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© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Biochars have emerged as a sustainable technology for converting waste into high-value, stable carbon products. Depending on its properties, biochar can retain various elements, including nitrogen (N) as ammonium (N-NH4+). This study aimed to evaluate the rapid retention of N-NH4+ in biochars produced from coffee husk (CH) and chicken manure (CM) at different pyrolysis temperatures (PTs) (300 °C, 400 °C, and 900 °C) and investigate the mechanisms involved. A rapid N-NH4+ adsorption experiment was conducted, in which an NH4Cl solution was passed through the biochars. The following analyses were performed: cation exchange capacity (CEC), surface area, pore volume and size, total N content, N retention, infrared analysis (ATR-FTIR), and leachate solution analysis, followed by chemical speciation using Visual MINTEQ software. The results indicated that different mechanisms were involved in rapid N-NH4+ retention. In CH-derived biochars produced at 300 °C, N-NH4+ retention occurred primarily through electrostatic interactions with negative charges (CEC), as confirmed by ATR-FTIR analysis. In CM-derived biochars produced at 400 °C, N-NH4+ retention was mainly through the formation of struvite (NH4MgPO4·6H2O), as confirmed by chemical speciation of leachate solution in Visual MINTEQ. In CH-derived biochars produced at 900 °C, N-NH4+ ions were trapped in the pores of the charred matrix due to the increased biochar surface area, pore volume, and decreased pore size. The biochars studied proved effective in retaining N-NH4+ through different mechanisms, suggesting that biochars can enhance rapid N retention and reduce N leaching, potentially serving as a source of N for crops.

Details

Title
Rapid Adsorption of Ammonium on Coffee Husk and Chicken Manure-Derived Biochars: Mechanisms Unveiled by Chemical Speciation, Physical, and Spectroscopic Approaches
Author
Everton Geraldo de Morais 1   VIAFID ORCID Logo  ; Silva, Carlos Alberto 1 ; Gao, Suduan 2 ; Leônidas Carrijo Azevedo Melo 1   VIAFID ORCID Logo  ; Pedro Antônio Namorato Benevenute 1 ; Bruno Cocco Lago 1 ; Jéssica, Cristina Teodoro 1 ; Luiz Roberto Guimarães Guilherme 1   VIAFID ORCID Logo 

 Department of Soil Science, Federal University of Lavras, University Campus, P.O. Box 3037, Lavras 37203-202, MG, Brazil[email protected] (J.C.T.) 
 United States Department of Agriculture (USDA)—Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648-9757, USA; [email protected] 
First page
1616
Publication year
2025
Publication date
2025
Publisher
MDPI AG
e-ISSN
20711050
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3171259298
Copyright
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.