Progress on fabrication and application of activated carbon sphere in recent decade

Activated carbon (AC) has a long history as an adsorbent material in many applications, including heavy metal and toxic gas removal as well as air and water filter applications. Activated carbon sphere (ACS) is a special type of activated carbon that has a high compressive strength and low ash content. Coal, asphalt, resins, polymers, lignin, carbohydrates, etc. can be utilized as precursors to prepare ACS using simple carbonization and activation processes. Various parameters such as carbonization temperature, rising rate of temperature, activation time, activation temperature, activator, different activation methods, etc. have significant effects on the performance and quality of the final product. As the size of ACS decreases, different preparation methods were adopted to prepare nano-sized or micron-sized spherical activated carbon. However, regardless of the size and shape of spherical activated carbon, it has a wide range of roles for the removal of heavy metals, organic dyes, carbon dioxide, volatile organic chemicals, catalyst carriers, gas and energy storage, chemical protection materials, and blood purification. This article mainly reviews preparation methods of ACS over the last decade, and its applications and the challenges faced by ACS are discussed.