Synthesis of cyclodextrin-based demulsifier for treatment of oily wastewater through hydrophobic modification strategy

Abstract

The discharge of oily wastewater not only has an impact on the environment, but also poses a threat to human health. Therefore, the treatment of oily wastewater is crucial. In current work, a novel demulsifier (CD-LA) was prepared using β-cyclodextrin (β-CD) as raw material by the acylation of –OH and subsequent grafting of dodecylamine. The demulsifier was intended for the treatment of oily wastewater. Detailed examinations were conducted on the surface morphology, chemical composition, interfacial activity, and the capacity of CD-LA to engage competitively at the interface. This substance demonstrated a pronounced ability to lower interfacial tension, indicating its utility in supplanting asphaltenes at the oil–water boundary. This action facilitates the weakening or disruption of the interfacial film, which is critical for the successful separation of oily wastewater. The findings revealed that CD-LA excelled in clarifying oily wastewater, proving effective under near-neutral conditions and in environments with elevated salinity. Separated water phase could obtain light transmittance (WT) of 89.75 % and oil removal rate (WR) of 99.83 % after the oily wastewater was demulsified with a concentration of 50 mg/L at room temperature.