Use of molecular dynamics to study the conformation of an anionic polyelectrolyte in saline medium and its adsorption on a quartz surface

In seeking to gain insights on the performance of long chain water-soluble polymer flocculants when conducting mineral processing in highly saline liquors, molecular dynamic simulation was used to study the effect of NaCl concentration on the conformation of an anionic polyelectrolyte and its adsorption on a quartz surface at pH values above its isoelectric point. Increased salinity led to two competing effects on the overall flocculation process: (i) increased polyelectrolyte adsorption on the quartz surface favours the initial aggregate-forming collisions, but (ii) the radius-of-gyration of the polyelectrolyte is reduced, which then may limit the aggregate size achieved. Such results support reported experimental trends and show the advantages of computational methodologies to describe complex systems.