Advancing Circular Economy in Chemical Engineering: Strategies for Waste Reduction and Resource Recovery

The circular economy (CE) paradigm offers a transformative pathway for chemical engineering by shifting industrial systems from the conventional linear “take-make-dispose” model toward regenerative, resource-efficient processes. This review critically examines strategies for waste reduction and resource recovery within chemical process industries, highlighting the integral role of chemical engineers in enabling circular systems. We explore the principles of circular process and product design, emphasizing green chemistry, atom economy, and design-for-reuse and recyclability strategies. Process intensification, modular manufacturing, and early integration of life cycle thinking are discussed as key enablers for minimizing waste at the source. The review further evaluates advanced resource recovery and valorization technologies, including mechanical and chemical recycling, thermochemical and biological conversion pathways, and the recovery of critical materials such as metals, nutrients, and CO₂. Systems-level circular engineering approaches, encompassing closed-loop process integration, carbon capture and utilization, digitalization, and incorporation of renewable feedstocks, are analyzed to illustrate pathways toward industrial-scale circularity. Sustainability assessment frameworks, including life cycle assessment (LCA), techno-economic analysis (TEA), and circularity performance metrics, are highlighted to quantify environmental, economic, and operational trade-offs. Finally, the review identifies key technical, economic, and regulatory challenges, and outlines emerging research frontiers such as hybrid thermochemical-biological systems, advanced catalysis, and smart manufacturing for circular process industries. This synthesis provides a comprehensive, high-level resource for researchers, engineers, and policymakers, aiming to guide the transition toward more sustainable, resilient, and economically viable chemical process systems aligned with circular economy principles.