Abstract:The quartz sand was surface modified using silane coupling reagent KH-550 to improve the hydrophobicity of filter medium as well as increase the oily wastewater treatment performance. The effect of the concentration of the silane coupling agent KH-550, modified temperature and stirring time on modification were studied by orthogonal and single-factor approach. Results show that when the KH-550 concentration was 15%, reaction temperature was 110℃ and stirring time was 15min, quartz sand modification had the best effect. Wetting weight of water could be reduced from 1.5589g to 0.0607g by surface modification while oil wetting weight were almost unchanged before and after modification. The adsorption capacity of modified quartz sand was greatly improved to 0.1843 for oil, and was 27.72% higher than unmodified quartz sand. XPS and SEM shown that KH-550 combined in the surface of the quartz sand with chemical bonds, form a solid organic coated layer.