Sorption enhancement of TBBPA from water by fly ash-supported nanostructured γ-MnO2

Tetrabromobisphenol A (TBBPA), an emerging contaminant, has been detected frequently in the environmental media. This study reports the adsorption kinetics, equilibrium and thermodynamics of TBBPA on fly ash modified by nanostructured MnO2 (FA@nM). The resulting nano-adsorbent was characterized by means of the Fourier transform infrared spectra (FT-IR), XRD and scanning electron microscope (SEM). The adsorption results showed that the equilibrium adsorption capacity has been significantly improved by increasing the initial TBBPA concentration and contact time. While a large reduction of TBBPA uptake was observed in alkaline conditions and at high temperatures and ionic strength. The equilibrium between TBBPA and FA@nM was achieved in approximately 40 min with removal of 98% of the TBBPA. The sorption kinetics were well described by a pseudo-first-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well at 298 K. Thermodynamic parameters suggested that the adsorption of TBBPA is exothermic and spontaneous at the temperatures studied. As fly ash is a low-cost material that is often available on-site, it offers an interesting alternative to high-cost advanced wastewater treatment systems for removing such organic pollutants.