Keiji Kusumoto

Application of pure silica gel as cation-exchange stationary phase in lon chromatography with indirect photometric detection for common mono-and divalent cations using aromatic monoamines as eluents

SummaryA pure silica gel (Pia Seed 5S-60-SIL), synthesized by the hydrolysis of pure tetraethoxysilane [Si(OCH2CH3)4], was applied as a cation-exchange stationary phase in ion chromatography with indirect photometric detection for common mono-and divalent cations (Li+, Na+, NH4+, K+, Mg2+, and Ca2+) using various protonated aromatic monoamines (tyramine [4-(2-aminethyl) phenol], benzylamine, phenylethylamine, 2-methylpyridine and 2,6-dimethylpyridine) as eluet ions. When using 0.75 mM tyramine-0.25 mM oxalic acid-1.5 mM 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) at pH 5.0 as the eluent, excellent simultaneous separation and highly sensitive detection at 275 nm for these mono-and divalent cations were achieved on the Pia Seed 5S-60-SIL column (150×4.6 mm I.D.) in 20 min.

Simultaneous separation of common mono- and divalent cations on a calcinated silica gel column by ion chromatography with indirect photometric detection and aromatic monoamines–oxalic acid, containing crown ethers, used as eluent

The application of unmodified silica gel (Super Micro Bead Silica Gel B-5, SMBSG B-5) as a cation-exchange stationary phase in ion chromatography with indirect photometric detection (IC-IPD) for the separation of common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) was carried out using various aromatic monoamines [tyramine [4-(2-aminoethyl)phenol], benzylamine, phenylethylamine, 2-methylpyridine and 2,6-dimethylpyridine] as eluents. When using these amines as eluents, the peak resolution between these mono- and divalent cations was not quite satisfactory and the peak shapes of NH4+ and K+ were largely destroyed on the SMBSG B-5 silica gel column. Hence, the application of SMBSG B-5 silica gel calcinated at 200, 400, 600, 800 and 1000 degrees C for 5 h in the IC-IPD was carried out. The peak shapes of the monovalent cations were greatly improved with increasing calcination temperature and, as a result, symmetrical peaks of these mono- and divalent cations were obtained on the SMBSG B-5 silica gel calcinated at 1000 degrees C as the stationary phase. In contrast, the peak resolution between these mono- and divalent cations was not improved. Therefore, crown ethers [18-crown-6 (1,4,7,10,13,15-hexaoxacyclooctadecane), 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane)] were added to the eluent for the complete separation of these mono- and divalent cations. Excellent simultaneous separation and highly sensitive detection at 275 nm were achieved in 25 min on a column (150x4.6 mm I.D.) packed with SMBSG B-5 silica gel calcinated at 1000 degrees C by elution with 0.75 mM tyramine-0.25 mM oxalic acid at pH 5.0 containing either 1.0 mM 18-crown-6 or 10 mM 15-crown-5.

Retention behavior of common mono- and divalent cations on calcinated silica gel columns in ion chromatography with conductimetric detection and the use of nitric acid, containing crown ethers, as eluents

Ion chromatographic behavior of common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) on columns packed with silica gels (Super Micro Bead Silica Gel B-5, SMBSG B-5) calcinated at 200, 400, 600, 800 and 1000 degrees C for 5 h was investigated using nitric acid containing crown ethers [18-crown-6 (1,4,7,10,13,15-hexaoxacyclooctadecane) and 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane)] as eluent. When using 0.5 mM HNO3 as the eluent, the calcination had almost no effect on the improvement of peak resolution between these mono- and divalent cations. In contrast, when using 0.5 mM HNO3 containing crown ethers as the eluent, with increasing the calcinating temperature, the amount of crown ethers adsorbed on the corresponding calcinated SMBSG B-5 silica gels columns increased and, as a consequence, peak resolution between these mono- and divalent cations was quite improved. Excellent simultaneous separation of these mono- and divalent cations was achieved on column (150x4.6 mm I.D.) packed with the SMBSG B-5 silica gel calcinated at 1000 degrees C by elution with 0.5 mM HNO3 containing either 1.0 mM 18-crown-6 or 5.0 mM 15-crown-5.

Environmental Friendly Ceramic Building Materials

The global warming is one of the most serious problems. The decrease of CO2 emissions in our daily life is an important subject today. Recently, an application of water retentive materials as a paving material has attracted a great deal of attention in Japan. This material is effective for reducing heat island phenomenon, which is also a recent problem in many cities in Japan. Water retained in the material during rainfall evaporates when heated by sunshine. The latent heat absorbed by evaporating water works to cool the surroundings. The water retentive ceramic products are expected to be useful for building materials as well as pavements. Several performances are required on the water retentive ceramics when it is used as building materials. Its cost and quality are the important factors. Porous ceramic materials formed by pressing without firing is one of ideal low cost and eco-friendly candidates. The porous ceramics is also expected to be produced from recycled ceramic materials. By optimizing its composition and forming method, a water retentive material with high performance was developed. The trial product had the properties as follows; fracture toughness: 1300N, bending strength: 175N/cm, water absorption: larger than 30%, and precision in size (length): +-0.5mm for 150mm. The product showed also enough frost resistance. In this paper, the fundamental properties of the porous ceramics prepared without firing are discussed with referring to the results of the field experiments.Another subject recently studied by several tile manufactures in Japan is the glazed tile with high solar reflectance. The exterior walls covered with such a high solar reflectance tile keeps the surface temperature of the wall lower under the strong sunshine of summer. It is effective against heat-island phenomenon. In this paper, the outline of the research results on visible and infrared reflectance of many kinds of glazes is also discussed.

Simultaneous separation of common mono- and divalent cations on an acid-treated silica gel column by ion chromatography with indirect photometric detection and tyramine-oxalic acid, containing 18-crown-6 as eluent

The application of unmodified silica gel (Super Micro Bead Silica Gel B-5, SMBSG B-5) as cation-exchange stationary phase in ion chromatography with indirect photometric detection for common mono- and divalent cations (Li+, Na+, NH4+, K+, Mg2+ and Ca2+) was carried out using 0.75 mM tyramine [4-(2-aminoethyl)phenol]-0.25 mM oxalic acid at pH 5.0 as the eluent. Although complete group separation between these mono- and divalent cations was achieved on the SMBSG B-5 column (150x4.6 mm I.D.) in 12 min, peak shapes of NH4+ and K+ were strongly tailed. Hence, the application of SMBSG B-5 silica gel treated with conc. hydrochloric acid at reflux-temperature for 12 h for the simultaneous separation of these cations was carried out. Although the retention volumes of these cations decreased on the acid-treated SMBSG B-5 silica gel column, the peak shapes of NH4+ and K+ were quite improved. Excellent simultaneous separation and highly sensitive detection at 275 nm [detection limits (signal-to-noise ratio of 3 and injection volume of 20 microl), 0.34 microM for Li+, 0.47 microM for Na+, 0.39 microM for NH4+, 0.59 microM for K+, 0.24 microM for Mg2+ and 0.28 microM for Ca2+] were achieved in 15 min on the acid-treated SMBSG B-5 column using 0.5 mM tyramine-0.2 mM oxalic acid-10 mM 18-crown-6 (1,4,7,10,13,15-hexaoxacyclooctadecane) at pH 5.5 as the eluent.

Solar Reflectance of Glazed Tiles

Exterior wall tiles with high solar reflectance are effective in mitigating heat-island phenomenon. Such walls have also the potential to decrease the warming up of building interiors in mid-summer. For the purpose of increasing the solar reflectance of wall tiles, several kinds of glazes were prepared to measure their visible and infra-red spectral reflectance by the spectrophotometer. The incident angle of sunlight on vertical exterior wall is larger than 70 degrees at midday of the summer season in Japan. The reflectance theoretically increases with the increase of incident angle. It is important to examine the reflectance against the sunlight with varied incident angles. The practical solar reflectance of glazed tiles is calculated by measuring the hemi-spherical integrated spectral reflectance with an oblique incident light. The glazed tiles having layered structure were also prepared and their spectral reflectance was investigated.

Development of Low-Temperature Sintering Stoneware Bodies

We studied on development of stoneware bodies, which sintered at low-temperature in ball clay-quartz-Indian feldspar system and ball clay-quartz-Indian feldspar-nepheline syenite system. It was found that the ceramics around 30wt% ball clay, 44wt% quartz, 26wt% Indian feldspar composition showed high shrinkage rate (9.4%) by sintering at 1200°C in ball clay-quartz-Indian feldspar system. Dense stoneware with low water absorption rate (0.1%) was fabricated by sintering mixtures composed of 30wt% ball clay, 44wt% quartz, 10wt% Indian feldspar, 16wt% nepheline syenite at 1100°C 2h in ball clay-quartz-Indian feldspar-nepheline syenite system.

Solar Reflectance of Glazes for Exterior Wall Tiles

Exterior wall tiles with high solar reflectance are effective in mitigating heat-island phenomenon. Such walls have also the potential to decrease the warming up of building interiors in mid-summer. Several kinds of glazes for wall tiles are characterized from the point of view of the visible and infra-red reflectance for the purpose of improving the solar reflectance. The incident angle of sunlight on vertical exterior wall is larger than 70 degrees at midday of the summer season in Japan. It is theoretically expected that the reflectance increases with the increase of incident angle. The practical solar reflectance of glazed wall tile is estimated by measuring the hemi-spherical integrated spectral reflectance with an oblique incident light. It was observed that even the reflectance of mat glaze increased dramatically with the increase of incident angle. This improvement of spectral reflectance occurred throughout the visible and near-infrared region and was independent of the color of the glaze.