Selective separation characteristics and mechanism of oil substances with different occurrence states in coal chemical wastewater

In response to the complex nature of oil substances in coal chemical wastewater (CCW), and the challenges they pose in separation and removal, this study conducted a detailed analysis of the occurrence, composition, and content of oil substances in CCW. The selective separation characteristics and mechanisms of various materials for oil substances in different occurrence states were explored. The results revealed four main states of oil substances in CCW: suspended oil, dispersed oil, emulsified oil, and dissolved oil, with respective contented of 37.17 %, 27.82 %, 17.79 %, and 17.22 %. These oil substances primarily consisted of alkanes, aromatic hydrocarbons, benzene series, and phenolic compounds, with a total concentration of 2942.18 mg/L. Based on the investigation of the characteristics of oil substances and relevant characterization analyses, the study further explored the selective separation characteristics and mechanisms of different materials for oil substances in various occurrence states. The results indicated that activated carbon, resin, fiber balls, and oil-absorbing felt exhibited excellent selective removal efficiency for dissolved oil, emulsified oil, suspended oil, and dispersed oil, with removal rates of 79.28 %, 63.33 %, 66.89 %, and 55.54 %, respectively. These findings provide theoretical support for the selective separation and recovery of oil substances in CCW, showcasing significant practical applications.