Comparative characterization of biochar obtained from cow dung and poultry litter

Purpose: The conversion of animal waste to biochar by pyrolysis remains the most sustainable alternative for proper management of cow dung and poultry litter in addressing soil infertility and environmental problems. Biochar serves multiple purposes, including waste management, organic fertilizer, carbon sequestration, soil improvement, and renewable energy production. Methods: Cow dung and poultry litter feedstocks were pyrolyzed for 1 hour at 400 o C in an oxygen limited reactor to produce biochar. Physico-chemical investigation of the produced biochar includes proximate analysis, microwave plasma atomic emission spectroscopy (MP-AES), scanning electron microscope - energy dispersive x-ray (SEM-EDX), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA and DTG). Results: Cow dung biochar (CDB) yield was 41% while poultry litter biochar (PLB) was 60.2% respectively. Poultry litter biochar showed a higher ash content of 53.2%, volatile matter 43.5%, bulk density 0.449 g/mL and electrical conductivity 0.25 g/mL than cow dung biochar. Investigation observed dominant macronutrients: N(28300 mg/kg), K(10560.05 mg/kg), Ca(972.17 mg/kg), Mg(4523.82 mg/kg) and micronutrients Cu(80.71 mg/kg), Zn(90.42 mg/kg), Na(2862.47 mg/kg), Fe(2014.25 mg/kg) in poultry litter biochar than cow dung biochar. SEM-EDX images were black and porous with embedded organic and inorganic components. Functional groups acting as cation adsorbents were identified using FTIR. Mass loss and sample disintegration were evident in TGA and DTG curves as temperature increased. Conclusion: Animal waste converted to biochar can act as a nutrient rich soil conditioner to address the mineral deficit in fruits and vegetables cultivated in acidic soils. Reusing agricultural waste in this way is a good idea. Research Highlights • Environmental problems such as pollution, global warming and poor soil fertility will be addressed through reuse of animal waste. • This study uses slow pyrolysis to compare the physicochemical characteristics of biochar made from cow dung and chicken litter. • Analysis was done on important parameters such yield, elemental composition, pH, nutritional content, and functional groups. • Cow dung biochar demonstrated a more stable structure and reduced ash level, but poultry litter biochar demonstrated higher production and nutritional contents. • The results point to possible uses for biochars in nutrient control and soil amendment.