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The adsorption process of phenol on silicalite-1 was studied by single-crystal X-ray diffraction. The loading of phenol on silicalite-1 was performed for 24, 48, 72, and 168 h. Phenol molecules first diffused through the intersection forming hydrogen bonds with the oxygen atoms of the framework and then subsequently turned into the sinusoidal channel. As adsorption progressed, phenol molecules were located at the intersection and in the sinusoidal channel, and these two kinds of phenols interacted with each other. High-loaded phenol–silicalite-1 (8.0 molecules/unit cell) was obtained after 168 h of adsorption. It is clear that hydrogen bonds were present in the framework, based on the results of the single-crystal XRD measurements and an IR study.

Effects of l -aspartic acid ( l -Asp) on dissolution of calcite were investigated. The step retreat velocity and dissolution rate of calcite were measured simultaneously using an AFM flow-through system. The etch-pit morphology of calcite was observed using confocal laser scanning microscopy. Results show that the etch-pit morphologies changed drastically depending on the l -Asp concentration ([ l -Asp]) in the order of rhomboidal, pentagonal, and triangular (not perfectly, but retaining an extra step). The change in obtuse step directions and appearance of the [0 1 0] step triggered these morphological changes. Addition of l -Asp accelerated all step retreats at [ l -Asp] l -Asp on the diffusive barrier. In contrast, at [ l -Asp]>0.01 M, l -Asp inhibited the retreats of obtuse steps and [0 1 0] step, although the retreat velocities of acute steps were constant irrespective of [ l -Asp]. These results suggest that the directional changes and the inhibition of retreat velocities of obtuse steps were attributed to the generation of [ 4 1 1] and [4 5 1 ] steps caused by l -Asp. Moreover, we confirmed the preferential effects of l -Asp on the [4 8 1 ]+ to [ 4 4 1]± step edge, and proposed the preferential effects of l -Asp on the [ 4 1 1] to [4 5 1 ] step edge.

Impurity effects of trace lanthanum ion (La 3+ ) on the dissolution and growth of calcium carbonate were studied with in situ observation techniques. Dissolution kinetics of two polymorphs of calcium carbonate, calcite and vaterite, were investigated by monitoring the pH in the solution with laser-induced fluorescence spectroscopy using a pH-sensitive reagent, seminaphthorhodafluors. No effect on dissolution of vaterite was observed with the spectroscopic observations, whereas calcite dissolution was significantly inhibited by lanthanum ion with concentrations higher than 1 μM. Crystal growth and dissolution processes of calcite under the lanthanum-doped condition were observed by means of atomic force microscopy. Step propagations during crystal growth and dissolution of calcite were inhibited by trace lanthanum ion (5 μM). An insoluble thin layer of lanthanum carbonate deposited on the step site of the calcite surface could be a possible cause of the inhibitions observed both for dissolution and growth.