Study on the deep dehydration of hydraulic oil by filtration via a ZnO/TiO2@STA mesh

Hydraulic oil is essential for machine operation, but water contamination can impair its functionality and lead to mechanical damage. Traditional dehydration methods, such as evaporation, are energy-intensive and may degrade the oil's quality. While filtration has been used to reduce water content in light oils, its application to highly viscous hydraulic oil remains unexplored. This study introduces a novel filter fabricated using ZnO, TiO₂, and stearic acid (STA)-modified mesh via a hydrothermal approach. The filter demonstrated the ability to reduce the water content in 46# hydraulic oil from 25,000 mg/L to below 162 mg/L, irrespective of the presence of surfactants. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and performance evaluations suggest that esterification between stearic acid and oxygen groups on the TiO₂ surface is the key mechanism driving the filter's dehydration efficiency. This work represents a significant advancement in the deep dehydration of viscous oils through filtration, offering a low-energy and effective solution for enhancing hydraulic oil performance.