Vol.:(0123456789) 1 3 Waste and Biomass Valorization https://doi.org/10.1007/s12649-019-00817-4 ORIGINAL PAPER Characterization of Bone Char and Carbon Xerogel as Sustainable Alternative Bioelectrodes for Bioelectrochemical Systems E. D. Isaacs‑Páez 1  · N. Medellín‑Castillo 2  · F. Manríquez‑Guerrero 1  · B. Cercado 1 Received: 30 July 2018 / Accepted: 23 September 2019 © Springer Nature B.V. 2019 Abstract Bioelectrochemical systems (BES) are growing future sustainable energy and chemical production technologies that combine biological catalytic redox activity with classic abiotic electrochemical reactions and physics. Several aspects of these systems, such as cell confguration, applied voltage, electrode materials, inoculum/substrate, and low-cost electrodes to facilitate scal- ing, have been studied and reported. This work focuses on the development of inexpensive materials with desirable charac- teristics for use as electrodes for BES. The two selected carbon-based anode materials were carbon xerogels and bone char; both have diferent surface morphologies and are carbonaceous materials with precursors that allow control of their porosity. Industrial-grade raw material and cattle bone waste were used to fabricate the anodes. The electrochemical properties of the bone char and carbon xerogel electrodes were characterized by the open circuit voltage (OCV), electrochemical impedance spectroscopy, and cyclic voltammetry. Chronoamperometry was recorded for 25 days to follow the setup bioanodes. When the microbial bioanode process was completed, the bioelectrodes were immersed into fresh inoculum/substrate, and BES were operated for 10 days at the OCV until a relatively constant cell voltage output was achieved. The results show that the carbon xerogel surface area (468 m 2 /g) is 5 times higher than bone char, but the xerogel surface roughness is lower than that of the char. Similar to the electrochemical properties, the current density of the xerogel (25 mA/cm 2 ) is 4 times less than that of the bone; therefore, the bioflm growth is promoted on the bone char surface. Our fndings show that the bone char bioanode has a capacitance feature of 1.65 F/m 2 , which is even higher than the double layer capacitances of carbon-based materials reported in the literature. Hence, it is possible to use BES for simultaneous production and storage of renewable electricity. Graphic Abstract Keywords Bone char · Carbon xerogel · Garden compost · Waste valorization · Bioanode · Biocapacitor * B. Cercado bcercado@cideteq.mx Extended author information available on the last page of the article