Effect of particle size and surface area on the adsorption of albumin-bonded bilirubin on activated carbon

The adsorption behavior of albumin-bonded bilirubin on different micrometer-sized granular activated carbons (GACs) with different BET surface areas of 913, 1173 and 1413 m² g⁻¹ and different pore size distributions in the micropore and mesopore range has been investigated in order to study the behavior of bilirubin from batch experiments. The extent of adsorption was measured from the residual concentrations of bilirubin in the solution after different adsorption times using visible absorption spectroscopy. It has been demonstrated that the adsorption rate of bilirubin increases with decreasing particle size and with increasing mesopore volume which was obtained from benzene isotherms. A diffusion coefficient of about D = 0.60 × 10⁻¹⁰ cm² s⁻¹ for bilirubin adsorption on activated carbon particles with a benzene mesopore volume of 0.18 cm³ g⁻¹ in the pore range of 2.35-44.0 nm was calculated from the Fick’s law of diffusion by using an intraparticle mass transfer model of sorptive uptake from a stirred solution of limited volume in spherical particles.