Bone black

Bone char, also known as bone black or animal charcoal, is a granular material produced by charring animal bones: the bones are heated to high temperatures (in the range of 400 to 500 °C) in an oxygen-depleted atmosphere to control the quality of the product as related to its adsorption capacity for applications such as defluoridation of water and removal of heavy metals from aqueous solutions.The quality of the bone char can be easily determined by its color. Black charcoals are usually undercharred bones that still contain organic impurities which may impart undesired odor and color to treated waters. White bone chars are overcharred bones that present low fluoride removal capacity. Grey-brownish bone char are the best quality chars for adsorption applications. The quality of the bone chars is usually controlled by the amount of oxygen present in the charring atmosphere. It consists mainly of calcium phosphate and a small amount of carbon. Bone chars usually have lower surface area than activated carbons, but presents high adsorptive capacities for copper, zinc, and cadmium

Bond strength

In chemistry, bond strength is measured between two atoms joined in a chemical bond . It is the degree to which each atom linked to a central atom contributes to the valency of this central atom. Bond strength is intimately linked to bond order.

Bond strength can be quantified by:

• bond energy: requires lengthy calculations, even for the simplest bonds.


• bond dissociation energy
  

Another criterion of bond strength is the qualitative relation between bond energies and the overlap of atomic orbitals of the bonds (Pauling and Mulliken). The more these overlap, the more the bonding electrons are to be found between the nuclei and hence stronger will be the bond. This overlap can be calculated and is called the overlap integral.