Activation parameter engineering for rational design of spent coffee grounds-derived activated carbon: A review of structure, performance, and applications

Spent coffee grounds (SCG), a substantial waste byproduct of the global coffee industry, are increasingly recognized as a sustainable precursor for the production of activated carbon (SCG-AC). This review systematically examines the pivotal influence of activation parameters, specifically focusing on activating agents (KOH, ZnCl₂, H₃PO₄) and activation atmospheres, on the resultant structural evolution and performance characteristics of SCG-AC. Through a critical analysis of existing literature, we elucidate the intricate relationships between the pore structure characteristics of SCG-AC and its efficacy in pertinent environmental applications, encompassing water treatment, energy storage, and catalysis. Economic evaluations consistently highlight the notable cost-effectiveness of SCG-AC production in comparison to commercially available activated carbons, thereby underscoring its potential for scalable industrial implementation. This review concludes in evidence-based recommendations for the rational optimization of activation strategies, providing a framework for the tailored design of high-performance SCG-AC materials and advancing the field of sustainable carbon material development.