Adsorption of Mono-, Di-, Tri- and Tetra-Glycine by Mesoporous Materials FSM-16

Abstract

Adsorption of mono, di-, tri-and tetra-gly by FSM-16 was attempted and isotherms for adsorption of them was drawn.The isotherms for adsorption were arranged from high to low that of tetra-, tri-, di-and mono-gly in order.The arrangement of the isotherms was dependent on the solubility of glycine and its oligomers. On the other hand, FSM-16 can function as the molecular sieve because FSM-16 has a mesopore.The effect of the molecular sieve showed very little in extend of the adsorption. IntroductionA mesoporous material, FSM-16 was synthesized by Yanagisawa et al. (1990) for the first time.[1] When a surfactant was intercalated into an interlayer of kanemite, the surfactant formed micelles between the interlayers. The shape of the micelle for the surfactant remained by the polymerization of silicate. FSM-16 was obtained by the removal of the surfactant from the interlayers. The characteristics of FSM-16 were investigated sufficiently. [1][2][3][4][5] For example, the pore size of FSM-16 is about 3 nm, the surface area is about 1000 m2/g, adsorption of water vapor by FSM-16 has been investigated, and the structure of FSM46 seldom collapsed by water, etc. The mesoporous material was expected to utilize a molecular sieve or a catalyst. Recently, the mesoporous material also began to be used as a space for the creation of a nanomaterial.The possibility of a molecular sieve occurring by the length of a molecule was investigated in this report. The organic compounds used were glycine (mono-gly), glycyl-glycine (di-gly), glycyl-glycyl-glycine (tri-gly) and glycyl-glycyl-glycyhglycine (tetra-gly). They do not have the functional group in the side chain and have one amino and one carboxyl group in both ends, respectively (Fig.1, (a)). Therefore, glycine and its oligomers are fit for the investigation of the effect of the molecular sieve for FSM-16. We attempted to make adsorption of mono-, di-, tri-, tetra-glycine by FSM-16. The isotherms for the adsorption of them were drawn up and the difference of them and the possibility of a molecular sieve of FSM-16 were discussed. Vol.14 Supplement (2003) The lengths of mono-gly and tetra-gly molecules are about 0.4 and 1.4 nm, respectively. Therefore, the lengths of the molecules of oligo-glycmes used are small enough for FSM-16. It is supposed that the adsorption of polymer will get smaller than that expected if the effect of the molecular sieve appears on the adsorption.That is to say that the polymer can adsorb only on the outer surface of the FSM-16 particle without the adsorption on the inside of the mesopore for FSM-16.However, the isotherm for adsorption of tetra-gly was higher than any other isotherms of adsorption as shown in Fig. 2. Therefore, the effect of molecular sieve for the pore size of FSM-16 might not appear clearly in this work.The arrangement of the isotherms for adsorption in Fig. 2 affects the solubility of glycine and its oligomers.As shown in Table 1, the solubility of tetra-gly is the smallest and that of mono-gly is the largest. The smaller the s...

Adsorption of Some Aromatic Compounds by a Synthetic Mesoporous Silicate

“…[6,7] The mesopores may also be used as reaction vessels in which new nanomaterials can be synthesized. [6,7] The mesopores may also be used as reaction vessels in which new nanomaterials can be synthesized.…”

“…[10,11] There is not much information in the literature on the removal of organic compounds and metal ions by mesoporous materials. [6] For organic pollutants, Zama et al found that FSM-16 grafted by Mo complexes could photocatalyze the hydroxylation of benzene to phenol using hydrogen peroxide as an oxidant under the irradiation of UV-light. FSM-16 showed a large capacity for adsorbing the enzyme when the pore sizes were larger than 5 nm.…”