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

Abstract

Abstract:The objective of this study was to study the structure and physicochemical properties of biochar derived from apple tree branches (ATBs), whose valorization is crucial for the sustainable development of the apple industry. ATBs were collected from apple orchards located on the Weibei upland of the Loess Plateau and pyrolyzed at 300, 400, 500 and 600 • C (BC300, BC400, BC500 and BC600), respectively. Different analytical techniques were used for the characterization of the different biochars. In particular, proximate and element analyses were performed. Furthermore, the morphological, and textural properties were investigated using scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, Boehm titration and nitrogen manometry. In addition, the thermal stability of biochars was also studied by thermogravimetric analysis. The results indicated that the increasing temperature increased the content of fixed carbon (C), the C content and inorganic minerals (K, P, Fe, Zn, Ca, Mg), while the yield, the content of volatile matter (VM), O and H, cation exchange capacity, and the ratios of O/C and H/C decreased. Comparison between the different samples show that highest pH and ash content were observed in BC500. The number of acidic functional groups decreased as a function of pyrolysis temperature, especially for the carboxylic functional groups. In contrast, a reverse trend was found for the basic functional groups. At a higher temperature, the brunauer-emmett-teller (BET) surface area and pore volume are higher mostly due to the increase of the micropore surface area and micropore volume. In addition, the thermal stability of biochars also increased with the increasing temperature. Hence, pyrolysis temperature has a strong effect on biochar properties, and therefore biochars can be produced by changing pyrolysis temperature in order to better meet their applications.

Application of Biochar Derived from Different Types of Biomass and Treatment Methods as a Fuel Source for Direct Carbon Fuel Cells

“…Generally, the ash content in rubber wood biochar reduces as the pyrolysis temperature increases. This might be attributed to the volatilization of inorganic compounds into gas or liquids at higher pyrolysis temperatures [22]. Conversely, pyrolysis temperature did not have a significant impact on the ash content in rice husk derived biochar.…”

Effects of Rice Husk Biochar and Calcium Amendment on Remediation of Saline Soil from Rice-shrimp Cropping System in Vietnamese Mekong Delta

“…Total surface area and pore volume of biochar likely depend on pyrolysis temperature. When pyrolysis temperature is above 600 o C, the correlation was not clear but below 600 o C, lower pyrolysis temperature produced biochar with a smaller surface area and pore volume [22,36,37]. Two biochars used in this study were produced with the same pyrolysis temperature (around 600 o C), but in different methods.…”

Torrefaction Characteristics of Japanese Cedar Sawdust with a Mechanical Compression in Air Atmosphere

“…However, the biochar prepared at 6 MPa changes in the form consisting of some pores beside a kind of vessel derived from the cell tubes (Figure 4(d)). The excessive compressive load no longer helps the volatiles to remain, and then the volatiles would escape and leave pores (Wafiq et al, 2016;Fan et al, 2017;Zhao et al, 2017). As the temperature and the load increase to 350°C and 20 MPa, respectively, more volatiles are produced, and macropores are identified on the biochar surface (Figure 4(e)).…”

“…At 350°C and 20 MPa, the release of most of the volatiles also makes the biochar structure degraded. The biochar became brittle and cracked (Ab Aziz et al, 2015;Zhao et al, 2017).…”