the adsorption and the desorption behavior of the molecules Equilibrium experiment was conducted to investigate the factors taking place adjacent to the surface of the stainless steel (1determining the adsorption of benzoic acid (BA) and its deriva-5). However, it does not seem to be easy, at least in the tives, m-and p-hydroxy BA, onto SUS316L stainless steel particles sense of experimental procedures, to express the adsorptionof 8-10 mm diameter and under 100 mesh. Adsorption isotherms desorption behavior for the stainless steel adsorbent because of these benzoic compounds were determined in the presence of the surface area is limited depending on the form of adsorbent 0.05 M NaCl at pH 4 and 30ะC. The adsorptions of the these used. Recent studies, however, have shown that adsorption compounds were described well by a Langmuirian model for both of bovine serum albumin onto SUS316L stainless steel can adsorbents. When the maximum number of the benzoic compound be adequately described using particles of stainless steel of adsorption sites was expressed on the basis of unit surface area (N, mol/m 2 ), the N values were relatively constant, while the the required surface area (8, 9).
greatest value of the affinity (K, ml/mmol) was obtained for p-In the present paper, we investigated the adsorption-dehydroxy BA, although its value was in the same range as that of sorption behavior of benzoic acid (BA) and its derivatives, the other two adsorbates. Diffuse-reflectance Fourier transform o-, m-, and p-hydroxy BA, using SUS316L stainless steel infrared spectra of the fine adsorbent (8-10 mm diameter) after particles as the model adsorbent for the fouling occurring in equilibration suggest that the adsorption mainly takes place industrial plants. The rationale for the use of the benzoic through the carboxyl group of the adsorbate-stainless steel surface compounds is that (i) these compounds are widely used as interaction for all adsorbates, whereas concomitant interaction ocpreservatives in medicine and cosmetics, (ii) the structure curs in part with participation of the phenolic hydroxyl group for of these benzoic compounds is well characterized and stereop-OH BA adsorbate, accounting for the difference in adsorption chemically simple, and, therefore, (iii) the effects of hyproperties.