| 摘要 |
PROBLEM TO BE SOLVED: To use a coal ash, which is an industrial waste, effectively and to prevent eutrophication by nutritious salts and gas in a closed sea area such as a bay and the deterioration of water quality associated with the eutrophication by placing artificial zeolite obtained by the hydrothermal chemical treatment of coal ash on the upper surface of a bottom earth layer in the sea area. SOLUTION: An artificial zeolite 10 obtained by the hydrothermal chemical treatment of coal ash is placed on the upper part surface of a bottom earth layer 20 in a closed sea area S such as a bay. In this way, coal ash, which is industrial waste, is used effectively, and the deterioration of water quality by the eutrophication etc., of the sea area S is prevented. The artificial zeolite 10 is obtained from a powdery material from which impurity NaOH was removed by a process in which for example, coal ash (fly ash) was heat-treated in a NaOH solution, and the product was washed with water. Phillipsite and faujasite, which are zeolite minerals, are formed on the surface to give a gas- barrier performance and a cation exchange capacity comparable to those of natural zeolite.
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