Preparation of Activated Carbon/TiO2 Nanohybrids for Photodegradation of Reactive Red-35 Dye Using Sunlight

Abstract

Activated carbon/titanium dioxide (AC/TiO2) nanohybrids were synthesized by a hydrothermal technique using various weight percent of commercial AC and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The synthesized nanohybrids were applied to photodegradation of Reactive Red-35 (RR-35) dye in aqueous solution using sunlight. Due to the synergistic effect of adsorption and photodegradation activity, AC/TiO2 nanohybrids were more efficient in treating the aqueous dye solution than that of AC and TiO2. The maximum (95%) RR-35 dye removal from the water was obtained with 20 wt% AC/TiO2 within 30 min at natural pH of 5.6. The possible photodegradation mechanism of RR-35 dye with AC/TiO2 was discussed from the scavenger test. Moreover, AC/TiO2 was found to be suitable for long-term repeated applications through recyclability experiments. Therefore, AC/TiO2 nanohybrid is a promising photocatalyst for treating azo dyes especially RR-35 from water.

Natural Sunlight Driven Photocatalytic Removal of Toxic Textile Dyes in Water Using B-Doped ZnO/TiO2 Nanocomposites

“…Scavenger studies also confirm that the [23]. The MB photocatalytic mechanism of B-ZnO/TiO 2 nanocomposites is expressed as follows in Equations ( 6)- (11) [33,50,56 of ZnO and TiO2, respectively, when exposed to sunlight. The ECB value of ZnO (−0.16 eV) is more negative than that of TiO2 (−0.14 eV).…”

“…About 54.46% of the dye was removed within 5 min, whereas the MB removal efficiency was 94.73% for 15 min of irradiation. After that, up to 25 min, dye removal efficiency increased slightly as the available dye molecules remaining in the solution were reduced [50].…”

“…To understand the reactive species involved in the B-ZnO/TiO 2 photocatalytic degradation process, scavenger studies were carried out under optimized conditions. Three different chemical scavengers, namely ascorbic acid, 2-propanol, and ammonium oxalate were employed to understand the roles of superoxide radical ions (•O − 2 ), hydroxyl radicals (•OH), and photogenerated holes (h + ), respectively [7,50,51]. The photocatalyst was added to the MB solution after the scavengers.…”

“…It was found that the MB removal efficiency was marginally decreased for the B-ZnO/TiO 2 photocatalyst in the successive cycles. Because of the poisoning effect of degradation products and the blockage of sunlight irradiation, the dye removal efficiency gradually declined through five cycles [50]. Hence, it can be inferred that B-ZnO/TiO 2 is appropriate for the removal of dye from textile wastewater over a long time and with repeated application.…”

Visible-Light-Active Photocatalysts for Environmental Remediation and Organic Synthesis

“…Currently, this issue has collected six papers addressing the preparation and characterization of novel photocatalytic materials and their use in the visible (or solar) lightdriven photocatalytic removal of pollutants from liquid phases and in the inactivation of bacteria [1][2][3][4][5][6]. The photocatalytic efficiencies of Ag 3 PO 4 nanoparticles [2], Bi 12 NiO 19 sillenite crystals [3], g-C 3 N 4 /nanodiamond heterostructures [4], Ag/Cu 2 O [5], and activated carbon/TiO 2 [6] are shown. An improvement in photocatalytic activity toward the simultaneous removal of phenol and Cr(VI) under visible light is also evidenced by MoS 2 decorated on a g-C 3 N 4 heterostructure catalyst [1].…”