Chemosphere 184 (2017) 43
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Chemosphere journal homepage: www.elsevier.com/locate/chemosphere
Advances in bioelectrochemical systems
Sustainable development is considerably dependent on advanced and efﬁcient production of energy as well as on environmental-friendly management of various waste fractions and residues generated by municipalities and industrial sectors. Findings of the past decade indicate well that bioelectrochemical systems (BESs) assisted by special exoelectrogenic microorganisms as biocatalysts can help to achieve these goals in a single process. Bioelectrochemical systems (BESs) such as Microbial Fuel Cells (MFCs) and Microbial Electrohydrogenesis (or Electrolysis) Cells (MECs) are able to assist the green conversion of a wide range of problematic feedstock either into electricity or to prosperous energy carrier e.g. hydrogen gas. The continuous improvement on BESs is the way to make their performances more attractive and as a result, facilitate their competitiveness in comparison with other traditional methods. This virtual special issue (VSI) brought all aspects (upstream, downstream) of bioelectrochemical systems under one umbrella in a wide range from biocatalysis to engineering, from system design to architecture and reliable operation. The papers cover various areas of (i) applications, (ii) constructions and (iii) microbiota. As to the application (i) a couple of contributions focus on the treatment of waste waters (both industrial e concerning textile and food industry e and municipal), where simultaneous waste reduction and energy recovery were expected. However, the organic substrates were not limited to various waste waters, there are other substrates applied, too, e.g. waste liquor coming from a solid waste treatment plant. There is a paper on detection of a special substance (ascorbic acid) and another one where the aim was production of value added biochemicals. These papers show clearly that BESs can be applied for unusual tasks, as well. More and more BESs are applied in a combination with other processes forming a sort of integrated system. Typically anaerobic processes, like biogas (CH4) production or biohydrogen fermentation are coupled with BESs. Regarding construction (ii) application of both classical twochamber, single-chamber and membraneless cells, moreover
http://dx.doi.org/10.1016/j.chemosphere.2017.05.164 0045-6535/© 2017 Elsevier Ltd. All rights reserved.
special bioreactors can be found in the articles. Innovative concepts on novel electrode (e.g. hydrogel bioanode) and membrane materials (e.g. supported ionic liquid membrane) are presented in the papers, where the design (including size, surface area, the distance of the electrodes … etc.), role, behaviour, electrical performance (e.g. power density) and operation of anodes, cathodes as well as membranes were studied in details. The electrical behaviour of the cells was characterized mainly by special electrochemical methods, like cyclic voltammetry. The bottlenecks associated with the conversion rate and yields, moreover with the scale up of BES technology is discussed. Thus it seems that architecture of bioelectrochemical systems is still needed to improve to achieve higher effectiveness. At last on the topic of microbiota (iii) various bioﬁlms e where microbial communities containing exo-electrogens live and work e were monitored and characterized by using advanced molecular techniques for identiﬁcation of electrogens. Their adaptation, immobilization on the electrode(s), behaviour and electrontransfer mechanisms was thoroughly described. Microalgae should be considered now as a new research trend in the area of BESs' bioﬁlm: two papers are dealing with them in this serial. Altogether 13 papers were published in the VSI, their authors are from all over the world, including three continents e America, Asia and Europe (the countries are China, Ecuador, Hungary, Japan, Korea, Malaysia, Mexico, Taiwan, Vietnam). I take the opportunity to thank the authors, co-authors for their high level manuscripts; moreover the great efforts and hard work of the referees (from even more countries) are gratefully acknowledged. Finally I highly appreciate the help of the co-editors and especially Peter Bakonyi. Katalin Belaﬁ-Bako, Managing Guest Editor
Available online 30 May 2017