Removal of heavy metals, especially lead, from aqueous systems containing competing ions utilizing amorphous tin and titanium silicates
AssigneeEngelhard Corporation
InventorsGlenn W. Dodwell, BethAnn Smith
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Abstract
A process for the removal of heavy metals such as lead, cadmium, zinc, chromium, arsenic and mercury from aqueous solutions containing one or more of said metals as well as competing ions such as calcium and/or magnesium by contacting said aqueous solution with amorphous titanium or tin silicates is disclosed. Said amorphous titanium and tin silicates are characterized by a silicon-to-titanium or tin molar ratio of from 1:4 to 1.9:1 and a cumulative desorption pore volume ranging from about 0.03 to about 0.25 cubic centimeters per gram.
Claims10
A process for the removal of heavy metals from aqueous solutions thereof containing one or more of said heavy metals as well as competing ions including calcium and/or magnesium which comprises contacting said aqueous solution with amorphous gels selected from the group consisting of titanium silicates and tin silicates having a molar ratio of silicon-to-titanium or tin of from 1:4 to 1.9:1 and having a desorption pore volume of from about 0.03 to about 0.25 cubic centimeters per gram, until such heavy metals are substantially removed from said aqueous solution.
A process for the removal of heavy metals from aqueous solutions thereof containing one or more of said heavy metals as well as competing ions including calcium and/or magnesium which comprises contacting said aqueous solution with an amorphous titanium silicate or tin silicate gel having a desorption pore volume of from about 0.03 to about 0.25 cubic centimeters per gram, prepared by reacting a sodium silicate solution having a concentration of between 0.05 and 1.4 molar with a 0.3-3.5 molar solution of a titanium or tin salt at a pH of from about 4 to 9 to form said amorphous gel, aging said gel, washing and drying the same and continuing said contact with said aqueous solution of heavy metals until such heavy metals are substantially removed from said aqueous solution.
Dependencies are inferred from the claim text.