6. EXPRESIONES DE SIMULTANEIDAD II: m(i)entre/-a /-as ( que ), interim (que),
6.2. Interim / ínterin / ynterin ( que )
Three models were examined to predict C aromaticity (fa) of biochars using data
from literature and that generated from this study. All models were found able to successfully fit the literature data when their atomic H/C ratio was below 1, and valid to
estimate fa of HF treated BSe and MAe biochars (H/C<1). Model 1, based on the H/C
ratio of biochar, demonstrated a good fit to literature data (RMSE=0.04, n=41) and an accurate estimation to our experimental data (RMSE=0.02, n=6). Model 2, which was based on biochar elemental composition (C, H, N and O) data, showed the most
accurate prediction, with a RMSE of 0.03 fa-unit (n=41) for literature data and 0.02 fa-
unit (n=6, H/C<1) for HF treated BSe and MAe biochars. Model 3’, which was based
on contents of FC and C, and modified with a correction factor of 0.96, displayed the
highest RMSE (0.06 fa -unit, n=19) among the three models. Models 1 and 2 did not
work properly for samples having an H/C ratio>1 and for those containing high concentrations of carbonate and inorganic H. The accuracy of model depends on the accuracy and precision of the data used for modelling. Future research on a wider range
61
of biochars is required before these models can be recommended for classification of biochar stability.
Acknowledgements
The authors acknowledge Dr J. Hindmarsh (IFNHH, Massey) for carrying out the NMR analysis; the Ministry of Agriculture and Forestry New Zealand (MAF) funded the research, and Massey University funded a fellowship for T.W. The contribution to this work from M.C.A. was funded by MAF and NZAGRC. Two anonymous reviewers are acknowledged for their constructive suggestions to the manuscript.
References
Almendros, G., Knicker, H., González-Vila, F.J., 2003. Rearrangement of carbon and nitrogen forms in peat after progressive thermal oxidation as determined by solid
state 13C- and 15N-NMR spectroscopy. Organic Geochemistry 34, 1559-1568.
Baldock, J.A., Smernik, R.J., 2002. Chemical composition and bioavailability of
thermally altered pinus resinosa (red pine) wood. Organic Geochemistry 33, 1093-
1109.
Bracewell, J.M., Campbell, A.S., Mitchell, B.D., 1970. An assessment of some thermal and chemical techniques used in the study of the poorly-ordered aluminosilicates in soil clays. Clay Minerals 8, 325-335.
Brewer, C., Unger, R., Schmidt-Rohr, K., Brown, R., 2011. Criteria to select biochars for field studies based on biochar chemical properties. BioEnergy Research 4, 312- 323.
Calvelo Pereira, R., Kaal, J., Camps Arbestain, M., Pardo Lorenzo, R., Aitkenhead, W., Hedley, M., Macías, F., Hindmarsh, J., Maciá-Agulló, J.A., 2011. Contribution to characterisation of biochar to estimate the labile fraction of carbon. Organic Geochemistry 42, 1331-1342.
Cao, X., Ro, K.S., Chappell, M., Li, Y., Mao, J., 2010. Chemical structures of swine- manure chars produced under different carbonization conditions investigated by
advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Energy &
Fuels 25, 388-397.
Cao, X., Pignatello, J.J., Li, Y., Lattao, C., Chappell, M.A., Chen, N., Miller, L.F., Mao, J., 2012. Characterization of wood chars produced at different temperatures using
advanced solid-state 13C NMR spectroscopic techniques. Energy & Fuels 26, 5983-
5991.
Gonçalves, C.N., Dalmolin, R.S.D., Dick, D.P., Knicker, H., Klamt, E., Kögel-Knabner,
I., 2003. The effect of 10% HF treatment on the resolution of CPMAS 13C NMR
spectra and on the quality of organic matter in ferralsols. Geoderma 116, 373-392. International Biochar Initiative, 2012. Guidelines for specifications of biochars for use
62
Kaal, J., Schneider, M.P.W., Schmidt, M.W.I., 2012. Rapid molecular screening of black carbon (biochar) thermosequences obtained from chestnut wood and rice straw: A pyrolysis-GC-MS study. Biomass and Bioenergy 45, 115-129.
Kloprogge, J.T., Ruan, H.D., Frost, R.L., 2002. Thermal decomposition of bauxite minerals: Infrared emission spectroscopy of gibbsite, boehmite and diaspore. Journal of Materials Science 37, 1121-1129.
Knicker, H., Totsche, K.U., Almendros, G., Gonzalez-Vila, F.J., 2005. Condensation degree of burnt peat and plant residues and the reliability of solid-state VACP MAS C-13 NMR spectra obtained from pyrogenic humic material. Organic Geochemistry 36, 1359-1377.
Kögel-Knabner, I., 1997. 13C and 15N NMR spectroscopy as a tool in soil organic matter
studies. Geoderma 80, 243-270.Lehmann, J., Gaunt, J., Rondon, M., 2006. Bio-char
sequestration in terrestrial ecosystems – a review. Mitigation and Adaptation
Strategies for Global Change 11, 395-419.
Maroto-Valer, M.M., Andrésen, J.M., Snape, C.E., 1998. Verification of the linear relationship between carbon aromaticities and hc ratios for bituminous coals. Fuel 77, 783-785.
Mazumdar, B.K., 1998. A direct route to the ring condensation index of coal and hence its aromaticity. Fuel 77, 1125-1127.
Mazumdar, B.K., 1999. Molecular structure and molar volume of organic compounds and complexes with special reference to coal. Fuel 78, 1097-1107.
McBeath, A.V., Smernik, R.J., Schneider, M.P.W., Schmidt, M.W.I., Plant, E.L., 2011. Determination of the aromaticity and the degree of aromatic condensation of a thermosequence of wood charcoal using nmr. Organic Geochemistry 42, 1194-1202. Preston, C.M., 1996. Applications of nmr to soil organic matter analysis: History and
prospects. Soil Science 161, 144-166.
Raveendran, K., Ganesh, A., Khilar, K.C., 1996. Pyrolysis characteristics of biomass and biomass components. Fuel 75, 987-998.
Reeves, J.B., 2012. Mid-infrared spectroscopy of biochars and spectral similarities to coal and kerogens: What are the implications? Applied Spectroscopy 66, 689-695. Rumpel, C., Rabia, N., Derenne, S., Quenea, K., Eusterhues, K., Kögel-Knabner, I.,
Mariotti, A., 2006. Alteration of soil organic matter following treatment with hydrofluoric acid (HF). Organic Geochemistry 37, 1437-1451.
Schimmelpfennig, S., Glaser, B., 2012. One step forward toward characterization: Some important material properties to distinguish biochars. Journal of Environmental Quality 41, 1001-1013.
Singh, B.P., Cowie, A.L., Smernik, R.J., 2012. Biochar carbon stability in a clayey soil as a function of feedstock and pyrolysis temperature. Environmental Science and Technology 46, 11770-11778.
Smernik, R.J., Oades, J.M., 2000. The use of spin counting for determining quantitation
in solid state 13C NMR spectra of natural organic matter: 1. Model systems and the
effects of paramagnetic impurities. Geoderma 96, 101-129.
Sun, K., Keiluweit, M., Kleber, M., Pan, Z., Xing, B., 2011. Sorption of fluorinated herbicides to plant biomass-derived biochars as a function of molecular structure. Bioresource Technology 102, 9897-9903.
Thipkhunthod, P., Meeyoo, V., Rangsunvigit, P., Rirksomboon, T., 2007. Describing sewage sludge pyrolysis kinetics by a combination of biomass fractions decomposition. Journal of Analytical and Applied Pyrolysis 79, 78-85.
Wang, J., Du, J., Chang, L., Xie, K., 2010. Study on the structure and pyrolysis characteristics of chinese western coals. Fuel Processing Technology 91, 430-433.
63
Wang, T., Camps Arbestain, M., Hedley, M., Bishop, P., 2012. Chemical and bioassay characterisation of nitrogen availability in biochar produced from dairy manure and biosolids. Organic Geochemistry 51, 45-54.
Yang, H., Yan, R., Chen, H., Lee, D.H., Zheng, C., 2007. Characteristics of hemicellulose, cellulose and lignin pyrolysis. Fuel 86, 1781-1788.
Yi, Q., Qi, F., Cheng, G., Zhang, Y., Xiao, B., Hu, Z., Liu, S., Cai, H., Xu, S., 2012. Thermogravimetric analysis of co-combustion of biomass and biochar. Journal of Thermal Analysis and Calorimetry, 1-5.