Titanium Dioxide\nNanoparticle-Loaded Silica Gel Spheres:\nA Superior Adsorbent for the Elimination of Trace Water in Transformer\nOil

Deteriorated transformer oil is classified\nas hazardous\nwaste under\nnational regulations. However, if properly managed, it also can be\ntransformed into a valuable recyclable resource. The main reason is\nthat high water content in the oil leads to a decline in insulation\nperformance, rendering it unsuitable for transformer applications.\nTherefore, this study presents the development of a novel nano titanium\ndioxide-loaded silica gel sphere (nTDSGS) adsorbent material aimed\nat effectively removing trace water from transformer oil. It systematically\ninvestigated the preparation method of this material, utilizing tetrabutyl\ntitanate and silica gel spheres as raw materials, along with hydrochloric\nacid and ethanol solutions. The mixture was subjected to thermal treatment\nat 500 °C for 4 h in a tube furnace. Following drying, a white\npowder of the new adsorbent was successfully obtained. The final product\nwas characterized using scanning electron microscopy, element analysis,\nthermogravimetric analysis, and X-ray photoelectron spectroscopy.\nThe adsorbed experiment examined various factors, including the stoichiometry\nof reactants, the amount of tetrabutyl titanate, the initial water\ncontent in the oil, and various materials, employing response surface\nmethodology to derive optimal reaction conditions and application\nranges. The results demonstrated that the adsorption efficiency exceeded\n80%, with the water content in the treated transformer oil falling\nbelow the national standard threshold (GB/T 7600, <35 μg/mL).\nFurthermore, gas chromatography–mass spectrometry analysis\nrevealed no significant changes in the primary components of the transformer\noil before and after treatment, ensuring the quality of the oil meets\nindustrial application requirements. Regeneration experiments indicated\nthat after each use, the adsorbent underwent drying and heating treatments,\nmaintaining 80% of its initial efficiency even after six regeneration\ncycles. The adsorption mechanism was explored, suggesting that silicon\nand titanium atoms form a Bronsted acid structure, which chemically\nadsorbs hydronium ions and physically adsorbs water molecules. In\nconclusion, this novel adsorbent material demonstrates remarkable\npotential in the treatment of transformer oil containing trace amounts\nof water. It not only alleviates the environmental pollution associated\nwith the degradation of oil quality that can render it hazardous waste\nbut also contributes to the regeneration and sustainable utilization\nof oil resources.