Commercialized silica is commonly produced from the hydrolysis of tetraethoxysilane TEES (or tetraethyl orthosilicate (TEOS)) via the sol-gel method. This method is a liquid phase process that requires the use of catalyst (usually acid) and solvent (mostly ethanol). Herein gaseous phase hydrolysis of TEES should be a promising process to produce silica without catalyst use. Therefore, we focus on the gaseous phase hydrolysis of TEES to produce amorphous silica. In general, the particle size of produced silica is one of the most important factors for its application. In the gaseous phase hydrolysis, the size and size distribution of silica particles might depend on the experimental conditions (geometry of the experiment device, temperature and flow rates of reactants). In the present study, we used two shapes of the reaction tube (reactor), reactor type 3 and reactor type 4. We also increased the temperature and the water steam flow rate. The results showed that with similar conditions of temperature and water steam flow rate, the particles synthesized inside the reactor type 4 (absence of back-flow) were smaller than those obtained inside the reactor type 3 (presence of back-flow). The increase of temperature and/or water steam flow rate accelerated the nuclei formation and inhibited their cohesion. In summary, the silica particle size tended to be smaller with temperature and water steam flow rate increase.

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The removal of Cr(VI) from aqueous solutions was studied using the seeds of the plant species Strychnos potatorum L. The plant is grown in India and is called as Nirmali tree or clearing nut tree. The dried Nirmali seeds were powdered and used as adsorbent for the removal of Cr(VI) from aqueous solution. The zeta potential measurements have indicated negative surface charge similar to that of natural anionic polyelectrolyte. Batch experiments were conducted to study the adsorption of Cr(VI) onto Niramli seed powder. The influence of pH, initial Cr(VI) concentration and the effect of anions on the removal of Cr(VI) was investigated. The removal of Cr(VI) was better in the acidic medium. The influence of anions such as Cl-, NO3- and SO42- on Cr(VI) removal was investigated and found that the removal was adversely affected in the presence of NO3- and SO42-. The results obtained from equilibrium adsorption studies were found to fit in to Langmuir adsorption isotherm and the maximum uptake of Cr(VI) was found to be 59 mg g-1. The rate of removal of Cr(VI) was found to follow the pseudo second order rate equation.

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In order to clarify the impact of typhoons on the nutrient concentration and the enhancement of phytoplankton, we measured nutrients, chlorophyll a and salinity at eight stations along the Toyo River transect in the Atsumi Bay estuary, Japan; pre- and post- the typhoons during the summers of 2010 and 2011. The results revealed the heavy rainfall associated with the typhoons Chaba, Ma-On and Roke increased discharges of freshwater and surface nutrient concentrations which caused subsequent phytoplankton blooms.

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Across the nation, the amount of coal ash as an industrial by-product of the operation of coal-fired power generation plants is increasing. Therefore, it is important to find applications for the effective use of this mountain of coal ash. We carried out this study for the purpose of creating granulated material with low abrasion loss required in road construction. While attempting in this study to develop a new type of granulated material from coal ash, various types of granular material were created from coal ash. These substances were subjected to a crush strength test and an abrasion test. In addition, as a measure of the quality of the granular materials, the correlation was examined between each granular material's crush strength (an easily measured parameter) and its abrasion loss. It was found that some of our granular materials satisfied the abrasion loss requirement for crushed stone used in road construction (35% or less) when used in the following conditions: the diameter of the granulator machine was 3.5m, 220kg of cement was used, and the cumulative temperature was more than 400°C-day. It was thus confirmed that a granular material made from coal ash as an industrial by-product can have the necessary mechanical characteristics for use as a roadbed material.

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A flow injection analysis based on spectrophotometry using diphenylcarbazide (FIA-DPC) was applied to the determination of Cr(VI) and total Cr (T-Cr) in order to understand the precipitation and coprecipitation behavior of Cr(III,VI) in wastewater. When 0.5 m of reaction coil, 100 μL of sample loop, and 1.2 mL/min of flow rate of carrier and reagent solutions were used, 10 μg/L - 3 mg/L of Cr(VI) could be determined. The limits of detection and quantification were 1.1 and 3.6 μg/L, respectively. T-Cr could also be determined by combining pre-oxidation with permanganate. The precipitation/coprecipitation behavior of Cr(III,VI) obtained by using the FIA-DPC method was almost the same as the theoretical one, indicating that the method is applicable to analyze the behavior of Cr in wastewater.

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An experiment to melt snow on the ground surface by heat transported from shallow underground was conducted from December 2010 to February 2011. Water filled in an underground tank was circulated through the tube buried just below the ground surface from the tank to under the ground surface. With the system, heat was transported from underground to the water through the wall of the underground tank. Although the temperature of the circulating water fell to 4 ﾟC at the beginning of February, it was found to be possible to melt snow. When snowfall rate was 10 cm or less in a day, it was melted in the day, while the depth of snowfall become to 10 cm or more in a day, it remained unmelted partly, but the whole quantity was melted in 2 or 3 days.

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Groundwater is indispensable source of drinking water for the residents in the arid region such as the central north province of Sri Lanka. In the central north province and southern of Sri Lanka, many residents suffer from dental fluorosis and skeleton fluorosis due to high concentration of fluoride in drinking and cooking water. Countermeasures to reduce fluoride concentration are required in order to mitigate the adverse effect of fluoride on human health. Chicken bone char is a promising material, since it is low cost, and it would be acceptable for the people in Sri Lanka from religious point of view. We investigated the effect of acid and alkaline treatment on chicken bone char on fluoride removal. It was found that alkaline treatment had no effect, but acid treatment had effect on fluoride removal．The optimum acid concentration was 0.01N and the optimum duration of the acid treatment was 60 minutes to remove fluoride. Absorption rate increased 30 % by the acid treatment with the optimum condition when compared to that without treatment.

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