Thermochemical conversion of sugarcane bagasse and bovine bone waste into biochars for use in soil terbuthylazine retention
Name: FERNANDA APARECIDA NAZÁRIO DE CARVALHO
Publication date: 27/02/2025
Examining board:
Name |
Role |
|---|---|
| ÁLISON MOREIRA DA SILVA | Examinador Externo |
| ANANIAS FRANCISCO DIAS JUNIOR | Presidente |
| ELIAS DA COSTA DE SOUZA | Examinador Externo |
| RODRIGO NOGUEIRA DE SOUSA | Examinador Externo |
Summary: The pyrolysis of agro-industrial residues, such as sugarcane bagasse and bovine bones, combined with alkaline hydrolysis, can be a promising approach for producing biochars for herbicide immobilization in soil, mitigating their environmental impacts. In this context, this study aimed to investigate biochars derived from sugarcane bagasse and bovine bones, with and without alkaline hydrolysis pretreatment, at different pyrolysis temperatures (350, 550, 750, and 950°C) to determine their efficiency in immobilizing the herbicide terbuthylazine in soil. For this purpose, the biochars were produced at a heating rate of 3°C min¹ and characterized based on their yield, bulk density, proximate composition, FTIR, SEM, and XRD analyses. The soil used was classified as a Yellow-Red Argisol for sorption-desorption and leaching studies to assess the potential of biochars for terbuthylazine immobilization. Overall, an increase in biochar yield and bulk density was observed in materials subjected to hydrolysis. In sugarcane bagasse biochar, hydrolysis caused fiber swelling, while in bovine bone biochars, the removal of organic matter highlighted the formation of larger hydroxyapatite molecules. For sugarcane bagasse biochar, the optimal sorption-desorption temperature was found to be 750°C, where 100% of the herbicide was sorbed. With alkaline hydrolysis pretreatment, the sorption efficiency temperature decreased due to changes in the material's chemical and physical properties, achieving sorption values of 96% at 350°C. For bovine bone biochar, higher temperatures (750°C and 950°C) resulted in more efficient sorption. However, bovine bone biochar with alkaline hydrolysis pretreatment did not show significant differences in sorption. Nevertheless, leaching results indicated improvements in material structure, with no detectable terbuthylazine in the leachate. Thus, alkaline hydrolysis pretreatment significantly alters biomass structure, enabling the production of biochars with good terbuthylazine immobilization capacity.
Keywords: Industrial symbiosis, circular economy, pyrolysis, alkaline hydrolysis, agrochemical immobilization, and leaching.
