A Simple Method to Determine Critical Coagulation Concentration from Electrophoretic Mobility

Critical coagulation concentration (CCC) is a key parameter of particle dispersions, since it provides the threshold limit of electrolyte concentrations, above which the dispersions are destabilized due to rapid particle aggregation. A computational method is proposed to predict CCC values using solely electrophoretic mobility data without the need to measure aggregation rates of the particles. The model relies on the DLVO theory; contributions from repulsive double-layer forces and attractive van der Waals forces are included. Comparison between the calculated and previously reported experimental CCC data for the same particles shows that the method performs well in the presence of mono and multivalent electrolytes provided DLVO interparticle forces are dominant. The method is validated for particles of various compositions, shapes, and sizes.

An evaluation of monovalent, divalent, and trivalent cations as aggregating agents for surface enhanced Raman spectroscopy (SERS) analysis of synthetic cannabinoids

Monovalent, divalent and trivalent chloride, sulfate and nitrate salts were examined to determine the critical coagulation concentration (CCC) for each salt and its corresponding effect on detection limits for SERS analysis of synthetic cannabinoids.

Bentonite clay suspension -coagulation process and identification of properties

The main aim of the research presented in this paper is study of volume coagulation of bentonite suspension. Investigation of physical properties included measurement of particle size distribution, chemical and phase analysis of prepared suspension, as well as preparation of sedimentation test graph and determination of dependence between concentration of the suspension and turbidity of the suspension. Relationship between coagulant dose and concentration was also determined during this analysis. This research could help in determination of critical coagulation concentration duringanalysis of coagulation process. Also it could be used duringsimulations of distribution of suspension in high - performance sedimentation settling tanks for suspension of similar origin in water treatment process.

A Modified Method to Calculate Critical Coagulation Concentration Based on DLVO Theory

The critical coagulation concentration (CCC) is defined as the minimum concentration of counterions to induce coagulation of colloidal particles. A modified calculation method was proposed to calculate CCC. Comparing the modified calculation method of CCC with the traditional calculation method, the critical condition of modified calculation method is stricter than traditional calculation method. The critical condition of modified calculation method is the maximum value of interaction force that is zero, and the critical condition of traditional calculation method is the maximum value of interaction energy that is zero. The calculation result of CCC based on interaction force is greater than the calculation value based on interaction energy. The CCC value of modified calculation method can ensure particles to coagulate definitely.

Deinking flexographic-printed papers: Destabilization of flexographic ink dispersions with copper compounds

Flexographic printing inks form electrosterically stabilized colloidal dispersions in water that display extreme stability at the alkaline pH values of most wastepaper deinking systems. A significant amount of U.S. newspapers are now printed using water-based flexographic inks, and the residual inks from these sources are problematic to remove in deinking plants. A successful flocculant for flexographic ink particles used in deinking plant filtrate streams requires that both the electrostatic and steric components of colloidal stabilization be eliminated simultaneously. The present study shows the advantageous characteristics of cupric chloride in achieving rapid flocculation of flexographic inks. Flocculation experiments were performed with a model ink as well as a mixture of offset and flexographic inks from recycled newspapers. The critical coagulation concentration of cupric chloride has been compared to other chloride, nitrate, and copper salts. Copper(II) chloride has been found to be significantly more effective than other such salts in achieving destabilization and aggregation of flexographic ink particles. A possible flocculation mechanism of flexographic ink particles by cupric chloride is presented.