Expanded graphite was discovered at the beginning of the 1860s, and many countries like to use it for research, which can achieve many unexpected results. How many times can expansion be magnified? That's right. It's twice as big or even times! It is a new carbon material! Many people don't know much about expanded graphite!

Graphite crystal is a two-layer structure of macromolecules. The C atoms in each plane are bound by C-C covalent bonds, and the layers are bound by a weak van der Waals force.

The layered structure of graphite is very typical. Each layer is a layer of carbon atoms. The carbon atoms in the layer form strong covalent bonds with sp2 hybrid orbitals, that is, one 2s electron and two 2p electrons hybridize the equivalent hybrid orbitals, which are located on the same plane and form each other σ The two 2P electrons that are not involved in the hybridization are perpendicular to the plane, forming a double bond π. The layered structure of graphite makes certain voids between layers. Therefore, under certain conditions, the atoms (or single molecules) of some reactants (such as acids, bases, halogens) can enter the interlayer space and form interlayer compounds with the carbon mesh plane.

The graphite intercalated with interlayer compound is expandable graphite. The carbon atom layers are connected by a very weak van der Waals force. This structure allows the intercalated materials to enter the carbon original layers smoothly without damaging the hexagonal network structure in the carbon atom layer. Therefore, natural graphite is the best parent material for preparing graphite intercalated compounds. Expandable graphite is a kind of crystal compound that uses physical or chemical methods to insert non-carbonaceous reactants into the graphite layer, and combines with the hexagonal network plane of carbon while maintaining the graphite layer structure. It not only maintains the excellent physical and chemical properties of graphite, but also presents new properties that the original graphite and the intercalated material do not have due to the interaction between the intercalated material and the graphite layer. When the graphite with intercalation compound encounters high temperature, the intercalation compound will decompose and produce a thrust along the C-axis direction of the graphite interlayer, which is far greater than the interlayer binding force of the graphite particles. Under the action of this thrust, the graphite interlayer is pushed away, so that the graphite particles expand exponentially along the C-axis direction, forming wormlike expanded graphite l2]. The graphite layer can be "embedded" with chemical substances and has expansibility. If sulfuric acid can be used to treat graphite, the graphite will expand at high temperature after drying, which is caused by the "embedding" of sulfuric acid molecules into the graphite layer. However, it can be seen from the existing literature that expanded graphite is an adsorbent with excellent performance, especially it has a loose porous structure and strong adsorption capacity for organic compounds. 1g of expanded graphite can adsorb oil, so expanded graphite is designed as an adsorbent for various industrial oils and industrial oils.

Expanded graphite is very easy to absorb oil, organic molecules and hydrophobic substances. It has irreplaceable effects for water environmental protection treatment. When it is used for oil removal on water surface in granular form, its dosage is 1~lo%/rn, and the adsorption time can vary from to several hours according to the size of oil area on water surface and the type of oil.

Expanded graphite is a special purpose graphite. Its chemical properties are very stable and its corrosivity is zero. Moreover, it can block the combustion of paint, and the demand is very wide. At low temperature, graphite will expand, and at high temperature, it can also expand.