Factors governing the rejection of trace organic contaminants by nanofiltration and reverse osmosis membranes

Abstract

A B S T R A C TThis study aimed to elucidate key factors governing the rejection of trace organic contaminants (TrOCs) by nanofiltration (NF) and reverse osmosis (RO) membranes. The rejection of 16 selected hydrophilic and hydrophobic TrOCs by an NF and an RO membranes was evaluated at different solution pH values using a cross-flow NF/RO filtration system. An analytical technique consisting of solid phase extraction followed by gas chromatography and mass spectrometry detection was used for the analysis of the TrOCs. In general, rejection increased in the order of decreasing membrane permeability, increasing molecular weight (or equivalent molecular width) of the TrOCs, and increasing hydrophilicity. Adsorption of hydrophobic TrOCs to the membrane could be observed based on a mass balance calculation. However, the correlation between adsorption and log D value (the logarithm of the octanol-water distribution coefficient) of the TrOCs (which indicates their hydrophobicity) observed in this study was rather weak. This is due to the adsorption being not only dependent on hydrophobicity, but also on other physicochemical aspects of TrOCs and the membrane material, such as molecular size, charge of the compounds, pore size, charge, and surface roughness properties of the membranes. Therefore, the results suggest that these factors may also govern the adsorption (and subsequently rejection) of TrOCs to NF/RO membranes.

Fate of pharmaceuticals and their transformation products in integrated membrane systems for wastewater reclamation

“…Furthermore, a number of studies have also shown that NF and ultralow pressure RO membranes are not perfect barriers for various micropollutants including endocrine disruptors and some PhACs such as SMX or CBZ [15,16]. Both membranes had a negative surface charge in the pH range used in the study [17,18], whereas the hydrophobic nature of a membrane is typically characterised by its contact angle. Alturki et al [7] measured the contact angle of both the NF90 and ESPA2 membranes for virgin membranes (1 hour use) and after 25 hours of use.…”

Impact of simultaneous retention of micropollutants and laccase on micropollutant degradation in enzymatic membrane bioreactor

“…Micropollutant concentration in the enzymatic bioreactor and membrane permeate was measured by High-performance liquid chromatography (HPLC) (Shimadzu, Kyoto, Japan) at the detection wavelength of 280 nm using a method reported previously (Nguyen et al, 2014b [8,40], [10,0], [22,0], [24,85]. The gradient of eluent B was then automatically adjusted as follows: [Time (min), B (%)]: [0, 15], [8,60], [10,100], [22,100], [24,15]. The limit of detection (LOD) for this method was approximately 10 µg/L.…”

“…Overall removal of micropollutantsIn this study, NF-EMBR achieved 92 to over 99% removal of the micropollutants(Figure 2). In general, NF membranes can remove micropollutants via the following mechanisms: (i) size exclusion; (ii) adsorption; and (iii) electrostatic interaction(Dang et al, 2014;Taheran et al, 2016). Micropollutants having a molecular weight higher than 200 g/mol have been reported to be effectively rejected by the NF90 membrane(Luo et al, 2014a).…”

Avaliação Da Interação Do Radiofármaco (18f-Fdg) Fluordesoxiglicose Em Usuários De Fármacos Hipoglicemiantes

“…Most of them are carried out in developed countries . Improvements in wastewater treatment field and the search for new treatment methods have been carried out, such as ozonation and osmosis, in order to effectively remove organic contaminants (PISARENKO et al, 2012;SHEN et al, 2014;DANG, NGHIEM and PRICE, 2014).…”