title: Hybrid ferrihydrite-MF/UF membrane filtration for the simultaneous removal of dissolved organic matter and phosphate.
abstract: Dissolved organic matter (DOM) and phosphorus promote microbial regrowth in water distribution networks. Ferrihydrite (Fh) has a high adsorption affinity with DOM and phosphate. Hence, a lab-scale unit of the hybrid Fh-MF/UF membrane filtration system was used to evaluate membrane fouling and the removal efficiency of DOM and phosphate. Suwannee River natural organic matter (SRNOM) was used as a surrogate for DOM in natural water. The Fh-membrane system demonstrated removal rates of dissolved organic carbon (DOC), UV254 and phosphate up to 50%, 80% and 90%, respectively, at the Fh dose of 17.5 mg/L. The effect of phosphate on the removal of DOM was different without or with the addition of Fh; namely, phosphate increased the DOM removal without Fh by interacting with the UF membrane made of regenerated cellulose (RC), but phosphate decreased the DOM removal by Fh due to the strong affinity of phosphate with Fh. Size exclusion chromatography revealed that phosphate mainly competed against smaller DOM molecules for Fh adsorption sites. Although the addition of Fh caused only a moderate flux decline with the RC membranes, the deposition of positively charged Fh on the surface of a negatively charged high-flux membrane, i.e., polyethersulfone (PES), caused a rapid decline of the permeation flux.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, No.19, Xinjiekouwai Street, Haidian District, Beijing 100875, China. Electronic address: yangyu@bnu.edu.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Urban Engineering, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. Electronic address: jenyuk@env.t.u-tokyo.ac.jp.
authors.forename: Jenyuk
authors.initials: J
authors.lastname: Lohwacharin
authors.affiliation: Department of Urban Engineering, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. Electronic address: takizawa@env.t.u-tokyo.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takizawa
mesh_terms: D000327:Adsorption; D002850:Chromatography, Gel; D005290:Ferric Compounds / Q000737:chemistry*; D005374:Filtration / Q000379:methods*; D008567:Membranes, Artificial; D009930:Organic Chemicals / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry; D014462:Ultrafiltration; D018508:Water Purification / Q000379:methods; D014881:Water Supply
chemical_list: D005290:Ferric Compounds; D008567:Membranes, Artificial; D009930:Organic Chemicals; D010710:Phosphates; D011108:Polymers; D013450:Sulfones; C022840:polyether sulfone; C092844:ferric oxyhydroxide
keywords: Adsorption; Dissolved organic matter (DOM); Ferrihydrite; Low- pressure membrane filtration; Membrane fouling