The effect of cationic polyamide-amine dendrimer on HLD equation and interface behavior of nonionic polyether water clarifier

Cationic polyamide-amine dendrimer can promote the clarification performance of nonionic block polyether water clarifier for treating produced water from heavy oil field, but the reason is lack of study. In this paper, a cationic polyamide-amine dendrimer TA which can effectively improve the oil removal speed of nonionic polyether DMEA-PE and reduce the onset temperature of DMEA-PE clarification performance was prepared, and the reason was explored from both thermodynamic and dynamic aspects by studying the effect of TA on the hydrophilic-lipophilic deviation (HLD) equation and oil-water interface behavior of DMEA-PE. The research results showed that TA moved up the HLD vs T curve of DMEA-PE and decreased its temperature corresponding HLD = 0, which was a favor of decrease in onset temperature of DMEA-PE clarification performance. TA had no effect on the DMEA-PE's capacity of oil-water interface adsorption and decreasing oil-water interface film strength. However, TA can reduce the electronegativity of oil droplet in water and enhance the oil droplets coalescence, hence the oil removal speed and efficiency of DMEA-PE were enhanced. This is the first time that HLD concept was used to investigate the action mechanism of composite water clarifier and the results are useful for the water clarifier design.