Critical Coalescence Concetration (CCC) as a Parameter for Evaluation of Selected Quaternary Ammonium Compounds

Szyszka, Danuta

Critical Coalescence Concetration (CCC) as a Parameter for Evaluation of Selected Quaternary Ammonium Compounds

Abstract

The objective of this paper was to determine the Critical Coalescence Concentration (CCC) of surfactants such as N(dodecyloxycarboxymethyl) N,N,N-(trimethylammonium) bromide (DMGM- 12), N-[2-(dodecyoxycarboxy)ethyl] N,N,N-(trimethylammonium) bromide (DMALM-12) and N-[3- (dodecanoyloxycarboxy)prophyl] N,N,N-(trimethylammonium) bromide (DMPM-11). The surfactants used represent quaternary ammonium compounds containing a hydrophobic moiety with an ester group (commonly known as “esterquats”). The CCC value was determined by analysis of the relationship between concentration of surfactant and average air bubble diameter. The values of the critical coalescence concentration (CCC) were estimated using a graphical method.

Description

In this paper selected cationic surfactants were tested in order to a valuate their possible use as flotation reagents. For this purpose, the critical coalescence concentrations (CCC) of the surfactants were determined. The CCC value represents such a concentration of a reagent at which the air bubbles start to merge, which results in less 112 Critical coalescence concetration (CCC) as a parameter for evaluation of ammonium compounds effective flotation process. Therefore, it is recommended to keep the surfactant concentration in the vicinity of CCC to prevent the occurrence of the coalescence phenomenon. Basing on the performed research it can be concluded that: 1. plotted graphs show that the coalescence disappears along with the increasing concentrations of the surfactants, 2. for all tested surfactants the values of critical coalescence concentrations (CCC) are similar and are in the range from 0.041 to 0.048 mmol/dm3, 3. the analysis of both obtained CCC values based on arithmetic and Sauter diameters demonstrates that no considerable variation of the CCC values was observed for the tested surfactants, 4. diameters of air bubbles measured for quaternary ammonium compounds containing a hydrophobic moiety with an ester group and for typical floatation frothers known under the trade name of Dowfroth gave similar CCC values. 5. the CCC values can be an important material constants for foaming agents. Determination of possibility to use cationic surfactants as flotation frothers and their impact on flotation efficiency should help to select appropriate flotation reagents so that, in addition to typical, already known frothers, other environment-friendly surfactants may be used in mineral processing technology.