Waste and Biomass Valorization

, Volume 10, Issue 7, pp 1979–1987 | Cite as

Characterization of Energy-Rich Hydrochars from Microwave-Assisted Hydrothermal Carbonization of Coconut Shell

  • Sunday E. ElaigwuEmail author
  • Gillian M. Greenway
Original Paper


In this study, microwave-assisted hydrothermal carbonization of waste coconut shell (feedstock) is reported. It is a thermo-conversion technique in which the feedstock was transformed into energy-rich carbonaceous material under mild conditions. The process was conducted in a microwave oven by heating the waste coconut shell in deionized water inside a pressurized vessel. The effects of different process conditions on the product yields, and the energy properties of the hydrochars were studied by varying the reaction temperature from 150 to 200 °C and residence time from 5 to 30 min. The results showed that there was transformation of the feedstock in the process due to the decarboxylation, dehydration, and demethanation reactions. This led to changes in the chemical and structural compositions, as well as increase in the energy properties of the prepared hydrochars. The higher heating value increased from 15.06 MJ/kg in the feedstock to 19.76 MJ/kg in the hydrochar. The energy properties of the hydrochars prepared in this study showed that microwave-assisted hydrothermal carbonization process could be a technique for converting waste coconut shell into high value-added product.


Microwave-assisted Hydrothermal carbonization Hydrochar Coconut shell Product yields Energy properties 



The authors wish to thank the Petroleum Technology Development Fund (PTDF), Nigeria for PhD studentship of Dr. Sunday E. Elaigwu. We also wish to thank Bob Knight of the Department of Chemistry, University of Hull for his assistance with CEM microwave oven.


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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of HullHullUK
  2. 2.Department of ChemistryUniversity of IlorinIlorinNigeria

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