Salt concentration influence on the efficiency of two cationic polymeric flocculants

Abstract

The influence of the increase of the solution ionic strength on the flocculation of charged latex particles in the presence of cationic polymers is reported. Empirical flocculation rate constants are experimentally determined using particle counting and for two cationic polymers, one linear and the second with two branches. Comparisons are made with a solution containing monovalent salt only at different ionic concentrations in the absence of polymers. In all cases, polymer-induced flocculation is significantly more efficient than charge screening effects using salt only. Analysis of zeta potential measurements indicates that the charge neutralization and surface charge variations dictate the stability of the latex suspensions. Moreover, the addition of a small amount of salt in the polymer-particle mixtures results in a dramatic decrease of the polymer efficiency which is more pronounced for the linear polymeric flocculant. By increasing further the ionic strength, the rates of polymer flocculation are found to increase again but remain smaller than in the absence of salt.

Effects of pH, Salinity, Biomass Concentration, and Algal Organic Matter on Flocculant Efficiency of Synthetic Versus Natural Polymers for Harvesting Microalgae Biomass

“…2e-h). The fact that the flocculation efficiency of Tanfloc does not differ between salinity conditions may be due to the different secondary structure of Tanfloc in comparison to Flopam, as Tanfloc is a branched rather than a linear polymer [33]. As a result, it may suffer less from coiling at high ionic concentrations than Flopam.…”

Comparative Study of the Effect of Aluminum Chloride, Sodium Alginate and Chitosan on the Coagulation of Polystyrene Micro-Plastic Particles

“…The zeta (ζ) potential is related to the electric potential at the boundary surface of the hydrodynamic shear which corresponds to the potential at the slipping plane of the diffuse layer with the bulk solution [27]. The ζ potential is related to particle stability.…”

Applying a logistic growth equation to model flocculation of sediment in the presence of living and dead organic matter

“…This is due to the fact that these polymers are mostly negatively charged particles and, hence, experience an electrostatic repulsion with the negatively charged clay. For this reason, the presence of salts and, in particular, cations is crucial, as these cations will help bridging the polymer and clay (Palomino et al, 2012). These cations usually become available in the transition zone between fresh water from rivers and sea water from the coast.…”