Gupta et al., in ACS Omega, explored the potential of converting marigold flower waste into biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More through pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More. The study focused on understanding the pyrolysis behavior, kinetic parameters, and biochar properties. Pyrolysis is a thermochemical process that involves the thermal decomposition of organic matter in the absence of oxygen. The researchers used thermogravimetric analysis (TGA) to examine the thermal degradation characteristics of marigold flowers under varying heating rates. They also produced biochar in a semibatch reactor and characterized its properties, including proximate and elemental analysis, calorific value, bulk density, BET surface area, pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, FTIR, FESEM, EDX analysis, and water-holding capacity.

The results showed that the decomposition of marigold flowers occurred in three stages: moisture removal, active pyrolysis, and residue formation. The kinetic analysis revealed a multistep reaction mechanism, with average activation energies of 236.35, 232.29, 234.74, and 221.50 kJ mol−1 derived from KAS, OFW, STM, and FM, respectively. The pyrolysis of marigold flowers yielded 36.64 wt % biochar at 450 °C and a 10 °C min−1 heating rate. The biochar exhibited a 57.10% carbon content, 33.57 MJ kg−1 higher heating value (HHV), 9.96 m2 g−1 BET surface area, and 29.14 mV zeta potential, demonstrating its potential for soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More, carbon sequestration, and pollutant adsorptionBiochar has a remarkable ability to attract and hold onto pollutants, like heavy metals and organic chemicals. This makes it a valuable tool for cleaning up contaminated soil and water.   More.

The study highlighted the potential of marigold flowers as a feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More for biochar production, contributing to circular economy initiatives. The use of waste flowers for biochar production not only reduces waste but also provides a valuable resource for sustainable agriculture and environmental remediation.

SOURCE: Gupta, R., Mishra, R. K., & Mohanty, K. (2025). Pyrolysis Behavior, Kinetic Analysis, and Biochar Production from Waste Flowers. ACS Omega. https://doi.org/10.1021/acsomega.4c10700