Activated waste cotton cellulose as renewable fuel and value-added chemicals: Thermokinetic analysis, coupled pyrolysis with gas chromatography and mass spectrometry

The bioenergy potential of waste textile cotton cellulose (BOC) and the activated waste textile cotton cellulose by H3PO4 (BOP) were assessed in this study. BOC and BOP were pyrolyzed in TG at four heating rates. The thermal weight-loss process of BOC and BOP can be separated into drying stage, rapid pyrolysis stage and carbonization stage. The kinetic and thermodynamic parameters of the pyrolysis reaction were evaluated using an isoconversion model. The Ea, ΔH and ΔG values of BOC are 84.79–206.79 kJ mol−1, 159.85–318.88 kJ mol−1 and 357.72–359.16 kJ mol−1, respectively. The Ea, ΔH and ΔG values of BOP are 101.81–453.85 kJ mol−1, 169.11–389.47 kJ mol−1 and 257∼335.78 kJ mol−1, respectively. Py-GC/MS analysis illustrated that the peak area percentages of the products of BOC/BOP, including Glucopyranose, Ketones, Cycloalkane, Aromatic, Furan, Aliphatic, CO2, and others, were 47.7%/5%, 4.66%/30.41%, 0%/27.12%, 16.64%/3.22%, 8.55%/12.44%, 12.75%/13.29%, 4.19%/3.91% and 5.51%/4.61%, respectively. Compared with BOC, the low-quality products of BOP, Glucopyranose and Aromatic, decreased from 47.7% to 16.64%–5% and 3.22%, respectively, and the high-quality products, Ketone and Cycloalkane, increased from 4.66% to 0%–30.41% and 27.12%, respectively. The complexity of bio-oil of BOP is reduced, which gives a positive prospect for the purification of backward position.