Hydrothermal carbonization of de-ashed seaweed in the presence of a deep eutectic solvent for producing crude biochemical and activated carbon material

This study aims to convert seaweed into biochemical and activated carbon by hydrothermal carbonization process at various temperatures (200C & 225 oC) and deep eutectic solvent ratio to water solution (1:1 and 1:2). This process is carried out with the activating agent CaCl2 and produces liquid products, hydrochar, and gas. Activated carbon is made from the activation process of hydrochar at a temperature of 800oC for 2 hours. The increase in hydrothermal temperature reduces the output of liquid and activated carbon products. Meanwhile, the increase in the ratio of the deep eutectic solvent increases the yield of activated carbon but decreases the liquid product. Analysis of the liquid product obtained that the main content is methyl cyclopentane with a composition reaching 89.58-92.71%, while the rest is in acetone, dimethoxymethane, and other compounds. The highest yield of activated carbon was 41.39% at a temperature of 200 oC and a ratio of 1:2. Porosity analysis of activated carbon has a mesoporous structure with a pore diameter of 3.08-4.13 and a surface area of 242.57-417.7 m2 g−1. Research findings provide a potential alternative for synthesizing biochemicals and biomaterials by hydrothermal carbonization and pyrolysis activation.