Microwave-assisted catalytic pyrolysis of apple wood to produce biochar: Co-pyrolysis behavior, pyrolysis kinetics analysis and evaluation of microbial carriers

This study investigated the behavior and kinetics of co-pyrolysis of apple wood (AW) with H3PO4 and K3PO4 as catalysts under microwave to prepare biochar as microbial absorbent. The kinetic studies indicate that the co-pyrolysis of AW with H3PO4 or K3PO4 can effectively improve the pyrolysis efficiency and enhance the biochar characteristics by reducing of the activation energy of the pyrolysis reaction. The kinetic parameters indicate that the activation energy of the mixtures in the main pyrolysis stage is lower than that of a single AW, which mean that the co-pyrolysis of AW with H3PO4 or K3PO4 shows excellent synergy. Biochar characterization showed that the yield of biochar reached the highest 58.6% when the ratio (H3PO4/AW) is 0.5. The adsorption results show that the bacteria SL-44 can be effectively loaded on the surface of the biochar, and the adsorption process is combined with Langmuir model and process can proceed spontaneously.