Waste-to-wealth conversion of coal fly ash into a catalyst for sustainable organic reactions

Title : Waste-to-wealth conversion of coal fly ash into a catalyst for sustainable organic reactions

Abstract:

The sustainable transformation of industrial waste into value-added functional materials has gained significant attention as a strategy to mitigate environmental pollution while promoting resource efficiency. Coal fly ash (CFA), a major by-product of thermal power plants, presents serious environmental and health challenges due to its large-scale generation, disposal issues, and toxic elemental composition. In the present study, CFA was effectively converted into Zeolite A (ZA) using an ultrasonication-assisted hydrothermal synthesis approach, followed by controlled acid treatment to obtain acid treated Zeolite A (HZA) with enhanced catalytic properties. The acid modification step substantially improved the physicochemical characteristics of the zeolite, resulting in increased surface area, improved pore distribution, and enhanced acidity. Comprehensive characterization using XRD, FE-SEM, EDS, XPS, FTIR spectroscopy, BET surface area analysis, and NH₃-TPD confirmed the successful formation of the zeolitic framework and the development of additional acidic active sites after acid treatment. The catalytic performance of HZA was evaluated in the synthesis of bis(indolyl)methanes (BMs), valuable heterocyclic compounds with pharmaceutical and biological significance. Reactions were conducted in ethanol at 60 °C under mild conditions, yielding a series of BM derivatives with moderate to excellent yields (35–94%). The catalyst exhibited notable stability and recyclability, maintaining consistent catalytic efficiency over five consecutive reaction cycles without significant structural degradation. Overall, this work demonstrates an environmentally benign waste-to-wealth strategy by converting coal fly ash into an efficient solid catalyst for green organic synthesis. The findings reinforce circular chemistry principles and contribute to Sustainable Development Goals 9 and 12, emphasizing responsible production and sustainable industrial innovation.

Biography:

Aashima Mahajan is a Ph.D. Scholar and Assistant Professor-I in the Department of Chemistry and Biochemistry at Thapar Institute of Engineering and Technology (T.I.E.T), Patiala, Punjab, India. Her research centers on materials science, with a focus on zeolite synthesis, advanced characterization, and catalytic applications aligned with circular economy principles. She earned her B.Sc. (Non-Medical) from Panjab University, Chandigarh, and her M.Sc. in Chemistry from T.I.E.T, Patiala, building a strong foundation for research. She has published three research articles in reputed journals. She aspires to build a distinguished academic career, advancing innovative research while inspiring and mentoring future scientists.