Superhydrophobic coating on quartz sand filter media for oily wastewater filtration

摘要

Deep bed filtration is commonly used to remove oil from oily wastewater. The wettability of the filter media greatly influences the oil removal efficiency. A filter with a strong hydrophobicity and oleophilicity results in a higher oil removal efficiency. To improve the hydrophobicity and oleophilicity, ZnO nanoparticles and octadecyltrichlorosilane (OTS) were coated on quartz sand filter media. SEM, FTIR and XPS were used to study the morphology and chemical composition of the filters, and adsorption capacity and oil removal efficiency experiments were performed to assess the oil removal performance. The results show that the OTS molecules are grafted onto the surface of the quartz sand filter through chemical bonding, and the OTS/ZnO-coated quartz sand filter is superhydrophobic and oleophilic, with a water contact angle of 154.1° and an oil contact angle of 0°. The OTS/ZnO-coated quartz sand filter has very high mechanical stability and acid resistance. The oily wastewater treatment performance is greatly improved after application of the OTS/ZnO coating, and the superhydrophobic quartz sand filter media can potentially be used to filter oily wastewater and achieve high oil removal efficiency.