Break

Coffee is the world’s second largest traded commodity, and its consumption inevitably results in waste, including spent coffee grinds (SCG). In this work, SGC is considered as a precursor for activated carbon (AC) production, with simultaneous Fe impregnation via ferric ammonium citrate (FAC). Three Fe:C mole ratios were considered (1:10, 3:10 and 5:10). SCG carbonization occurred in 0.5 liters per minute (LPM) N₂ at up to 600 ^oC for 1 h. Physical activation of the recovered char occurred in 0.5 LPM CO₂ at 800 ^oC for 30 min with a ramp rate of 10 ^oC/min. Products were characterized using scanning electron microscopy with energy dispersive x-ray spectroscopy, x-ray diffraction, pH of the point of zero charge, thermogravimetric analysis, bulk elemental analysis, and N₂ adsorption. Prepared carbon support were porous, with BET surface areas as high as 180 m²/g. Bulk iron loadings reached 2.4 wt%, with partially reduced Fe₃O₄ as the primary impregnated iron species. High nitrogen content in SCG and FAC jointly contribute to nitrogen-doping of Fe/C products. Performance testing for environmental applications was completed using volatile organic compounds and hexavalent chromium. Achieved contaminant removals are attributed to adsorptive and/or reductive properties of Fe/C materials. In sum, this work utilizes a plentiful industrial waste to produce tailored Fe impregnated ACs that exhibit promising performance for gaseous and aqueous pollutant removal.