Saccharina japonica seaweed-derived biochar production at various pyrolysis temperatures

Biochars from the seaweed Saccharina japonica were obtained by stepwise pyrolysis at temperatures of 300, 400, 500, 700, 900 °C. Its characteristics and properties were studied: elemental composition, specific surface area and total pore volume, particle size distribution, as well as characteristic functional groups were determined using IR-Fourier spectroscopy. With an increase in the pyrolysis temperature from 300 °C to 900 °C, the biochar yield decreases from 50.4% to 22.7%. The biochar obtained at 500 °C has the largest specific surface area – 38.6 m2/g. As the pyrolysis temperature increases, the elemental composition of the biochar changes: the content of carbon, hydrogen, nitrogen decreases, and the content of sulfur and oxygen increases.