Coupled use of Fe-impregnated biochar and urea-hydrogen peroxide to simultaneously reduce soil–air emissions of fumigant and improve crop growth

Authors: QIN, JIAOLONG - Shanghai Jiaotong University; ASHWORTH, DANIEL - University Of California; Yates, Scott; SHEN, GUOQING - Shanghai Jiaotong University

Submitted to: Journal of Hazardous Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2020
Publication Date: 4/19/2020
Citation: Qin, J., Ashworth, D., Yates, S.R., Shen, G. 2020. Coupled use of Fe-impregnated biochar and urea-hydrogen peroxide to simultaneously reduce soil–air emissions of fumigant and improve crop growth. Journal of Hazardous Materials. 396. https://doi.org/10.1016/j.jhazmat.2020.122762.
DOI: https://doi.org/10.1016/j.jhazmat.2020.122762

Interpretive Summary: Reducing the emissions of soil fumigants is essential to protecting air quality. One approach to reducing emissions is to add amendments to soil which adsorb fumigants and prevent their release into the atmosphere. However, some amendments are more effective than others at permanently preventing the release of the fumigant. In this study, we compared the performance of two amendments: pristine biochar (a charcoal-like substance made from burning organic wastes) and iron-impregnated biochar. The results indicated that the iron-impregnated biochar was about 54 times more effective than pristine biochar. The findings of this study provide a new approach for biochar application, especially for the emission reduction of hazardous volatile organic compounds from soil.

Technical Abstract: Reducing the emissions of soil fumigants such as 1,3-dichloropropene (1,3-D) is essential to protecting air quality. Although biochar is useful in reducing such emissions, biochar-adsorbed fumigants may desorb and cause secondary air pollution. This study investigated the degradation of 1,3-D on iron (Fe)-impregnated biochar (FBC) amended with urea-hydrogen peroxide (UHP). The results indicated the degradation rate of trans-1,3-D on FBC-UHP was 54-fold higher than that on pristine biochar (PBC). Electron paramagnetic resonance (EPR) combined with other characterization methods revealed that the presence of semiquinone-type radicals in FBC effectively accelerated the Fe(III)/Fe(II) cycleto maintain enough Fe(IIII) for UHP activation and ·OH generation.·OH, rather than ·O2 -, was the dominant active oxidant. Soil column tests showed that application of FBC to the soil surface reduced cumulative 1,3-D emissions from 34.80 % (bare soil) to 0.81%. After the column experiment, the mixing of the FBC with UHP resulted in the residual cis-isomers decreasing from 32.5% to 10.5%. Greenhouse bioassays showed that mixing post-1,3-D degradation FBC-UHP with soil significantly promoted lettuce growth relative to PBC. The findings of this study provide a new approach for biochar application, especially for the emission reduction of hazardous volatile organic compounds from soil.