Adhesion of gypsum crystals to polymer membranes: Mechanisms and prediction

Abstract

In view of the scaling problem in the membrane water treatment process, the adhesion mechanism of gypsum crystals on different commercial microfiltration membranes in aqueous solution was firstly investigated using experimental methods and molecular dynamics simulations. The membrane chemistry has the most significant impact on its adhesion potential to gypsum crystals. Hydrophilic membranes have higher potential to scaling by the gypsum crystals compared to the hydrophobic membranes. The number of polar groups in the membrane molecules has higher effect on the adhesion energy than the variety of polar groups. The anti-adhering properties of the membranes increase with decreasing absolute adhesion energy. Physical structure of membranes was also crucial to its adhesion behavior under the condition that the adhesion energy of membranes was close to each other. The larger pore that exceeds a proper range leads to less adhesion mass. Subsequently, the membranes potentially used for membrane distillation were successfully predicted from the aspect of membrane chemistry in terms of their anti-scaling propensity using molecular dynamics simulations. This article provides an insight for the mechanism of gypsum scaling, and gives the prediction on the anti-scaling performance of the potential polymer membranes in membrane distillation.