Development of titanium dioxide nanoparticles for catalytic and waste water treatment applications

Abstract

Water is a fundamental and vital resource for all life on Earth. Its importance cannot be overstated, as it plays numerous critical roles in the environment and human society. Water is essential for the survival of all living organisms. It is required for hydration, metabolic processes, and the growth of plants and animals. Water sustains aquatic ecosystems, providing habitats for a wide variety of species. It also contributes to the overall health of terrestrial ecosystems through processes like precipitation, runoff, and groundwater recharge. Water is a fundamental resource in agriculture, used for irrigation to grow crops and raise livestock. Adequate water supply is crucial for food production. Many industries rely on water for manufacturing processes, cooling, and cleaning. Clean water is essential to maintain the efficiency and sustainability of these processes. Access to safe and clean drinking water is a fundamental human right. It is crucial for public health and helps prevent waterborne diseases. Clean water bodies, such as rivers, lakes, and oceans, are essential for recreational activities like swimming, boating, and fishing. They also attract tourists and contribute to local economies. Water is a source of renewable energy through hydropower generation. Dams and hydroelectric power plants harness the kinetic energy of flowing water to produce electricity.Photocatalysis in water treatment: Photocatalysis is a promising technology that can be used to treat and purify water, addressing various water-related challenges: 1. Pollutant removal: Photocatalysis involves the use of photocatalysts (usually semiconductors like titanium dioxide) that, when exposed to light (typically UV or visible light), can catalyze chemical reactions. These reactions can break down and degrade various water pollutants, including organic compounds, dyes, pesticides, and even certain pathogens.2. Demineralization: Photocatalysis can be effective in removing heavy metals and other inorganic contaminants from water, making it suitable for consumption and industrial use. 3. Disinfection: Photocatalysis can also disinfect water by inactivating harmful microorganisms, such as bacteria and viruses, through the production of reactive oxygen species. 4. Environmental remediation: Photocatalysis can be employed for environmental remediation, such as cleaning up contaminated groundwater or surface water bodies by degrading persistent pollutants. 5. Green and sustainable: Photocatalysis is considered an environmentally friendly and sustainable technology since it relies on renewable energy sources like sunlight. It doesn't produce harmful by products and can be integrated into wastewater treatment processes. Photocatalysis can also contribute to energy storage through processes like photoelectrochemical water splitting. It converts excess energy (e.g., from solar panels) into chemical energy stored in the form of hydrogen, which can be used later for electricity generation or fuel production. Photocatalytic degradation, a promising technique for eliminating organic contaminants from water systems, has gained recognition. In this study, here investigated the photocatalytic degradation of Rhodamine B (RhB) dye using various catalysts, including TiO2 solvothermal, TiO2 hydrothermal, TiO2 annealed, and the corresponding composite of annealed TiO2 with gC3N4 and exfoliated g-C3N4 (Exf gC3N4). The aim was to evaluate the effectiveness of these photocatalysts in breaking down hazardous RhB dye and to explore the collaborative interactions between titanium dioxide (TiO2) nanoparticles and graphitic carbon nitride (gC3N4), as well as exfoliated graphitic carbon nitride (Exf gC3N4). The synthesis of titanium dioxide and the nanocomposites involved a hydrothermal method followed by annealing. To assess the structural,morphological, compositional, and optical, electro-chemical characteristics of the photocatalysts, the synthesized samples are employed some sophisticated techniques such as Powder X-ray diffraction (PXRD), Field emission scanning electron microscopy (FESEM), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (DRS), Photoluminescence spectroscopy (PL), Mott- Schottky, etc. The results revealed that the most significant improvement in photocatalytic activity was observed in the annealed TiO2/Exf gC3N4 photocatalyst, achieving a degradation rate of 99.84% within 90 minutes irradiation under UV light. The breakdown of RhB dye occurred under UV light radiation, with its concentration monitored at regular intervals using UV-Vis spectroscopy. Both pristine tungsten trioxide and its nanocomposites exhibited substantial photocatalytic activity in RhB dye degradation. The nanocomposite containing exfoliated graphitic carbon nitride displayed enhanced degradation efficiency, indicating potential synergistic effects with titanium dioxide. The photocatalytic process followed pseudo-first-order kinetics, and the degradation rate constants were determined. Incorporating exfoliated gC3N4 with TiO2 enhanced photocatalytic performance, showcasing the potential of this nanocomposite for organic pollutant treatment in wastewater remediation. These findings contribute to the development of efficient and durable photocatalytic materials for environmental remediation applications.In summary, photocatalysis offers a versatile and sustainable approach to addressing various energy and environmental challenges. By harnessing the power of sunlight or artificial light sources, it can contribute to clean energy production, efficient resource utilization, and the remediation of polluted environments. Its applications span from solar energy conversion to wastewater treatment and air purification, making it a valuable technology in the quest for a more sustainable and environmentally friendly energy future.