Adsorption Study of Cu²⁺ by Using CO₂/Electric Potential-Responsive Polymeric Monoliths Prepared by Medium Internal Phase Emulsion

Environmental contamination resulting from heavy metals is regarded as a fundamental issue in environmental biology. In this study, a polyacrylamide-based adsorbent stabilized by a styrene–maleic anhydride copolymer (SMA) functionalized with l-histidine was utilized for the removal of copper metal from aqueous solutions. The objective of this research is to investigate the feasibility of utilizing this adsorbent for the purpose of adsorbing copper ions (Cu2+) from an aqueous solution under various environmental conditions. The Taguchi method was employed to figure out the optimal conditions for removal based on a series of 25 experimental trials. The study’s findings indicated that Cu2+ removal had an efficiency range of 42.9% to 81.8%, with variations shown based on the combination of controllable parameters. The controllable parameters of Cu2+ removal were shown to have a variety of influences, with pH having the most impact, followed by initial Cu2+ concentration, contact time, and the stabilizer’s l-histidine mole ratio, in descending order. We present an environmentally beneficial desorption and regeneration concept that involves the use of a polymeric adsorbent that responds to carbon dioxide (CO2) and electric potential (EP). This concept has not been previously reported and is exhibited through the use of the medium internal phase emulsion (MIPE) method. Most notably, at room temperature and atmospheric pressure, CO2 bubbling can desorb and recover Cu2+ ions in 5 min. Then, by simply applying EP, the adsorbent can be returned to its adsorptive form and reused after the CO2 has been removed.