Effect of magnetic multi-walled carbon nanotubes coupled with magnetic field on anaerobic digestion

Conductive composite materials have been used to enhance methane production in anaerobic digestion (AD), and magnetic field will affect microbial activity. In this study, magnetic multi-walled carbon nanotubes (Fe3O4@CNTs) were prepared and coupled with magnetic field (MF) simultaneously during a 54-day AD process to evaluate the effects on methane production and microorganisms. The group with magnetic materials addition coupled with MF improved methane production by 5.07 % compared to the control group and enriched the abundance of acetic acid-trophic methanogens. High-throughput sequencing analysis showed that the microbial communities varied with the addition of Fe3O4@CNTs, MF, and Fe3O4@CNTs coupled with MF. The Fe3O4@CNTs coupled with MF group had the highest diversity. This study provides the possibility to enhance the performance of anaerobic digestion by applying magnetic material coupled with magnetic field.