Advanced TiO₂-SiO₂-Sulfur (Ti-Si-S) Nanohybrid Materials: Potential Adsorbent for the Remediation of Contaminated Wastewater

In this present work, TiO₂-SiO₂-sulfur (Ti-Si-S) nanohybrid material was successfully prepared using TiO₂ nano powder, TEOS sol-gel precursor, and elemental sulfur as raw material by sol-gel process and hydrothermal method at 120 °C temperature. Raman spectroscopy, XRD, SEM, TEM, and N₂ absorption-desorption characterized the synthesized nanohybrid material. The characterization results confirmed the homogeneous distribution of sulfur in the nanohybrid material. The size of the Ti-Si-S nanohybrid material is vary between 20 and 40 nm and the surface areas of the nanohybrid material was measured using N₂ absorption-desorption, which showed value of 57.2 m² g^-1. The potential of Ti-Si-S nanohybrid material as an adsorbent was further tested to adsorb methylene blue (MB) from aqueous solution. Adsorption performance of hybrid material was highly influenced by the solution pH and mass of adsorbent. The adsorption of MB using Ti-Si-S nanohybrid material was homogeneous monolayer adsorption, which followed the Langmuir adsorption isotherm with a q_e,max value of 804.80 mg g^-1 and pseudo-second-order rate equation. The dye diffusion mechanism partially followed both intraparticle and liquid film diffusion mechanisms. Thermodynamics studies predicted the spontaneous and endothermic nature of the whole adsorption process. The Ti-Si-S nanohybrid material was used for six repeated cycles of MB dye adsorption-desorption.