photocatalytic properties

Photo-electro-catalysis process has received major attention in the past decade as a substitutional wastewater treatment technology. Photo-electro-catalysis process is widely employed for removing different pollutants (organic, and inorganic (cationic and anionic)) from wastewater. It has been recently developed by modifying the photo-reactor system, the experimental parameters, and the structure of photo-anodes during preparation to enhance the pollutants removal from wastewater, reduce their adverse health risk resulting from environmental accumulation, and give a chance to reuse the treated wastewater for a variety of applications. This review aims to summarize recent studies (especially in the last five years) that developed the photo-electro-catalytic degradation system of organic, heavy metal, and mixed pollutants under UV light, visible light, and sunlight. This review demonstrates the effect of experimental variables, photo-reactor arrangements, mass transfer, phase, length, and diameter of nanoparticles or tubes on the anode, type of deposition on the anode, and cathode characteristics (type and dimensions) on the photo-electro-catalytic technologies. The drawbacks of photo-catalysts, affecting the photo-electro-catalytic properties, are also discussed and solved. Finally, the review focuses on the photo-electro-catalysis enhancements by combining this process with other proven treatment processes. This review can provide perspectives on the important factors that evolve photo-electro-catalysis for the complete purification of polluted wastewater in the future.

Hierarchical Cadmium Sulphide (CdS) thin films with high-surface area were deposited on a glass substrate using a hydrothermal technique at various deposition periods' durations for the first time. As-deposited CdS films have been investigated structural, optical, morphological, and photocatalytic properties. The results demonstrate that the deposition period has a substantial impact on the physical and chemical characteristics of these films. X-ray diffraction (XRD) revealed that the structural characteristics of all samples are hexagonal and cubic phases. Field emission scanning electron microscopy (FE-SEM) reveals the development of hierarchical nanoflowers with tiny gaps at lower deposition times; nevertheless, the density of the nanoflakes rises as the deposition time increases. Atomic force microscope (AFM) images of the films indicate morphological alterations and an increase in surface roughness from 4.58 nm to 7.26 nm. In conjunction with different time deposition, the photoluminescence (PL) behavior of the samples is outstanding, with acceptable transmittance spectra in the visible range. The optical band gap is directly connected to the deposition conditions, according to the transmittance data analysis; a direct bandgap ranging from 2.34 to 2.17 e V was calculated. The nanoflowers cadmium sulfide films exhibited unprecedented photocatalytic activities for the decomposition of methyl blue (MB) and methyl violet (MV) dyes, because high surface area, low energy gap, and efficient charge separation properties for prepared films.

In this study, single-phase bismuth ferrite (BiFeO3) was synthesized using hydrothermal method. The effect of KOH concentration and temperature during the reaction on morphology, particle size, and phase formation was investigated. Then, the structural properties of the samples were assessed using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) analysis. XRD analysis results revealed that the samples were fabricated in distorted rhombohedral perovskite structure with R3C space group. Also, BiFeO3 (BFO) was formed in a single-phase at 220 °C and 4M concentration of KOH. The magnetic properties of the optimal sample were determined by VSM analysis and very weak magnetic properties were observed in pure nanoparticles. Also, the optical properties and photocatalytic properties of the optimal sample were investigated by UV-visible and Photoluminescence (PL) analysis. The optical gap of BFO was recorded by 2.8 and its photocatalytic properties were investigated at three different pHs (2, 6, and 10) at a concentration of 20 ppm Congo red. The results demonstrated that BFO nanoparticles nearly destroyed dye structure after 120 min at pH = 2.

With pathogenic microorganisms such as bacteria around our lives, research and finding an effective antibacterial agent is essential. This study prepared and developed a novel nanocomposite based on photocatalytic properties. For grafting of copper (I) oxide nanoparticles in reduced graphene oxide sheets, the simultaneous reduction reaction of graphene oxide and copper (II) acetate monohydrate salt in the presence of sodium borohydride was used to reduce agent. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron (XPS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray (EDAX), and Raman spectroscopy studied and identified the prepared nanocomposite. These studies showed that 2D rGO is well-decorated by Cu2O nanoparticles. The results of antibacterial tests showed that the synthesized nanocomposite has excellent antibacterial properties, and due to exposure to UV light for 6 h, these properties have been increased. Also, the toxicity of nanocomposite indicated that this agent had biocompatibility properties.

In this work, sol-gel process was chosen to produce a photocatalytic film to degrade methylene blue. To study the structural and morphological properties, a base sol of TTIP, I-PrOH, and DEA were created. Then, with addition of 45 g/L PEG 2000, 30 g/L TiO2, and 15 g/L PEG 2000+30 g/L TiO2, three other additional sols were produced. The results of the thermogravimetry and differntial thermal analysis indicated that a calcination temperature of 550 °C is sufficient to calcinate all four layers formed in four sols. Structural X-ray studies showed that, calcination temperature is dependent of the composition. The results of this study revealed that, substrate will have an effect on the photocatalytic behavior. It was concluded that the rough sand blasted surface because of creating more film islands that enhances photocatalytic behavior is a better substrate surface condition. Degradation of Mb showed that as a result of more TiO2 corporation in the film produced by the fourth sol, the fourth sol is superior in terms of photocatalytic behavior. Also it was found that, degradation of Mb is dependent on the initial concentration; and the higher initial concentration, the lower is the efficiency.