Visible light photocatalytic activity of TiO2 deposited on activated carbon

Abstract

Abstract:© Versita Sp. z o.o. Four photocatalyst samples, prepared from beech sawdust, were synthesized by an original method, combining pyrolysis and impregnation -two of them: TiO 2 + activated carbon and other two -only activated carbon. The pyrolysis process has been carried out at two different temperatures -680°C and 830°C. The prepared samples were characterized by a series of methods -XRD, BET, SEM and DTA/TG. The most important result was achieving visible light photocatalytic activity with an azo dye pollutant for both materials. The TiO 2 /AC-680°C sample demonstrated higher activity under visible light illumination than the TiO 2 /AC-830°C sample. The visible light activity was attributed to the active carbon component in the composite materials, which was evidenced by the photocatalytic tests with bare carbon (without any TiO 2 ) manifesting visible light activity. The AC-680°C carbon was superior to the AC-830°C under visible illumination probably due to its higher specific surface area and porous texture. UV-light testing of the photocatalytic activity revealed that the TiO 2 /AC-680°C sample was higher than that of the TiO 2 /AC-830°C under polychromatic UV-A illumination (320-400 nm with a maximum at l = 365 nm). The TiO 2 /AC-680°C sample was also more efficient with the monochromatic UV-C illumination (l = 254 nm). Keywords: UV-Vis photocatalysis • Photodegradation • Azo dye • Nanosized titania • Active carbon

Preparation of TiO2/Activated Carbon Composites for Photocatalytic Degradation of RhB under UV Light Irradiation

“…In comparison, the photocatalysis is a promising advanced oxidation process, which usually uses heterogeneous titanium dioxide (TiO 2 ) as a photocatalyst to degrade the contaminants by the decomposition and oxidation processes on its surface [13][14][15]. However, there are some disadvantages of TiO 2 used in advanced oxidation process as TiO 2 powder is easy to agglomerate, with poor adsorption capacity, and is difficult to be separated and recycled from the solution [5,16,17]. For the purpose of overcoming the drawbacks of these two approaches, the combination of adsorption and photocatalytic processes was previously proved to be a very promising technology for the treatment of wastewater.…”

“…Jamil et al [30] synthesized photocatalyst by AC impregnated with TiO 2 for the removal of methyl orange from water, and the synergistic effects of adsorption and photocatalytic activity in TiO 2 / AC for the degradation of the methyl orange have been found. Eliyas et al [17] prepared a TiO 2 /AC composite by an original method combining impregnation and physicochemical pyrolysis, and the photocatalytic decomposition of an azo dye pollutant under visible light illumination and ultraviolet (UV) light irradiation was studied. Zhang et al and He et al [6,31] investigated the degradation of methyl orange and Rhodamine B (RhB) by microwave-induced photocatalytic technology using TiO 2 /AC composites.…”

Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

“…Their use has been often prohibited mainly due to their relatively high cost, low selectivity and regeneration problems; they can be regenerated by thermal desorption of the adsorbed substances or by liquid phase extraction in the case of soluble adsorbed species, although the former method is not very environmentfriendly and leads to partial mass loss of the adsorbent [12,16,24,32,48,52,54,63]. The microporous nature of the majority of porous activated carbons is well suited to many applications, including molecular sieving, sorption and catalytic reactions of small molecules.…”

Photocatalytic decolorization of reactive red 198 dye by a TiO2–activated carbon nano-composite derived from the sol–gel method

“…It has been reported that an AC-TiO 2 mixture has a positive effect on photocatalytic activity in the degradation of organic pollutants. In other words, AC, due to its high adsorption capability, can aid in enriching the organic pollutant around the TiO 2 nano-particles, increasing the pollution transfer process and, hence, promoting photocatalytic efficiency [11][12][13][14][15][16][17][18].…”