Slow Pyrolysis of <i>Ulva lactuca</i> (Chlorophyta) for Sustainable Production of Bio-Oil and Biochar

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 kg−1, 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

Slow Pyrolysis of Ulva lactuca (Chlorophyta) for Sustainable Production of Bio-Oil and Biochar

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&ndash;600 &deg;C and times of 10&ndash;50 min. The results showed that significant compounds obtained in U. lactuca&rsquo;s bio-oil are carboxylic acids (22.63&ndash;35.28%), phenolics (9.73&ndash;31.89%), amines/amides (15.33&ndash;23.31%), and N-aromatic compounds (14.04&ndash;15.68%). The ultimate analysis revealed that biochar&rsquo;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&ndash;21.61 MJ kg&minus;1, 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&rsquo;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

Catalytic Upgrading of Bio-Oil over Cu/MCM-41 and Cu/KIT‑6 Prepared by β‑Cyclodextrin-Assisted Coimpregnation Method

Cu loaded MCM-41 and KIT-6 are prepared by β-cyclodextrin (CD) assisted coimpregnation method (Cu/MCM-41-CD and Cu/KIT-6-CD) for in situ catalytic upgrading of bio-oil derived from the fast pyrolysis of biomass. It is found that Cu/MCM-41-CD and Cu/KIT-6-CD exhibit higher catalytic activity for promoting the deoxygenation from the bio-oil when compared with those prepared by conventional impregnation method. 20 wt % of Cu loaded MCM-41-CD and KIT-6-CD shows the highest catalytic activity, by which the upgraded bio-oil is rich in monocyclic aromatic hydrocarbons such as benzene, toluene, and xylene with the total relative maximum hydrocarbon amounts of 73.2% and 86.1%. After reuse of the regenerated catalyst for four cycles, no serious reduction of total relative hydrocarbon amount is found. The possible upgrading mechanism is proposed. It is expected to provide a new direction with a green method for development of the catalyst for the upgrading of bio-oil