Fabrication of Ti₂SnC-MAX Phase Blended PES Membranes with Improved Hydrophilicity and Antifouling Properties for Oil/Water Separation

In this research work, the Ti2SnC MAX phase (MP) was synthesized via the reactive sintering procedure. The layered and crystalline structure of this MP was verified by SEM, HRTEM, and XRD analyses. This nano-additive was used for improvement of different features of the polyethersulfone (PES) polymeric membranes. The blended membranes containing diverse quantities of the MP (0–1 wt%) were fabricated by a non-solvent-induced phase inversion method. The asymmetric structure of the membranes with small holes in the top layer and coarse finger-like holes and macro-voids in the sublayer was observed by applying SEM analysis. The improvement of the membrane’s hydrophilicity was verified via reducing the contact angle of the membranes from 63.38° to 49.77° (for bare and optimum membranes, respectively). Additionally, in the presence of 0.5 wt% MP, the pure water flux increased from 286 h to 355 L/m2 h. The average roughness of this membrane increased in comparison with the bare membrane, which shows the increase in the filtration-available area. The high separation efficiency of the oil/water emulsion (80%) with an improved flux recovery ratio of 65% was illustrated by the optimum blended membrane

Decoration of carbon nanotubes in the substrate or selective layer of polyvinyl alcohol/polysulfone thin-film composite membrane for nanofiltration applications

Nanofiltration (NF) membranes demonstrate considerable promise for desalinating saline water and wastewater containing mineral salts to overcome the lack of fresh water and improve drinking water quality. This research work aims to detect the influence of carbon nanotubes (CNTs) on the filtration performance of polyvinyl alcohol (PVA)/polysulfone (PSf) thin-film composite NF membranes. For this purpose, CNTs were incorporated in the PSf substrate/PVA selective layer to fabricate a thin-film composite (TFC) with nanocomposite substrate (nTFC) and a thin-film nanocomposite (TFN) membranes, respectively. To fabricate TFC membranes, PSf substrates with different concentrations (16–20 wt%) were made using the phase inversion technique. Then, the selective layer of PVA was formed on the PSf support through cross-linking with glutaraldehyde during dip-coating. The membranes’ NF performance was assessed by filtration of NaCl and Na2SO4 solutions at a relatively low pressure of 0.3 MPa. The salt rejection of all prepared membranes followed the sequence of Na2SO4 > NaCl, indicating the characteristics of negatively charged membranes. By embedment of 0.05 wt% CNT in the PSf substrate/PVA selective layer, the rejections of over 43% for NaCl and over 80% for Na2SO4 were obtained, which is higher than that of TFC-16 as a control membrane (18.1% for NaCl and 74.7% for Na2SO4). Furthermore, in the presence of CNTs, the permeance and fouling resistance of the nTFC and TFN membranes have been improved compared to the TFC-16 membrane

Synthesis and Characterization of Dysprosium-Doped ZnO Nanoparticles for Photocatalysis of a Textile Dye under Visible Light Irradiation

Dy-doped ZnO nanoparticles were synthesized with a sonochemical method. X-ray diffraction, inductively coupled plasma, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, and scanning electron microscopy analyses confirmed the successfully synthesis and nanometric diameter of the samples. Dy-doped ZnO nanoparticles were used for photocatalytic decolorization of C. I. Acid Red 17 solution under visible light irradiation. Among different amounts of dopant agent, 3% Dy-doped ZnO nanoparticles indicated the highest decolorization. Decolorization efficiency increased from 14.3 to 57.0% with an increase in catalyst dosage from 0.25 to 1 g/L, while further increment in the catalyst dosage up to 2 g/L caused an obvious decrease in decolorization efficiency. The addition of 0.1 mM peroxydisulfate (S₂O₈^2–) resulted in a decolorization efficiency of nearly 100% after irradiation for 180 min. The trend of inhibitory effect in the presence of different radical scavengers was Cl^– > C₂H₅OH > HCO₃^– > CO₃^2–