Influence of hydrothermal carbonization conditions on the porosity, functionality, and sorption properties of microalgae hydrochars

Physicochemical characterization and DoE model responses

Individual response models were constructed based on the analyses of feedstock and hydrochar properties to assess the impact of carbonization temperature, residence time, and initial pH. The chosen responses were the solid yield (% dw), O:C atomic ratio, ash content (% dw), specific surface area (m² g⁻¹), pore volume (cm³ g⁻¹), and average pore size (nm) of the hydrochars. To facilitate interpretation, the D-optimal design model responses were visualized using surface plots (Fig. 1), with darker colours corresponding to higher…