Photocatalytic and biomedical investigation of green synthesized NiONPs: Toxicities and degradation pathways of Congo red dye

In this study the biomedical and catalytic ability of green synthesized nickel Oxide nanoparticles (NiONPs) was investigated. The extract of medicinal plant Tribulus terrestris were used to synthesized NiONPs. The as-synthesized NiONPs were in nano scale and were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Energy Dispersive X-ray spectroscopy (EDX). The synthesis of NiONPs was ensured with surface Plasmon resonance (SPR) at 425 nm and the strong EDX. The effect of different concentrations of plant extract on the size of NiONPs was evaluated. The HRTEM results showed particle size between 60 - 90 nm. The study showed that lesser the extract concentration, more spherical and small sized particles were obtained without aggregation. The biological applications of NiONPs were evaluated against different fungal species like Asper gillusflavus, Asper gillusfumigatus, Asper gillusniger and standard medicine Terbinafine. A. niger, A. flavus and A. fumigatus exhibited 57, 63 and 52 % inhibition compared with inhibition of the reference medicine which is 98, 100 and 100%. NiONPs have been shown to be more effective against gram-positive bacteria than gram-negative bacteria like E. Coli 9(±0.7) and S. aureus13 (±0.8). Moreover, antioxidant properties of the as-synthesized NiONPs were evaluated with 2, 2 diphenyl-1-picrylhydrazyl) (DPPH). The catalytic ability of green synthesized of NiONP was investigated for the degradation of Congo red dye (CR) as a hazardous environmentally contaminations in water. The biosynthesized NiONPs were found to be active catalytic for the degradation toxic dyes like CR. the catalytic activity of NiONPs can be explained by its small size compared with balk material. Mechanisms for CR degradation have been proposed. The Ecotoxicity of CR and components derived from dye was investigated with Ecological Structure Activity Relationship (ECOSAR) program

Sonochemical synthesis and characterization of Ho-Cu-O nanostructures and their application as photocatalyst for degradation of water-soluble organic pollutants under UV light

Water pollutants have been a significant concern in recent years. It is essential to use advanced materials that effectively reduce these pollutants. This work introduces Ho2Cu2O5/Ho2O3 nanocomposites as a novel catalyst for photodegradation of various water-soluble organic pollutants. First, Ho2Cu2O5/Ho2O3 nanocomposites were prepared via a simple and fast ultrasonic-assisted route. The chemical and morphological features of the as-synthesized sample were determined using VSM, FTIR, XRD, EDS, SEM, and TEM analysis. Also, the optical bandgaps and pore diameter were determined to be 3.1, 3.6 eV, and 12.74 nm via ultraviolet–visible diffuse reflectance spectroscopy and Brunauer-Emmett-Teller (BET) for Ho2Cu2O5 and Ho2O3, respectively. The findings revealed that the prepared nanocomposite could act as a photocatalyst for removing various organic pollutants from water. 93.01% and 92% of Eriochrome black T (ECBT) and Acid yellow (AY) were degraded under UV irradiation at optimum conditions after 120 min (0.03 g of photocatalyst and 10 ppm of pollutants). The kinetics of the ECBT removal was studied through the Langmuir-Hinshelwood model, and the apparent rate of the pseudo-first-order reaction (k = 0.03465 min−1) was obtained. The use of different scavengers made it clear that formation •O2– species were primarily responsible for the photodegradation of pollutants