Cadmium Removal from Water Using Conventional and Emerging Adsorbents: Current Status, Challenges, and Future Perspectives

Cadmium is one of the most hazardous waste products of industrial operations including metallurgical processes, electroplating, manufacturing of batteries, and mining. Cadmium is carcinogenic in nature and extensive exposure to it via food chain can lead to human diseases. This review provides a critical evaluation of research work conducted on the technical feasibility of multiple adsorbents (carbon-based materials, agriculture waste biomass, microbial biomass, cellulose and chitosan, metallic nanoparticles, clays, MOFs, zeolites, Mxenes and aerogels) used for the removal of cadmium from aqueous media. The study is distinguished from previous works by synthesizing and comparing a wide range of both conventional and emerging Cd adsorbents within a unified mechanistic and practical framework that links material characteristics to operational performance and feasibility considerations. It highlights the fundamental trade-offs between lab-scale efficiency and real-world viability, with a specific focus on scalability, regeneration, and cost-effectiveness. It also highlights the fundamental divergence between theoretical efficiency and practical application, contrasting the high-cost, high-performance of engineered materials with low-cost natural adsorbents. This unique approach simplifies the complex decision-making process for researchers to choose a viable adsorbent and offers a clear roadmap for future research in the field of adsorption technology for the removal of cadmium.