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Summary: In this study, styrene‐butadiene‐styrene (SBS) was used to develop a novel functionalized electrospun membrane for the effective treatment of heavy metals in direct contact membrane distillation (DCMD) applications. Functionalization was achieved by the addition (doping) of the super hydrophobic Al2O3 nanoparticles (Al NPs) within the matrix of the membrane during electrospinning. Neat (pristine nondoped) and doped SBS membranes were tested. The performance of the SBS membranes were also compared with fabricated polyvinylidene fluoride membranes with and without doping with Al NPs. The membrane characteristics were tested via Fourier transform infrared, scanning electron microscopy, pore size, and porosity investigations. The wettability of the membranes was investigated with respect to the liquid entry pressure (LEP) and contact angle. The performance of the membranes was tested in a DCMD setting for its ability to treat water containing salt (NaCl) and heavy metals (Cr (VI), Cd, Pb) in various concentration in a single and multicomponent systems. The SBS member exhibited excellent hydrophobicity characteristics such as a high LEP (16.87 psi) and contact angle (141° ± 2°). It also had superior permeate flux rate compared to the other prepared membranes (54.4 LMH). The addition of the Al2O3 nanoparticles enhance the performance of the membranes substantially. Slight decline in the flux was observed after 14 hours of continuous operating time that could be attributed to agglomeration, adsorption, or temperature polarization effects. The SBS AL NPs membranes also demonstrated excellent flux for saline solutions of varied concentrations with 99% salt rejection. [ABSTRACT FROM AUTHOR]

In this paper, commercially available graphene oxide (GO) was used as nanomaterials to modify polyamide reverse osmosis (RO) membrane surface. After functionalization, the membrane surface properties were improved as the water contact angle was reduced from 41.7 ± 4.5⁰ to 26.9 ± 0.9⁰ demonstrating improvement in hydrophilic properties besides decreasing membrane surface roughness. Membrane scaling tests were done in the presence of CaSO 4 solution at 20 mM concentration as feedwater showed that the modified membranes (GO@RO) had superior anti-scaling properties. Results indicated that the permeate flux was reduced by only 15% at the end of the scaling experiment as opposed to the bared RO membrane which faced up to 22% decline in flux. The results of scanning electron microscopy, Fourier transform infrared, and X-ray diffraction confirmed that the bared RO membrane was extensively scaled by the CaSO 4 precipitates. The results of antibacterial tests showed that GO functionalization caused an inhibition of bacterial growth by 81.7% as compared to the unmodified RO membrane. Moreover, experiments were also performed to investigate microbially induced calcium sulfate precipitation on membranes. Overall, it was found that GO functionalization not only reduces biofouling but can also inhibit mineral scaling and microbially induced mineral formation. Image 1 [ABSTRACT FROM AUTHOR]

To address the problem of ever-increasing oily wastewater management, due to its directional liquid transport property, membranes with asymmetric wettability can be effectively used for emulsion separation. This study reports the synthesis of electrospun polymer–clay nanocomposite nanofibers, using co-polyamide polymer (COPA) and halloysite nanotubes (HA) as filler. The influence of clay content on the morphological, thermal and dielectric properties of the polymer composite nanofiber was investigated comprehensively to address the material characteristics of the developed system. The surface structure analysis and contact angle measurements of the electrospun composite nanofibers confirms the change in surface roughness and wettability when the fillers are added to the polymer. The porosity of the composite electrospun nanofiber membrane was found to be 85% with an oil adsorption capacity of 97% and water permeability of 6265 L/m2 h. Furthermore, the asymmetric wettability-driven oil/water emulsion separation abilities of the as-synthesized membranes shows that the separation efficiency of the composite fiber membrane is 10% improved compared to that of the neat fiber membrane, with improved separation time. [ABSTRACT FROM AUTHOR]