Mesoporous TiO2 has been prepared using a nonionic block copolymer (Pluronic P-123) as structure-directing agent with sol-gel method. Characterization of the product was carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetrydifferential scanning calorimetry (TG-DSC), Nitrogen sorption isotherms, and UV-vis absorption spectroscopy. These analyses showed that under controlled synthesis conditions, a wormlike mesostructured TiO2 with high surface area (110 m2g-1) and appropriated band gap (~3 eV) is obtained. Moreover, the pore walls of the nanostructured TiO2 solid are formed by incipient crystallites of ANATASE, which is a significant achievement regarding its possible photocatalytic applications. The activity of the prepared photocatalyst was evaluated by degradation of Congo Red azo dye. It has excellent photocatalytic efficiencies and more than 76% dye was decolorized in 90 minute.

Photocatalytic process is one of the best methods for degradation of organic pollutants from wastewater. The separation of photocatalyst from the treated wastewater is of great importance from engineering point of view. In this article, the ANATASE synthesized by sol-gel method was coated on meta-kaolin support through the polymeric binders. The photocatalytic activity of fabricated packed beds was evaluated by degradation of wastewater contaminated by methylene blue under solar irradiation using UV-Vis spectroscopy. Two polymeric binders employed to coat titanium dioxide on extruded ceramic supports. Moreover, the dye degradation kinetics in the presence of packed beds and ANATASE powder were studied to understand the role of support on wastewater treatment. The structure of support was identified by XRD and FESEM before and after photocatalyst coating. The obtained results showed that the 3-(Aminopropyl) triethoxysilane is favorable to be applied as a binder in comparison to methacrylic acid. Approximately, 65% of methylene blue is degraded during 60 minutes. J. Color Sci. Tech. 12(2019), 281-292© . Institute for Color Science and Technology.

Background and Objectives: Groundwater sources, as strategic sources of water supply, are of particular importance for human beings. Arsenic is a toxic and carcinogenic contaminant that has been reported to be widely found in groundwater sources. In recent years, adsorption property of nanoparticles has been used to remove arsenic. The present study was performed with the aim of assessing the arsenic reduction process in the aqueous environment under groundwater-like conditions using titanium dioxide (TiO2) nanoparticles (ANATASE). Methods: In this experimental study, using batch experiments, the effect of changes of time, nanoparticles concentration, and pH factors, were investigated on the changes in arsenic concentration in aqueous solution. The specific surface area of the adsorbent was 200-240m2/g. Data were statistically analyzed by measures of central tendency. Results: In this study, more than 90% of arsenic concentration in the solution, was absorbed after about 30 minutes of exposure to ANATASE nanoparticles, however, it took 60 minutes to reach drinking water standard level of arsenic (10μ g/L). Increasing adsorbent concentration caused an increase in arsenic adsorption. In natural pH range of groundwater, TiO2 nanoparticle can absorb near 100% of arsenic (200μ g/l), but, increase in pH increased this ability. Also, adsorption of arsenic by ANATASE nanoparticles was more consistent with the Freundlich isotherm. Conclusion: The results of the current study showed that TiO2 nanoparticles are efficient adsorbents for removal of arsenic from aqueous solutions under natural groundwater conditions.

Titanium oxide nanoparticles were synthesized via a solvothermal treatment of titanium isopropoxide in the presence of L-lysine (lysine). The prepared nanostructures characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), diffraction scanning calorimetry (DSC), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Results exhibited that peptization in the absence of the additive led to the non-uniform (from nano to micro size) ANATASE particles, while well-dispersed ANATASE nanoparticles were obtained in the small range from titania-lysine precursor. Well-organizing the growth of ANATASE particles during the calcinations can be attributed to initial amorphous phase of the as-synthesized lysine sample.