Preparation and performance study of Mn-doped TiO2-loaded kapok-based activated carbon fibers

Abstract

Due to its various advantages, such as a large specific surface area, high adsorption capacity, rapid adsorption rate, and moderate pore size, activated carbon fiber (ACF) has been extensively employed in wastewater treatment. In this study, the sol–gel-adsorption method was utilized to effectively synthesize Mn-doped TiO2-loaded kapok-based activated carbon fibers (Mn-TiO2/ACF). Several characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption were employed to investigate the Mn-TiO2/ACFs. The resulting Mn-TiO2/ACFs exhibited a combination of anatase and rutile forms in the produced TiO2. The introduction of Mn doping was found to hinder the crystal development, agglomeration, and crystallization of TiO2. The Mn-doped TiO2/ACFs demonstrated significant visible-light photocatalytic activity, attributed to the synergistic effects of two factors: the photocatalytic degradation of TiO2 films and the absorption capacity of ACF. The optimal molar ratio (Mn: Ti) for Mn-TiO2/ACFs in visible-light photocatalytic applications was determined to be 1:150. A pseudo-second-order kinetics model was employed to investigate the adsorption process of methyl bromide on Mn-TiO2/ACFs samples. The experimental results indicated that Mn-TiO2/ACF was reusable, with a removal efficiency exceeding 53% for all five cycles.