Semiconductor titanium dioxide in its basic form or doped with metals and non-metals is being extensively used in wastewater treatment by photocatalysis due to its versatile nature. Other numerous characteristics including being environmentally friendly, non-pernicious, economical, multi-phase, highly hydrophilic, versatile physio-chemical features, chemical stability, suitable band gap, and corrosion-resistance, along with its low price make TiO₂ the best candidate in the field of photocatalysis. Commercially, semiconductor and synthesized photocatalysts—which have been investigated for the last few decades owing to their wide band gap—and the doping of titania with p-block elements (non-metals) such as oxygen, sulfur, nitrogen, boron, carbon, phosphorus, and iodine enhances their photocatalytic efficiency under visible-light irradiation. This is because non-metals have a strong oxidizing ability. The key focus of this review is to discuss the various factors affecting the photocatalytic activity of non-metal-doped titania by decreasing its band gap. The working parameters discussed are the effect of pH, dyes concentration, photocatalyst’s size and structure, pollutants concentration and types, the surface area of photocatalysts, the effect of light intensity and irradiation time, catalyst loading, the effect of temperature, and doping impact, etc. The mechanism of the photocatalytic action of several non-metallic dopants of titanium dioxide and composites is a promising approach for the exploration of photocatalysis activity. The various selected synthesis methods for non-metallic-doped TiO₂ have been reviewed in this study. Similarly, the effect of various conditions on the doping mode has been summarized in relation to several sorts of modified TiO₂.

Background: Currently, developing methods for the formation of nanoparticles with antimicrobial properties based on green chemistry are the research hotspots. In this research, green biosynthesis of Eriobotrya japonica extract loaded silver nanoparticles and their characterization were the main objectives to achieve. Methods: Green synthesis of E. japonica leaves extract-loaded silver nanoparticles (AgNPs) was carried out and its effect on bacterial growth was examined. The reduction of silver ions in the solution was observed using a UV-Vis spectrophotometer. The properties of AgNPs were assessed using Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Xray Diffraction (XRD). Also, their antibacterial effects were checked against Staphylococcus aureus and Escherichia coli. Results: It was revealed that 5-50 nm sized spherical to elongated nanoparticles were synthesized that possessed comparatively better antibacterial potential against E. coli and S. aureus than the conventional extract of the E. japonica leaves. Conclusions: Green synthesis and effective utilization of Eriobotrya japonica extract loaded silver nanoparticles are a promising approach for nanoparticle production avoiding negative environmental impacts.

Metal nanoparticles are being used for different applications especially for the removal of toxic pollutants from different environmental segments. In this study, chitosan supported AgCdO nanoparticles have been prepared for the removal of toxic dyes from aqueous medium. Chitosan supported AgCdO nanoparticles (AgCdO-BMNPs@Ch) were synthesized and characterized using different techniques including UV/Vis, FT-IR, XRD and SEM to assess their formation as well as morphology. Crystallite size of bimetallic nanoparticles and composite was found to be 42.15 nm and 38.23 nm respectively. Particle size of nanoparticles as well as composite was also calculated using SEM images and flower Dahlia-like morphology of AgCdO nanoparticles was observed while the composite displayed colonies. In addition, the samples were than studied for catalytic degradation of cationic dyes Malachite green, Rhodamine-B and Methylene blue (MG, Rh-B and MB). Removal of the dyes via catalytic degradation using synthesized samples was recorded up to 91.62 %, 92.42 %, 96.16 % for RhB, MG and MB respectively. Performance of samples was also tested under different conditions and their recyclability was also evaluated. On the basis of current study, authors recommend the preparation of biopolymer supported bimetallic nanoparticles to improve their stability as well as efficiency.