Removal of Bromophenols from Wastewater by Sorption

Abstract

Poly(ether-block-amide) copolymer (PEBA) was used as an adsorbent for sorptive removal of bromophenols, particularly 4-bromophenol (BP), 2,6-dibromophenol (DBP), and 2,4,6-tribromophenol (TBP) from wastewater. Batch sorption experiments were carried out to examine the bromophenol removal efficiency under different conditions, including temperature, pH, solute concentration, as well as sorbent forms (e.g., size). Both the Langmuir and Freundlich models were fitted to the sorption data well, and the sorption capacities of the three bromophenols were evaluated using the isotherm model. The pseudo-second order kinetics model best fitted the kinetic sorption data, and the rate constants of the phenol sorbates were determined. It was shown that both the internal diffusion and surface “reaction” were important during the sorption process. The activation energies for sorption based on pseudo-second order rate constants were found to be 38.0, 29.7 and 27.7 kJ/mol for BP, DBP and TBP, respectively; while the activation energies based on internal diffusion were 41.7, 32.5 and 28.5 kJ/mol, respectively. The sorption performance of bromophenols on PEBA from industrial effluents related to tetrabromobisphenol A (TBBPA) production was evaluated, and the effects of pH, temperature, phenol concentration, contact time on the bromophenol sorption were investigated. The potential use of PEBA sorbent for treating phenol containing industrial effluents was demonstrated. In addition, regeneration tests of PEBA membrane were performed using deionized water and ethanol (99.5% v/v) as regenerating agents, and the feasibility of reusing the regenerated PEBA membrane in treatment of wastewater from TBBPA industry was confirmed.