Synthetic studies towards polymeric membranes bearing ion-selective receptors for electro-driven separation of ions.

Introduction: Water treatment is at the heart of sustainable development. In recent years, many innovative technologies in water treatment have been improved. Some of these current technologies have paved the way for removal of particles and dissolved matter from used water streams. Wastewater typically contains a large amount of nutrients which need to be recovered. However, the current recovery processes for nutrients –particularly phosphates and nitrates– are mainly based on precipitation and they are not eco-friendly and selective enough. Goal: The aim of this PhD project is design, synthesis and characterization of ultra-thin, nanometer-sized and ion-selective polymeric membranes which will be used in electro-driven separation processes. Selectivity of membranes will be introduced and tuned by the incorporation of ionophores which can capture specific ions. The polymeric membranes bearing ion-selective receptors will be adsorbed onto the porous carbon electrodes. These modified porous electrodes will be used in ion-selective recovery system. An applied electrical potential will be used to facilitate the motion and uptake/release of ions. Although this proposal mainly deals with high-value nutrients, selective removal of some undesirable anions and cations (like sulphate anions and some heavy metal ions such as Hg2+ and Pb2+) from wastewater can be an additional goal. Another focus of this project will be monovalent/bivalent cation separation. Hard water usually contains high levels of Ca2+ and Mg2+ cations which are not hazardous but can cause undesirable effects on plant growing. In this project, pressure-driven separation of Na+ and Mg2+ using non-functionalized PEMs will be investigated.