Liquid bio-fuels and carbon adsorbents production via pyrolysis of non-edible feedstock

摘要

The slow pyrolysis of milk thistle (Silybum marianum L.) seeds (MTS) in a lab-scale batch reactor to investigate the influence of heating rate, temperature, contact period, and particle size on the yields of bio-oil (BO) and biochar (BC) was presented for the first time. The maximum yield of BO (49.55 +/- 2.50 %) was obtained at a pyrolysis temperature of 475 degrees C for 60 min using a 0.25 mm MTS particle size at 20 degrees C/min heating rate. The chemical composition of BO from MTS was identified by FTIR, H-1 NMR, and GC-MS techniques. Following the FTIR outcomes, aldehydes, alcohols, phenols, acids, and alkanes are present in the BO. Also, results from H-1 NMR spectrum indicated that the percentage of the aliphatic compounds in the as-synthesized BO was greater than that of the aromatic compounds. The GC-MS analysis exhibited that the MTS derived BO is rich in higher acids (38.64 %), higher esters (21.30 %), and hydrocarbons (11.39 %). The elemental analysis consequences revealed that the attained BO possessed a higher carbon content and a lower oxygen content than its respective MTS with a chemical formula of CH1.67N0.025O0.10. Additionally, the BO owned a calorific value of 39.47 MJ/kg, close to that established for petro based liquid fuels and comparable to those of BOsamples declared in the literature. Besides, the physic-chemical properties of the MTS derived BO were close to those specified for conventional fossil fuels. Proximate analysis, elemental composition, higher heating value, iodine number, surface area, and morphology of the attained biochar were determined. The ZnCl2 activation method was employed to synthesize activated carbon from the produced BC via the optimized procedure. An impregnation ratio of 1.5:1 ZnCl2:BC, 500 degrees C, 60 min activation period, and 0.21 mm particle size were the best conditions to yield an activated carbon with 638.66 mg/g iodine number and 677.22 m(2)/g surface area. The FESEM results affirmed the mesoporosity of the attained activated carbon compared to the macroporosity of the pristineBC.