Upcycling wildfire-impacted boreal peats into porous carbons that efficiently remove phenolic micropollutants

Abstract

Activated carbons have been widely used for water treatment due to their large surface area and structural stability. Their high cost has motivated the development of sustainable bio-based sorbents. However, their industrial acceptance within the water industry is limited by lower surface areas and poorer adsorptive capacities as compared with commercial sorbents. We herein report a green, high performance porous carbon produced from boreal peats for organic micropollutant removal. Boreal peatlands are increasingly damaged due to climate change-induced wildfires and droughts, which lead to increased run-off and impeded forest regrowth. Fire-impacted peatland soils therefore were excavated and converted into value-added porous carbons through ZnCl2 activation at low temperature (400 – 600 °C). These products have significantly higher surface areas (> 1377 m2/g) than commercial activated carbon Norit GSX (965 m2/g). Adsorption of p-nitrophenol, a micropollutant, onto the porous carbons is efficient, and superior to that of Norit GSX and most sorbents reported in the literature. Adsorption mainly occurred through multi-layer chemisorption and was impacted by the electron donor-acceptor complexes mechanism, π-π interactions and steric effects. Because of the massive environmental and economic benefits, peat porous carbons are strong candidates for use in large-scale water treatment facilities.