Study on the interaction effect of seaweed bio-coke and rice husk volatiles during co-pyrolysis

Biomass is a wide-spread resource that have been studied for decades to realize energy utilization is a renewable and sustainable way. It was reported that there is a synergistic interaction during co-pyrolysis of different biomasses such as algae and terrestrial plants, but the mechanism is still unclear. This study aims to investigate the heterogeneous interactions between rice husk (HU) volatile and Enteromorpha clathrate (EN) bio-coke during co-pyrolysis using a sectional tubular pyrolysis furnace. Physical and chemical properties of the interacted bio-coke were studied using N2 isothermal absorption method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In addition, the obtained bio-oil was also characterized by gas chromatography-mass spectrometer (GC/MS). The changes in specific surface area of the pyrolyzed bio-coke indicated the significant effect of HU volatiles on EN bio-coke microstructure. After flew through by rice husk volatiles, the adsorption capacity of EN bio-coke improved. Owing to the free radicals in HU volatile, polycondensation and aromatization reactions were enhanced in EN bio-coke resulting in aromatic compounds with higher cyclization of nitrogenous compounds. On the other hand, EN bio-coke participated the decomposition of carbohydrates in HU volatiles to increase the content of aldehydes and furans in the produced bio-oil. In addition, the significant Maillard reaction accelerated the production of ketones and phenols in the bio-oil and reduced the content of N in EN bio-coke at 400 °C. The present study confirmed that there is a significant interaction between seaweed bio-coke and rice husk volatiles during co-pyrolysis.