“Nanomaterials in membranes for water treatment and gas separation”, Dr. Konstantinos S. Andrikopoulos [July24, 2018]


“Nanomaterials in membranes for water treatment and gas separation”

Dr. Konstantinos S. Andrikopoulos Institute of Chemical Engineering Sciences (ICE-HT)

Abstract

Membrane gas separation is an expanding technology with various applications. In many of these applications this technology possesses in addition an energy impact; by the replacement for example of the typical industrial distillation columns that are particularly energy consuming. The specificity of the membrane type for each application is determined by the properties of the materials used as well as their architecture. To this end, new materials would result in an even faster technological growth. Most of the current applications involve CO2 removal or capture and olefin/paraffin separation. Nevertheless, the field of air and natural gas dehydration has shown commercial success as well; mostly based on the overall technologies for separation of solvents forming azeotropes with water. Membrane processes generally require different membranes to be developed for each category of mixture. The most critical parameters that have to be dealt with are selectivity and permeability. Typically these factors are competitive and it’s actually a challenge for a material to enable increase of both factors. Carbon based materials, such as Carbon Nanotubes (CNTs) and Graphene based materials (Graphene, GOs and materials resulting from their structural manipulation) seem to be challenging since they, at least from the theoretical point of view, enable flow of water (and water vapors), which is orders of magnitude higher than the conventional theories of fluids predict. In the current presentation several types of membranes focusing mostly on gas separation and water treatment will be referred. These membranes were developed in the laboratories of FORTH/ICEHT and most of the work that will be presented refers to:

(i) the experimental characterization of the membranes at molecular level in an attempt to describe the mechanisms that rule the processes involved (e.g. how does water vapor transmission rate correlate to the GO structure), (ii) the factors affecting the water vapor permeability in mixed matrix membranes (e.g. the CNTs concentration & dispersion of the CNT-iPP membrane type),
(iii) the methodologies developed in order to non-destructively characterize critical factors (such as the CNTs concentration) that affect the membrane’s operation (e.g. evaluation of CNTs concentration in the selective layer of porous membranes prepared by the phase inversion method)

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