Exploring of the sorption mechanism of endocrine disruptors on a newly developed cost-effective microporous material derived from puck (Afroxtyrax lepidophyllus) shell

Abstract

Tetrabromobisphenol A (TBBPA), due to its recognized dangerous effects such as interfering in the hormonal system, requires special attention for scientists. This work opens with the aim of depolluting TBBPA in the environment by adsorption in batch mode using activated carbon prepared from puck shell. Absorbent prepared from the puck shells (CRP) bio-based material have been characterized by advanced techniques such as iodine number, EDX mapping, FT-IR, FE-SEM, XRD, N2 adsorption/desorption. Analysis show a high carbon rate in the activated carbons obtained with a surface essentially made up of acid functions. In addition, the Activated carbon derived from puck shell (CRP) exhibited an amorphous phase consisting of mesopores and micropores. The specific surface area obtained from the BET was 502 m²/g. Optimum conditions of TBBPA adsorption obtained from response surface methodology using Box-Behnken model were 200 mg for activated carbon, 15mg/L for TBBPA concentration at pH 7.6, a stirring time of 89 minutes, with a retention percentage of 87.9%. The mechanism explained from the adsorption isotherms and kinetics showed a multilayer and favorable adsorption involving π-π interactions, possibility of ion exchange, Van der Waals and hydrogen bonds. Computational modeling was carried out through functional density theory and Monte Carlo molecular modeling to elucidate the underlying mechanism. These confirmed the experimental results indicating a strong affinity between CRP and TBBPA in a slightly basic medium with adsorption energy of -135.25 Kcal/mol. The results of desorption process using sodium hydroxide, water and ethanol as desorbing agents obtained show that the CRP are indeed reusable.