The role of nanoengineered biochar activated with Fe for sulfanilamide removal from soils and water

Authors: GAMIZ, BEATRIZ - Instituto De Recursos Naturales Y Agrobiologia De Sevilla (IRNAS-CSIC); VELARDE, PILAR - Instituto De Recursos Naturales Y Agrobiologia De Sevilla (IRNAS-CSIC); Spokas, Kurt; COX, LUCIA - Instituto De Recursos Naturales Y Agrobiologia De Sevilla (IRNAS-CSIC)

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2022
Publication Date: 11/1/2022
Citation: Gamiz, B., Velarde, P., Spokas, K.A., Cox, L. 2022. The role of nanoengineered biochar activated with Fe for sulfanilamide removal from soils and water. Molecules. 27(21). Article 7418. https://doi.org/10.3390/molecules27217418.
DOI: https://doi.org/10.3390/molecules27217418

Interpretive Summary: There is a growing issue of antibiotic chemicals being detected in the environment. This research examined the potential use of biochar to reduce the presence and availability of antibiotics in agricultural soils, as well as simple pretreatments of the biochar with iron salt solutions to increase the removal capacity of the biochar. We observed that modifying the biochar with an iron-salt solution did increase the observed sorption capacity of the biochar nearly 2-times. Additionally, adding the iron-treated biochar to the soil system at 2% (w/w) did increase the dissipation half-life from 4 to 6.4 days, but this increase was not as large as the change in sorption capacity. This suggests that the additional soil minerals also interacted with the biochar and reduced the importance of the pretreatment. These results are significant to assist scientists and engineers as well as supplying guidance for the influence of biochar additions to mitigate the potential negative aspects of antibiotics in the soil system.

Technical Abstract: Biochar is a nanoengineered sorbent proposed to control the contamination derived from the presence of residual concentrations of sulfonamides in soil. In this work, we evaluated the sorption of sulfanilamide (SFA) in commercial biochar (BC) produced at 500 'C from oak hardwood (Quercus ilex) and its analog activated with 2% (w/w) Fe (BC-Fe). Subsequently, the effect on dissipation and transport of SFA in untreated soil and soil treated with BC and BC-Fe was also assessed. Laboratory batch studies revealed that BC-Fe increased the sorption of SFA as compared to the pristine BC with Kd of 278 and 98 L/kg, respectively. The dissipation of SFA in either untreated soil or soil treated with BC or BC-Fe was similar, displaying half-lives ranging between 4 and 6.4 days. Conversely, the concurrent determination of sorption during the incubation experiment showed that lower amounts of SFA in solution at the beginning of the experiments were bioavailable in BC-Fe-treated soil when compared to the rest of the treatments shortly after application. Leaching column studies confirmed the amendment’s capability to bind the SFA compound. Therefore, the decrease in bioavailability and movement of SFA in treated soils suggest that biochar soil application can reduce SFA soil and water contamination. According to our results, BC surface modification after Fe activation may be more appropriate for water decontamination than for soil since there were no significant differences between the two types of biochar when added to the soil. Therefore, these outcomes should be considered to optimize the SFA mitigation potential of biochar.