Facile synthesis of activated biomass loaded with ZnCl2 as eco-friendly adsorbent for BPA and BPS removal: Comparative study on Batch, column and breakthrough performance

Abstract

The presence of endocrine-disrupting chemicals (EDCs) in water bodies presents hazards to human health and the environment, hence it is important to research methods that are cost-effective and eliminate these pollutants. In this work, untreated coir pith (CP-N), activated coir pith at 700 °C (ACP), and Zinc chloride activation with ACP (ACP-Zn1.5) adsorbents were compared for efficient removal of bisphenol A (BPA) and bisphenol S (BPS) in a single and binary system for batch study. Furthermore, the parameters related to isotherms, thermodynamics, and kinetics were established. The ACP-Zn1.5 exhibited a maximum sorption capacity of 42.58 and 32.25 mg/g for BPA and BPS. The isotherms and kinetics correspond to the Freundlich model and pseudo-second-order kinetics for both BPA and BPS. For binary systems, BPA and BPS exhibit combative and mutual effects by achieving a maximum sorption capacity of 39.69 and 19.45 mg/g. To assess the effectiveness of ACP-Zn1.5, studies in a fixed bed column were also conducted with variations in the flow velocity, bed height, and initial BPA and BPS concentration. The adsorption mechanism investigations have demonstrated that the main forces underlying the process are surface interactions such as the formation of hydrogen bonds and π-π interactions. As a result, the obtained ACP-Zn1.5 shows considerable potential for removing bisphenols by adsorption from the aqueous system.