Leaf Extract Arbitrated Biogenic Synthesis of Silver Nanospheres by a Medicinal Plant from the Western Ghats with Enhanced Antimicrobial Property

In the present study, we report the greener, simple, cost effective, non-hazardous and ecofriendly synthesis of silver (Ag) nanoparticles from Alstonia scholaris (L.) R. Br. for the first time. The synthesis of silver nanoparticles using the leaf stock acted as a reducing as well as the capping agent simultaneously. The bio-reduced silver nanoparticles were characterized using ultra violet-visible spectroscopy (UV) exhibiting blue shift absorption peak in the region 440 nm. The newly synthesized Ag NPs were sphere-like in structure and grew well with a crystalline size of 16.57 nm. The Fourier transform infrared (FT-IR) analysis identifies the biomolecules which are involved during the synthesis process. The synthesized nanocatalyst served as a good catalyst for degrading methyl orange dye under solar light irradiation and was monitored spectrophotometrically. Furthermore, the antimicrobial potential of Ag NPs was evaluated an could competently inhibit different pathogenic organisms, including bacteria and fungi. Additionally, the efficiency of the silver nanoparticles was tested against the photocatalytic degradation of methyl orange dye pollutant. Different operational parameters such as catalyst weight dosage, dye concentration and different pH were optimized. The pollutants were degraded within 35 min. The present research work opens a pathway to synthesize nanomaterial by applying the principles of green chemistry

Novel CuO/chitosan nanocomposite thin film: Facile hand-picking recoverable, efficient and reusable heterogeneous photocatalyst

The present work demonstrates a new simple hand-picking technique for the 100% recovery of a photocatalyst. CuO nanospheres were synthesized by a simple wet chemical method and were subsequently embedded into the biopolymer matrix (chitosan) under mild conditions by the solution cast method and its photocatalytic application towards the degradation of organic pollutants was measured for the first time. The crystal structure, optical properties, surface and bulk morphology were discussed in detail. ICP-OES analysis showed 3.025% copper embedded in the chitosan (CS) matrix. Efficiency of the CuO/chitosan was evaluated against the degradation of rhodamine B dye as a probe. The combination of CuO nanospheres with chitosan leads to the higher efficiency of up to 99% degradation of the dye with 60 minutes of irradiation. This may be attributed to many features such as the slow electron hole pair recombination rate of nanosized CuO in the biopolymer matrix, the large surface area of the CuO and the high adsorption efficiency of the chitosan. The major advantage of this present protocol is that it is not only restricted to azo type dyes but can also be adopted for different kinds of organic pollutants. For all the types of organic contaminants tested, the CuO/chitosan nanocomposite thin film photocatalyst showed excellent activity. The facile hand-picking recovery and recyclability of this novel thin film likely opens up a new straightforward strategy in the effective photocatalytic degradation of organic contaminants