Scientists at Leibniz Institute for Agricultural Engineering in Potsdam and Humboldt University Berlin developed a simple process for direct synthesis of magnetic carbon composites through hydrothermal carbonization (HTC) and demonstrated their useful application in biogas production. The carbon particles have a moderate surface area and, as a novelty, a magnetic core. This unique combination opens the door for various applications including fixation of microbial biomass or removal of problematic substances in bioprocesses, wastewaters or the environment.
Anaerobic biological processes like biogas production are limited in their performance and usability due to slow microbial growth and inhibition effects by several chemical compounds such as ammonium. Until today, common techniques for the accumulation of microorganisms in a biogas reactor are usually based on their retention through sedimentation or installations inside the reactor, on which the microflora can settle and form biofilms. However, both require a low-solid fermentation liquor. In biogas reactors fed with solid feedstocks such as manure or maize silage the viscosity is often too high.