Characterization and selection of biochar for an efficient retention of tricyclazole in a flooded alluvial paddy soil

8 páginas.-- 4 figuras.-- 6 tablas.-- 70 referencias.-- Appendix A. Supplementary data ( 1 figura)© 2014 Elsevier B.V. Biochars, from different organic residues, are increasingly proposed as soil amendments for their agronomic and environmental benefits. A systematic detection method that correlates biochar properties to their abilities to adsorb organic compounds is still lacking. Seven biochars obtained after pyrolysis at different temperatures and from different feedstock (alperujo compost, rice hull, and woody debris), were characterized and tested to reveal potential remedial forms for pesticide capture in flooded soils. Biochar properties were determined by nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy, specific surface area (SSA) assessment and scanning electron microscopy. In addition, dissolved organic matter (DOM) from these biochars was extracted and quantified in order to evaluate the effect on pesticide sorption. The biochars from alperujo compost presented very high affinity to the fungicide tricyclazole (55.9, 83.5, and 90.3% for B1, B4, and B5, respectively). This affinity was positively correlated with the pyrolysis temperature, the pH, the increased SSA of the biochars, and the enhanced aromaticity. Sorptive capacities were negatively related to DOM contents. The amendment with a mixture of compost and biochar endows the alluvial soil with high sorptive properties (from Kfads(soil)=9.26 to Kfads(mixture)=17.89) without impeding the slow release of tricyclazole.This research was supported by the Ministry of Economy and Competitiveness (AGL2010-21421 and AGL2013-48446-C3-1-R) and the Autonomous Government of Andalusia (PAIDI AGR-264). The projects were co-financed with European funds (FEDER-FSE PO2007-13). Manuel García-Jaramillo thanks MEC/FECYT for a doctoral fellowship through AGL2010-21421-CO2-01 project of MICINN. Further, we would like to thank to the Analytical Service of the IRNAS (CSIC) and to the Center of Research Technology and Innovation of the University of Seville (CITIUS) for their technical assistance.Peer Reviewe