Aromatic poly (amino acids) as an effective low-temperature demulsifier for treating crude oil-in-water emulsions

Zhuyu Wu; Qiliang Yang; Can Cui; Yiyi Wu; Yadian Xie; Huanjiang Wang

doi:10.1016/j.jhazmat.2024.134608

Aromatic poly (amino acids) as an effective low-temperature demulsifier for treating crude oil-in-water emulsions

J Hazard Mater. 2024 Jul 5:472:134608. doi: 10.1016/j.jhazmat.2024.134608. Epub 2024 May 15.

Authors

Zhuyu Wu¹, Qiliang Yang¹, Can Cui¹, Yiyi Wu², Yadian Xie¹, Huanjiang Wang³

Affiliations

¹ School of Chemical Engineering, Key Laboratory of Low-Dimensional Materials and Big Data, Guizhou Minzu University, Guizhou Provincial Key Laboratory of Low Dimensional Materials and Environmental and Ecological Restorations, Guiyang, Guizhou 550025, PR China.
² School of Chemical Engineering, Key Laboratory of Low-Dimensional Materials and Big Data, Guizhou Minzu University, Guizhou Provincial Key Laboratory of Low Dimensional Materials and Environmental and Ecological Restorations, Guiyang, Guizhou 550025, PR China. Electronic address: yiyiwu@gzmu.edu.cn.
³ School of Chemical Engineering, Key Laboratory of Low-Dimensional Materials and Big Data, Guizhou Minzu University, Guizhou Provincial Key Laboratory of Low Dimensional Materials and Environmental and Ecological Restorations, Guiyang, Guizhou 550025, PR China. Electronic address: whj2017@gzmu.edu.cn.

PMID: 38754229
DOI: 10.1016/j.jhazmat.2024.134608

Abstract

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) (PBLG₁₅-b-PPA₁₅) 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) (PTyr₁₅-b-PPA₁₅) 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.

Keywords: Aromatic poly (amino acids); Demulsification mechanism; Low-temperature demulsifier; O/W emulsions.