Effect of K+ Doping on Pyrolysis of Sawdust Based Biochar

Biochar can be used as a form of carbon sequestration, as a soil amendment, or as an alternative fuel source. Biochar is made by thermally decomposing a plant waste-based feedstock in an inert atmosphere at high temperatures in a process called pyrolysis. Prior experiments established a correlation between inorganic content and relative mass yield of biochar and had results which contradicted each other. In preexisting studies, ash content was adjusted by selecting different plant-based feedstocks with known ash content values. In this study feedstocks were doped with inorganics (1-5% K+) to minimize the impact of non-independent variables on biochar yield. The experiment reveals a strong positive correlation between K+ content and final relative mass at the end of the pyrolysis reaction as well as a lowering of the reaction temperature by 70°C. The increase in biomass yield may be caused by an alternative reaction pathway enabled by the catalytic effect of K+ ion or the OH- ion reacting to increase the porosity of the sawdust and increasing the surface area of the overall reaction.