Photocatalytic and antimicrobial activity of sulfur functionalized TiO 2 containing composite films

Facile sulfation of TiO2 semiconductor photocatalyst was achieved by a simple grinding and calcination method using elemental sulfur from desulfurization of petroleum. The successful sulfation of the prepared visible-light-active photocatalyst was also proved by infrared and X-ray photoelectron spectroscopic measurements. Photocatalytic tests revealed that the most efficient member of the series has higher photocatalytic activity than TiO2 in the photodegradation of formic acid under both UV and visible-light activation. Moreover, the improved electrokinetic and water dispersibility behaviors of the sulfur-modified photocatalyst allowed the preparation of polyacrylate-based photoreactive thin films with increased photocatalytic activity, strong antimicrobial properties, and improved mechanical behavior

Application of BiVO4/TiO2/CNT Composite Photocatalysts for Membrane Fouling Control and Photocatalytic Membrane Regeneration during Dairy Wastewater Treatment

This study aimed to investigate the performance of composite photocatalytic membranes fabricated by incorporating multiple nanoparticles (TiO2, carbon nanotubes, BiVO4) into polyvinylidene fluoride membrane material for real dairy wastewater treatment. The composite photocatalytic membranes exhibited superior antifouling behavior, lower filtration resistance, better flux, and higher flux recovery ratio than the pristine membrane. Salinity, pH, and lactose concentration are determinant factors that affect filtration resistance and rejection performance during the ultrafiltration of dairy wastewater. Generally, higher irreversible and total resistances and slightly lower chemical oxygen demand (COD) rejections were found at higher salinity (expressed by electric conductivity values of >4 mS/cm) than lower salinity (<4 mS/cm) levels. The presence of lactose in dairy wastewater increased irreversible resistance and severely reduced COD rejection during ultrafiltration due to the ability of lactose to pass through the membranes. It was ascertained that membranes require further treatment after filtrating such wastewater. Lower resistances and slightly better COD rejections were observed at pH 7.5 and pH 9.5 compared to those observed at pH 4. Photocatalytic membranes fouled during the ultrafiltration of real dairy wastewater were regenerated by visible light irradiation. The membrane containing all constituents (i.e., TiO2, carbon nanotubes, and BiVO4) showed the best regeneration performance, exceeding that of the pristine membrane by 30%

Noble metal modified (002)-oriented ZnO hollow spheres for the degradation of a broad range of pollutants

Zinc oxide hollow spheres were fabricated by applying sucrose-derived carbon spheres as templates that were eliminated through calcination. For this purpose, two synthesis methods were examined and compared, chemical impregnation and solvothermal method. The most suitable ZnO hollow structure was selected for noble metal deposition (Au and Pt at 1 wt%) to further increase the photocatalytic activity. The photocatalytic activity was examined by the decomposition of three different model pollutants (phenol, Na-ibuprofen and diuron) under UV irradiation. The as-synthesized hollow sphere structures and its noble metal composites were further examined by XRD, SEM, IR, DRS, PL. The templates did not modify the structure of ZnO only the morphology and contributed to the preservation of the original structure during calcination. The structural, optical and photo- catalytic activity was correlated with both the application of carbon sphere template, and noble metal deposition respective their role in the improvement of the photocatalytic activity

Investigation of the applicability of TiO2, BiVO4, and WO3 nanomaterials for advanced photocatalytic membranes used for oil-in-water emulsion separation

In the present study, a commercial TiO2, several BiVO(4)photocatalysts, a WO(3)nanomaterial, and their composites were used to prepare photocatalytic polyvinylidene fluoride (PVDF) ultrafilter membranes. Their photocatalytic activities and the effects of coatings on the filtration of oil-in-water emulsion (crude oil; c(oil)= 100 mg L-1) were investigated. Fluxes, filtration resistances, purification efficiencies, and fouling resistance abilities-like flux decay ratios (FDRs) and flux recovery ratios (FRRs)-were compared. The solar light-induced photocatalytic decomposition of the foulants was also investigated. WO(3)was used as a composite component to suppress the electron-hole recombination with the goal of achieving higher photocatalytic activity, but the presence of WO(3)was not beneficial concerning the filtration properties. However, the application of TiO2, one of the investigated BiVO(4)photocatalysts, and their composites was also beneficial. In the case of the neat membrane, only 87 L m(-2)h(-1)flux was measured, whereas with the most beneficial BiVO(4)coating, 464 L m(-2)h(-1)flux was achieved. Pure BiVO(4)coating was more beneficial in terms of filtration properties, whereas pure TiO(2)coating proved to be more beneficial concerning the photocatalytic regeneration of the membrane. The TiO2(80%)/BiVO4(20%) composite was estimated to be the most beneficial combination taking into account both the aspects of photocatalytic activity and filtration properties