Carbon blacks as model porous adsorbents

• Published in: Journal of colloid and interface science 1968-01, Vol.27 (1), p.1-6
• Main Authors: Abram, J.C, Bennett, M.C
• Format: Article
• Language: English
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(68)90002-7

A series of carbon blacks has been used to calibrate two surfactants, cetyltrimethyl-ammonium bromide (CTAB) and sodium di-2-ethylhexylsulfosuccinate (“OT”), adsorbed from aqueous solution, for use in the assessment of carbon adsorbent activity. For some blacks, the manufacturer's data for B.E.T. and electron-microscope area suggested the absence of porosity, but de Boer's t-plots drawn from our own nitrogen adsorption data indicate some area in pores of width less than 7A. The area per molecule for the two surfactants has been determined on nine of these blacks using the t-plot area in pores of width greater than 7 A. For other blacks, t-plots indicate bands of pores at 11 and 15 A width. It appears that the limiting pore width for penetration by CTAB must lie between 11 and 15 A, and for penetration by “OT,” somewhat above 15 A. It is noted that these pore widths are approximately twice the effective diameter of the surfactant molecules.