Modification of EPVC membranes by incorporating tungsten trioxide (WO3) nanosheets to improve antifouling and dye separation properties

Modification of reinforced hollow fiber membranes with WO3 nanosheets for treatment of textile wastewater by membrane bioreactor

In this study, performance of braid reinforced hollow fiber membrane containing polyvinylidene fluoride (PVDF) embedded with tungsten trioxide (WO₃) nanosheets in a membrane bioreactor (MBR) was examined for textile wastewater treatment. The WO₃ nanosheets was synthesized and blended at different concentrations (0.1-0.02 wt%) in casting solutions of the membranes. The WO₃ nanosheets characterized using various tests such as XRD, FTIR, SEM, EDS, dot-mapping, and TEM. Furthermore, the effects of the increased WO₃ nanosheets into the PVDF matrix on the membrane morphology, hydrophilicity, permeability, antifouling, and COD and color removal efficiency was investigated. The addition of 0.1 wt% of the nanosheets reduces the water contact angle from 69.3° to 62.5° while increasing overall porosity from 37.5 to 43.2%. COD and color removal for PVDF/0.10 wt% WO₃ membrane was between 86-89% and 72-76%, respectively. While the TMP of modified WO₃ membranes did not significantly increase due to antimicrobial properties of the WO₃ nanosheets, the TMP of the pure PVDF membrane increase, indicating considerable cake layer fouling. The results of this study showed that modification of PVDF braid reinforced hollow fiber membrane using WO₃ nanosheets is promising membrane for MBR systems.

One-pot synthesis of graphene hydrogel/M (M: Cu, Co, Ni) nanocomposites as cathodes for electrochemical removal of rifampicin from polluted water

Nowadays, the removal of pharmaceutical contaminants from water resources and wastewater is of great importance due to environmental and health issues. Over the decades, various methods have been reported to remove pollutants from wastewater. Among the developed methods, advanced oxidation processes (AOPs) have received significant attention from researchers. In this study, we report the one-pot synthesis of graphene hydrogel-metal (GH-M, M: Co, Ni, Cu) nanocomposites via the combination of polyol and hydrothermal methods. The structure of the resulting nanocomposites was examined by transmission electron microscopy (TEM), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy methods. Afterward, as-prepared GH-Cu, GH-Co, and GH-Ni nanocomposites were used to prepare cathodes for the electro-Fenton (EF) process to remove rifampicin (RIF) from polluted water. The effect of operational parameters, including current density (mA/cm²), initial pH, initial RIF concentration (mg/L), and process time (min) was investigated via response surface methodology (RSM). The optimal values for current density, pH, initial RIF concentration, and process time using GH-Ni as cathode were 30 mA/cm², 5, 30 mg/L, and 90 min, respectively. The results at optimal values showed that the maximum RIF removal efficiency for GH-Cu, GH-Co, and GH-Ni cathodes was 90.47, 92.60, and 93.69%, respectively. Brunauer Emmett Teller (BET), atomic force microscopy (AFM), energy-dispersive X-ray (EDX), and cyclic voltammetry (CV) analyses were performed to investigate the performance of the cathodes for the RIF removal. Finally, total organic carbon (TOC), gas chromatography-mass spectrometry (GC-MS), and atomic absorption spectroscopy (AAS) analyses were performed for further investigation of the RIF removal from polluted water. The results claimed that one-pot synthesized GH-M cathodes can effectively remove RIF from polluted water through EF process.