C-S-H phase is one of the main hydrates in hardened cement paste and binds chloride ions. The purpose of this study is to quantify equilibrium amount of chloride adsorption bound by C-S-H phase with various Ca/Si ratios. C-S-H phase can absorb chloride ions with 3 steps. In the C-S-H phase with low Ca/Si ratios, momentary physical adsorption could not be expected. Physical adsorption is strongly dependent on electro-kinetic interaction between surface area of C-S-H phase and chloride ions. In previous research, C-S-H phase showed binding behavior with 3 stages including the stage of instantaneous physical adsorption other stages. Thus, this study examined the equilibrium amount to express chloride binding isotherm of C-S-H with various Ca/Si ratio.

In order to develop a dye coloring technology on Conchiolin layer in cultured pearls, appropriate dyes were selected, their solubilities in various solvents were studied, and adsorption and desorption experiments were performed. Solubilities of several basic dyes known to suitable for the pearl coloring, i.e., Rhodamine 6G(R6), Rhodamine B(RB) and Methylene Blue(MB), in several solvents (distilled water, methanol, ethanol, and acetone) were investigated. Among these dyes, R6 was chosen as a dye for single component adsorption and desorption experiment due to the relatively good solubility in various solvents tested. Solubilities of dyes were judged to be enough to color the pearls since dye concentrations in pearl coloring are, in general, not so high. The internal surface area of the pearl layer is believed to be directly related to the dye adsorption; the single-point internal surface area of the pearl layer measured at the nitrogen relative pressure of 0.3 was found to be 0.913㎡/g, and the BET internal surface area, 1.01㎡/g. The most probable diameters of micropores and macropores were found to be 40Å and 5000Å, repectively, from the pore size distribution d/ata. Adsorption isotherm was well fitted to the Langmuir isotherm model, resulting in q=1.62C/1+1.09C˙

The biosorption of dye, Rhodamine B(Rh-B), onto waste activated sludge was investigated. The biosorption capacity and contact time were shown as a simulation of dye adsorption equilibrium and kinetics models. We observed that biosorption of Rh-B occurred rapidly less than 4hr. These experimental data could be better fitted by a pseudo-second-order rate equation than a pseudo-first-order rate equation. The equilibrium dependence between biosorption capacity and initial concentration of Rh-B was estimated and it was found that the equilibrium data of biosorption were fitted by four kinds of model such as Langmuir, Freundlich, Redlich- Peterson, and Koble-Corrigan model. The average percentage errors, ε(%), observed between experimental and predicted values by above each model were 21.19%, 9.97%, 10.10% and 11.76%, respectively, indicating that Freundlich and Redlich-Peterson model could be fitted more accrately than other models.