Comparative Analysis of Biochar Derived from Rice Straw and Soybean Straw

Aim: Recycling agricultural postharvest waste and re-introducing it again into farmland is one of the tangible ways to address zero waste dream, soil infertility and climate change. Pyrolysis of crop leftovers into biochar remains the most acceptable alternative for proper management of crop waste. The possibility of sustainable biochar production practices and multi-functionality features makes it promising to fufill an increasing demand for soil amendment, agricultural sustainability, environmental protection, cutting-edge materials and mitigation of climate change.

Methodology: Same amount (14450 g) in feedstock of rice straw (RS) and soybean straw (SS) undergo slow pyrolysis separately to produce biochar. Physical (percentage yield, moisture, ash, volatile matter, bulk density, pH, electrical conductivity), chemical characterization (Microwave Plasma Atomic Emission Spectroscopy (MP-AES), Scanning Electron Microscope Energy Dispersive X-ray (SEM-EDX), Fourier Transformed Infrared (FTIR) and Thermogravimetric Analysis and Derivative Thermogravimetry (TGA and DTA)) and evaluation of bochar was determined.

Results: Rice straw biochar (RSB) recorded a higher char yield of 42.1%. Both lignocellulosic biochars were black and porous with a higher silica (10.6%) content in RSB and higher carbon (82.2%) content in SSB as was revealed by SEM-EDX. Higher ash 27.1%, volatile matter (VM) 31.3% and moisture 29.4% content was seen in RSB compared to SSB because of feedstock composition. Rice straw biochar show higher peaks of macro and micro mineral elements K(14561.21mg/kg), Ca (2401.28 mg/kg), and Na(1735.27 mg/kg) than soybean straw biochar. FTIR was used to identify functional groups that might act as cation adsorbents. As the temperature increased, the TGA and DTG graphs showed mass loss and sample breakdown.

Conclusion: Rice and soybean crop wastes were converted into biochar, a nutrient-rich material that maybe utilized to balance acidic soils promoting healthy plant growth and also protecting the environment.