title: High flux and antifouling properties of negatively charged membrane for dyeing wastewater treatment by membrane distillation.
abstract: This study investigated the applicability of membrane distillation (MD) to treat dyeing wastewater discharged by the textile industry. Four different dyes containing methylene blue (MB), crystal violet (CV), acid red 18 (AR18), and acid yellow 36 (AY36) were tested. Two types of hydrophobic membranes made of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) were used. The membranes were characterized by testing against each dye (foulant-foulant) and the membrane-dye (membrane-foulant) interfacial interactions and their mechanisms were identified. The MD membranes possessed negative charges, which facilitated the treatment of acid and azo dyes of the same charge and showed higher fluxes. In addition, PTFE membrane reduced the wettability with higher hydrophobicity of the membrane surface. The PTFE membrane evidenced especially its resistant to dye absorption, as its strong negative charge and chemical structure caused a flake-like (loose) dye-dye structure to form on the membrane surface rather than in the membrane pores. This also enabled the recovery of flux and membrane properties by water flushing (WF), thereby direct-contact MD with PTFE membrane treating 100 mg/L of dye mixtures showed stable flux and superior color removal during five days operation. Thus, MD shows a potential for stable long-term operation in conjunction with a simple membrane cleaning process, and its suitability in dyeing wastewater treatment.
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China. Electronic address: alicia.kjan@cityu.edu.hk.
authors.forename: Alicia Kyoungjin
authors.initials: AK
authors.lastname: An
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Guo
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Biological and Environmental Science & Engineering (BESE), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Jeong
authors.affiliation: School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Eui-Jong
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Biological and Environmental Science & Engineering (BESE), Thuwal 23955-6900, Saudi Arabia.
authors.forename: S Assiyeh Alizadeh
authors.initials: SAA
authors.lastname: Tabatabai
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Biological and Environmental Science & Engineering (BESE), Thuwal 23955-6900, Saudi Arabia.
authors.forename: TorOve
authors.initials: T
authors.lastname: Leiknes
mesh_terms: D057168:Distillation; D057927:Hydrophobic and Hydrophilic Interactions; D008567:Membranes, Artificial; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification
chemical_list: D008567:Membranes, Artificial; D062065:Wastewater
keywords: Dyeing wastewater; Hydrophobic membrane; Membrane distillation; Membrane fouling; Water flushing