Adsorption of antioxidants by carbon blacks

The adsorption of p-nitrophenol, methylene blue and antioxidants have been examined on two carbons of high surface area but manufactured from different feedstocks using various methods of activation for developing the pore structure. Black Pearls 2000 is a thermally produced steam activated carbon black, whereas activated char is a wood-based product activated chemically with phosphoric acid followed by steam treatment. Adsorption studies using methylene blue as solute indicate that in both carbons, around 65% of the total surface is present in pores of less than 2.8 nm radius. Adsorption studies using very large solutes, e.g, antioxidants, indicate that activated char behaves as non-porous towards these large molecular area solutes. There is indication that the antioxidants are present as aggregates in methanol solution and are adsorbed as such on the substrates. (C) 1998 Elsevier Science Ltd. All rights reserved.