Lignin-derived layered 3D biochar with controllable acidity for enhanced catalytic upgrading of Jatropha oil to biodiesel

Biochar materials have wide applications in soil improvement/remediation, water pollution control, gas storage, and heterogeneous catalysis, while usually suffering from low surface areas and harsh preparation conditions. In this study, a green, environmentally friendly, and low-cost biochar catalyst (PAP-MEPP-C) was prepared by thermochemical treatment of lignin-derived monomers at a low temperature (80 degrees C), and further developed for high-efficiency production of biodiesel from non-edible Jatropha oil (JO). The characterization results showed that the structure of the PAP-MEPP-C biochar catalyst was layered and 3D structure, and its acidity could be controlled by changing the monomeric composition. The reaction conditions of preparing biodiesel catalyzed by PAP-MEPP-C were optimized by the response surface method, and the obtained maximum biodiesel yield was 97.2%. The kinetics of the (trans)esterification reaction over the developed biochar catalyst PAP-MEPP-C was studied, and its superior catalytic performance to other tested acid catalysts could be supported by a relatively lower activation energy (36 kJ mol- 1). In addition, the biochar catalyst was highly stable and could be recycled four times with more than 90% biodiesel yield.