Phenomenological prediction of desalination brines nanofiltration through the indirect determination of zeta potential

Abstract

The prediction of nanofiltration (NF) performance at environmentally relevant conditions, e.g.: highly saline brine solutions, is becoming of increasing interest for the recovery of waste materials in the water desalination industry. In this work, the prediction of the separation of sulfate and chloride contained in the retentate of reverse osmosis brackish water desalination by means of the commercial NF270 membrane is studied.Prior to theoretical modelling, streaming potential measurements were performed for aqueous single and binary mixtures of NaCl and Na 2 SO 4 within the range of ionic strengths 0.001-0.1 M. Zeta potential values were obtained applying an extrapolation method from recent literature to allow the calculation of surface charge density under higher ionic strengths found in reverse osmosis desalination brines (0.1 to 1.2 M). The obtained surface charge density was then used to simulate sulfate, chloride and sodium rejections by means of the Donnan steric pore model (DSPM), in the pressure range 2 -20 bar. The good agreement between experimental and simulated rejection values allows to validate this approach that enables the prediction of NF performance for the separation of monovalent and divalent anions, of interest for the purification of desalination brines before their further exploitation as a source of sodium chloride concentrated solutions.

Thiol-Affinity Immobilization of Casein-Coated Silver Nanoparticles on Polymeric Membranes for Biofouling Control

“…Streaming zeta potential is used to demonstrate the surface charge of the solid materials in an aqueous solution [36,50]. It is an important parameter to understand surface chemistry and the interactions between the surface and the surrounding environment [36].…”

Investigation of dielectric constants of water in a nano-confined pore

“…8 which clearly puts in evidence a distribution of the correlation times inside the nanopore with a delayed relaxation with respect to the bulk phase (see dotted line in Fig. 8) and a monotonous increase in the relaxation time when water molecules approach the pore surface (in the rst interfacial shell we found s > 200 ps from eqn (11)). This indicates a decrease in the rotational dynamics of water dipoles close to the pore surface.…”

“…[3][4][5][6] Among which, nanoltration (NF) membranes have been widely used in drinking water preparation, wastewater treatment, product desalination and purication and other elds due to its excellent separation performance. [7][8][9][10][11][12][13] However, due to the special effect brought by the complex structure of nanoltration membrane, research on the separation mechanism and theoretical model of nanoltration has become one of the difficulties in the eld of nanoltration research, which limits the development and application of nanoltration membranes. In recent years the special effect caused by the nanoscale size of nanoltration membrane has been paid more and more attention.…”

Tuning the Ion-Selectivity of Thin-Film Composite Nanofiltration Membranes by Molecular Layer Deposition of Alucone

“…The zeta potential measurement (indicating surface charge) of NF270 is well-reported in the literature. 47 Based on the pKa values of the surface functional groups, at a pH < iso-electric point (IEP), the functional groups of the active layer are protonated (R-COOH and R-NH 3 + ), while above the IEP, they are deprotonated (R-COO – and R-NH 2 ). This explains the negative charge on the NF270 membrane at pH > 4.0.…”