Hydrotalcite like substance, process for producing the same and method of immobilizing hazardous substance

摘要

A hydrotalcite-like substance capable of ion exchange with target anions, being of small crystal size that exhibits large basal spacing and excels at anion exchange performance; a process for producing the same; and a method of immobilizing hazardous substances. The hydrotalcite-like substance is produced by mixing an acidic solution containing aluminum and magnesium ions with an alkaline solution containing an alkali to synthesize a hydrotalcite-like substance, followed by, without ageing, water removal or neutralization. The molar ratio of aluminum ions and magnesium ions is preferably in the range of 1:5 to 1:2. Hazardous substances can be immobilized by pulverizing the hydrotalcite-like substance after synthesis and adding the powder to a subject, or adding a hydrotalcite-like substance in slurry form to a subject, or carrying out addition so as to cause the synthesis directly at the position of the subject. Furthermore, anion adsorption can be performed by a filter containing the hydrotalcite-like substance.

主权项

1. A process for immobilizing a hazardous substance, which comprises the step of adding a hydrotalcite-like substance to an object to be immobilized in a manner that the synthesis of the hydrotalcite-like substance occurs directly on the object to be immobilized through the mixing of an acidic solution containing aluminum ions and magnesium ions with an alkaline solution containing alkali, and then subjecting the hydrotalcite-like substance to water removal process or neutralization process;
wherein the hydrotalcite-like substance is represented by a general chemical formula: Mg2+1-xAl3+X(OH)2(An−)x/n·mH2O, said An− being anion with charge −n, and wherein zeolite and/or bentonite are/is used together with said hydrotalcite-like substance.