Membrane distillation (MD) is a thermally driven process that uses low‐grade energy to operate and has been extensively explored as an alternative cost‐effective and efficient water treatment process compared to conventional membrane processes. MD membranes are synthesized from hydrophobic polymers, e.g. polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) or polypropylene (PP), using various methods including phase inversion and electrospinning techniques. Recent literature on MD membranes clearly shows their important role in surface water/wastewater treatment and seawater desalination. Modification of MD membranes with nanoscale materials significantly improves their performance, preventing wetting and fouling. This review presents a critical assessment of the progress on the use of nanomaterials for the modification of MD membranes. The techniques commonly used to synthesize MD membranes, the modifications that have been adopted for the incorporation of nanomaterials onto membranes, and the unique properties these nanomaterials impart on the membranes are discussed. The use of modified membranes in different MD configurations and their application in groundwater, surface water, wastewater, brackish water and seawater treatment is reviewed. Finally, cost implications, commercial viability, environmental sustainability, and future prospects of MD are also discussed to elucidate promising approaches for a future and successful implementation of MD at an industrial scale. © 2019 Society of Chemical Industry

No abstract

No abstract

This work reports the synthesis of β-cyclodextrin (β-CD)/cellulose (CA) nanofibers embedded with silver (Ag) and silver/iron (Ag/Fe) nanoparticles (NPs) via a benign process involving in situ electrospinning of the biopolymers with Ag and Fe salts. The electrospun nanocomposite fibers containing Ag+/Fe3+ ions were then subjected to UV photochemical reduction in the presence of water vapor under inert atmosphere to reduce the ions to zerovalent state. SEM and TEM revealed that the average diameter of the β-CD/CA nanofibers was 382.12 ± 30.09 nm and that the diameters of Ag and Ag/Fe NPs were 38.81 ± 8.21 nm and 56.29 ± 12.64 nm, respectively, after reduction. The XRD and EDS analysis confirmed the presence of the Ag and Fe NPs on the surface of the nanofibers. The effect of UV irradiation time on the reduction of the Ag+ and Fe3+ was studied by measuring the UV–vis absorbance of the reduced NPs. The biocidal effect of Ag and Ag/Fe was investigated using 12 different strains of bacteria. The Ag and Ag/Fe NPs embedded on the β-CD/CA nanofibers exhibited a strong biocidal effect on all of the bacteria strains.

No abstract

Zeolites synthesized from biomass waste materials offer a great opportunity in the sustainable utilization of the waste.

Abstract:The problem of limited water supply in the Vhembe District (Limpopo Province, South Africa) is exacerbated by a preponderance of dissolved salts, which cause disagreeable taste and odour in the water as reported by the communities using this water for drinking. The water treatment plant that supplies the treated water to the communities in the District sources this raw water from the Nandoni Dam at the Luvuvhu river catchment. There are no scientific studies that have been reported in the literature that focused on determining the levels of water salinity from various water sources in the municipalities of the District. Water samples from various sites across the Nandoni Dam, a primary source of domestic water supply in the region, were collected through each season over a period of twelve months in order to ascertain the concentrations of dissolved salts in the dam. Onsite analyses of the water samples were conducted using the YSI ProDSS multimeter, while the laboratory water analyses were conducted using the spectroquant and atomic absorption spectrometers. Although salinity tests seem to indicate that the water sampled across most of the Nandoni Dam is brackish during all seasons of the year with the highest being 750 mg/L, water samples from the dam mid-outlet and the treatment plant are slightly below the World Health Organization (WHO) brackish water bracket of 500 mg/L with unfavourable taste for drinking. Results from this study indicate that the water sourced from the Nandoni Dam is not suitable for human consumption and therefore requires integrated water resource management, as well as robust and cost-effective water desalination treatment.

No abstract