Impact of Pyrolysis Temperature on the Properties of Eucalyptus Wood-Derived Biochar

Abstract

Pyrolysis conditions directly influence biochar properties and, consequently, influence the potential use of biochar. In this study, we evaluated the effects of different pyrolysis temperatures (450, 550, 650, 750, 850, and 950 °C) on the hydrogen potential, electrical conductivity, ash content, yield, volatile matter content, elemental analysis, Fourier-transform infrared spectroscopy results, X-ray diffraction results, scanning electron microscopy results, specific surface area, and micropore volume of eucalyptus wood-derived biochar. The degree of linear association between pyrolysis temperatures and biochar properties was examined using the Pearson correlation coefficient. The results showed a positive correlation of the pyrolysis temperature with the hydrogen potential value, electrical conductivity, and elemental carbon. There was a negative correlation of the pyrolysis temperature with the yield, volatile matter content, elemental oxygen, elemental hydrogen, surface area, aromaticity, hydrophilicity, and polarity indexes. The Fourier-transform infrared spectroscopy data indicated an increase in aromaticity and a decrease in the polarity of high-temperature biochar. The increased pyrolysis temperature caused the loss of cellulose and crystalline mineral components, as indicated by X-ray diffraction analysis and scanning electron microscopy images. These results indicated that changing the pyrolysis temperature enables the production of biochar from the same raw material with a wide range of physicochemical properties, which allows its use in various types of agricultural and environmental activities.

Physicochemical and Optical Characterization of Citrus aurantium Derived Biochar for Solar Absorber Applications

“…A decrease in yield of 7.52% from 400 °C to 600 °C suggests that most of the lignocellulosic material was decomposed, while a decrease of 1.69% from 600 °C to 800 °C, which is much smaller than the previous amount, suggests the formation of more stable biochar with a much lower material loss. This negative effect of temperature on the carbonization yield is consistent with previous studies, such as that reported by Chaves Fernandes et al, where a negative correlation between the pyrolysis temperature and the Eucalyptus biochar yield was found, mainly in the range of 450–650 °C [ 20 ]. Similar behaviors have been shown in other carbonaceous materials, which presented this reduction of yield at higher temperatures until they became lower and constant.…”

“…Table 1 also shows a yield decrease of 7.52% from 400 °C to 600 °C and a moderate decrease of 1.69% from 600 °C to 800 °C. As a lignocellulosic material, sour orange peel can be composed of three main building blocks, namely hemicellulose, cellulose, and lignin, as well as some extractives [ 19 ], it is expected that temperature increase favors the decomposition of these constituents as well as the release of gases and volatiles caused by this decomposition [ 20 ]. A decrease in yield of 7.52% from 400 °C to 600 °C suggests that most of the lignocellulosic material was decomposed, while a decrease of 1.69% from 600 °C to 800 °C, which is much smaller than the previous amount, suggests the formation of more stable biochar with a much lower material loss.…”

“…Li et al reported the same negative effect on the yield of the biochars obtained from different feedstocks, where a decrease in yield was observed, whereas an increase in bio-oil and syn gas yields was shown with an increase in temperature [ 21 ]. On the other hand, the decrease of yield was moderate as the temperature increased, which is attributed to a major carbonization is completed at temperatures in the range of 600–800 °C [ 20 , 21 ].…”

“…Elemental analysis data can be related to the biochar stability [ 20 ]. As N and S are minor elements of biochar, the unsaturation or aromaticity may be assessed by the C, H, and O compositions and H/C and/or O/C ratios.…”

Biochar from Pine Wood, Rice Husks and Iron-Eupatorium Shrubs for Remediation Applications: Surface Characterization and Experimental Tests for Trichloroethylene Removal

“…It is well known that many parameters influence the final characteristics of BC, which is why its production and surface alteration certainly select its final application [16,[26][27][28][29]. When the pollutant is hydrophobic or aromatic, the aromatization of BC is a fundamental characteristic to increase the adsorption capability.…”