Degradation of Hazardous Dyes in Wastewater using Nanometer Mixed Crystal TiO2 Powders under Visible Light Irradiation

Abstract

The partial phase transformation of nanometer TiO 2 powder from anatase phase to rutile phase was realized by heat-treatment and a new TiO 2 photocatalyst which could be excited by visible light was obtained. The heat-treated TiO 2 powder at different stage of transition crystal was characterized and monitored by XRD, TEM, FT-IR and UV-vis DRS methods. The test of photocatalytic activity of the heat-treated TiO 2 powder was carried out by the photocatalytic degradation of rhodamine B and acid orange II dyes, respectively, in aqueous solution under visible light irradiation. The results indicate that the nanometer TiO 2 photocatalyst heat-treated at 500°C for 60 min shows the highest photocatalytic activity, that is, it can effectively degrade the rhodamine B and acid orange II under visible light irradiation. The remarkable improvement of photocatalytic activity of heat-treated TiO 2 powder at 500°C for 60 min was mainly illustrated by the formation of special interphase between rutile and anatase phases, which not only restrains the recombination of photogenerated electrons and holes, but also reduces the adsorbability of nanometer anatase TiO 2 powder properly for various dyes. Additionally, the effects of dye-assisting chemicals such as Na 2 CO 3 and NaCl on the photocatalytic degradation were also studied.

Impact of Ti‐V ratio on the crystalline phase/visible light activity of TiV‐oxide photocatalyst

“…The band at 1630 cm 21 could also belong to TiÀ ÀO [15]. The conversion of mixed phase to rutile is observed in the spectra wherein a shoulder at 550 cm 21 corresponding to anatase (present in the mixed phase) gets converted to sharp peaks at 530 and 640 cm 21 corresponding to rutile phase [16] confirming the XRD results. The band at 985 and 598 cm 21 could be due to V¼ ¼O and VÀ ÀO vibrations, respectively [8].…”

Photocatalytic degradation of Amaranth and Brilliant Blue FCF dyes using in situ modified tungsten doped TiO2 hybrid nanoparticles

“…The rate constants are 0.075 min À1 and 0.063 min À1 for Brilliant Blue FCF and Amaranth, respectively. 27 3.4.2 Effect of light source and its duration on photocatalytic degradation of Brilliant Blue and Amaranth. Fig.…”

Catalytic damage of bovine serum albumin by metronidazole under ultrasonic irradiation in the presence of nano-sized TiO2 powder

“…Due to the phys iological importance, easy separation and purifica tion, the bovine serum albumin (BSA) is often selected as a model globular protein in biological and medici nal chemistry [9][10][11][12]. Otherwise, because the semi conductor TiO 2 has many advantages, such as chemi cal stability, photocatalytic activity, high catalytic effi ciency, nontoxicity and low cost, it has been widely used as a photocatalyst for degradation of environ mental contaminants [13][14][15][16][17][18]. In the previous research work, our research group had reported that the nanosized TiO 2 powder as a sonocatalyst to dam age BSA molecules [2].…”