Evaluation of critical flux and cleaning efficiency for electrospun nanofiber microfiltration membrane

• Published in: Desalination and water treatment 2017-11, Vol.97, p.87-93
• Main Authors: Ko, Younghoon, Choi, Yongjun, Jang, Youngsun, Choi, Jihyeok, Lee, Sangho
• Format: Article
• Language: English
• Subjects: Chemical cleaning; Critical flux; Electrospun nanofiber membrane; Fouling; Microfiltration; Physical cleaning
• ISSN: 1944-3986
• DOI: 10.5004/dwt.2017.21649

This study examined fouling characteristics of a commercial grade electrospun nanofiber membrane, which has the nominal pore size of 0.23 μm and the thickness of 165 μm. A set of filtration experiments were carried out in a bench-scale equipment using real wastewater with the mixed liquor suspended solid of 6,500 mg/L. Critical flux was experimentally determined and analyzed using mathematical models such as pore blocking, pore constriction, and cake formation equations. Techniques for physical cleaning of the membrane were applied and compared, including periodic pump stop and backwash. The efficiency of chemical cleaning was measured using NaOCl solutions of different concentrations. Scanning electron microscopy was applied to examine the membrane surfaces before and after chemical cleaning. Results showed that the electrospun membrane has potential for high fouling resistance and effective cleaning. The critical flux seems to exist between 20 and 30 L/m2 h and the cake formation model resulted in the best fit to the experimental data. The transmembrane pressure increase was reduced by 88% after the application of backwash and the efficiency of chemical cleaning ranged from 84% to 91%.