Removal of azo dyes in textile wastewater using microbial fuel cells and membrane technology by Raul Alfonso BAHAMONDE SORIA

For the degree of Doctor of Engineering Sciences and Technology

In recent years, bioelectrochemical systems (BES), such as microbial fuel cells (MFC), have been explored for their benefits in the treatment of complex wastewater.

Textile wastewater mixtures are far from ideal electrolytes for an electrochemical process, generating bioincubations on electrodes and separators, which greatly affect cell performance. There is an extensive literature on the methodology of modification and preparation of nanofiltration membranes with antifouling properties for membrane tegnology, which, added to the potential advantages of these membranes (oxygen retention and lower electrical resistance compared to ion selective membranes), generates a great expectation for the use of this type of separators never before used in bioelectrochemical systems.

The objective of this work is to explore the modification processes of nanofiltration membranes to provide them with antifouling properties and efficient separators in microbial fuel cells and in a new gereration of microbial (osmotic) nanofiltration fuel cells, for the treatment of textile wastewater.

The bio-inspired modification method used polydopamine and photocatalysts as antifouling agents. Tests showed that membranes modified with poldopamine and ZnO or with a mixture of catalysts (TiO2:ZnO) acquired antibacterial and antifouling activity. Thus, the modification process was applied in low-cost membranes as separators of MFCs, which showed significant improvement in COD and color removal and electricity production in MFCs. In order to improve the visible light activation efficiency of the catalyst and the antifouling properties of the membranes, a new catalyst (ZnO Er/Al) was synthesized. The new catalyst was used in the production of nanofiltration microbial fuel cells with antifouling membranes, which showed both the efficiency of these membranes to maintain a constant water flux during long osmotic periods of evaluation and excellent antifouling properties. These results and the wide variety of available nanofiltration membranes show a promising future of research.

Jury members :

• Prof. Patricia Luis Alconero (UCLouvain, Belgium), supervisor
• Prof. Hervé Jeanmart (UCLouvain, Belgium), chairperson
• Prof. Laurent Francis (UCLouvain, Belgium)
• Prof. Denis Dochain (UCLouvain, Belgium)
• Prof. Anthony Szymczyck (Université de Rennes 1, France)
• Prof. Korneel Rabaey (Ghent University, Belgium)
• Prof. Pablo Bonilla (Central University of Ecuador)

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