Recent Developments in Membrane, Adsorption, and Electrochemical Sustainable Approaches for Cadmium Removal from Contaminated Water

The issue of cadmium (Cd(II)) contamination of the water is a serious concern of the environmental and health problem, and this requires effective technology to remove the problem of toxic element. It is the purpose of this review paper to give an overview of several techniques of cadmium removal, such as polymer membranes and composites, adsorption using green materials, and electrochemical methods. The important conclusions are presented regarding the effectiveness of the polymer and composite membranes; e.g., the efficacy of the PES/HPEI-SH membrane that reached 99% removal of Cd(II) in 20 min with adsorption capacity of 135.59 mg/cm 2 , and the PVA/IC/PANI/GO nanofiber composite that indicates high adsorption of the 459 mg/g. The electrochemical process, i.e., electro-membrane extraction, exhibits 90% removal at 60 V, whereas the adsorption-based electro-membrane extraction contains an extraordinary capacity of 496.51 mg/g, using Fe@HC nanocomposites. Furthermore, the removal efficiencies of solar-powered electrocoagulation reached a percentage of 99.1% with respect to Cd(II). The review ends by stating that the tools to resolve cadmium removal problem include advanced materials and hybrid technologies and are promising, but various challenges such as membrane fouling and scalability are undeniable. Future studies ought to emphasize on improving reusability, expense effectiveness, and long-term applicability to address these challenges, thus contributing to the attainment of the United Nations Sustainable Development Goals (SDGs), particularly Goal 6: Clean Water and Sanitation, by guaranteeing the availability and sustainable management of water resources.