Studies on the Interfacial Characterization of O/W Emulsion for the Optimization of Its Treatment

Abstract

Wastewater produced in the form of an o/w emulsion is difficult to treat properly because of its complex behavior. To acquire information for the optimization of emulsion controlling processes, the interfacial features of emulsion systems have been investigated in this work. The surface tension is found to decrease as the oil content is increased, and contact angle is influenced by the hydrophobicity of the substrate. The work of adhesion for substrates with different degrees of hydrophobicity has been estimated from the contact angle and surface tension. Temperature and pH have a significant influence on the turbidity and surface tension, and it is observed that electrophoretic characteristics of oil droplets are closely related with turbidity. Also, effects of inorganic salts and surfactants on the electrokinetic properties of emulsions have been considered, and the influence of coagulant on the stability is discussed through the calculation of potential energy of interaction between oil droplets. Adsorption and electrocoagulation processes have been attempted under various conditions in order to examine the practical treatment efficiencies of emulsion in relation to its interfacial characteristics.

Destabilization‐Enhanced Centrifugation of Metalworking Oil‐in‐Water Emulsions: Effect of Demulsifying Agents

“…1 illustrates the turbidity of the aqueous phase after centrifugation and shows the zeta potential as a function of coagulant concentration. Similar results have been reported in the literature on emulsion stability [16,21]. The addition of small amounts of coagulant resulted in a large reduction of absolute values of zeta potential, until a plateau around neutrality was reached.…”

Treatment of a waste oil-in-water emulsion from a copper-rolling process by ultrafiltration and vacuum evaporation

“…3. Zeta potential is a useful parameter to determine emulsion stability; when it approaches zero, coalescence takes place [12]. A large reduction in the absolute zeta potential, reaching a plateau around zero, was observed when either NAL or CaCl 2 was added to the waste emulsion, an indication that emulsion destabilization occurs, in agreement with the results shown in Figs.…”

Coagulation and electrocoagulation of oil-in-water emulsions

“…These emulsions become exhausted with use as they loose their properties, and turn into residues that must be treated to reduce the impact of their discharge. The treatment of theses wastes has been addressed by different techniques, but the most commonly used are membrane processes (microfiltration and ultrafiltration) [1,2], chemical destabilization (conventional coagulation) [3][4][5][6] and electrochemical destabilization (electrocoagulation) [7][8][9][10][11]. Less commonly used are the biological processes, as these kinds of industrial fluids contain biocides (such as heterocyclic sulphur and nitrogen compounds) to prevent their degradation [12].…”