Search

Graphene oxide (GO) nanosheets have been experimentally proved to be a highly efficiency, rapid and universal demulsifier to break up the crude oil-in-water emulsion and/or the emulsified oily waste water in our previous study. To recycle the GO nanosheets and avoid the possible contamination of GO for crude oil, in this work, the magnetic graphene oxide (M-GO) was successfully synthesized and used for separating oil/water emulsions. Demulsification tests indicated that M-GO could separate the oil/water emulsions within a few minutes and recycle 6–7 times without losing its demulsification capability. The residual oil content in the separated water was as low as ∼10 mg/L, corresponding to a demulsification efficiency of 99.98% at an optimal dosage. Quantum chemical calculation results indicated that the π-π/σ-π interactions between GO materials and asphaltene molecules are the major driven forces for the high demulsification performance of M-GO nanosheets. This work not only provides a promising demulsifies to demulsify the crude oil-in-water emulsion or the oily wastewater but also give a deep understanding on the intrinsic interaction between demulsifiers and asphaltenes. [ABSTRACT FROM AUTHOR]

Amphiphilic aromatic poly (amino acids) polymers were designed as biodegradability demulsifiers with higher aromaticity, stronger polarity, and side chain-like combs. The effects of demulsifier dosage, structural characteristics and emulsion properties such as pH, salinity, and oil content on the demulsification efficiency were investigated. The results show that the poly (L-glutamic-benzyl ester)-block-poly (L-phenylalanine) (PBLG 15 - b -PPA 15) as the demulsifier can remove more than 99.97% of the oil in a 5.0 wt% oil-in-water (O/W) emulsion at room temperature within 2 min. The poly (L-tyrosine)-block-poly (L-phenylalanine) (PTyr 15 - b -PPA 15) with environmental durability demonstrates high effectiveness, universality, and demulsification speed. It achieves a remarkable demulsification efficiency of up to 99.99% for a 20.0 wt% O/W emulsion at room temperature. The demulsification mechanism indicates that demulsifiers have sufficient interfacial activity can quickly migrate to the oil-water interface after being added to the emulsions. Additionally, when demulsifiers are present in a continuous phase in the molecular form, their "teeth" side chains are beneficial for increasing coalescence and flocculation capacities. Furthermore, according to the Density Functional Theory (DFT) calculations, enhancing the intermolecular interactions between demulsifiers and the primary native surfactants that form an oil-water interfacial film is a more efficient approach to reducing demulsification temperature and improving demulsification efficiency and rate. [Display omitted] • Proposed a strategy for developing a low-temperature oil-in-water demulsifier. • Improving the polarity and aromaticity of demulsifiers enhances their performance. • Aromatic poly (amino acids) demulsifiers perform well at low temperatures. • The intermolecular interactions determine the deoiling temperature and efficiency. [ABSTRACT FROM AUTHOR]