Bio-Char Characterization Produced from Walnut Shell Biomass through Slow Pyrolysis: Sustainable for Soil Amendment and an Alternate Bio-Fuel

Abstract

Bio-char has the ability to isolate carbon in soils and concurrently improve plant growth and soil quality, high energy density and also it can be used as an adsorbent for water treatment. In the current work, the characteristics of four different types of bio-chars, obtained from slow pyrolysis at 375 °C, produced from hard-, medium-, thin- and paper-shelled walnut residues have been studied. Bio-char properties such as proximate, ultimate analysis, heating values, surface area, pH values, thermal degradation behavior, morphological and crystalline nature and functional characterization using FTIR were determined. The pyrolytic behavior of bio-char is studied using thermogravimetric analysis (TGA) in an oxidizing atmosphere. SEM analysis confirmed morphological change and showed heterogeneous and rough texture structure. Crystalline nature of the bio-chars is established by X-ray powder diffraction (XRD) analysis. The maximum higher heating values (HHV), high fixed carbon content and surface area obtained for walnut shells (WS) samples are found as ~ 18.4 MJ kg−1, >80% and 58 m2/g, respectively. Improvement in HHV and decrease of O/C and H/C ratios lead the bio-char samples to fall into the category of coal and confirmed their hydrophobic, carbonized and aromatized nature. From the Fourier transform infra-red spectroscopy (FTIR), it is observed that there is alteration in functional groups with increase in temperature, and illustrated higher aromaticity. This showed that bio-chars have high potential to be used as solid fuel either for direct combustion or for thermal conversion processes in boilers, kilns and furnace. Further, from surface area and pH analysis of bio-chars, it is found that WS bio-chars have similar characteristics of adsorbents used for water purifications, retention of essential elements in soil and carbon sequestration.

Elaeis guineensis leaves for potential renewable sub‐bituminous coal: Optimization of biochar yield by response surface methodology and product characterization

“…The reduction in peak intensity at 22° and the presence of a new peak at 38° in the OPL biochar indicate that cellulose has been partially decomposed, resulting in a lower crystallinity. The presence of a peak at 24° in the OPL biochar suggests that it contains silica 84 . The OPL feedstock exhibited peaks similar to cellulose, which typically has three peaks at 15.0° (101), 22.5° (002), and 34.5° (040), which can be attributed to the transverse arrangement of microcrystals and the longitudinal structure of the polymer 85,86 .…”

“…The presence of a peak at 24° in the OPL biochar suggests that it contains silica. 84 The OPL feedstock exhibited peaks similar to cellulose, which typically has three peaks at 15.0° (101), 22.5° (002), and 34.5° (040), which can be attributed to the transverse arrangement of microcrystals and the longitudinal structure of the polymer. 85,86 The peak obtained for the OPL feedstock is similar to those seen in other lignocellulosic biomasses, such as potato peel.…”

Unlocking the potential of teak seed waste: carbonization for sustainable resource transformation

“…Within the FTIR spectra, a discernible peak at 3596 cm −1 emerged, indicating the presence of O─H stretching vibrations typically associated with alcohol functional groups. [41][42][43] A singular band at 3283 cm −1 was identified concurrently, attributed to the presence of O─H groups inherent in carboxylic and phenolic functional groups.…”

Biochar: A Sustainable Alternative in the Development of Electrochemical Printed Platforms

“…[9][10][11][12][13][14][15][16], and its production requires a lower overall energy input than activated carbon, resulting in lower net energy consumption with a low net cost. Its morphological and physicochemical properties can strongly vary with the feedstock source choice and the conditions of the pyrolysis treatment [17][18][19][20][21][22][23]. In addition, the high porosity combined with its surface being rich in functional groups on one side and its excellent electrical conductivity and biocompatibility on the other expand its applications in different fields.…”

“…in the production of biosensors were carefully studied and discussed [37]. Until a few years ago, biochar has been used in a large number of applications such as adsorbent for wastewater treatment and agronomic applications (i.e., immobilizing organic and inorganic pollutants), or as an amendment in agricultural soils (effects on soil, agricultural yields, and nitrogen leaching and emissions) [18,[20][21][22][23][24][25][26]. However, recently, its potential as an eco-friendly and smart nanomaterial for several electrochemical applications is increasingly exploited [27].…”