The primary difference between carbon and activated carbon is the surface area to volume ratio. Regular carbon has a significantly lower surface area to volume ratio when compared to activated carbon. This means that activated carbon has higher adsorption capabilities.

Activated carbon is porous carbon material. Due to its highly developed porous structure and huge specific surface area, activated carbon has very strong adsorption capacity. 

Activated carbon used for gold smelting, dechlorination, deoiling of industrial water such as food, chemical industry, electric power, electric plate, etc, and further purifying treatment of potable water and sewage water.