Composite resins for selective germanium removal from aqueous solutions

A method of preparing a mesoporous boron-based composite material for selective germanium removal, comprising:

• dissolving a surfactant in deionized water to form a surfactant solution;
• adding boric acid to the surfactant solution under stirring;
• preparing a melamine solution separately;
• combining the melamine solution with the boric acid-surfactant solution and heating the combined mixture to form a gel;
• drying the gel to form a dried gel;
• and
• calcining the dried gel at a temperature of at least 500° C. to obtain the mesoporous boron-based composite material.

A method of selectively removing germanium from an aqueous solution containing germanium and gallium, comprising:

• contacting the aqueous solution with a mesoporous boron-based composite material comprising a boron-containing matrix, a nitrogen-containing component derived from melamine, and a tin dopant;
• adsorbing germanium onto the mesoporous boron-based composite material while gallium remains substantially in the aqueous solution;
• and
• separating the aqueous solution from the mesoporous boron-based composite material to obtain a germanium-depleted solution.