Investigation of the hydrogen evolution phenomenon on CaCO3 precipitation in artificial seawater

Abstract

Precipitation of CaCO3, as the most important part of scales, causes a serious problem in industrial equipment such as pipelines and desalination plants. The effect of the hydrogen evolution phenomenon on the electrochemical precipitation was studied through varying different factors including cathodic potential (CP), bicarbonate concentration, and solution temperature. The application of CP from −0.8 VSCE to −1.2 VSCE, an increase in bicarbonate concentration and temperature elevation from 25 °C to 45 °C led to the increase of scaling time (ts) and residual current density (ir). In all cases, it was indisputably found that the hydrogen evolution phenomenon had a predominant effect on the calcium carbonate precipitation. The surface analyses by means of scanning electron microscopy (SEM) showed formation of crystals in two defined forms of calcite and aragonite. Moreover, the energy dispersive spectroscopy (EDS) technique confirmed the formation of CaCO3 crystals.