Method for removing heavy metals and radionuclides from an aqueous solution

A method for removing heavy metals or radionuclides from an aqueous solution comprising contacting said aqueous solution with an ion exchange material selected from a liquid ion exchange material, or mixtures of a solid and a liquid ion exchange material, wherein said ion exchange material is prepared by the process comprising:

• (a) contacting clinoptilolite with an alkaline solution at a temperature of about 85° C. to about 300° C. and for a sufficient time to form a treated slurry comprising a solid fraction and a liquid fraction, and optionally
• (b) separating the solid fraction from said treated slurry and washing the solid fraction to produce said solid ion exchange material;
• and
• (c) recovering the liquid fraction of said treated slurry from step (b) to produce said liquid ion exchange material;
• wherein said alkaline solution comprises from about 10,000 mg/L to about 200,000 mg/L hydroxide ion;
• and
• wherein when a solid ion exchange material is used, said solid ion exchange material is the solid ion exchange material of step (b);
• when a liquid ion exchange material is used, said liquid ion exchange material is the liquid ion exchange material of step (c);
• and when a mixture of said solid ion exchange material and said liquid ion exchange material is used, said mixture can be said treated slurry produced in step (a) or said mixture can be prepared by mixing said solid ion exchange material of step (b) with said liquid ion exchange material of step (c).