Fouling study on vacuum-enhanced direct contact membrane distillation for seawater desalination*. Issue 22 (8th May 2016)

• Record Type: Journal Article
• Authors: Naidu, Gayathri; Jeong, Sanghyun; Vigneswaran, Saravanamuthu; Jang, Eun-Kyung; Choi, Yong-Jun; Hwang, Tae-Mun
• Is Part Of: Desalination and water treatment. Volume 57:Issue 22(2016)
• Page Start: 10042
• Page End: 10051
• Publication Date: 2016-05-08
• Subjects: Fouling -- Humic substances -- Low molecular weight organics -- Seawater -- Vacuum-enhanced DCMD; Saline water conversion -- Periodicals; Saline water conversion; Water -- Purification; Periodicals; 628.167
• DOI: 10.1080/19443994.2015.1040266
• Languages: English
• ISSNs: 1944-3994

Abstract

Abstract: Vacuum-enhanced direct contact membrane distillation (VE-DCMD) has been proposed to improve the DCMD system performance with better effective energy efficiency. However, the higher driving forces by the presence of vacuum pressure at permeate side of the VE-DCMD system could contribute to higher fouling development. In this study, thus, the biochemical fouling development of VE-DCMD with different vacuum pressures (700, 500, and 300 mbar) for seawater desalination was investigated in comparison with DCMD (1, 000 mbar of pressure applied). VE-DCMD showed a significant increase in initial permeate flux while its flux decline was faster than DCMD. Low molecular weight (LMW) organics were found to be a dominant organic foulant on DCMD with thermally disaggregated humic substances (HS) to LMW HS-like organics. On the other hand, the presence of vacuum reduced the disaggregation HS to LMW HS-like organics. However, high driving force of VE-DCMD caused higher deposition of organic foulant including the LMW organics as well as HS. It also led to the higher LMW organic contents in permeate. Fluorescence excitation–emission matrix (F-EEM) analysis result showed that fulvic-like organic is a dominant HS foulant in VE-DCMD. Fouling development on membrane was observed using scanning electron microscope, contact angle, and confocal laser scanning microscope.