Effects of Different Carbonization Conditions on the Color Change of Biochar

Abstract

The aim of this research was to determine the effects of different carbonization temperature, gas flow rate and heating rates on biochar's color change. Three different carbonization temperatures (400°C, 500°C, and 600°C), two different gas flow rates (0.2 l min-1 and 0.5 l min-1) and two different heating temperature rates (30°C min-1 and 60°C min-1) were used in the experiments. The color changes of biochar were examined utilizing the international approved L*, a*, b* system. Atriplex nitens Schkuhr was used as a biomass source in the experiments. High carbonization temperature and high gas flow rate caused a decrease in the “L” value of biochar. It is an indication that the color is getting darker, when the L value approaches zero. In the study, only the effect of gas flow rate on the "a" value was found to be statistically significant (P≤0.05). The increase in gas flow rate caused the biochar to become darker by increasing the deep red tone. Heating rate and gas flow speed significantly influenced the "b" values of biochar. The slow heating rate and high gas flow rates made the biochar color darker. At end of the research, it can be said that the biochar produced at high carbonization temperature, low heating rate and high gas flow rates will have darker tones.

Keywords

• Atriplex nitens Schkuhr
• pyrolysis
• color analysis
• biochar
• biomass

References

1. Abu-Hamdeh NH and Reeder RC (2000). Soil thermal conductivity: effects of density, moisture, salt concentration, and organic matter. Soil Science Society of America Journal, 64: 1285-1290.
2. Brassard P, Stephane G and Vijaya R (2016). Soil biochar amendment as a climate change mitigation tool: Key parameters and mechanisms involved. Journal of Environmental Management, 181: 484-497.
3. Castellini M and Ventrella D (2015). Impact of conventional and minimum tillage on soil hydraulic conductivity in typical cropping system in Southern Italy. Soil & Tillage Research, 154: 1-13.
4. Dec D, Dörner J and Horn R (2009). Effect of soil management on their thermal properties. Journal of Plant Nutrition and Soil Science, 9: 26-39.
5. Ding Y, Liu YG, Liu SB, Li, ZW, Tan XF and Huang XX (2016). Biochar to improve soil fertility: A review. Agronomy for Sustainable Development, 36: 36.
6. Genesio L, Miglietta F, Baronti S and Vaccari FP (2015). Biochar increases vineyard productivity without affecting grape quality: results from a four years field experiment in Tuscany. Agriculture, Ecosystems & Environment, 201: 20-25.
7. Genesio L, Miglietta F, Lugato E, Baronti S, Pieri M and Vaccari FP (2012). Surface albedo following biochar application in durum wheat. Environmental Research Letters, 7: 014025.
8. Hardie M, Clothier B, Bound S, Oliver, G and Close, D (2014). Does biochar influence soil physical properties and soil water availability? Plant Soil, 376: 347-361.

9. Lal R (2015). Biochar and soil carbon sequestration. In: M. Guo, Z. He, and M. Uchimiya, editors, Agricultural and environmental applications of biochar: Advances and barriers. SSSA Spec. Pub. 63. SSSA, Madison, WI.
10. Lehmann J, Rillig MC, Thies J, Masiello CA, Hockaday WC and Crowley D (2011). Biochar effects on soil biota: A review. Soil Biology & Biochemistry, 43: 1812-1836.
11. Logsdon SD, Green TR, Bonta JV, Seyfried MS and Evett SR (2010). Comparison of electrical and thermal conductivities for soils from five states. Soil Science, 175: 573-578.
12. Meyer S, Bright RM, Fischer D, Schulz H and Glaser B (2012). Albedo impact on the suitability of biochar systems to mitigate global warming. Environmental Science & Technology, 46: 12726-12734.
13. Mukherjee A and Lal R (2017). Biochar and soil characteristics. In R. Lal, ed. Encyclopedia of soil science. 3rd ed. Taylor & Francis, Abingdon, UK. p. 183-188.
14. Oguntunde PG, Abiodun BJ, Ajayi AE and Van De Giesen N (2008). Effects of charcoal production on soil physical properties in Ghana. Journal of Plant Nutrition and Soil Science, 171: 591-596.
15. Paz-Ferreiro J, Méndez J, Tarquis AM, Cerdà and Gascó G (2014). Preface: environmental benefits of biochar. Solid Earth, 5: 1301-1303.
16. Suthar RG, Wang C, Nunes MCN, Chen J, Sargent SA, Bucklin RA, Gao B (2018). Bamboo biochar pyrolyzed at low temperature improves tomato plant growth and fruit quality. Agriculture, 8(10): 153.
17. Usowicz B, Lipiec J and Ferrero A (2006). Prediction of soil thermal conductivity based on penetration resistance and water content or air-filled porosity. International Journal of Heat and Mass Transfer, 49: 5010-5017.
18. Usowicz B, Lipiec J, Lukowski M, Marczewski W and Usowicz J (2016). The effect of biochar application on thermal properties and albedo of loess soil under grassland and fallow. Soil & Tillage Research, 164: 45-51.
19. Usowicz B, Lipiec J, Usowicz J and Marczewski W (2013). Effects of aggregate size on soil thermal conductivity: comparison of measured and model-predicted data. International Journal of Heat and Mass Transfer, 57: 536-541.
20. Ventura F, Salvatorelli F, Piana, S, Pieri L, and Pisa PR (2012). The effects of biochar on the physical properties of bare soil. Earth Environ. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 103: 5-11.
21. Verma M, Godbout S, Brar SK, Solomatnikova O, Lemay S P and Larouche JP (2012). Biofuels production from biomass by thermochemical conversion technologies. International Journal of Chemical Engineering, 2012, 542426.
22. Zhang Q, Wang X, Du Z, Liu X and Wang Y (2013). Impact of biochar on nitrate accumulation in an alkaline soil. Soil Research, 51: 521-528.