A special issue of Desalination looks at recent advances in nanofiltration (NF) membrane research, covering essentially all the different aspects important for NF membrane processes.
About one-quarter of the papers focus on the use of nanofiltration for environmental applications. These include two that compare the performance of NF and reverse osmosis (RO) membranes in the treatment of produced water, with performance measured in terms of detailed analysis of water quality and toxicity. The other papers report on using NF for water reuse from municipal wastewater, recovery of chromium from a salt mixture, and removal of heavy metals.
Nanofiltration membrane fabrication is also addressed. The main topics here are optimisation of TiO2 modified thin-film composite (TFC) NF membranes, preparation and characterisation of PPEES/chitosan composite NF membranes, the effect of amine salt surfactant on TFC NF membranes, and TFC NF membranes with improved acid stability.
Several papers discuss fundamental issues related to NF membrane characteristics and modelling. The dielectric properties of NF membranes have been investigated in detail, and a better experimental method is proposed to measure the physical parameters from membrane and streaming potential.
Two papers look at the different approach of modelling of NF membrane performance, using the Spiegler–Kedem–Kachalsky model to predict the removal of 4-chlorophenol, and the crossed mixture-process-design approach to model non-dilute multi-ionic solutions.
In addition, threshold flux measurement is proposed through conversion of critical flux data, and the behaviour of organic molecules across NF membranes has been investigated, both for low and high MW compounds during NF of red grape must, and the transmission behaviour of p-anisic.
The rest of the papers discuss other important issues in nanofiltration, including the effect of natural organic matter (NOM) molecular weight and microcystins on NF fouling, and experience of scaling-up from lab to pilot plant for desalination effluents treatment using NF. In addition, NF of partial oxidation products and copper from wet peroxidation of phenol is discussed, and the permeation of organic solutes in water–ethanol mixtures is described.