Surface-engineered polyethersulfone membranes with inherent Fe-Mn bimetallic oxides for improved permeability and antifouling capability.

In recent years, bimetallic oxide nanoparticles have garnered significant attention owing to their salient advantages over monometallic nanoparticles. In this study, Fe2O3-Mn2O3 nanoparticles were synthesized and used as nanomodifiers for polyethersulfone (PES) ultrafiltration membranes. A NIPS was used to fabricate asymmetric membranes. The effect of nanoparticle concentration (0-1 wt.%) on the morphology, roughness, wettability, porosity, permeability, and protein filtration performance of the membranes was investigated. The membrane containing 0.25 wt% nanoparticles exhibited the lowest water contact angle (67°) and surface roughness (10.4 ± 2.8 nm) compared to the other membranes. Moreover, this membrane exhibited the highest porosity (74%) and the highest pure water flux (398 L/m2 h), which was 16% and 1.9 times higher than that of the pristine PES membrane. The modified PES membranes showed an improved antifouling ability, especially against irreversible fouling. Bovine serum albumin protein-based dynamic five-cycle filtration tests showed a maximum flux recovery ratio of 77% (cycle-1), 67% (cycle-2), and 65.8% (cycle-5) for the PES membrane containing 0.25 wt% nanoparticles. Overall, the biphasic Fe2O3-Mn2O3 nanoparticles were found to be an effective nanomodifier for improving the permeability and antifouling ability of PES membranes in protein separation and water treatment applications.

Surface modification and characterization of carbonaceous adsorbents for the efficient removal of oil pollutants.

In this study, the impact of different oxidizing agents on the structural integrity of activated carbon (AC) and multiwalled carbon nanotubes (MWCNTs) was studied for the removal of BTX from aqueous solution. Seven different combinations of green oxidizing agents (mild organic acids) in conjugation with NaOCl (basic oxidizing agent) were used. The modified adsorbents were analyzed by Brunauer, Emmett, and Teller (BET) surface area analyzer, Fourier transform infrared spectroscopy (FTIR), Boehm titration, Raman spectroscopy, thermal gravimetric analysis (TGA), x-ray diffraction (XRD), zeta potential, and variable pressure field emission scanning electron microscope (VPFESEM). The results suggested that the carbonaceous sorbents modified with combination of citric acid tartaric acid, malic acid and salicylic acid (CTMS-I) showed increased surface area (O-AC: 871.67 m2/g, O-MWCNTs: 336.37 m2/g) and total pore volume (O-AC: 0.59 cm3/g, O-MWCNTs: 0.04 cm3/g), with the significantly improved thermal stability. Preliminary batch adsorption experiments conducted using the present prepared O-AC and O-MWCNTs, showed an improved performance towards the adsorption of BTX, compared with other available reported adsorbents in the literature.