Sai Bhaskar Reddy Nakka1,*
1Geoecology Energy Organisation [GEO], Hyderabad, India
Keywords: Charcoal, Material, Construction, Carbon, Sequestration
Biochar is the charcoal produced from biomass used for good purpose. Biochar is produced from the thermal decomposition of biomass in a low- or zero-oxygen environment, at relatively low temperatures (<700°C) (Lehmann and Joseph, 2009). The highly porous surfaces of Biochars have been shown to adsorb N2O, CO2 and CH4 (Hitoshi, et al, 2002). There are many advantages of using the Biochar as a component in Green Buildings for clean indoor air and carbon sequestration. The half-life of Biochar carbon in soil is in excess of 1000 years (Laird, 2008). Biochar is found in earth walls of over 100 years old, is still intact. Biochar can be mixed in different proportions with sand / cement / earth / other suitable material to produce bricks / panels / blocks for construction.
The percentage of Biochar for use in construction of buildings can be decided based on the purpose and product properties. Biochar use makes the building walls light and insulate. The Biochar produced from different biomasses, temperatures and processes have different properties. Some types of Biochar properties are that Coconut shell Biochar is hard, rice-husk Biochar having high silica content, etc.
Life cycle assessment was used to estimate the energy and climate change impacts and the economics of biochar systems. The feedstocks analyzed represent agricultural residues (corn stover), yard waste, and switchgrass energy crops. The net energy of the system is greatest with switchgrass (4899 MJ t−1 dry feedstock). The net greenhouse gas (GHG) emissions for both stover and yard waste are negative, at −864 and −885 kg CO2 equivalent (CO2e) emissions reductions per tonne dry feedstock, respectively. Of these total reductions, 62−66% are realized from C sequestration in the biochar. (Kelli G et al, 2010)
Every 1 ton of Biomass yields 1/3 ton Charcoal for soil Sequestration (= to 1 Ton CO2e) + Bio-Gas & Bio-oil fuels = to 1MWh exported electricity, so is a totally virtuous, carbon negative energy cycle. (Erich J. Knight, 2009)
Char micropores are filled with variable amounts of volatile matter which carries most of biochar’s acidity, negative charge, and cation complexation ability. (Zimmerman et.al. 2010). Micropores contribute most to surface area and are responsible for the high absorptive capacity; mesopores are important for liquid solid adsorption processes; and macropores are important for aeration (Kolb, 2007).
Table 1 Biochar components as a percentage of total weight. Source: Verheijen et al (2010)
Component Proportion (%)
Fixed carbon 50-90
Volatile matter 0-40
Ash (mineral matter) 0.5-5
Table 2 Biochar properties from a variety of feedstocks and pyrolysis conditions. Source: Chan and Xu (2009)
From to Mean
ph 6.2 9.6 -
C (g/kg) 172 905 543
N (g/kg) 1.7 78.2 22.3
NO-3, NH4+ (mg/kg) 0.0 2.0
P (g/kg) 0.2 73 23.7
Pa (g/kg) 0.015 11.6 -
K (g/kg) 1.0 58 24.3
The Biochar when used in green buildings some of these green house gasses are sorptioned (adsorption and absorption). The Biochar in the debris when used in green buildings, after reaching landfill sites reduce the GHGs emissions from landfill sites and prevent leachets. Biochar can be used as screen for purification of air entering into buildings. Biochar regulates humidity indoors; the emissions from indoor toilets are absorbed. The Biochar urinals reduce NOx emissions as well tap urea from urine for later use as soil amendment. It can be applied to the soil for indoor plants / gardens, as air purifier in refrigerator, for water filtration in aquariums, etc., for reducing emissions from various sources.
Considering the life, source and property of Biochar, it is a means for carbon sequestration. It also brings other benefits; temperature is regulated through insulation, as a light weight material suitable for high raise buildings and reduces cost of construction. Biochar is resistant and repels termites and ants. Biochar is the source of negative ions, emit far infrared radiation. These characteristics of Biochar improve the living conditions in a house. Biochar improves the indoor air and benefits the user and environment, can be used in all the green buildings as per the need.
Chan, K.Y. and Xu, Z., 2009. Biochar: nutrient properties and their enhancement. IN Lehmann J. and Joseph, S. (Eds.) Biochar for environmental management: Science and Technology. London, Earthscan.
Erich J. Knight, 2009 Biochar and Biofuels, Sustainability Summit, Location: Dave’s Taverna
Hitoshi, T., Ai, F and Haruo, H, 2002. Development of advaced utilization technologies for organic waste: (Part 1) Greenhouse gas and nutrient salt adsorption properties of wood-based charcoal, Denryoku Chuo Kenkyujo Abiko Kenkyujo Hokoku, Research Report of Abiko Research laboratory, no U02010
Kelli G. Roberts, Brent A. Gloy, Stephen Joseph, Norman R. Scott and Johannes Lehmann, 2010.Life Cycle Assessment of Biochar Systems: Estimating the Energetic, Economic, and Climate Change Potential, Environ. Sci. Technol., 44 (2), pp 827–833
Kolb, S., 2007. Understanding the mechanisms by which a manure-based charcoal product affects microbial biomass and activity (doctoral dissertation). University of Wisconsin.
Laird, D. 2008. The Charcoal Vision: A win-win-win scenario for simultaneously for producing bioenergy, permanently sequestrating carbon while improving soil and water quality. Agronomy Journal 100: 178-181
Lehmann, J. and Joseph, S. 2009 Introduction. In Lehmann, J. and Joseph, S. (Eds.) Biochar for environmental management, Science and technology. London: Earthscan.
Tom Miles, 2007. Charcoal Use in Japan, Japanese Market News: Charcoal 2000,
IBPC Osaka Network Center. http://terrapreta.bioenergylists.org/japancharcoal2000
Verheijen, F., Jeffery, S., Bastos, A.C., van der Velde, M. and Diafas, I., 2010. Biochar application to soils - A critical scientific review of effects on soil properties, processes and functions. Scientific and Technical Reports. Ispra (Italy): European Commission, Joint Research Centre, Institute for Environment and Sustainability
Zimmerman, Andrew R., Mukherjee, Atanu, and Kasonzi, Gabriel N., 2010. Variations in the properties of laboratory produced Biochars : Surface Chemistry, Lability and interaction with soil organic matter, GSA Denver Annual Meeting (31 October–3 November 2010), Paper No. 62-4