A large quantity of waste plywood panel for concrete form has been generated with the progress of construction industry and its effective utilization becomes an urgent social problem. In this study, the production of charcoal from waste plywood panel (charcoal W) and its adsorption characteristics of anionic dyes were investigated. The plywood panel was first pulverized as a chip and carbonized under nitrogen atmosphere. The content of metal ions was found to be considerably larger in the charcoal W than in that from virgin panel (charcoal V). The partial graphitization of the charcoal W was proceeded by the catalytic action of the contained metal ions, causing the specific surface area of the charcoal W to became larger than that of the charcoal V. The adsorption isotherms of three anionic dyes were obtained and well treated by the Freundlich adsorption equation. The adsorption ability of acid blue 92 and acid blue 90 with the charcoal W of large molecular size became larger than those of the charcoal V and activated carbon (AC). The charcoal W was also found to have four times more mesopores capacity compared to AC. The charcoal W can be useful in environmental purification as an excellent absorbent.

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15BaO-10PbO-5SrO-70P₂O₅ phosphate glass has been prepared by 2.45 GHz microwave heating. The glass prepared by microwave heating (MW glass) had higher stability against temperature and humidity than the glass prepared by conventional electric furnace heating (EF glass). In order to know the structural difference between MW and EF glasses, we measured ³¹P MAS NMR. Q₀ band for single PO₄ group at 0.0 ppm, Q₁ band for end PO₄ group at -12.0 ppm and Q₂ band for middle PO₄ group at -28.0 ppm were observed in the spectrum of EF glass. It is noteworthy that in the spectra of MW glasses, the strong Q₃ band for branching PO₄ group newly appeared around -45 ppm in addition to Q₀, Q₁ and Q₂. Furthermore, MW glass has higher value of the degree of polymerization than EF glass. The presence of branching points means that MW glass has three-dimensional structure by normal condensation polymerization as thermal effect and radical polymerization as non-thermal microwave effect. Three-dimensional glass network and higher polymerization lead to higher stability of MW glass.

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The simple and effective removal method of fluoride ions in wastewater has been investigated by using a powdery fine calcium oxide as the removal reagent for fluoride ions.
It was found that the treatment using the calcium oxide could reduce fluoride ions to a lower level below 8 mg · dm^-3 than the use of industrial calcium hydroxide and that the treatment is made further efficient by multiple addition method of the calcium oxide, i.e., it was found that only 0.5 mass% calcium oxide in the wastewater containing large amount of fluoride ions (200 mg · dm^-3) is fully enough to treat the wastewater.
The technology of treating wastewater containing fluoride ions by adding the calcium oxide seems to be simple and effective method overcoming the disadvantages of the conventional treatment method using calcium hydroxide and high aluminum salts.

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During the production of paper, a large amount of ash is produced from incineration of paper sludge. Because the ash is alkaline, it is used as a remediation agent for acidic soils. Recently, due to pollution concerns it has become important to reduce elution of fluoride ions from the ash of the incinerated paper sludge.
In this study, suppression of fluoride ion elution by the addition of waste soda-lime glass was investigated using NaF as model contamination. NaF was added to soda-lime glass and heated. Then elution test of fluoride ion was performed. The optimum glass quantity content and heating conditions were evaluated and sufficient suppression of fluoride ion elution was attained. Effect of addition of soda-lime glass on the suppression of fluoride ion elution in the actual incinerated paper sludge was examined. The suppression of fluoride ion elution was successfully performed. The ability to remediate acidic soils was maintained in the material developed in this study.

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Lead-free glasses with a low melting point and good chemical durability are desirable for the sealing process in the ceramic and electronic fields. In this study, Li₂B₄O₇, ZnO, and BaO were used to prepare lead-free sealing glasses with a low melting temperature. Glass transition temperature, softening temperature, and thermal expansion coefficients were measured in detail in the ternary systems (Li₂B₄O₇-ZnO-BaO). The glass forming region, thermal stability, and surface morphology were evaluated. The dependencies of these properties on composition were quantitatively characterized. The ternary system glass (57.1 mol%Li₂B₄O₇-33.9 mol%ZnO-8.97 mol%BaO) exhibited a low melting property, expedient thermal expansion coefficient, an amorphous structure, and good sealing properties. Especially, the ternary lead-free glass (25.6 mol%Li₂B₄O₇-17.8 mol%ZnO-56.6 mol%BaO) showed the lowest glass transition temperature. To date, as borate glasses with the lower melting property are not developed, lead-free glasses proposed in this study will be epoch-making sealing materials for electronic products.

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