Adsorption of Bisphenol S from aqueous solution on powdered activated carbon and chronic toxicity evaluation with microcrustacean Ceriodaphnia dubia

Abstract

Due to its toxic effects in aquatic organisms and in humans, Bisphenol A (BPA) has been replaced by Bisphenol S (BPS) as additive in the production of epoxy glues, baby bottles, cardboard, thermal paper, among others. In this study, the removal of chronic toxicity of BPS from aqueous solution was evaluated by adsorption on powdered activated carbon (PAC) using commercial carbons from two distinct matrices (vegetal and mineral). The characterization of adsorbents was performed by infrared spectroscopy, surface area BET (Brunauer, Eminett e Teller), Scanning Electron Microscopy (SEM) and zeta potential. The adsorption kinetics and isotherms were evaluated. The chronic toxicity was measured through assays with the organism Ceriodaphnia dubia for 7 days. The kinetics for both absorbents were fitted to pseudo-second-order models in experimental initial conditions of 2 mg L−1 and 30 mg L−1, pH 6.5 and temperature of 25 °C, with removal efficiency of 94 % at equilibrium in 60 min for mineral PAC and of 88 % in 120 min for vegetal PAC. Furthermore, the isotherm model proposed by Freundlich presented the best settings for both PAC. Activated carbon adsorption may be an efficient method for the reduction of chronic toxicity, reaching no observed effect concentration (NOEC) in the organisms at 1.56 μg BPS L−1.