Self-assembling of 3D layered flower architecture of BiOI modified MgCr2O4 nanosphere for wider spectrum visible-light photocatalytic degradation of rhodamine B and malachite green: Mechanism, pathway, reactive sites and toxicity prediction.

In this study, 3D BiOI nanoparticle (BOI NPs) modified MgCr2O4 nanoparticle (MCO NPs) was fabricated by simple sonochemical and coprecipitation method for the enhanced photocatalytic activity. The morphological structure of the MgCr2O4-BiOI nanocomposite (MCO-BOI NCs) was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS), electron impedance spectroscopy (EIS) and photo luminescence (PL). The lower in the PL intensity and small arc in EIS for NCs shows the effective charge separation and lower in rate of recombination of charge carriers in NCs than the pure MCO and BOI NPs. The degradation efficiency of Rhodamine B (RhB) and malachite green (MG) by MCO-BOI NCs was found to be 99.5% and 98.2% receptivity. In addition, the photocatalytic degradation of RhB and MG was studied under various environmental parameters (different pH, varying the concentration of NCs and dyes) and response surface (RSM) plot was performed. The complete mineralization of RhB and MG by MCO-BOI NCs was determined by TOC. In addition, the photocatalytic degradation pathway was elucidated based on GC-MS results and Fukui function. In addition, the toxicity of intermediate formed during the degradation of RhB and MG was predicted by ECOSAR. The present work highlights the application of MCO-BOI NCs in environmental remediation for toxic pollutant removal.

A novel biogenic Allium cepa leaf mediated silver nanoparticles for antimicrobial, antioxidant, and anticancer effects on MCF-7 cell line.

In the present study, Allium cepa leaf extract was utilized to reduce the silver nitrate into the nanoscale range of silver ions (Ag NPs). The biosynthesized Ag NPs were extensively characterized by X-ray diffraction analysis (XRD), Dynamic light scattering analysis (DLS), UV-Visible spectroscopy (UV-vis), Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). The antioxidant activity of synthesized Ag NPs was verified by DPPH assay. From the results obtained from XRD and DLS studies, the size of Ag NPs was determined to be around 54.3 nm. The measured zeta potential value of -19.1 mV confirms the excellent stability of biosynthesized Ag NPs. TEM analyses reveal that the biosynthesized Ag NPs have a spherical structure of 13 nm in size. The presence of various functional groups was confirmed through FTIR studies and EDAX verifies the weight percentage of silver content in biosynthesized nanoparticles to be 30.33%. In the present study, anti-cancer activity was carried out by using breast cancer cell line MCF-7. Further, silver nanoparticles exhibited antimicrobial effectiveness against gram-positive Bacillus cereus and gram-negative Escherichia coli. The MTT assay also showed better cytotoxic activity against the MCF- 7 cell line.