3. Results and discussion
3.1 Spent coffee grounds
The composition of the SCG is shown in Table 1.
Table 1. Composition of spent coffee grounds
Parameter This work Reference value
Moisture (%) 12.2 1.18-5.54 (a)
Total carbon (%) 52.2 47.8-58.9 (b,c)
Total nitrogen (%) 2.1 1.9-2.3 (b,d)
Protein (gprotein/100 g) 13.3 6.7-13.6 (a,e)
Ash (%) 1.43 0.43-1.6 (a,e)
Cellulose (%) 13.8 8.6 (f)
Klason lignin (%) 31.9 -
Soluble lignin (%) 1.7 -
Total lignin (%) 33.6 -
Higher heating value (MJ/kg) 4619.2 21.8-26.9 (g)