Rejection of disinfection by-products by RO and NF membranes: Influence of solute properties and operational parameters

Abstract

100-200words)The objective of this study was to determine the influence of solute properties and operational parameters on disinfection by-product (DBP) rejection by reverse osmosis (RO) and nanofiltration (NF) membranes. This was achieved by assessing the removal efficiency for 29 DBPs likely to be formed during disinfection of secondary effluents. The DBPs investigated were trihalomethanes, iodinated-trihalomethanes, haloacetonitriles, chloral hydrate, haloketones, halonitromethanes and haloacetamides.The performance of an NF and a low pressure RO membrane was investigated within a range of different pHs, temperatures, transmembrane fluxes, crossflow velocities and ionic strengths. Rejection decreased significantly with increasing temperature and decreasing transmembrane flux, while the influence of the other operational parameters was minimal with a few exceptions detailed in the manuscript.Multiple linear regression was used to determine the physico-chemical solute properties contributing significantly to DBP rejection. For NF, geometric parameters were revealed to be the dominant molecular descriptors influencing rejection, whereas for RO, besides size exclusion, solute-membrane interaction played an important role. A predictive model based on multiple linear regression was established that could forecast rejection of DBPs as a function of membrane operation parameters and DBP properties. 2 Abbreviations BCAcAm Bromochloroacetamide BCAN Bromochloroacetonitrile BCIM Bromochloroiodomethane BDCAcAm Bromodichloroacetamide BDCM Bromodichloromethane BDIM Bromodiiodomethane BIAcAm Bromoiodoacetamide CDIM Chlorodiiodomethane CH Chloral hydrate CIAcAm Chloroiodoacetamide DBAcAm Dibromoacetamide DBAN Dibromoacetonitrile DBCAcAm Dibromochloroacetamide DBCM Dibromochloromethane DBIM Dibromoiodomethane DBP Disinfection by-product DCAcAm Dichloroacetamide DCAN Dichloroacetonitrile DCIM Dichloroiodomethane DHAN Dihalogenated acetonitriles DIAcAm Diiodoacetamide DM Dipole moment GC-ECD Gas chromatograph with electron capture detector HAA Haloacetic acids HAcAm Haloacetamides HAN Haloacetonitriles 4 HK Haloketones HNM Halonitromethanes

Disinfection by-product formation during seawater desalination: A review

“…Rejection of HAAs were consistently high (>90%) and did not vary with log K OW (octanolewater partition coefficient), while for all other DBPs, present as neutral molecules, rejection was variable and decreased with decreasing log K OW . Doederer et al (2014) observed that increasing transmembrane flux led to increased rejection of DBPs due to hydrophobic interactions between DBPs and the membrane, and there was no discernible impact on rejection by RO with change in crossflow velocity. They also observed that increasing temperature led to a considerable decrease in DBP rejection, and increasing pH and ionic strength did not have discernible impact on DBP rejection during low pressure RO filtration.…”

Assessment of the hindered transport model in predicting the rejection of trace organic compounds by nanofiltration

“…Nowadays, NF is increasingly used to remove trace organic compounds (TOrCs) from either source water or finished drinking water which is contaminated by these compounds [9][10][11]. However, both laboratory and onsite studies showed that the rejection ratios for TOrCs were greatly dependent on the membrane characteristics and the physicochemical properties of their own [12,13].…”

Disinfection and DBPs removal in drinking water treatment: A perspective for a green technology

“…A modern maturation in water treatment is the introduction of membrane filtration to potable water treatment (Rojas et al, 2008;Lin et al, 2006;Williams et al, 2012). Membrane filters have been revised to the level where, in some situations, they are appropriate as stand-alone remediation for small set-ups (Singh et al, 2010;Patsios et al, 2013;Oh et al, 2007;Doederer et al, 2014). To a greater extent, they are utilized in coupling with other treatment techniques to economically enhance the global quality of finalized potable water (Rachwal and Judd, 2006;Guo et al, 2016).…”