Selective adsorption of phenanthrene on activated carbons for surfactant

Selective adsorption of phenanthrene on activated carbons for surfactant reuse in soil washing process 

Effectiveness of selective adsorption of phenanthrene in Triton X-100 solution depends on surface area, pore size distribution, and surface chemical properties of adsorbents. Since the micellar structure is not rigid, the monomer enters the pores and is adsorbed on the internal surfaces. The size of a monomer of Triton X-100 (27 A) is larger than phenanthrene (11.8 A) [4]. Therefore, only phenanthrene enters micropores with width between 11.8 A and 27 A. Table 1 shows that the area only for phenanthrene adsorption is the highest for 20 40 mesh. From XPS results, the carbon content on the surfaces was increased with decreasing particle size. Thus, 20 40 mesh activated carbon is more beneficial for selective adsorption of phenanthrene compared to Triton X-100. 

L 4 12 mesh, M 12-20 mesh, S 20-40 mesh. Amt total surface area, Aext external surface area, Aphe surface area for phenanthrene adsorption, Atx surface area for Triton X-100 adsorption 

The adsorption isotherms for each chemical, Triton X-100 or phenanthrene, on the activated carbons were shown in Figs. 1 and 2. The adsorption isotherms are expressed as qg [g g ], the amount of compounds adsorbed per unit mass of adsorbent, as a fimction of Q [g l ], the concentration in solution at equilibrium [5, 6]. The best-fit parameters for Freimdlich isotherms (g = or linear isotherms (q - Kj C ) were summarized in Table 2. The 

The effect of initial surfactant concentration was different according to the particle size of GACs (Fig. 4). In large particle size, selectivity was increased with increasing surfactant concentration unlike small particle size. This is because excess surfactant did not adsorb onto activated carbon due to small Ajx- 

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