(568a) Potential of Mineral Resource Recovery From Macroalgal Biochar Derived From a Fixed-Bed Pyrolysis Reactor

Macroalgae, also known as seaweed, have been regarded as a promising feedstock for biorefinery due to their high photosynthetic efficiency, fast growth rate, and considerable sea-farming scale for mass cultivation. Compared with land biomass, macroalgae have higher contents of nutrient such as nitrogen and phosphorus as well as various trace metals since macroalgae uptake and accumulate these elements over whole body from seawater. The macroalgae-specific characteristic provides fresh possibilities in the field of biorefinery processes. Biomass pyrolysis, one of thermochemical biorefineries, has several advantages to obtain bio-oils, value-added chemicals, and biochar regardless of the type of carbon sources. Even though most biochar products, produced from pyrolysis of lignocellulosic biomass as a reaction residue, tend to be utilized as a soil amendment to enhance soil quality and carbon sink capacity, biochar derived from macroalgae pyrolysis could be another potential approach to recover natural mineral resources from the oceanic reservoir. In this study, we estimated changes of certain mineral contents in a raw material and its biochar produced from a fixed-bed pyrolysis of brown seaweed, Laminaria japonica, with different temperatures (200, 400, and 600 °C) as well as its thermal and chemical properties by using ICP, TGA, FTIR, and ultimate analyzer. The analyzed elements, which are needed to maintain the economy (e.g. the electronics industry), are anticipated to face supply risk, but estimated much abundant in oceanic reservoir. Furthermore, mineral resource potential of the macroalgal biochar was evaluated by using two impact-based life cycle assessment methodologies, the CML 2001 and EPS 2000, to reflect aspects of resource reserves and socioeconomic dimension.