High yield carbonization and mesoporous activated carbon production from acid-treated spent coffee grounds

An increase in the specific surface area (SSA) of activated carbon (AC) derived from spent coffee grounds (SCG) was achieved by improving the carbonization yield and developing more micropores. The carbonization yields for methanesulfonic acid-treated, sulfuric acid-treated and benzenesulfonic acid-treated SCG were 41.3, 35.4, 46.1 wt%, respectively. These values were significantly higher than that of non-treated SCG (25.3 wt%). A longer activation time was required for acid-treated SCG carbon than non-treated SCG. Nitrogen adsorption-desorption measurements revealed that acid-treated SCGACs have a larger mesopore (several tens nm) than non-treated SCGAC (5 nm). Acid-treated SCGACs had a higher SSA and total yield than those of non-treated SCGAC, especially for benzenesulfonic acid-treated SCGAC, where the SSA reached 1,500 m2/g or more (15% higher than a non-treated one).