jianzhong Xia from Shenzhen University developed an anti -alkali pervaporation membrane. The work is published in Limitations of Chemistry and Engineering and March 28, 2022.
In this process, they added a super alkali-resistant polymer-sodium carboxymethyl cellulose, and covered it on a solid polyethylene porous substrate. They also developed a welding technology to solve the various problems between the hydrophobic polyethylene layer and the sodium carboxymethyl cellulose layer. The pervaporation flux of the composite membrane was up to 35 ± 2 kg · m2· H−1 with a sodium chloride solution of 99.9% ± 0.1% dissolving a 3.5 wt-% sodium chloride solution at 70 ° C. The desalination process was stable after boiling the membrane in a 20 wt-% solution. NaOH at room temperature for 9 days and at room temperature 10 wt-% NaOH at 60 ° C for 80 h. In addition, the membrane was stable to 4 wt-% sulfuric acid and about 500 mg · L−1 sodium hypochlorite solution. In the process of fixing a NaOH solution from 5 to 10 wt-% at 60 ° C, an average water flow rate of 23 kg · m.2· H−1 with a NaOH resistance over 99.98% obtained.
Due to the good alkali stability of the composite membrane, the membrane material exhibits good application conditions such as alkali transfer in paper making, electroplating industry, water return in coal chemistry, and so on. with alumina manufacturing process.
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Guiqin Bai et al, Effect of high pervaporation composite membrane for the recovery of alkaline wastewater, Limitations of Chemistry and Engineering (2021). DOI: 10.1007 / s11705-021-2078-2
Presented by Higher Education Press
Directions: Pervaporation membranes show promise for the return of alkaline wastewater (2022, April 12) retrieved April 12, 2022 from https://phys.org/news/2022-04-pervaporation- membranes-alkaline-wastewater-reclamation.html
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