Bamboo charcoal photos of Scanning Electron Microscopy: cross-section(right) and vertical section(left)
There are 1400 woody bamboo species and 32 mil ha bamboo forest around the world. Bamboo is a widely distributed sustainable natural resource in Asia, America and Africa and has more than 10000 uses in the world. Bamboo is playing more and more important role in the changing world to environment, livelihood and economy. One of the important products is bamboo charcoal.
Bamboo charcoal, which is from destructive distillation of bamboo, is a sort of porous functional material and one of sorts of environmental protection material as well. It can be classified into two main kinds: culm charcoal and stick powder charcoal according to its origin. The former is made of bamboo culms that are dealt with such procedures as airing, treating with smoke, loading kiln, heating, and carbonizing. The latter is made from bamboo processing residual with various shapes and size by means of breaking down, drying, extruding into sticks, loading kiln, and carbonizing. Accordance with shape, bamboo charcoals made from culms can be assorted into cylinder, piece, particle, and powder. According to use, they are named for purifying drinking water, for regulating room humidity, for preserving freshness of vegetables, fruits and flowers, and for health caring etc.
In China bamboo charcoal is produced primary by brick kiln and retort.
Brick kiln: the bamboo in the kiln is heated by fuel (bamboo or wood) to produce bamboo charcoal. It takes about 7-21 days for the production. Its bamboo charcoal rate is around 20 %. The kiln is cheaper than retort, its refined temperature is higher, and bamboo charcoal density is also higher, but the quality is not so stable.
Retort: it is primarily an external hot-vertical retort. Because bamboo is sealed from oxygen, there is almost no carbon oxidation, the bamboo charcoal rate is a high, between 25 to 35 %, and the carbonization needs about 24 to 72 hours. But its refining temperature is not high which affects bamboo charcoal density; single retort has small volume and low productivity.
The specific surface area defines the summation of inner and outer surface area in one gram of bamboo charcoal and it indicates the capacity of absorption. Bamboo charcoal specific area can be up to 300-500 m2/g compared to less than 30 m2/g of most wood charcoal. Because of its outstanding absorption capacity, bamboo charcoal is used as deodorants and many other uses.
Water purification: Bamboo charcoal could reduce pollutants by absorbing chlorine, pesticides, heavy metals, at the same time bamboo charcoal could release microelements which are helpful to health. Therefore Bamboo charcoal is used for water and rice cooking. Bamboo charcoal is also used in aquarium, fish pool and spring to purify water.
Air purification: Bamboo charcoal can be used as an absorber of poisonous gases. Pollution indoors caused by poisonous materials would be absorbed if bamboo charcoal is used. In newly built or decorated houses, new laminated furniture or new vehicles, bamboo charcoal could absorb poisonous gases such as formaldehyde and methylbenzene etc released from glues, painting and plastic items. The nicotine and other poisonous materials would be absorbed if cigarette filters were made of bamboo charcoal. Due to its conductivity bamboo charcoal could shield off electromagnetic waves.
Soil improvement and bio-char: As a carrier of organic manure and micro-organism in the soil, bamboo charcoal can improve the vigour of the soil, so people use it as a good soil enhancer. Bamboo charcoal is a kind of bio-char, it contributes also to carbon sequestration besides as fertilizer.
Fresh-keeping: Bamboo Charcoal can adsorb ethylene released from fruit, vegetable and flower in the storage and extend their storage time. Bamboo charcoal could reduce unhappy smell in a refrigerator and keep vegetables and fruits fresh stored in it.
Humidity control: Bamboo charcoal could reduce humidity in the humid seasons, especially in the humid summary when bamboo charcoal powders are put in the corners or under the floor. Bamboo charcoal could also make furniture dry to avoid moulding.
Medicine and health care:
Bamboo charcoal releases far-infrared, Far-infrared improves blood circulation of body tissue surface, warming and metabolism. When bamboo charcoal meets water molecules from the air, then let water molecules electrolyzes into negative oxygen ions which increases in the content of negative oxygen ion in the air. High negative oxygen ion content makes people fresh and comfortable. For these reasons bamboo charcoal pillows and mats l can soothe the nerves, relax backaches, and control snoring. Bamboo charcoal also has the functions of deodorization, dehumidifier and fungicide, which are essential to family needs.
Waste water treatment: It is discovered that bamboo charcoal loaded with microorganism could purify waste water efficiently. Three main fungus groups: photosynthetic bacterium, lactobacillus and microzyme loaded into the pore carrier of special bamboo charcoal, hybrid the oxygen and anti-oxygen microbe through fermentation; different microbes live on the pollutant as “food”, so as to maintain the metabolism. In this way, the improved biological bamboo charcoal functions together with the various microbes during the water purification process to decompose the pollutant into water and CO2 through complicated absorbing and biological processes. Based on this theory, the water purification treatment through improved biological bamboo charcoal technology was invented.
It is reported in Japan that bamboo charcoal could absorb radioactive Iodine and Cesium. Only 10kg bamboo charcoal could absorb the Cesium of 360,000 liters. Bamboo charcoal could absorb radioactive elements in the polluted soil.
Nano Tio2 loaded bamboo charcoal is bamboo charcoal loaded with nano TiO2. The combination has both advantages of bamboo charcoal for its strong absorption capacity and nano TiO2 for its decomposition ability. Based on different purposes bamboo charcoal could be loaded with inorganic antimicrobial, tantalite and nano TiO2, which could remove pollutants such as benzene, methylbenzene, dimethylbenzene, styrene, ethylbenzene, formaldehyde, aldehyde and alcolein etc. in the air and microorganism, residual chlorine, heavy metals and organic materials etc. in the water.
Other fields: Bamboo charcoal can be made into many kinds of compound materials in the material industry such as bamboo charcoal pottery, bamboo charcoal board and paper etc. The composite material of bamboo charcoal pottery was made from pottery and bamboo charcoal powder as the major materials, which was manufactured by mixing, shaping, drying, calcining. It shows that bamboo charcoal particles embedded in the clay matrix and kept their original mesoporous structure. In addition the bamboo charcoal particles bear the structure characterization of graphite. Bamboo charcoal pottery possesses larger specific surface area and its pore structure is dominated by mesoporous. It could absorb noxious gases such as formaldehyde and benzene efficiently. A certain amount of bamboo charcoal can improve the far-infrared emissivity of bamboo charcoal pottery. It is higher than the pottery and bamboo charcoal. It also can be made into handicrafts, feed additives and textile added with bamboo charcoal etc. Bamboo charcoal is also used as cosmetic and hygienic products such as bamboo charcoal soap, shampoo, cream, facial mask. Traditionally charcoal is used to treat stomach problem to remove harmful material from your body. Bamboo peanuts, cakes and noodles are also available.
Activated bamboo carbon: Bamboo charcoal can be used as the raw materials of bamboo active carbon. Bamboo charcoal shows strong absorption because of the special structure of micro holes of the bamboo stem, and the function would be more outstanding after it is activated. Bamboo activated carbon is used as key material for super capacitor. It has high energy density, high electric capacity density, low electric insistence and stable electric chemical properties. It could be widely used power of electric vehicles, powerful UPS, Li-batteries and other super capacitor etc.
Annually over 100,000 tons bamboo charcoal is been produced in China. The bamboo charcoal is used as above mentioned purposes and can sequestrate and store almost 400,000 CO2 annually. Because of its good market, the annual production of bamboo charcoal is increasing very fast, hence bamboo charcoal is playing a more and more role to mitigate climate change as well other benefits on economy.
In many countries woodfuel and wood charcoal are rural and urban household energy source, but woodfuel and wood charcoal supply is a problem due to increasing demand and decreasing forest resource. Bamboo charcoal from an easily renewable and sustainable bamboo resource could be the substitute of wood charcoal and supply household energy for many countries. Bamboo biomass could be used directly or processed into pellets for heating, gasification and liquefaction, and green electricity generation. We have implemented bamboo biomass energy project-- Bamboo as sustainable biomass energy: A suitable alternative for firewood and charcoal production in Africa. Bamboo charcoal and its briquettes are smokeless and no smell, they could be good alternative for wood charcoal for household energy.
1. FAO FRA 201
2. China Flora 2013
3. Fu Jinhe, Improved biological bamboo charcoal for wastewater treatment, FAO NON-WOOD NEWS No. 14 January 2007
4. Fu Jinhe, Bamboo charcoal and bamboo vinegar, FAO's NWFP-Digest-L NO. 2, 2002.
6. Zhang Wenbiao, Li Wenzhu, Zhang Weigang etc, Preparation and structure characterization of bamboo charcoal pottery composite, Scientia Silvae Sinicae, No.3, Vol 47, 2013.
7. Fu Jinhe, Special Issue for bamboo charcoal, World Bamboo and Rattan, Vol. 7 No. 5, 2009
8. Bamboo charcoal encyclopedia in Chinese: ttp://baike.baidu.com/view/20725.htm