Preparation of multi-purpose TiO2 pigment with improved properties for coating applications

Bioremediations analysis using multifactorial porous materials derived from tea residue

Titanium dioxide nanoparticles (TiO₂ NPs) are becoming more and more renowned as biocompatible nanomaterials with diverse biological functions. In the present study, the aqueous extract of tea residue (tea filtered waste powder) was used to synthesize the TiO₂ NPs and treated for effluent bioremediations. Maximum absorption in the UV-Vis spectrum of the TiO₂ NPs was seen at 358 nm, and the XRD pattern reveals peaks at 2 h values of 25.78, 38.24, 47.98, 54.76, 55.32, 62.64, 69.05, 70.15, 75.24, and 83.59 that may be indexed to the (101), (004), (200), (105), (211), (204), (116), (220), (215) and (303). The FT-IR spectra of TiO₂ NPs showed a peak at 3420, 2925, 1621, 1382, 1098, and 687 cm-1. The spherical form and size were disclosed by FE-SEM analyses, and the EDAX pattern verified the purity of the TiO₂ NPs. The average particles size of the TiO₂ NPs was 32 nm. The photodegradation of paper mill waste water is significantly deteriorated up to 99.08% for 600 min, but textile waste water is degraded up to 98.06% for the same duration. Furthermore, we reported that TiO₂ NPs may rapidly breakdown industrially hazardous effluents when exposed to sunshine. Overall, this new, straightforward, and environmentally beneficial strategy may be of interest to the management of efficient degradation of dye solutions in the polluted regions.

Consideration of Photoactivity of TiO2 Pigments via the Photodegration of Methyl Orange under UV Irradiation

Developing a rapid and reliable method for measuring the photoreactivity of TiO₂ pigments is of great importance for industrial application. The photoactivity of industrial TiO₂ pigments were evaluated via the photodegradation of a model azo dye, methyl orange (MO), in the present work. The TiO₂ pigments were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. The photoactivity test results showed that the anatase TiO₂ pigment was responsible for accelerating MO degradation, while the rutile pigment acted as a stabilizer, and effective UV absorber retarded the photodegradation of MO. It was found that the photodegradation of MO was driven mainly by photoholes (h⁺) and hydroxyl radicals (•OH), in the presence of TiO₂ pigment with high photoactivity. With the help of the degradation intermediates during the photodegradation process and the calculated data, the preliminary degradation mechanism including azo bond cleaving, h⁺ oxidation, and hydroxylated products' generation for MO was also elucidated. The photoactivity of TiO₂ pigments can be rapidly evaluated in this work, which would be an efficient approach for assessing the product quality control and the end-use performance of TiO₂ pigments.