KOH-activated hydrochar with engineered porosity as sustainable adsorbent for volatile organic compounds

The pore structure of materials plays a key role in adsorption, and it is of great significance to regulate the porosity of adsorbent for specific adsorbate. Herein, porous carbons (PCs) with engineered porosity were synthesized as adsorbents for volatile organic compounds (VOCs), which employed sucrose-based hydrochar via KOH activation. Surface area of 2604 m2/g together with pore volume of 1.685 cm3/g could be reached when KOH/hydrochar ratio was 3. The adsorption capacities of three typical VOCs were in the order of toluene > acetic ether > acetone, with the vapor pressure had greatest effect on adsorption among the properties of adsorbates. Influence of carbon porosity was further investigated, showing that micropores in the range of 1–3 times of the VOC diameter were crucial to the adsorption process. In addition, more than 90 % of the initial adsorption capacity could be reached after four regeneration cycles. Considering economic and environmental aspects, we demonstrated porous carbons derived from hydrothermal carbonized sucrose could be promising materials in adsorption. This work could also provide guidance for the porosity regulation of adsorbents for different VOCs.