Overview of integrated electrocoagulation-adsorption strategies for the removal of heavy metal pollutants from wastewater

Abstract

Removal of heavy metal pollutants from wastewater is critical for preserving a clean environmental setting and guaranteeing universal well-being. Physical, chemical, and biological approaches have been devised for the removal of heavy metals from various wastewater sources. Methods used include electrocoagulation (EC) and adsorption (AD). Although both methods are reported to be efficiently applied in wastewater treatment, the EC method is impeded by high energy consumption, particularly when treating concentrated effluents, as it demands substantial current for coagulant formation. Alternatively, the AD process is hindered by adsorbent saturation and the competitive effects of specific chemicals. Here, we only found limited studies on integrated EC-AD combined process, where the AD and EC were either used in separate or combined system vessels to augment the removal efficiency of heavy metal ions from wastewater or synthetic solutions. It is imperative to conduct more studies on synergistic approaches that combine adsorption with other wastewater treatment methods to address current limits and optimize removal processes. The review identified current density, pH, time, temperature, and adsorbent dosages as factors influencing the EC-AD process in heavy in the removal of heavy metals from wastewater. Although electrocoagulation combined with adsorption has been explored in several studies which have been confined to synthetic effluents, limiting their relevance to real-world scenarios. Therefore, this review proposes for development and design of EC-AD combined technologies to exploit their strengths and minimize associated limitations. Overall, the combined strategies proved more effective and economical compared to individual adsorption and electrocoagulation methods.