Preparation And Adsorption Property Of Na₂Ti₃O₇/Titanium Peroxide Composites

Cationic dyes are extensively used in textiles, leather, paper and plasticsindustries, leading to the increasing discharge of dye to the water, which threatens thewater security for human and animals, which resulted in a demand to remove the dyesfrom these effluents. Therefore the treatment of cationic dyes raised much attentionand adsorption has been found to be superior to other techniques for dyeing waterpurification in terms of initial cost and flexibility.It had been found that titanate played an important role of adsorbent in theremoval of dyes. This led to the search for more efficient and cheaper alternateadsorbents. In recent year, there was an increasing interest in the utilization of titanatein environmental studies. It had been found that titanate played roles of adsorbent andphotocatalyst simultaneously in the removal of dyes. Consequently, they wereconsidered as promising adsorbents for dye removal. Moreover, procedures ofdifferent ways to prepare titanate were relatively complex or need a relatively hightemperature, which increased the cost, so an easy way to prepare the titanate isnecessary. In this work, sodium titanate power was prepared with the reaction of Tiplates, NaOH and H2O2at80°C for24h. Sodium titanate was characterized by X-raydiffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanningelectron microscopy (SEM). The typical morphology of the sodium titanate preparedwas consisted of a large number of nanofibers with a diameter of40-50nm. Thesodium titanate possessed low crystallinity. Thanks to the large amount of hydroxylgroups adsorbed on the surface of the sample, the sodium titanate prepared in alkalineexhibited excellent adsorption capability for neutral red (NR), methylene blue (MB),malachite green (MG) and crystal violet (CV), and the saturated adsorption capacitieswere337.84,238.10,266.67and208.77mg/g。Our research team prepared the titanium peroxide power with the reaction of titanium sulfate and H2O2, which showed good selective adsorption property oncationic dyes. As an extension, Na2Ti3O7/titanium peroxide composites (TN-TP) wassuccessfully prepared with the reaction of Ti foils, NaOH and H2O2at60°C for24h inwater bath. The Na2Ti3O7at composites appeared as nanorods. Water bathtemperature, water bath time and the concentration of H2O2and NaOH were crucial.The reaction mechanism was proposed. TN-TP was characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electronmicroscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Thermogravimetricand differential scanning calorimetry (TG–DSC). TN-TP was mesoporous materialand exhibited stronger adsorption capability for neutral red (NR), malachite green(MG), methylene blue (MB) and crystal violet (CV) than pure Na2Ti3O7and puretitanium peroxide, and the saturated adsorption capacities were497.51,331.13,395.26and304.88mg/g at25°C, respectively. It was found that thepseudo-second-order kinetic model and the Langmuir model could well describe theadsorption kinetic and isotherm of cationic dyes studied. Results of this work are ofgreat significance for environmental applications of TN-TP as a promising adsorbentmaterial for dyeing water purification.