Similar to wood charcoal, bamboo charcoal is a micro-porous material with excellent adsorption property for its large specific surface area. Adsorption of bamboo charcoal is theoretically classified into physical adsorption and chemical adsorption. Physical adsorption is caused by molecule acting force (van der Waals force) between adsorbent and adsorbate that doesn’t change the surface composition of adsorbent and the situation of the molecule of adsorbate. Chemical adsorption is by chemical bond between adsorbent and adsorbate in which the exchange and transference of electrons happen to result in rearrange of atoms and chemical bond formation or destroying.
Physical adsorption goes fast and is reversible. It usually carries through in lower temperature without selection and acts in monolayer or multilayer because there is van der Waals force on one layer of molecule of adsobate.
Similar to chemical action, chemical adsorption needs activation energy. It is not reversible and usually carries through in higher temperature companying chemical output. It is always monolayer adsorption with distinct selection.
The electric conductivity of bamboo charcoal will be reinforced with the rising of terminal pyrolysis temperature. When terminal pyrolysis temperature reaches 700℃, the resistance in bamboo charcoal becomes very small, only 5.40×10-6 Ω﹒M, meaning good conductivity.
Therefore, bamboo charcoal carbonized under high temperature has effective property for shielding electromagnetism.
As the industrialization worldwide speeds up, air pollution and water pollution are becoming serious environmental problems. Bamboo charcoal is functional material for environment protection and developed fast in recent years for the reasons that (1) the wood that can be used as high-grade charcoal reduced rapidly and almost exhausted; (2) the harvest cycle of bamboo is short because it grows very fast. As a result, making bamboo charcoal doesn't destroy forest and environment; (3) bamboo charcoal are similar in properties to and can replace the high quality wood charcoal made from hardwood; (4) bamboo charcoal is good in strength and easy to process into different shapes.
At present, a series of bamboo charcoal products have been manufactured by taking advantage of the excellent adsorption and infrared radiation. These products involve in a variety of fields such as purifying drinking water and indoor air, adjusting humid in house,health care, odor adsorption, bamboo charcoal arts and so on. Some of products with shielding electromagnetism and anti-radiation are in research.