Search

Abstract Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only limited to ground waters only. There are serious concerns with the treatment of ground water resources, including landfill leachates, agricultural contaminations (pesticides, herbicides, and fertilizers), and rural contaminations. Membrane separation has been proved to be the governing technology in water and wastewater treatment plants, as these methods are responsible for more than half of the market share of the world's desalination capacity. This study intends to offer a holistic view of the groundwater contamination with specific focus on Saskatchewan province in Canada, and the recent efforts in the groundwater treatment using thin film composite membrane technology. This study begins with an introduction of the general aspects of ground water and membrane separation, polluting agents, and their sources. It is followed by a discussion of Saskatchewan's groundwater status and various issues. Furthermore, the recent research that became available since 2010 is reviewed in details and the results are summarized with respect to purification efficiency. Different affecting parameters in a groundwater-thin film composite system are synthesized and an in-depth overview is presented. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract: Antibacterial polysulfone ultrafiltration membranes were fabricated using different silver nanoparticles in the casting solution. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle and dead end filtration experiment were carried out to characterize the morphology and performance of the prepared membranes while inhibition zone and filtration of bacterial suspension were used to investigate the antibacterial behavior of the membranes. Sliver release was measured in order to investigate the kinetic of silver leaching from the membranes. Less crystalline structure was obtained for membrane with smaller silver nanoparticles as confirmed by the XRD patterns. In addition, SEM studies also showed that surface pores size was reduced by adding silver nanoparticle in the casting solution. Cross section of membranes were totally affected by the addition of silver nanoparticles so that tighter finger-like structure appeared by adding 70nm silver nanoparticles. As shown in SEM images, a dense cross section was formed by addition of 2wt.% silver nanoparticles with size of 30nm in the casting solution. Surface roughness parameters obtained from AFM images showed that the silver nanoparticles with size of 70nm caused rougher surface for membrane. However, the silver nanoparticles with the size of 30nm resulted in formation of membranes with smoother surfaces. Contact angle measurement also proved more hydrophilic surface for silver modified membranes. Inhibition zone and bacterial filtration showed higher antibacteriality for membranes with smaller silver nanoparticles. [Copyright &y& Elsevier]

Computational frameworks have been under specific attention within the last two decades. Molecular Dynamics (MD) simulations, identical to the other computational approaches, try to address the unknown question, lighten the dark areas of unanswered questions, to achieve probable explanations and solutions. Owing to their complex microporous structure on one side and the intricate biochemical nature of various materials used in the structure, separative membrane materials possess peculiar degrees of complications. More notably, as nanocomposite materials are often integrated into separative membranes, thin-film nanocomposites and porous separative nanocomposite materials could possess an additional level of complexity with regard to the nanoscale interactions brought to the structure. This critical review intends to cover the recent methods used to assess membranes and membrane materials. Incorporation of MD in membrane technology-related fields such as desalination, fuel cell-based energy production, blood purification through hemodialysis, etc., were briefly covered. Accordingly, this review could be used to understand the current extent of MD applications for separative membranes. The review could also be used as a guideline to use the proper MD implementation within the related fields. [Display omitted] • Overview of molecular dynamics simulation for membrane separation and porous materials. • MD-driven Initial Parameters. • Contribution of Computational Tools to Different Membrane Technology Subsections. • Instances of MD Applications for Characterization Membrane Materials. [ABSTRACT FROM AUTHOR]

Amine functionalized Multi-walled carbon nanotubes (F-MWCNTs)/polyethersulfone (PES) membranes were prepared using phase inversion induced by immersion precipitation. Crude MWCNTs were chemically treated using strong acids (H2SO4/HNO3) and 1,3-phenylenediamine (mPDA) to produce the functional amine groups (NH2) on their surfaces. F-MWCNTs with different concentration were blended in the casting solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAC). Pure water was used as non-solvent. The FTIR spectra indicated that the amine functional groups were produced on the surface of MWCNTs. The membranes prepared with different concentrations of F-MWCNTs were characterized using contact angle, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and permeation tests. The surface hydrophilicity of membranes was significantly improved by addition of F-MWCNTs in the casting solution. An increment in the porosity, pore size and surface roughness of the membranes was observed by increasing F-MWCNTs content up to 1 wt.%. Further addition of F-MWCNTs caused a reduction in porosity and roughness of formed membrane. The membranes prepared with 0.5 and 1 wt.% of F-MWCNTs showed higher performance than neat membrane. Addition of F-MWCNTs in the casting solution improved the BSA rejection and antifouling properties of PES membrane. [ABSTRACT FROM AUTHOR]

• State-of-the-art ultrasound technique for membrane fouling control and cleaning was reviewed. • Cavitation phenomenon as well as theory of ultrasonic-assisted effects were discussed. • Operational factors that influence the effectiveness of the ultrasound treatment were explained. • Effects of ultrasonic irradiation on integrity of the membranes were discussed. • The economic aspect of ultrasonically cleaning of membranes as a determinative parameter was investigated. Fouling is one of the most challenging problems impacting the performance of membrane-based separation technology. In recent years, ultrasound have been widely applied as an unconventional method to control membrane fouling, as well as to enhance membrane cleaning. The aim of the present work is to review the current literature and the recent developments related to the use of ultrasound as an innovative and alternative approach to improve the fouling behavior of membrane separation processes. The theory underlying ultrasonic-assisted phenomena is reviewed, together with operational factors that influence the effectiveness of the ultrasound treatment, such as frequency, power intensity, pressure, temperature, pH, and operation mode. Ultrasound irradiation effectively aids the cleaning of contaminated surfaces and enhances the permeate flux, owing to cavitation phenomena and powerful convective currents, associated with secondary phenomena, such as microstreamers, shock waves, and heating. However, the lifetime of the membranes should be carefully evaluated when applying ultrasonication as a technique of cleaning or controlling membrane fouling. Indeed, the integrity of membranes after sonication and the control of erosion produced by high ultrasonic intensities are key issues hindering the scale-up of this approach in the membrane industry. This reviews highlights the topics requiring more investigations, specifically to evaluate the economic aspects of ultrasonic assisted fouling control and cleaning in membrane processes. [ABSTRACT FROM AUTHOR]