(2017) Journal of CO₂ Utilization_Co-pyrolysis of paper mill sludge and spend coffee ground using CO₂ as reaction medium

Cho D.-W., Kwon E.E., Kwon G., Zhang S., Lee S.-R., Song H.

(Elsevier Ltd) Journal of CO2 Utilization ISSN: 22129820 Vol.21 Issue. Article No. DOI: 10.1016/j.jcou.2017.09.003

Here in this study, co-pyrolysis of paper mill sludge (PMS) and spent coffee ground (SCG) was conducted to mainly recover energy and additionally produce engineered biochar as an adsorbent. More specifically, to enhance the generation of syngas (H₂ and CO) through co-pyrolysis of PMS and SCG and modify the physico-chemical properties of biochar, carbon dioxide (CO₂) was used as reaction medium. The CO₂ co-feeding impact on co-pyrolysis with various mass ratios of PMS and SCG was also evaluated to explore any catalytic effects arising from CO₂ and Fe/Ca species in PMS. The decrease in pyrolytic oil substances was apparent due to the synergistic effects of CO₂ and Fe/Ca species. Moreover, the generation of CO was catalytically enhanced in the presence of Fe/Ca species in PMS. Co-pyrolysis in CO₂ not only converted the impregnated Fe ions into magnetite (Fe₃O₄), but also created porous biochar. One biochar fabricated at the optimal mass ratio (PMS:SCG = 7:3) exhibited the highest adsorption capability toward As(V) due to adequate balancing between the amount of Fe/Ca solid minerals and biochar porosity. As a result, co-pyrolysis using CO₂ as reaction medium can be a feasible option for the generation of CO along with production of biochar as a byproduct which can be used in environmental application. © 2017 Elsevier Ltd. All rights reserved.

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education ( 2017R1D1A1A09000800 ).