Title : The role of complexation during membrane separations in water treatment process
Abstract:
Membrane material may serve as a porous media but its physical and chemical properties depending on the medium matrix play a real role as material directly implicated in the transport and separation phenomena of substances. The development of membranes with specific selectivity deal to the introduction of new concept of separation based on the formation of complexes into membrane material during the process of transport by chelation, conferring on the membrane a highly selective character regarding particular species existing in a very heterogeneous environment.
Our work, for more than two decades, has focused on the study of various aspects of acid-base and complexing behavior of polyethyleneimine in aqueous solutions and within membranes as a surface modifier and as facilitator of ion transport by complexation jumping. Copper ion has been widely explored; it forms a complex having a very intense blue coloration which absorbs in the visible and ultraviolet ranges at 630 and 280nm respectively.
Other molecules were also used to provide synergy with PEI or as alternatives such as polyvinylpyrrolidone (PVP) for cobalt, thiourea for the separation of copper and silver, D2EHPA for the transport of chromium, or the extraction of rare earths as well as other complexing agents.
