Production of crude bio-oil and biochar from hydrothermal conversion of jujube stones with metal carbonates

ABSTRACT

In this study, hydrothermal processing was employed to produce crude bio-oil and biochar from waste jujube stones by deploying metal carbonates as catalysts. The effects of metal carbonate catalysts (K₂CO₃, Na₂CO₃ and SrCO₃) in different concentrations on the product yields and properties were tested for the conversion studies. The use of metal carbonates (K₂CO₃, Na₂CO₃ and SrCO₃) increased the yield of bio-oil almost twofold, with the highest yield (18.66 wt%) obtained using K₂CO₃ at a concentration of 10 wt%. (E)- 9-octadecenoic acid (elaidic acid), 2,6-dimethoxyphenol (syringol) and 2-methoxyphenol (guaiacol) were some of the prominent compounds found in the crude bio-oils. The process also resulted in an efficient conversion of jujube stones to biochar with high content of oxygenated functional groups which makes it an effective precursor for various applications. The heating values of the bio-oils and biochars were significantly improved compared to those of the feedstock.

KEYWORDS:

• Hydrothermal process
• biocrude
• biochar
• waste biomass
• jujube stone

Acknowledgements

The financial support under the contract (KBÜ-BAP-14/2-YL-021) from Karabük University is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Karabük University [grant number KBÜ-BAP-14/2-YL-021].