Forward osmosis (FO) membranes have been used for wastewater recovery and desalination as apromising technology. This research studies the natural organic matter (NOM) fraction causingfouling on the active (AL) and support layer (SL) of a FO membrane, with the active layer facingthe feed side (AL-FS), using a secondary wastewater effluent (SWWE) as feed water, andseawater as a draw solution (DS). Liquid chromatography with organic carbon detection (LCOCD)chromatograms and fluorescence excitation-emission matrixes (F-EEM) spectra of theinitial and final DS and SWWE suggested that protein-like substances and polysaccharidespresent in the SWWE were forming a fouling layer on the AL of the FO membrane, reducing theflux of water permeating through the membrane. NOM fouling shows a 90% reversibility whenair scouring for 15 minutes within the concentrated feed water (CFW) is applied. When chemicalcleaning of the AL (Alconox solution and EDTA) was performed after the former air scouring,the flux increased by 3%, and the irreversible fouling was quantified as 8.2%. Transparentexopolymer particles (TEP) were identified on the support layer of the FO membrane in contactwith the seawater, reducing the flux of the FO membrane in ≤ 8.2% of the initial flux. Chemicalcleaning of the SL with a solution of 1% NaOCl during 10 minutes was effective in removing theTEP accumulated on the membrane.
展开▼
