ZnO and 2%Fe-ZnO nanomaterials were prepared by using a low-cost sol-gel method. The synthesized nanomaterials were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The XRD and SEM studies reveal that the synthesized nanomaterials have a hexagonal wurtzite structure with average crystalline size ~ 22 to 23 nm. EDX analysis confirmed the composition and purity of synthesized nanomaterial. The photocatalytic activity of synthesized nanomaterials was monitored using the spectrophotometric method. Also, the photocatalytic removal of methylene blue (MB) dye from its aqueous solution by using ZnO and 2%Fe-ZnO nanopowder under UV light irradiation was studied. The effect of various parameters such as pH of dye solution, dye concentration, contact time and catalyst dose were investigated. Results of the current study demonstrated that, the maximum degradation using ZnO was 86% and that for 2%Fe-ZnO was 92% (under the optimum condition initial dye concentration = 10 mg/L and pH = 2). This study showed that 2%Fe-ZnO is a promising and better photocatalysts than ZnO.

This work sought to draw a comparison between the photocatalytic proficiency of NiO nanoparticles (NPs) for the degradation of Methylene blue (MB) and Rhodamine B (Rh B) dye. The NiO NPS were synthesized by a facile straightforward chemical route by utilizing NiCl 2 and NaHCO 3 as a precursor. The morphological characteristics of the synthesized NiO NPs have been characterized by using SEM. In addition XRD, FTIR and EDX analysis were also carried out to investigate the crystalline size, functional group and elemental composition of the NPs. The NiO NPs were subsequently used for the photocatalytic degradation of the MB and Rh B in the presence of the visible light irradiation. For evaluation of photocatalytic proficiency, the influence of various key parameters viz. pH of the dye solution, initial dye concentration, Irradiation time and amount of the catalyst were investigated. The extent of photocatalytic degradation of MB and Rh B was found to be 98.7 and 80.33% at pH 2 and 10 respectively. The kinetic investigation of photocatalytic degradation followed a pseudo-first-order rate kinetics for MB and Rh B dye with rate constant 4.6 × 10 −1 and 3.6 × 10 −2 . Additionally, the synthesized NiO NPs was used for the antimicrobial activity against the few gram-positive and gram-negative microorganisms. Highlights• The NiO nanocrystalline semiconducting photocatalyst was successfully synthesized by a facile straightforward chemical route by utilizing NiCl 2 and NaHCO 3 as a precursor. • Novel simple chemical route synthesis at room temperature.• First time report a combine study of photocatalytic degradation of Methylene blue and Rhodamine B dye by using NiO as a photocatalyst. • Also, Antimicrobial study was examined which clearly indicate the biocompatibility of synthesized NiO nanoparticles.

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The photocatalytic degradation of Cr(VI) from wastewater by using nanomaterials TiO 2 , ZnO, and CdS. All the experiments were carried out in the batch process. The wastewater obtained from various industries. The amount of chromium was removed using photocatalyst with UV light and in the dark at different pH range. The maximum removal of Cr(VI) was observed at pH 2; out of these photocatalyst TiO 2 showed highest capacity for Cr(VI) removal than TiO 2 thin film. The removal of chromium has been studied by considering influent concentration, loading of photocatalyst, pH, and contact time as operating variables. The degradation was characterized by FTIR, XRD, SEM, and EDX analysis before and after application of photocatalysts.

The present work deals with the development of a new method for the removal of dyes from an aqueous solution using polyaniline (PANI)-Fe 3 O 4 magnetic nanocomposite. It is synthesised in situ through self-polymerisation of monomer aniline. Photocatalytic degradation studies were carried out for cationic acid violet 19 (acid fuchsine) dye using PANI-Fe 3 O 4 nanocomposite in aqueous solution. Different parameters like catalyst dose, contact time and pH have been studied to optimise reaction condition. The optimum conditions for the removal of the dye are initial concentration 20 mg/l, adsorbent dose 6 gm/l, pH 7. The EDS technique gives elemental composition of synthesised PANI-Fe 3 O 4 . The SEM and XRD studies were carried for morphological feature characteristics of PANIFe 3 O 4 nanocomposite. The VSM (vibrating sample magnetometer) gives magnetic property of PANI-Fe 3 O 4 nanocomposite; also FT-IR analysis gives characteristics frequency of synthesised PANI-Fe 3 O 4 . Besides the above studies kinetic study has also been carried out.