Carbon composites for rapid and effective photodegradation of 4-halogen-ophenols: characterization, removal performance, and computational studies

The research deals with the facile ultrasound-assisted in situ sol-gel synthesis of composites of titania and granular activated carbon targeting for the efficient and fast photocatalytic removal of 4-halogenophenols (4HPhs), which possess an adverse effect to humans and ecosystem health. The combination of state of art analytical techniques, such as TEM, BET, XRD, XPS, IR, and DRS revealed the potentially useful photocatalytic properties of synthesized materials based on the availability of titania polymorphs and the contribution of high surface area of activated carbon. Removal efficiency of all composites towards a variety of 4-HPhs was really high (up to 99.9 %) and rapid (1 h). The degradation rate of composite materials was higher than for bare photocatalysts that can be interpreted by the presence of additional elimination forces, mainly, the adsorption on activated carbon. XPS studies of the materials after photocatalysis showed their potential in cyclic usage. The DFT modelling revealed the formation of strong (H-bonds) and weak van der Waals interactions between 4-chlorophenol (4-CPh) and the synthesized materials. The ALIE minima have indicated the most reactive sites in 4-CPh molecule, which were under attack during photocatalysis. The present study proposes the materials with selfcleaning properties to be utilized in chemical pollution treatment.

Automated summary

The research focuses on the synthesis of composites of titania and activated carbon using ultrasound-assisted sol-gel method, aiming at efficient photocatalytic removal of 4-halogenophenols. The analytical techniques used in the study showed the potential photocatalytic properties of the synthesized materials based on the availability of titania polymorphs and the high surface area of activated carbon. The composites exhibited high removal efficiency of up to 99.9% and rapid degradation rate, attributed to the additional elimination forces provided by activated carbon. XPS studies also indicated the potential of the materials for cyclic usage. DFT modelling revealed the interaction between 4-chlorophenol and the synthesized materials during photocatalysis. The study suggests the potential application of the materials in chemical pollution treatment.