Removal of Bisphenol S (BPS) by Adsorption on Activated Carbons Commercialized in Brazil

This study assessed three powdered activated carbons (BETM, COCO, and SIAL) commercialized in Brazil at the bench scale in agitated reactors, analyzing their kinetic behavior and adsorptive capacity for BPS and BPA in ultrapure water. BETM exhibited the highest adsorption capacities (Q⁰_max) for BPS and BPA at 260.62 and 264.64 mg/g, respectively, followed by SIAL, with a Q⁰_max of 248.25 mg/g for BPS and for 231.20 mg/g BPA, and COCO, with a Q⁰_max of 136.51 mg/g for BPS and 150.03 mg/g for BPA. The Langmuir isotherm model can describe the processes well. A pseudo-second-order model can describe the adsorption kinetics, and SIAL carbon had the highest rate constants (7.45 × 10^-3 mg/g/min for BPS and 2.84 × 10^-3 mg/g/min for BPA). The Weber-Morris intraparticle diffusion model suggests intraparticle diffusion as the rate-limiting step of all adsorption processes. Boyd's model confirmed more than the mechanism actuating in the bisphenol adsorption. The results suggest that adsorbents with basic surfaces, high specific surface areas, and high mesopore volumes tend to remove BPS and BPA efficiently. Therefore, activated carbons can effectively complement the existing treatment in Brazilian water treatment plants (WTPs).