Droplets of water-in-oil-in-water (w/o /w) emulsion were prepared by utilizing sodium alginate solution (microorganism protectant and phase-separation material) incorporated microorganism (denitrifying bacteria : Paracoccus denitrificans IF013301) [internal aqueous solution] and dichloromethane (DCM) dissolved polymethylmethacrylate (PMMA, wall material) possessing good chemical and mechanical strength, polyethylene glycol (PEG) and sorbitan monooleate (emulsion stabilizer) [organic solution]. These droplets could be formed core-shell microcapsules with a large single core and a porous wall by the combination of phase separation and solvent evaporation. The internal aqueous solution was necessary to form hollow structure, and the optimum concentration of the sodium alginate solution that functions as microorganism protectant and phase-separation material was 3% (w/w). PEG and sorbitan monooleate were so important factor to prepare excellent microcapsules influenced on hollow structure and surface morphology. Moreover, the thickness of PMMA shell could be controlled by changing the concentration of PMMA for DCM. In the composition condition of PMMA 1.5 g/DCM 20 g, the prepared microcapsules had an average wall thickness of 30 pm and a large hollow core. Although PMMA shell was tended to thicken by adding 1 g of the microorganism, this phenomenon could be improved by decreasing the quantity of the microorganism to 0.2 g. Thus, in this study, the materials that compose the PMMA microcapsules were clarified the influence on the capsule structures.
Getting the landfill space for the municipal solid waste incinerator ash is the very important issue. In order to reduce the volume of the municipal solid waste incinerator ash, ash melting furnaces were introduced in Japan late in 1990's. The molten ash is rapidly cooled by being put into water, resulting in shrunken vitrified slag. Such furnaces, however, require high temperatures such as 1300-1500°C, consuming high energy. Molten ash quickly erodes refractory of the furnace. These lead to a high cost of the maintenance. This study developed a new method, in which a mixture of incinerated ash and molten slag was heated under small pressures, resulting in a decrease in its volume. The molten slag itself softened between 800°C and 900°C. The incinerator ash had a void of about 65%. It was predicted that 2 times mass of molten slag can be pushed into the void of the incinerator ash. When a mixture of the incinerator ash and the molten slag with the ratio of 1 : 2 was heated at 900°C under a pressure of 0.52 MPa, it was shrunken to the ideal volume. At a lower temperature, 800°C, it could be shrunken to almost the ideal volume by an increased pressure of 2.3 MPa.
The lightweight ceramics were fabricated by firing the mixtures of fly ash (FA) and incinerated ash of sewage sludge (IASS). FA content in the mixtures was varied from 0 to 100 vol%. The mixtures were pressed into a rectangular body (3×0.5×0.4 cm3) and the body was fired at the temperature range from 1000 to 1350°C for 1 h. Bulk density, apparent density, apparent porosity, and flexural strength were measured, and the microstructure of the cross section of fired mixtures were observed by SEM. The lightweight ceramics that have the apparent porosity under 1 g · cm-3 was obtained by firing the mixtures with 72-80 vol% FA at the temperature range from 1200 to 1300°C. The lightweight ceramics did not sink in the water at all. The flexural strength of the mixtures with 72-90 vol% FA fired at up to 1150°C was over 5 MPa. The flexural strength of the fired mixtures was reduced rapidly when FA ratio increased up to a certain value. The reason was assumed that the FA spherical body was not connect enough due to the reduction of the content of IASS.
Exhaust dust from diesel engine car included particulate carbon with an average diameter of 7.2 μm consisted of organic carbon such as polycyclic aromatic hydrocarbon and inorganic carbon such as graphite, whereas exhaust dust from heavy oil boiler included particulate carbon with an average diameter of 37.2 μm mainly consisted of inorganic carbon. These dusts are found to undergo combustion decomposition from the in-situ CO2 detection using a crucible inside-coated with SiC by 2.45 GHz microwave irradiation. Diesel dust showed a CO2 release spectrum with double peak associated with combustion of organic and inorganic carbons. The first peak corresponds to exothermic peaks at 300°C and 362°C in the DTA curve, and the second peak corresponds to an exothermic peak at 492°C. Boiler dust showed a CO2 release spectrum with single peak associated with combustion of inorganic carbon, corresponding to an exothermic peak at 515°C.