Application of direct contact membrane distillation for treating high salinity solutions: impact of membrane structure and chemistry

In this work, we examine membranes consisting of different materials, different pore sizes and thicknesses. The objective is to elucidate structural- and chemical-property relationships of direct contact membrane distillation for brine concentration using three different salts (MgCl2, KCl, or NaCl) at near saturation conditions (up to 4 M). All membranes show excellent performance (high water flux and salt rejection above 99.5% for each salt). In general, the thinnest membranes exhibit the highest flux while lower porosity membranes have lower flux. Pore size is shown to have only a modest impact on performance. Solutes will also play an important role in MD water flux.