Adsorption of Cu²⁺ Ions using Rubber-Based Hydrogel

Abstract

Hydrogels are one of the most powerful adsorbents for removing heavy metal ions among all adsorbents. However, most of today's hydrogels are synthetic polymers with high costs, non-environmentally friendly, and have low stability. Therefore, in this study, natural rubber (NR) was used as the basic material for hydrogels due to its high mechanical properties, plasticity or viscosity, elasticity, and tensile strength. This study is focusing on the Cu adsorption method using a rubber-based hydrogel that is prepared with a combination of acrylic acid (AA) and methylenebisacrylamide (MBA). The rubber-based hydrogel was immersed in the synthetic Cu wastewater, and the percentage removal was calculated. Cu initial concentration, contact time, and rotation speed were the three independent variables used for optimization using Response Surface Methodology (RSM). With an initial Cu concentration of 47.66 mg/L, a contact time of 10 hours, and a rotation speed of 91.32 rpm, RSM optimization shows that the best conditions for Cu removal are 72.19%. The SEM-EDX micrograph of the hydrogel before adsorption shows numerous pores, but after adsorption it is smoother and has fewer holes. This study will contribute to the development of a new method to remove Cu from wastewater.