Effects of pyrolysis temperature on the physicochemical properties of empty fruit bunch and rice husk biochars

Abstract

Biochar has received great attention recently due to its potential to improve soil fertility and immobilize contaminants as well as serving as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochars were produced from empty fruit bunch (EFB) and rice husk (RH) by slow pyrolysis at different temperatures (350, 500, and 650°C) and their physicochemical properties were analysed. The results indicate that porosity, ash content, electrical conductivity (EC), and pH value of both EFB and RH biochars were increased with temperature; however, yield, cation exchange capacity (CEC), and H, C, and N content were decreased with increasing pyrolysis temperature. The Fourier transform IR spectra were similar for both RH and EFB biochars but the functional groups were more distinct in the EFB biochar spectra. There were reductions in the amount of functional groups as pyrolysis temperature increased especially for the EFB biochar. However, total acidity of the functional groups increased with pyrolysis temperature for both biochars.

Effect of Temperature on the Structural and Physicochemical Properties of Biochar with Apple Tree Branches as Feedstock Material

“…Sun et al also found a decrease in the concentration of Ca and Mg as the pyrolysis temperature increased from 450 to 600 • C using hickory wood as feedstock [21]. Thus, both the volatility of the nutrients and the influence of temperature on the composition and chemical structure of biochar can significantly affect the concentration of nutrients during the process [13].…”

“…As the pyrolysis temperature increased, FTIR spectra of biochars revealed a decrease in the stretching of O-H (3200-3500 cm −1 ) and C-H (2935 cm −1 ) [13], this was attributed to the acceleration of dehydration reaction in biomass [30], which suggested a decrease in the polar functional groups with an increase in pyrolysis temperature [50]. In particular, biochars began to increase aromatic C=C stretching (1440 cm −1 ) [29] and out-of-plane deformation by aromatic C-H groups (885 cm −1 ) [51], while the symmetric C-O stretching (1030-1110 cm −1 ) for the source material began to disappear with the increasing pyrolysis temperature [51].…”

“…Energies 2017, 10, 1293 6 of 15 both the volatility of the nutrients and the influence of temperature on the composition and chemical structure of biochar can significantly affect the concentration of nutrients during the process [13].…”

“…During pyrolysis, biomass undergoes a variety of physical, chemical and molecular changes [11]. Previous studies indicated that pyrolysis condition and feedstock type significantly affect the structural and physicochemical characteristics of the resulting biochar products [12][13][14]. Generally, woody biomass provides a more C-rich biochar compared to other feedstocks since it contains varying amounts of hemicellulose, cellulose, lignin and small quantities of other organic extractives and inorganic compounds [15].…”

The Effect of Biochar Application on Nutrient Availability of Soil Planted with MR219

“…The variability of the nutrients in the biochars with increasing temperature is due to their volatility and effect of pyrolysis temperature on both composition and chemical structure of biochars. Besides the concentration of the nutrients in the biochar also depend on the process of partial devolatilization of the nutrients at elevated temperatures [9].…”