Modification and activation of hydrochar obtained by the hydrothermal carbonisation process of invasive plant biomass

Abstract

Invasive plants produce significant amounts of biomass and their spreading are one of the major factors influencing biodiversity. This article demonstrates the possibilities of hydrothermal carbonisation (HTC) for the treatment of invasive Sosnowsky's hogweed biomass to achieve its safe utilisation simultaneously producing new sorbent materials. Two different N-doping methods of hydrochar (HC) including impregnation and HTC approaches, followed by activation, and three oxidation approaches like cold KOH activation, Fenton's oxidation and UV treatment have been evaluated to obtain the perspective material for carbon capture and environmental technologies. The most optimal oxidation approach to obtain adsorbent for environmental technologies was HCs cold activation with KOH, which provides high sorption capacities concerning metallic ions and organic substances (Cu 18 mg/g, and methylene blue 146 mg/g). Evaluating various N-doping approaches, the highest CO2 adsorption capacity was obtained for impregnated samples, that were thermally activated using KOH, reaching up to 3.9 mmol/g.