Recently, at UGent, Rishav Phukan obtained his FWO-SB scholarship on the ‘Development of novel fouling resistant ion-exchange membranes for electrodialysis in bio-based applications’. In this project PaInT will team-up with VITO in a 4 year collaboration which started on November 2019.
The objective of this research project is to develop polyelectrolyte (PE) coated IEM’s that allow the transport of charged components (recovery of acids), as well as, remove the inhibitory components (organics), without hampering the neutral molecules. Once the PE coating is heavily fouled, it can be removed and replaced (regenerated) with a new one. The concept of “sacrificial layer” shall be used in this case.
Why do we need this research?
Agricultural and forestry residues containing lignocellulose are abundant and cheap, and therefore are a readily available source of plant biomass. A variety of bio-based chemicals can be processed from the lignocellulose derived building blocks such as organic acids, sorbitol, glycerol etc. The production of these valuable chemicals requires an extensive production process such as pre-treatment of biomass, detoxification, bio-chemical conversion, and downstream processing. For the pre-treatment step, acid hydrolysis is a widely used technology that breaks down the lignocellulose into cellulose, lignin, hemicellulose and in the process forms various complex by-products that are inhibitory to the downstream process. For this reason, a detoxification step is necessary to counteract the inhibition problems. Different physical, chemical and biological methods have been used in the past, but these techniques have considerable downsides to them. Electrodialysis (ED) is proposed as an alternative for detoxification. This technology uses ion-exchange membranes (IEM) and an applied electric potential to separate ionic species from aqueous feed streams.
As in all membrane processes, fouling is one of the key problems that ED applications face. Fouling increases electrical resistance and decreases permselectivity (transport of counter ions). In recent research, it has been seen that state of the art IEM’s are far from optimized and show significant loss of performance when organic compounds (e.g. sodium dodecyl benzene sulfonate, sodium alginate, sodium humate etc) are present in the feed stream. Thus, the cleaning procedure, as well as, replacement of fouled IEM’s takes up to 40 -70 % of the operational costs.
Ir. R Phukan1, Dr. M Vanoppen1, Dr. L Gutierrez1, Dr. W De Schepper2, Prof. E Cornelissen1, Prof. A Verliefde1
1 Particle and Interfacial technology (PaInT), Coupure Links 653, 9000 Ghent, Belgium
2 Vlaamse Instelling voor Technologisch Onderzoek (VITO), Boeretang 200, 2000 Mol, Belgium