Pondering performance of hybrid microfiltration and membrane distillation (MF-MD) process for purifying chromium-contaminated groundwater: Optimization, fouling control, and long-term operation

• Published in: Desalination 2024-09, Vol.585, p.117757, Article 117757
• Main Authors: Qoriati, Dian, You, Sheng-Jie, Wang, Ya-Fen, Thi, Phuong-Tram Tran, Le, Nguyet-Nhi Tran
• Format: Article
• Language: English
• Subjects: Air gap membrane distillation; Chromium-contaminated groundwater; Long-term operation; Microfiltration; Ultrasonication
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2024.117757

Nowadays, a hazardous compound such as Chromium (Cr) in groundwater is an emerging issue worldwide due to its environmental and health impacts. Membrane distillation (MD) is a promising technique to purify Chromium-contaminated groundwater (CCG). Assisted microfiltration (MF) is lodged to overcome a major problem in MD, specifically membrane fouling. In this work, a hybrid MF-MD process is proposed with fouling control incorporated into long-term operation. Derived from the results, mixed cellulose ester with 0.1 μm of pore size (MCE0.1) at 3-min ultrasonication cleaning is chosen as the optimal parameter in the MF process, because of superior flux recovery ratio (FRR) with negligible flux deficiency of approximately 10 %. Permeate flux and total suspended solids (TSS) rejection of MCE0.1 was achieved around 440 Lm−2h−1bar−1 and > 90 %, respectively. The optimized parameters in MD were selected accordingly: feed temperature of 80 °C, and feed and coolant flow rates at 4 L/min. Eventually, the long-term batch operation was executed by obtaining average flux and permeate conductivity was 7.5 LMH and around 10 μs/cm, respectively. The Cr concentration in permeate was relatively stable around 0.05 mg/L, which meets the wastewater discharge limit of 0.5 mg/L. [Display omitted] •Hybrid MF-MD processes are explored to purify high Cr-concentration from contaminated groundwater•MF pretreatment promoted the particles and suspended solids diminishment and membrane fouling alleviation in the MD process•Fouling mitigation by ultrasonication in MF operation is performed•Influence of parameter conditions in MF and MD are individually analyzed•Long-term batch operation of hybrid MF-MD is investigated