Influence of dilute acid, alkali and hydrothermalpretreatments on methane improvement from datepalm waste “Takarboucht” cultivar

Abstract

This research assesses the impacts of hydrothermal (120 °C for 30 min), dilute acid (2%(w/w) H2SO4 at 120 °C for 30 min) and alkali (6% (w/w) NaOH at 35 °C for 24 h)pretreatments on the methane yield from date palm waste “Takarboucht” cultivar. The pretreated and untreated date palm waste (DPW) were digested at mesophilic temperature (36 °C) for 20 days. The highest soluble chemical oxygen demand (sCOD) was obtained by DPW hydrolysate from alkali pretreatment. The highest methane yield of 161.86 ml/g VS was obtained from untreated DPW. Among all pretreatments, higher methane yield was obtained from hydrothermally pretreated DPW (153.35 ml/g VS), followed by acid pretreated DPW (141.65 ml/g VS) and alkali pretreated DPW (50.78 ml/g VS). Alkali pretreatment improved the solubilization of DPW, however, it may not necessarily provide an enhancement in the methane yield. The optimization of the conditions of each pretreatment is proposed.

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Acknowledgments

Ikram Mehrez gratefully acknowledges Pr. Gopalakrishnan Kumar for offering aninternship at the University of Stavanger. The authors gratefully acknowledge the financialsupport from the University of Stavanger, Stavanger 4036, Norway. The authors gratefullyacknowledge DGRSDT (The Directorate-General for Scientific Research and TechnologicalDevelopment in Algeria).

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Highlights

• Hydrothermal, dilute acid and alkali pretreatments of DPW on BMP were compared.

• Alkali, dilute acid and hydrothermal pretreatments resulted in an inhibition of AD.

• The maximum solubilization was achieved for alkali pretreatment of DPW

• The maximum methane yield was 161.86 ml/g VS for untreated DPW.

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Mehrez, I., Djaafri, M., Semaan, G. et al. Influence of dilute acid, alkali and hydrothermalpretreatments on methane improvement from datepalm waste “Takarboucht” cultivar. Biomass Conv. Bioref. (2021). https://doi.org/10.1007/s13399-021-01296-1

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Keywords

  • Date palm waste “Takarboucht” cultivar
  • Solubilization
  • Pretreatments
  • Methane yield