Advanced membranes that enable ultrafast water flux while demonstrating anti-biofouling characteristics can facilitate sustainable water/wastewater treatment processes. MXenes, two-dimensional (2D) metal carbides and nitrides, have attracted attention for applications in water/wastewater treatment. In this work, we reported the antibacterial properties of micrometer-thick titanium carbide (Ti3C2Tx) MXene membranes prepared by filtration on a polyvinylidene fluoride (PVDF) support. The bactericidal properties of Ti3C2Tx modified membranes were tested against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) by bacterial growth on the membrane surface and its exposure to bacterial suspensions. The antibacterial rate of fresh Ti3C2Tx MXene membranes reaches more than 73% against B. subtilis and 67% against E. coli as compared with that of control PVDF, while aged Ti3C2Tx membrane showed over 99% growth inhibition of both bacteria under same conditions. Flow cytometry showed about 70% population of dead and compromised cells after 24 h of exposure of both bacterial strains. The damage of the cell surfaces was also revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis, respectively. The demonstrated antibacterial activity of MXene coated membranes against common waterborne bacteria, promotes their potential application as anti-biofouling membrane in water and wastewater treatment processes.

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Forward osmosis (FO) is a membrane separation process using a highly concentrated draw solution with high osmotic potential to draw water across a semi-permeable membrane from a feed source. This feed source may be seawater, wastewater or other natural or contaminated water sources. Unlike other membrane driven purification processes, the product is not clean water, but a diluted draw solution. As a result a second step is often needed to produce a pure water product. A major advantage of FO is that the low hydrodynamic pressure involved leads to lowered fouling of membranes and greater flux recovery after cleaning, as well as often providing a low energy process which can recover clean water from difficult or highly fouling sources. Selection of an appropriate and effective draw solution is essential for the practical operation of an FO process. This review will give an overview of the theoretical underpinnings of draw solution performance and a comprehensive summary of the current literature regarding the different types of draw solutions which have been investigated and their respective benefits and detriments. Highlights  Literature on draw solutions used in forward osmosis processes reviewed including the state-of-the-art  Overview of theoretical underpinning of draw solution performance  Up to date developments of draw solutes  Comparison of draw solute recovery methods

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Kinetics of spreading of aqueous trisiloxane surfactant T(n) (with n = 4, 6, and 8 ethoxy groups) solutions and conventional aqueous surfactant solutions (Tween 20, C12E4, SDS) over silicon wafers coated with PTFE AF is experimentally investigated. It has been found that trisiloxane solutions spread on highly hydrophobic PTFE AF coated silicone wafers; however, they do not show superspreading behavior on these highly hydrophobic substrates. Solutions of conventional nonionic surfactants investigated show kinetics of spreading similar to trisiloxanes. Three regimes of spreading have been identified (i) complete non-wetting during the spreading process at low concentrations, (ii) a transition from initial nonwetting to partial wetting at the end of the spreading process at intermediate concentrations, and (iii) partial wetting both at the beginning and the end of the spreading process at higher concentrations. Transition from the first regime (i) to the second regime (ii) takes place at the critical aggregation concentration (CAC) or critical micelle concentration (CMC), transition from regime (ii) to regime (iii) happens at the critical wetting concentration (CWC). In the case of regime (i) the spreading of nonionic surfactants solutions investigated on PTFE AF coated silicone wafers is slow and follows a theoretically predicted law (Starov; et al. J. Colloid Interface Sci. 2000, 227 (1), 185). In the case of regimes (ii) and (iii), the spreading of the nonionic surfactant solutions investigated proceeds in two stages: the fast short first stage, which is followed by a much slower second stage. It is shown that the slow stage develops according to a previously described theoretical model. According to this theory the surfactant molecules adsorb in front of the moving three-phase contact line (autophilic phenomenon), which results in a partial hydrophilisation of an initially hydrophobic substrate and a spreading as a consequence. We assume that the first stage of the spreading is related to the disintegration of surfactant aggregates in the vicinity of the moving three-phase contact line.

 Various percentages of minimal-size ZnO and ZnO-GO for PSF membrane enhancement.  5 times reduction of ZnO usage with the introduction of GO nanosheets as support.  ZnO-GO composite is more hydrophilic compared to other GO-nanohybrid.  ZnO-GO membrane exhibits excellent antifouling and antibacterial properties.

A membrane material that can concurrently provide commercially acceptable levels of water permeability, high salt rejection, and of sufficient stability to withstand mechanical and chemical stresses seems to be necessary to guarantee the energy and environmental sustainability of desalination systems and other membrane separation processes. Recent developments in desalination have shown that bio-inspired membranes are moving steadily in this direction. Sustainable desalination via aquaporin-based bio-inspired membranes is elucidated in this paper in terms of recent commercialization exploitation and progress towards real operations. Current large-scale applications, viable opportunities, remaining challenges and sustainability of operations, in terms of comparison with established technologies, are discussed in this paper. The major drawback of aquaporin-based membranes, which has been highlighted repeatedly in recent studies, is the stability of the membranes during real operations. This review is focused on recent solutions provided by scientists towards the mitigation of these problems and commercialization of aquaporin-based membranes.