biochar Research

This paper aims to examine the influence of biochar produced from lawn waste in accelerating the degradation and mineralization rates of food waste compost. Biochar produced at two different temperatures (350 and 450 °C) was applied at the rates 10 and 15% (w/w) of the total waste to an in-vessel compost bioreactor for evaluating its effects on food waste compost. The quality of compost was assessed against stabilization indices such as moisture contents (MC), electrical conductivity (EC), organic matters (OM) degradation, change in total carbon (TC) and mineral nitrogen contents such as ammonium (NH4+) and nitrate (NO3−). The use of biochar significantly improved the composting process and physiochemical properties of the final compost. Results showed that in comparison to control trial, biochar amended compost mixtures rapidly achieved the thermophilic temperature, increased the OM degradation by 14.4–15.3%, concentration of NH4+ by 37.8–45.6% and NO3− by 50–62%. The most prominent effects in term of achieving rapid thermophilic temperature and a higher concentration of NH4+ and NO3− were observed at 15% (w/w) biochar. According to compost quality standard of United States (US), California, Germany, and Austria, the compost stability as a result of biochar addition was achieved in 50–60 days. Nonetheless, the biochar produced at 450 °C had similar effects as to biochar produced at 350 °C for most of the compost parameters. Therefore, it is recommended to produce biochar at 350 °C to reduce the energy requirements for resource recovery of biomass and should be added at a concentration of 15% (w/w) to the compost bioreactor for achieving a stable compost.

Thermochemical conversion of agricultural wastes to bioenergy has a potential to play forefront roles within the context of the food, energy, and water nexus. The biochar solid product of pyrolysis is a promising tool to manage food crop production and water resources by means of soil amendment. The goal of this study was to understand the fate of surface functional groups and higher-atomic-mass elements during the pyrolysis of pecan shell, which is known to accumulate calcium oxalate. Pecan shell feedstock and biochars were analyzed ex situ using X-ray computed microtomography and solid-state 13 C cross-polarization and magic-angle-spinning NMR spectroscopy; the pyrolysis kinetics was monitored in situ by thermogravimetric analysis−gas chromatography (TGA−GC). The NMR spectra indicated the greatest (i) reduction in O/N alkyl functionality and (ii) increase in the aromatic peak between 300 and 500 °C. Primary physical transformation was observed near 400 °C in the tomography slice images and corresponding attenuation coefficients. Key changes in physical structure (microtomography) as well as chemical constituents (solid-state NMR) of pecan shell at 300−500 °C coincided with the evolution of gaseous products (hydrogen, methane, carbon monoxide, carbon dioxide, ethylene, and ethane, as monitored in situ by TGA−GC) occurring at 200−500 °C. These observations followed the reported (i) formation and removal of carboxyl surface functional groups of biochar and (ii) conversion of calcium oxalate to carbonate, both occurring at the key transition temperature near 400 °C. Combined with the mass balance (99.7%) obtained for gas-, liquid-, and solid-phase products, these findings will facilitate reactor design to optimize syngas and bio-oil yields and manipulate the surface reactivity of biochar soil amendment.

This research aimed to study the process and analyzes the chemical and physical properties of biochar from rice husk, corncob, and longan peel on the pyrolysis process. In this study, 50 liters of biochar kiln used for the pyrolysis process. The parameters of fuel combustion used for the biochar kiln of 3, 4, and 5 kg, respectively. The results showed that the highest yield of longan peel rice husk and corncob on 5 kg fuel were 49.14%, 42.03%, and 38.63% respectively. The results of chemical and physical properties analysis showed that the heating value of biochar had the highest heat content of 4,236 6,235 and 5,445 Cal/g for 5 kg fuel briquette. The elemental composition of longan peel yield was 101.37, 101.60, and 101.48 ppm, respectively. The C/N ratio analysis the biochar production from peels of longan was 12: 1.