Barium sulfate (BaSO4), as a common scale, inflicts continuous oil production. During oil and gas extraction, various organics are present, so it is vital to understand the kinetic and mechanisms of BaSO4 nucleation and growth at organic-water interfaces. In this study, self-assemble monolayers (SAMs) terminated with different functional groups (i.e., –COOH, –SH, or mixed –SH & COOH) were coated on glass. Barite precipitation from supersaturated solution (saturation index, SI = 1.1) with Ba2+/SO42- on bare quartz and SAM-coated substrates were quantified using grazing-incidence small angle X-ray scattering technique (GISAXS) for 1 h. Only small amounts of big BaSO4 particles were observed on quartz surfaces and –COOH coated substrate, while nucleation and growth were explicitly observed for –SH and mixed –SH & COOH coated glasses, with mixed –SH & COOH provided the fastest nucleation. To understand the controlling mechanisms, Ba2+ adsorption onto substrates were quantified using quartz crystal microbalance dissipation (QCM-D), and the hydrophobicity and surface zeta potentials of the substrates were measured using contact angle goniometer and dynamic light scattering (DLS), respectively. The mixed –SH & COOH coated glass were observed to be the most hydrophobic (89.5 ± 0.6°), indicating a lower interfacial energy for heterogeneous barite nucleation, resulting in the fastest barite nucleation on it. Also, Ba2+ adsorption, which was controlled by the functional groups on the substrates, was found to promote heterogeneous barite precipitation. While surface charges of the substrates surfaces were found to have no significant contribution to heterogeneous barite precipitation. This study provides unique information on heterogeneous barite precipitation at organic-water interfaces, and the interactions among Ba2+ ions, organic surfaces, and BaSO4 precipitates were also systematically investigated. Such information can be helpful for predicting barite nucleation and growth in relevant natural and industrial settings, and controlling BaSO4 scale formation.

Heterogeneous nucleation and growth of barium sulfate nanoparticles at organic-water interfaces

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.