Hydrothermal biosynthesis of chromium sulphide nanoparticles using egg yolk and its catalytic activity in degradation of dyes

Enhanced irreversible stabilisation of hexavalent chromium in field-scale industrial waste disposal

Numerous industrial processes generate hazardous by-products, including persistent pollutants like chromium which pose a threat. Safe and cost-effective management of chromium is a major challenge in developing countries. This study investigates the selection and efficacy of chemical stabilizing agents for reducing hexavalent chromium (Cr(vi)) to trivalent chromium (Cr(iii)) in contaminated soil from a mining region in India. Various combinations of stabilizing reagents-including ferrous sulphate (FeSO4), sodium sulphide (Na2S), sodium sulphite (Na2SO3), sodium metabisulphite (Na2S2O3), and sodium thiosulphate (Na2S2O3)-in conjunction with binding agents (fly ash and lime) were evaluated using response surface methodology. The optimized reagent combinations resulting from the response outcome were applied to the contaminated soil samples to assess for irreversibility, leachability, and longevity, ensuring adherence to landfill disposal standards. The study established sodium thiosulphate as the most potent stabilizing reagent, requiring a mere 3.00% (by weight) dosage for treating Cr(vi) contaminated soil by 99.56% while maintaining irreversibility. Analytical determinations using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Fourier transform infrared spectroscopy were performed to determine the crystallinity, surface morphology, and functional groups present in the stabilized material synthesized with Na2S2O3 to devise a stabilization reaction mechanism of Cr(vi) to Cr(iii) transformation. Ultimately, an economic analysis comparison supported the establishment of a combination of Na2S2O3, lime, and fly ash in the ratio of 3.00% : 35.00% : 29.00% as the most cost-effective solution, surpassing conventional reagents' expenses by up to 356.00%.

Smartphone enabled miniaturized temperature controller platform to synthesize nio/cuo nanoparticles for electrochemical sensing and nanomicelles for ocular drug delivery applications

Undoubtedly, various kinds of nanomaterials are of great significance due to their enormous applications in diverse areas. The structure and productivity of nanomaterials are heavily dependent on the process used for their synthesis. The synthesizing process plays a vital role in shaping nanomaterials effectively for better productivity. The conventional method requires expensive and massive thermal instruments, a huge volume of reagents. This paper aims to develop an Automatic Miniaturized Temperature Controller (AMTC) device for the synthesis of nickel oxide (NiO), copper oxide (CuO) nanoparticles, and nanomicelles. The device features a low-cost, miniaturized, easy-to-operate with plug-and-play power source, precise temperature control, and geotagged real-time data logging facility for the producing nanoparticles. With a temperature accuracy of ± 2 °C, NiO and CuO nanoparticles, and nanomicelles are synthesized on AMTC device, and are subjected to different characterizations to analyze their morphological structure. The obtained mean size of NiO and CuO is 27.14 nm and 85.13 nm respectively. As a proof-of-principle, the synthesized NiO and CuO nanomaterials are validated for electrochemical sensing of dopamine, hydrazine, and uric acid. Furthermore, the study is conducted, wherein, Dexamethasone (Dex) loaded nanomicelles are developed using AMTC device and compared to the conventional thin-film hydration method. Subsequently, as a proof-of-application, the developed nanomicelles are evaluated for transcorneal penetration using exvivo goat cornea model. Ultimately, the proposed device can be utilized for performing a variety of controlled thermal reactions on a minuscule platform with an integrated and miniaturized approach for various applications.