In a recent study published in 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, Liu et al., investigated the impact of field-aged biochar (FABC) on the transport of weakly hydrophobic antibiotics in purple soil. The study compared fresh biochar (FBC) with biochar aged for one year (ABC1) and five years (ABC5) to evaluate how aging affects biochar’s properties and its ability to retain antibiotics.  

Biochar has shown promise in enhancing soil fertility and remediating contaminated soil. However, biochar’s characteristics change over time through a process called aging, which can affect its effectiveness. This study examines how biochar aging influences the adsorption and transport of antibiotics in soil.  

The researchers found that aging significantly alters biochar’s physicochemical properties. Over time, the carbon content in biochar decreased by 10.40%, while the oxygen content increased by 40.52%. One-year aged biochar (ABC1) demonstrated optimal performance, with a 99.28% increase in specific surface area (SSA) and more oxygen-containing functional groups. This enhanced biochar resulted in maximum antibiotic retention rates of 16.57% for sulfadiazine (SD) and 24.78% for florfenicol (FF).  

Although five-year aged biochar (ABC5) showed decreased SSA and adsorption capacity, it maintained stable remediation effects. This stability is attributed to enhanced biochar-soil interactions, as indicated by increased dispersivity and hydrodynamic dispersion coefficient (D). The study also used a two-site chemical nonequilibrium model (TSM) to analyze antibiotic adsorption, revealing that the fraction of equilibrium adsorption sites increased from 0.1164 to 0.3514 after aging, which signifies improved antibiotic retention.  

In conclusion, the study demonstrates that one-year aging enhances biochar’s remediation capacity, while five-year aging stabilizes its environmental effects through modified soil structure. The findings contribute to a better understanding of how biochar aging influences soil processes and antibiotic transport, which is crucial for optimizing its application in environmental remediation.  

Source: Liu, X., He, Y., Li, J., Li, J., Zhang, J., & Tang, X. (2025). Does biochar field aging reduce the kinetic retention for weakly hydrophobic antibiotics in purple soil? Biochar, 7(1), 69.