Characterization and thermal decomposition of demineralized wastewater algae biomass

Rowena B. Carpio, Yuanhui Zhang, Chih Ting Kuo, Wan Ting Chen, Lance Charles Schideman, Rizalinda L. de Leon

Research output: Contribution to journalArticlepeer-review


Demineralization pretreatments by leaching using different solvents including deionized water (DI-H2O), acetic acid, formic acid, and sulfuric acid were evaluated for their ash removal efficiency and effects on the physical structure, chemical composition and thermal behavior of wastewater algae biomass (WA). The apparent activation energy of the thermal decomposition (Ea) was estimated using isoconversional methods proposed by Friedman, Flynn-Wall-Ozawa, and Kissinger-Ahakira-Sunose. Dilute-acid leaching substantially reduced the ash content in WA from 40.07% dw (dry weight) to as low as 25.70% dw, with the higher heating value (HHV) considerably improved from 13.08 MJ/kg up to 15.84 MJ/kg. Leaching using formic acid was found the most effective (36.86% ash removal efficiency), while DI-H2O was the least effective (2.94% ash removal efficiency) in reducing the ash content in WA. Both formic acid and sulfuric acid treatments resulted in a decreased of Ea by 10% and 7%, respectively, while no significant change was observed with acetic acid treatment. These results suggest that selective dilute-acid leaching can improve the thermal decomposition of WA, which may benefit subsequent thermochemical conversion processes.

Original languageEnglish (US)
Article number101399
JournalAlgal Research
StatePublished - Mar 2019


  • Activation energy
  • Ash
  • Demineralization
  • TGA
  • Wastewater algae

ASJC Scopus subject areas

  • Agronomy and Crop Science


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