Introducing a new co-polymeric adsorbent with fast sorption rate and high sorption capacity for removing the heavy metal ions: A thermodynamic and kinetic study

Heavy metal ions have been recognized as the most hazardous contaminants of water sources. In this study, a novel polymeric adsorbent based on 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AA), and 1,4-butanediol dimethacrylate (BDDMA) was successfully synthesized and its efficiency in removal of selected heavy metal ions (Pb2+ and Cd2+) were investigated. The role of significant parameters such as pH, contact time, adsorbent dose, metal ions concentration and temperature on removing harmful metal ions were logically studied. Results showed that the amount of pH, contact time and polymer adsorbent dose had direct relation in adsorption of metal ions. While increasing metal ion concentrations have no significant effect in metal ions adsorption and that was fixed up to 15 mg/L. Adsorption isothermal process of the new polymeric adsorbent was studied by several selected models and also maximum values of adsorption capacities of the introduced adsorbent for Pb2+ and Cd2+ ions were characterized. Adsorption /desorption cycles of synthesized polymer adsorbent were around 15 times. According to the modeling of adsorption data, the pseudo-second-order kinetic equation could best describe the adsorption kinetics. According to the intra-particle diffusion studies adsorption of heavy metal ions might be dominated by external diffusion mechanism.