Study on modified graphene oxide-based emulsion cleaner for oily sludge

Oily sludge is a complex system that is inevitably generated during the process of oil extracting and processing. It will cause serious environmental pollution and waste of resources if untreated sludge is discharged. In this paper, a composite emulsion cleaner based on modified graphite oxide and surfactants was developed for cleaning oily sludge. First, graphite oxide (GO) was functionally modified with butylamine, and its structures were verified by Fourier transform infrared spectroscopy (FTIR), X-ray electron spectroscopy (XPS), thermogravimetric analysis (TGA), and environmental scanning electron microscopy (SEM). Then, the oil-in-water composite emulsion cleaner was prepared by using butylamine modified graphite oxide and surfactants. The conditions for emulsion preparation and oil sludge cleaning were modelled and optimized by the response surface methodology. The obtained optimal formulations were: surfactant content was 2.17 ‰ with SDS/AEO-3 ratio of 9:1, GO-A4 content was 0.96 ‰, water-oil ratio was 5:5, and the oil removal rate was 97.45 %. The optimal cleaning conditions were: liquid-solid ratio of 3.2:1, cleaning time of 32 min, cleaning temperature of 28.7 °C, and oil removal rate of 99.02 %. The solid sediments were characterized by FTIR and SEM, which proved the feasibility of cleaning oily sludge with the emulsion.