Biochar from Swine Manure: An Alternative for Nutrient Recovery and Slow-Release Fertilization
The production of swine manure (SM) biochar was optimized to improve the nutrient recovery. SM was activated with KOH, HCl, or MgCl<sub>2</sub> at different ratios (1:1 and 3:1, v/w) and carbonized at 400, 600, and 800 °C. Results showed that MgCl<sub>2</sub>-activated biochar at 800 °C (3:1) showed enhanced production (84.9%) and the highest phosphate adsorption (2.93 mg g<sup>-1</sup>) and ammonium adsorption (1.27 mg g<sup>-1</sup>). Adsorption followed Langmuir isotherm for phosphate (q<sub>m</sub> = 67.56 mg g<sup>-1</sup>) and Freundlich for ammonium (q<sub>m</sub> = 17.48 mg g<sup>-1</sup>). Adsorption kinetics indicated that phosphate uptake was best described by the Elovich model (R<sup>2</sup> = 0.99), while ammonium followed pseudo-second order kinetics (R<sup>2</sup> = 0.90), suggesting distinct but predominantly chemisorption-controlled mechanisms. Desorption tests showed a limited solubility of phosphate in water and partial ammonium release, supporting the use of biochar as a slow-release fertilizer. Overall, MgCl<sub>2</sub>-activated biochar at 800 °C proved to be the most effective condition, combining high adsorption capacity with nutrient release potential, highlighting its value for sustainable nutrient recovery in agriculture.
Authors
- Larissa Almeida Nascimento (ORCID: https://orcid.org/0000-0002-2282-8859)
- Renata Pereira Lopes Moreira
- André Pereira Rosa
- Rita de Cássia Superbi de Sousa
- Augusto Vilela França
Institutions
- Universidade Federal de Viçosa (BR)
Publication Details
- Journal
- ACS Omega
- Published
- 2026-02-25
- DOI
- https://doi.org/10.1021/acsomega.5c12363
- Primary Topic
- Phosphorus and nutrient management
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Fundação de Amparo à Pesquisa do Estado de Minas Gerais