ABSTRACT
Utilization of efficient, stable and reusable catalysts for wastewater treatment and catalytic elimination of toxic pollutants is a challenge among researchers. This present work shows the synthesis of high-surface-activity Ag nanoparticle decorated gC3N4 modified MCM-41 and its efficiency towards catalytic hydrogenation of organic dye in the presence of reducing agent NaBH4. The proposed mechanism is based on the transfer of H+ and 2e- between the dye and the catalyst. Adsorption of dye stuff on the catalyst is a rate-determining step and is accelerated by the MCM-41 support which enhances the surface area. The catalytic efficiency and optimum time requirement were examined through the adsorption-desorption equilibrium, pseudo-first-order reaction kinetic model for the dye. The result obtained was 98% catalytic efficiency followed by the catalytic hydrogenation reaction.
ABSTRACT
The natural beauty and purity of our planet has been contaminated deeply due to human selfish activities such as pollution, improper waste management, and various industrial and commercial discharges of untreated toxic by-products into the lap of nature. The collective impact of these hazardous suspensions into the natural habitat is very deadly. Challenges due to human activity on the environment have become ubiquitous. The chemical industry has a major role in human evolution and, predictably, opened gates of increased risk of pollution if the production is not done sustainably. In these circumstances, the notion of Green Chemistry has been identified as the efficient medium of synthesis of chemicals and procedures to eradicate the toxic production of harmful substances. Principles of Green Chemistry guide the scientist in their hunt towards chemical synthesis which requires the use of solvents. These solvents contaminate our air, water, land and surrounding due to its toxic properties. Even though sufficient precautions are taken for proper disposal of these solvents but it is difficult to be recycled. In order to preserve our future and coming generation from the adverse impacts associated with solvents it is very important to find alternative of this which will be easy to use, reusable and also eco-friendly. Solvents are used daily in various industrial processes as reaction medium, as diluters, and in separation procedures. As reaction medium, the role of solvent is to bring catalysts and reactants together and to release heat thus affecting activity and selectivity. The proper selection of the solvent considering its biological, physical and chemical properties is very necessary for product separation, environmental, safety handling and economic factors. Green solvents are the boon in this context. They are not only environmentally benign but also cost effective. The biggest challenge faced by the chemists is adaptation of methods and selection of solvents during chemical synthesis which will give negligible waste product and will remain human and nature friendly. During designing compounds for a particular reaction it is difficult to give assurance regarding the toxicity and biodegradability of the method. Chemists are still far away from predicting the various chemical and biological effects of the compounds on the back of the envelope. To achieve that point is formidable task but it will definitely act as inspiration for the coming generation of chemists. The green solvents are undoubtedly a far better approach to eliminate the negative impacts and aftermath of any chemical synthesis on the environment. Our study in this review covers an overview of green solvents, their role in safer chemical synthesis with reference to some of the important green solvents and their detail summarization.
