To propose a simple and primitive genetic model before appearance of the current gene such as RNA and DNA, we investigated the information transfer between clay minerals, which have existed since ancient times, and organic molecules. A porphyrin synthesis was attempted in clay dispersion, expecting that the cationic porphyrin synthesis would be promoted on the surface of the anionic clay minerals due to the similarity of their average charge sequences. In the control experiment in water without clay, it was found that there were optimum values for concentration and pH conditions, and the estimated yield was about 20% at maximum. However, in clay dispersion, the estimated yield was 2%. This result suggests that the substrate enrichment effect on the clay surface of the electrostatic field had a pronounced influence, and the expected enhancement of porphyrin formation based on charge sequence similarity could not be confirmed. However, the suppression of intramolecular motions due to the electrostatic interactions between the reaction intermediates and the clay surface was observed, indicating that the clay surface has a specific effect on organic reactions that is different from that in solution. In other word, the reactions that make the linear multimer were accelerated and the cyclization that produces the porphyrinogen was suppressed by the effect of the surface.

A Si–Al–Mg mixed hydrous oxide sample was synthesized with a metal composition ratio of Si : Al : Mg=0.1 : 0.1 : 0.8, hereafter referred to as SAM118. The main components of SAM118 are amorphous Mg (OH)₂ and hydrotalcite (Mg/Al double hydroxide) as observed by XRD. Granulated SAM118 was investigated for its adsorption capacity using batch and column tests. The fluoride adsorption capacity of granular SAM118 (<1.0 cm) was demonstrated in batch adsorption tests and compared with that of powder SAM118 (<150 µm). The adsorption capacity was 11.0 mg/g for the powder SAM118, and the granular SAM118 exhibited a similar performance. Column tests of granular SAM118 were conducted at various space velocities (SVs) to investigate the breakthrough curves (adsorption performance). The breakthrough point, defined as the moment when the fluoride concentration in the effluent reaches 8.0 mg/L, was observed. The through-flow capacity was measured at SVs ranging from 0.31 to 0.82/h for aqueous solutions and 1.09/h for Matsue Shinjiko Onsen hot spring water. The fluoride breakthrough capacity of granular SAM118 was consistent with the SV effect. SAM118 demonstrated a high fluoride adsorption performance, achieving an adsorption amount of 5.27 mg/g at an SV of 0.31/h in NaF aqueous solution. Therefore, it can help meet the Japanese standard of fluoride concentration of 8.0 mg/L in wastewater.

This study examines the potential of sulfuric acid treatment on naturally occurring mordenite to enhance its inhibitory effect on the alkali-silica reaction (ASR). Mordenite was subjected to varying concentrations of sulfuric acid to convert its exchangeable cations to H⁺. The efficacy of this conversion and its impact on inhibiting the ASR were subsequently assessed. With increasing sulfuric acid concentration, the contents of exchangeable Na and K cations in the mordenite decreased. Notably, treatment with 9 M sulfuric acid successfully converted ∼64% of the exchangeable cations to H⁺, although at the cost of 16% loss of exchange sites. Structural characterization confirmed that the zeolite framework was preserved following two acid treatments. However, there was no increase in the ion exchange cation, and the sulfur content increased relative to that after a single treatment. To assess the inhibitory effect of the acid-treated mordenite on the ASR, accelerated expansion tests were conducted. Mortar specimens with drilled holes were filled with cementitious grout incorporating mordenite pre-treated with 9 M sulfuric acid. Compared to the control samples devoid of the treated mordenite, the expansion rate of the sample containing the acid-treated mordenite grout decreased significantly by 67%. This inhibitory effect outperformed that achieved with the previously developed Li-EDI zeolite, which decreased the expansion rate by 33%.

Four smectite clays in CSSJ reference samples were examined using TEM/STEM imaging and energy-dispersive X-ray spectroscopy (EDS) in SEM and STEM in order to characterize their chemical compositions, grain sizes, impurity minerals, and other properties. Fine calcite particles were commonly found along with quartz in the Tsukinuno samples (JCSS-3101, 3101b), which served as the primary source of calcium, as reported in previous bulk analyses. Cristobalite, quartz, and feldspar are the prevalent impurity minerals in the Mikawa sample (JCSS-3102), and STEM-EDS analysis revealed that the composition of the smectite clay is definitely montmorillonite, with subtle differences from Tsukinuno montmorillonite. The synthetic saponite (JCSS-3501) displayed a wide range of crystal sizes. Sulfate and sodium ions were concentrated in the aggregates of very fine saponite crystallites when compared to particles with larger sizes.