Nitrate Absorption and Desorption by Biochar

• Published in: Agronomy (Basel) Vol. 13; no. 9; p. 2440
• Main Authors: He, Zijian, Wang, Chao, Cao, Hongxia, Liang, Jiaping, Pei, Shuyao, Li, Zhijun
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2023
• Subjects: Absorption; absorption and desorption performance; Agricultural production; biochar; Charcoal; Desorption; Experiments; Fertilizers; Nitrogen; Nutrient release; Nutrients; optimum biochar use; Product development; regeneration; Slow release fertilizers; slow-release material; Soil improvement; Soil mixtures; Soils; Spectrum analysis; United States > US; China
• ISSN: 2073-4395; 2073-4395
• DOI: 10.3390/agronomy13092440

Biochar is a potential solution for addressing environmental problems related to excessive nitrogen (N). However, there is still some debate about the absorption and desorption of nitrate nitrogen (NO3−-N). Therefore, this study investigated the NO3−-N adsorption and desorption performance onto biochar and biochar-soil mixture to address this gap. The results showed that the biochar produced from apple branches had the ability to absorb NO3−-N with an absorption capacity of 3.51 mg·g−1. The absorption data fitted well with the pseudo-second-order kinetic model and Langmuir model. The application of biochar significantly improved soil absorption capacity and slow release of NO3−-N. While higher NO3−-N concentrations had better NO3−-N supply capacity and poorer slow-release effect. Integrating nutrient supply and slow-release effect, it is recommended to control the application ratio of biochar to NO3−-N at 34–42.75 g·g−1. Although the unoptimized biochar application rate cannot be directly applied to the soil as a slow-release fertilizer carrier to meet commercial standards, biochar modification provides new possibilities for this purpose. Moreover, compared with traditional slow-release fertilizer, biochar had good stability and regeneration performance, alleviating the high cost due to the biochar price. In general, biochar still has potential and prospects as a slow-release material. This study provides support for biochar in mitigating environmental problems associated with excess N.