Abstract
The aim of this study was to modify surface properties of immobilized rutile TiO2 using Argon cold plasma treatment and to evaluate the performance of the catalyst in photocatalytic elimination of synthetic dyes in UV/TiO2/H2O2 process. The surface-modified TiO2 was characterized by XRD, EDX, SEM, UV-DRS and XPS analyses. Response surface methodology was adopted to achieve high catalyst efficiency by evaluating the effect of two main independent cold plasma treatment parameters (exposure time and pressure) on surface modification of the catalyst. The increase of the plasma operation pressure led to higher decolorization percentage, while the increase of plasma exposure time decreased the decolorization efficiency. RSM methodology predicted optimum plasma treatment conditions to be 0.78 Torr and 21 min of exposure time, which resulted in decolorization of 10 mg/L solution of the malachite green solution by 94.94% in 30 min. The plasma treatment decreased the oxygen to titanium ratio and caused oxygen vacancy on the surface of the catalyst, resulting in the superior performance of the plasma-treated catalyst. Pseudo first-order kinetic rate constant for the plasma-treated catalyst was 4.28 and 2.03 times higher than the rate constant for the non-treated photocatalyst in decolorization of aqueous solutions of malachite green and crystal violet, respectively.
Highlights
About 1–20% of total annually produced synthetic dyes are released into the effluents of the textile, paper, pharmaceutical, food, and plastic industries [1,2]
To modify the surface of rutile TiO2 nanoparticles immobilized on glass plates, cold plasma in
Photochemical decolorization was conducted in a rectangular batch reactor (3 cm × 3 cm × 21 cm) containing TiO2 nanoparticles immobilized on glass plates
Summary
About 1–20% of total annually produced synthetic dyes are released into the effluents of the textile, paper, pharmaceutical, food, and plastic industries [1,2]. TiO2 and reported that after 120 min of plasma exposure time, specific surface area increased, and oxygen vacancies formed. As a result, they managed to increase decolorization efficiency of various dyes [41]. Rutile phase TiO2 nanoparticles were immobilized on glass plates and their activity for decomposition of malachite green and crystal violet dyes was examined using UV/TiO2 /H2 O2 process. In order to obtain the optical band gap energy of the samples, (αhv) was plotted versus hv (Figure 3(b)) and Eg was calculated. Optical band gap energy for Ar plasma and non-treated samples were found as 2.94 and 2.97 eV, respectively. Optical band gap energy for Ar plasma and non-treated. (c) HR-XPS spectra of O1s. (I) and non-treated TiO2 (II): (a) Wide scan spectra; (b) HRFigure
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