Modification of Immobilized Titanium Dioxide Nanostructures by Argon Plasma for Photocatalytic Removal of Organic Dyes

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.

Angle-Sensitive Photonic Crystals for Simultaneous Detection and Photocatalytic Degradation of Hazardous Diazo Compounds

“…Furthermore, as established in this study, the photon lifetime could be elongated on the PhC surface, and the optical absorption could be enhanced because the PhCs had unique optical characteristics that allowed them to manipulate and confine the light incident on their surface [34]. In addition, the nanostructured materials such as PhC supported photocatalysts were reported to show an increase in their photocatalytic degradation efficiency [17,35]. Therefore, it was shown that the 2D-PhC underneath the TiO 2 coating played a synergistic role in enhancing the rate of UV mediated photocatalytic degradation of CR and AB-10 significantly after the timepoints of 60 and 80 min.…”

“…The absorbance values at~494 for CR and~630 nm for AB-10B (λ max) were measured before and after UV irradiation. The degradation rate (η) of the respective dyes on TiO 2 coated 2D-PhC was calculated by Equation (1) [17]:…”

Modeling and optimization of simultaneous degradation of rhodamine B and acid red 14 binary solution by homogeneous Fenton reaction: a chemometrics approach

“…The distribution of residual among the performed experiments is demonstrated in Figure 4. Random distribution of residuals, observed in this figure, signals the reliability of proposed models [36]. Figure 5 presents the normal probability plot of residuals of simultaneous RB and AR14 degradation process.…”

ANOVA Design for the Optimization of TiO2 Coating on Polyether Sulfone Membranes

“…In summary, this research performed an investigation of different parameters on membrane fabrication and various parameters on the fabrication of a nanocomposite PES/TiO 2 membrane. Fabrication variables, including exposure time [31], immersion time [32], the solvent ratio (ratio of less volatile solvent (NMP) to more volatile solvent DMAc), glycerol time (pore filling time), and the nonsolvent ratio (isopropanol to water) were set individually. According to the analysis of the two-level factorial design, glycerol time, solvent ratio, and nonsolvent ratio were the most important factors which should be set accurately.…”