From classic to cutting-edge solutions: A comprehensive review of materials and methods for heavy metal removal from water environments

Waterborne heavy metals pose significant threats to both the environment and public health, causing neurological damage, developmental disorders, organ damage, and cancer. It is essential to address the contamination of various water bodies by these hazardous substances due to their persistent nature and lack of biodegradability. This review thoroughly explores traditional and modern strategies utilized to remedy water sources contaminated with various heavy metals and evaluates the effectiveness and potential scalability of each method. A literature survey reveals several effective strategies for removing heavy metals from water: adsorption, flotation, ion exchange, chemical precipitation, membrane-based filtration, coagulation, flocculation, phytoremediation, and electrochemical methods. In our examination, we discussed the agents/adsorbents used, the efficiency of the removal technique, operating conditions, and the intrinsic advantages and disadvantages of each approach. Summarizing key findings, we noted a significant focus on adsorption techniques; however, challenges include selectively removing diverse ions, prolonged retention times, and cycling stability. While chemical and membrane methods are practical, persistent issues like large-volume sludge formation exist. Although electrical-based methods appear promising, solutions are needed for large-volume sludge and industrial-scale separation as well. Prioritizing real wastewater samples in heavy metals removal studies is crucial. Future research should emphasize eco-friendly, cost-effective methods.