Abstract:
Ulva Lactuca is a fast-growing algae that can be utilized as a bioenergy source. However,
the direct utilization of U. lactuca for energy applications still remains challenging due to its high
moisture and inorganics content. Therefore, thermochemical processing such as slow pyrolysis to
produce valuable added products, namely bio-oil and biochar, is needed. This study aims to conduct
a thorough investigation of bio-oil and biochar production from U. lactuca to provide valuable data
for its further valorization. A slow pyrolysis of U. lactuca was conducted in a batch-type reactor at a
temperature range of 400–600 C and times of 10–50 min. The results showed that significant compounds
obtained in U. lactuca’s bio-oil are carboxylic acids (22.63–35.28%), phenolics (9.73–31.89%),
amines/amides (15.33–23.31%), and N-aromatic compounds (14.04–15.68%). The ultimate analysis
revealed that biochar’s H/C and O/C atomic ratios were lower than feedstock, confirming that
dehydration and decarboxylation reactions occurred throughout the pyrolysis. Additionally, biochar
exhibited calorific values in the range of 19.94–21.61 MJ kg1, which is potential to be used as a solid
renewable fuel. The surface morphological analysis by scanning electron microscope (SEM) showed
a larger surface area in U. lactuca’s biochar than in the algal feedstock. Overall, this finding provides
insight on the valorization of U. lactuca for value-added chemicals, i.e., biofuels and biochar, which
can be further utilized for other applications.
