Activated Carbon Filters

Activated (active) carbon (“activated charcoal) is a form of carbon processed to have small, low-volume pores that inc4rease the surface area available for adsoption. it is produced from carbonaceous source materials such as nutshells, coconut husk, peat, wood, coal and petroleum pitch.

Activated carbon is an inexpensive natural material having extensive non-specific adsorption properties and is used as an adsorbent or as a decolorant in the industrial fields such as production of chemicals and foods, sewage or waster water treatment, and water filtration.

How Activated Carbon is Produced

Activated carbons are characterized by a large specific surface area typically in the range of 500-2500 m2/g, Commercial grades are designated as either gas phase or liquid phase adsorbents. Liquid phase carbons generally may be powdered, granular or shaped; gas phase are hard granules. Commercial activated has been made from material of plant origin such as hardwood and softwood, corncobs, kelp, coffee beans, rice hulls, fuit pits, nutshells and wastes such as bagasse and lignin. AC also has been made from peat, lignite, soft and hard coals, tars and pitches, aslphalt, petroleum residues and carbon black. Activation of the raw material is accomplished by one of two distinct processes: 1) chemical activation or (2) thermal activaiton. (Tolles &S 5,204,310)

Use in Antibody Purification

Activated carbon (AC) is compatible with all common solution conditions found throughout the downstream process. It is capable of operating in acidic and basic pH ranges as well as high and low olution condcitivties. Since AC can be operated in flow through mode under typical process pH and conductivities, the possibility to connect it with adjacent IEX chromatogrpahy steps becomes attractice. Millistak+ CR40 media is formulated with AC retained in a rigid structure by a cellulose matrix and can be used to reduce HCP present in Protein A elution pools. (“The use of Millistak+ Activated Carbon (AC) for downstream purification of monoclonal antibodies” 2015). 

Skudas (US 15/524824, published as US 2017/033741) discloses a method for puriying an antibody away from exctables/leachables using activated carbon in a filtration device.