Fixed-bed adsorption of bisphenol A onto organoclay: Characterisation, mathematical modelling and theoretical calculation of DFT-based chemical descriptors

Abstract

Bisphenol A (BPA) is a noteworthy and ubiquitous chemical of concern. Up to this day, several methods of water remediation have already been tested, however, few studies have addressed the fixed-bed adsorption of this contaminant. In this regard, this work aimed to evaluate the continuous adsorption of BPA using an organoclay (Spectrogel® type-C) as an adsorbent. The material passed through a series of characterisation techniques to elucidate the impact of the contaminant uptake onto the organoclay. The effect of the operation conditions on the adsorption behaviour was evaluated through breakthrough curves and the calculation of mass transfer and efficiency parameters The system conducted at 0.6 mLmin−1 and 0.2 mmolL−1 obtained the highest removal (95%) until breakthrough point (19.29 h), as well as greater breakthrough and exhaustion adsorption capacities (0.0424 and 0.2151 mmolg−1, respectively). The breakthrough curves were correlated by five distinctive models and the modified dose response model showed the finest fitting to the data (R2 >0.97). Furthermore, the regeneration potential of the spent adsorbent was investigated. It was observed that NaOH solution was a satisfactory eluent. Moreover, density functional theory (DFT) calculations were studied to give further insights regarding BPA adsorption.