Bioelectrosynthesis

Principles and Technologies for Value-Added Products

Aijie Wang, Wenzong Liu, Bo Zhang, Weiwei Cai, Aijie Wang, Wenzong Liu, Bo Zhang, Weiwei Cai

• Publisher: Wiley-VCH
• Year: 2020
• ISBN:
  9783527343812
• Edition: 1
• Topic: Technologie et ingénierie
• Subtopic: Agriculture durable

Introduces basic principles and mechanisms, covers new developments, and provides a different view of the main facets of bioelectrosynthesis Bioelectrosynthesis represents a promising approach for storing renewable energy or producing target chemicals in an energy-sustainable and low-cost way. This timely and important book systemically introduces the hot issues surrounding bioelectrosynthesis, including potential value-added products via bioelectrochemical system, reactor development of bioelectrosynthesis, and microbial biology on biofilm communities and metabolism pathways. It presents readers with unique viewpoints on basic principles and mechanisms along with new developments on reactor and microbial ecology. Beginning with a principle and products overview of bioelectrosynthesis, Bioelectrosynthesis: Principles and Technologies for Value-Added Products goes on to offer in-depth sections on: biogas production and upgrading technology via bioelectrolysis; organic synthesis on cathodes; chemical products and nitrogen recovery; external electron transfer and electrode material promotion; and the microbiology of bioelectrosynthesis. Topics covered include: hydrogen production from waste stream with microbial electrolysis cell; microbial electrolysis cell; inorganic compound synthesis in bioelectrochemical system; microbial growth, ecological, and metabolic characteristics in bioelectrosynthesis systems; microbial metabolism kinetics and interactions in bioelectrosynthesis system; and more. * Comprehensively covers all of the key issues of biolelectrosynthesis
* Features contributions from top experts in the field
* Examines the conversion of organic wastes to methane via electromethanogenesis; methane production at biocathodes; extracellular electron transport of electroactive biofilm; and more Bioelectrosynthesis: Principles and Technologies for Value-Added Products will appeal to chemists, electrochemists, environmental chemists, water chemists, microbiologists, biochemists, and graduate students involved in the field.

Section II
Biogas Production and Upgrading Technology via Bioelectrolysis

2
Hydrogen Production from Waste Stream with Microbial Electrolysis Cells

Defeng Xing, Yang Yang, Zhen Li, Han Cui, Dongmei Ma, Xiaoyu Cai, and Jiayu Gu

Harbin Institute of Technology, School of Environment, State Key Laboratory of Urban Water Resource and Environment, No. 73 Huanghe Road, Harbin, 150090, China

Hydrogen is attracting more and more attention as renewable energy carrier, which is clean, highly efficient, and cost effective, and with the tremendous potential to replace nonsustainable fossil fuels [1, 2]. However, the conventional methods of hydrogen production, such as steam reforming, high-temperature electrolysis, and thermochemical cycle, are all energy-intensive processes and have nearly the same negative impact toward the environment as direct combustion of fossil fuels [3]. Therefore, it is imperative to develop environment-friendly and sustainable technologies for producing H₂. Biohydrogen production using organic matter has been studied extensively as a promising approach including dark fermentation, photo-fermentation, and microbial electrolysis cell (MEC) [4]. However, photo-fermentation is limited by light requirement and oxygen sensitivity, which causes high design cost and low hydrogen yield, while dark fermentation is limited by substrate utilization, which can only produce about 2 mol H₂/mol glucose that is much lower than the theoretical level (12 mol H₂/mol glucose). MEC, as an electrochemical device which uses electroactive microorganisms as catalysts to convert the organic matter to hydrogen, provides a novel approach for economically viable H₂ production from a wide range of renewable biomass energies [5]. In addition to the above three main methods, many coupling processes have been developed to enhance the hydrogen production [6].

In MEC system, H₂ generation is accomplished by the cooperation of a succession of microorganisms under electrochemistry conditions. The complex waste biomass with high molecular weight firstly breaks down by polymer-degrading bacteria and then by fermentative bacteria into simple organic matter (such as volatile fatty acids [VFAs], ethanol, amino acids, and so on). Then, the electroactive microbes (or called exoelectrogens), which are attached on the anode surface and have the ability to facilitate the transfer of electrons from the substrate to the conductive anode, oxidize these simple organic products into CO₂, electrons, and protons with the anode serving as the electron acceptor [7]. Exoelectrogens, such as Geobacter, Shewanella, and Pseudomonas spp., have outer membrane cytochromes and/or nanowires involved in electron transfer, which allow them to have the ability of extracellular electron transfer (EET) and passing electrons to the anode. A small additional voltage is applied in the MEC system to promote the proceeding of the cathodic H⁺ ion reduction reaction because it has a lower redox potential than the anode. The electrons then travel through the external circuit, and the protons in the solution pass across the membrane and combine at the cathode to generate hydrogen (Figure 2.1).

In this chapter, operation and characteristics of MEC at the laboratory scale and pilot scale are discussed. Advantages and application potential of different electrode materials including the common anode materials, cathode materials, and cathode catalysts are summarized. The optimization of the MEC operating conditions are discussed from different aspects such as substrate, applied voltage, pH, temperature, and the inhibition methods on methanogenesis. The researches on electroactive microbiome and syntrophic interaction under different conditions are also provided, and the development of analysis technique on microbial community is briefly introduced. In addition, the research hotspots such as electron transfer pathways in electrodes of MEC, coupling MEC with other systems to enhance hydrogen production, are also investigated to predict the prospect of MEC future development in biohydrogen production process.

2.1 Construction of MEC and Scale-up

The primary laboratory experiments on hydrogen-producing MECs generally used cation exchange membranes (CEMs) or anion exchange membranes (AEMs) to isolate the anode and cathode electrolytes. The main benefit of using ion exchange membranes (IEMs) i...