Performance of green antiscalants in preventing calcium sulfate dihydrate mineral scale formation

In several industrial processes that rely on water handling systems (e.g., oil or geothermal energy production, water desalination), the precipitation of mineral scales leads to costly problems including pipeline or membrane clogging. The use of additives to retard mineral formation is a promising approach to mitigate industrial scaling. In addition, the two main requirements for a ‘proper’ inhibitor are namely their efficiency at low concentrations and their biodegradability (green inhibitors). Here, we report results from a study on the nucleation and growth kinetics, as well as the structure and morphology of calcium sulfate dihydrate scale minerals that were precipitated in the presence and absence of biodegradable polymers. In this research 20 ppm PESA and PASP, were added to calcium sulfate dihydrate (gypsum) crystallization solution and the turbidity changes were evaluated by in situ UV-Vis spectrophotometry. XRD and SEM were also employed for phase and morphological studies. According to the results PASP performed far better than PESA as it completely hindered the formation of gypsum. The turbidity plots, and the morphological changes in shape and size, indicate that the additives adsorbed to the surfaces of the growing crystals.

Keywords:

gypsum , mineral scale formation , inhibitor , UV-VIS , SEM