Pollutant removal from gaseous and aqueous phases using hydrochar-based activated carbon

In this study, hydrochar (HC) produced at industrial scale by hydrothermal carbonization of municipal woody and herbaceous prunings was used for producing activated carbon by KOH chemical activation. Different KOH/HC ratios were studied to produce highly porous materials with high surface area. Activated carbon with a BET surface area up to 1739 m2/g was obtained for a 3:1 KOH/HC ratio. Adsorption properties of obtained samples were studied for removing pollutants both from gas and liquid phases. Thermogravimetric analyzer (TGA) was used for evaluating the removal capacities of CO2from a gaseous phase, while UV-Vis spectroscopy was used for evaluating the removal capacities of an emerging contaminant from an aqueous phase. All samples showed a good CO2adsorption capacity at 27 °C, reaching 84.5 mg CO2/g sorbent for hydrochar activated with an impregnation ratio of 2:1. Moreover, activated chars exhibited a high removal efficiency (up to 97.9 % for a 3:1 KOH/HC ratio) for atrazine, which is one of the most common pesticides detected in superficial and groundwater aquifers.