Propensity of gypsum precipitation using surface energy approach

Abstract

In-depth knowledge of the mechanisms underlying the precipitation, and deposition of precursors would help to rigorously scale formation. This, in turn, is closely associated with the solid/fluid interfacial interactions. In this study, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, rather than total surface energy, is sought to investigate the precipitation phenomenon for an aqueous solution containing gypsum. To do so, intermolecular interaction energies are evaluated for two identical gypsum particles immersed in brine where the gypsum surface energy and its components play a pivotal role. The resultant findings show that Lewis acid-base and Lifshitz-van der Waals interactions referred to as the grouped determinative interaction (GDI) would project whether precipitation takes place or not. Even though the electrostatic double layer interaction is one to three orders of magnitude lower than the last two, especially at lower zeta potentials as well as at smaller Debye-Hückel lengths, nonetheless it gains significance as the brine salinity decreases. Finally, the precipitation of gypsum particles from an aqueous solution would increase when the two gypsum particles (precursor particles) having Lewis base polarity less than unity, are located at distances below 7 nm.