Durian shell biochar catalyst with excellent aromatic selectivity and deoxygenation performance: application in catalytic co-pyrolysis of pretreated Chlorella and waste vegetable oil

In order to achieve catalytic co-pyrolysis of pretreated microalgae with waste vegetable oils for quality enhancement, durian shells, a typical fruit waste, were used to prepare biochar-based catalysts, and CaO, which is believed to possess high deoxygenation activity, was loaded onto the durian shell biochar (DSBC). The prepared catalyst xCaO-DSBC was found to possess a specific surface area of more than 1200 m2/g with a typical micro-mesoporous composite structure. When the catalyst was applied to catalytic pyrolysis of pretreated microalgae, the relative content of aromatics in the bio-oil was enhanced from less than 20 %–62.86 %. When the catalyst was used in the catalytic co-pyrolysis of microalgae and waste vegetable oil, 85.55 % of aromatics were achieved with a total relative content of 40.75 % of BTEXs, n-propylbenzene and naphthalene, while the relative content of oxygenated components was only 2.01 %. After the catalyst has been used four times, the total relative content of aromatics and hydrocarbons in the liquid product is still more than 73 %, while the relative content of oxygenated components is less than 5 %. Overall, the prepared durian shell biochar-based catalysts possessed excellent deoxygenation performance and aromatic selectivity.