Fabrication and characterization of a thin coated adsorbent for antibiotic and analgesic adsorption: Experimental investigation and statistical physical modelling

Abstract

Sulfamethoxazole (antibiotic) and acetaminophen (analgesic) are classed as common Contaminants of Emerging Concern (CEC) that have been detected in significant quantities in sewage treatment plants in Malaysia and other countries. Unfortunately, the conventional sewage treatment plants are not effective to reduce the concentrations of these compounds. Therefore, this study introduces a novel Contaminant Emerging Remover (COATER) to face the pollution caused by these CECs. This COATER was formulated using epoxidized neutral rubber (ENR-50) and poly(vinyl) chloride (PVC) as binders besides activated carbon as an adsorbent, which was coated on white cotton fabric (substrate) via brushing technique. Characterization analysis of this COATER was performed using SEM-EDX, FTIR and BET quantifications to study the surface chemistry and to obtain insights about the adsorption mechanism. Results of surface morphology analysis showed a good distribution of activated carbon onto the substrate where the surface area and pore volume of the COATER were 64.3 m2/g and 0.07 cm3/g, respectively. Adsorption isotherms of tested CECs on COATER were experimentally quantified at different temperatures. A monolayer adsorption model based on statistical physics was used to understand the adsorption mechanism. Modelling results showed that the adsorption orientation of tested molecules was similar but it could occur a change in the interaction of these pollutants with the adsorption sites of COATER surface during the removal process since this adsorbent contained a variety of functional groups. It was concluded that the adsorption mechanism of tested adsorbates on COATER included pore interaction, chemical bonding and electrostatic forces.