Research Projects

Spent catalysts from petrochemical industries are often landfilled and this contributes to polluting the environment due to the presence of heavy metals and PAHs (Polyaromatic hydrocarbons). Lack of proper disposal & treatment methods are a concern for the petrochemical industries, municipalities and general public as well. Hence, recycling of such wastes is highly essential in terms of developing a clean and green technology using the principles of 3Rs (Recycle, Reduce & Reuse) from a circular economic point-of-view. It is very important to note that biotechnological applications are gaining a lot of popularity for spent catalyst treatment; however, with regards to the Indian context, such studies are very limited with lack of a dedicated concept for safe treatment. As our natural mineral resources are depleting at a faster rate, the focus is now on the utilization of secondary resources for metals supply and spent catalysts from the petrochemical industries are a good source of such metals e.g. the Nickel Spent Catalyst. This catalyst can contribute Ni supply for Li-ion batteries, as a raw material, since “Ni” is expected to substitute “Co” for the next generation batteries. The “technological limitations”, “raw material (e.g. metal) applications for battery sector” and the prospects of “green recycling of industrial waste” through microbial systems provide the main rationale. Hence, the current proposal is designed with the hypothesis that bio-recycling of spent-catalysts in a “closed-loop system” can supply metals (e.g. Ni) for the next generation batteries in addition to lowering the toxicity levels of this waste to a larger extent. The overall concept of the project lies in developing a biotechnological “proof-of-concept” where waste is converted into resource. At first the spent catalyst will be characterized for its mineralogy/metal content. Acidophilic bacterial consortium (lab stock) will be employed to leach Ni from the spent catalyst sample and several physico-chemical and biological process parameters will be optimized. The bioleach liquor generated under optimum bioleaching conditions will be characterized for PAH and other standard parameters as per “Standard Methods for Examination of Water and Wastewaters, American Public Health Association (APHA), 2005 guidelines”. PAH biodegrading microbes will be isolated from mine sites and enriched over the sample to improve PAH biodegradation in the bioleach liquor. PAH biodegradation studies will follow with model/standard compounds after their identification from the liquor. The bioleach liquor will further be processed through electrowinning technique to recovery Ni metal. Throughout the project, at several points, microbial consortia will be characterized and the microbial community dynamics will be studied. In this way, a “proof-of-concept” will be developed as per the project objectives. This work is highly novel as such studies are not only lacking in India but also globally.