Removal of heavy metals, especially lead, from aqueous systems containing competing ions utilizing amorphous tin and titanium silicates

• US 5,053,139 A
• Filed: 12/04/1990
• Issued: 10/01/1991
• Est. Priority Date: 12/04/1990
• Status: Expired due to Term

• Current Assignee: Engelhard Corporation (BASF SE)
• Original Assignee: Engelhard Corporation (BASF SE)
• Inventors: Dodwell, Glenn W., Smith, BethAnn
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Shideler, Krisanne
• Application Number:
  US07/625,731
• Time in Patent Office: 301 Days
• Field of Search: 210/679, 210/688, 210/912, 210/913, 210/914
• US Class Current: 210/688
• CPC Class Codes: B01J 39/14 Base exchange silicates, e.g. zeolites
• CPC Class Codes: C01B 33/20 Silicates persilicates C01B15/14 ; containing aluminium C01B33/26
• CPC Class Codes: C22B 3/42 by ion-exchange extraction
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y10S 210/912 Heavy metal
• CPC Class Codes: Y10S 210/913 Chromium
• CPC Class Codes: Y10S 210/914 Mercury

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.

Claims

1. 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.

2. The process of claim 1 wherein said amorphous gel is titanium silicate.

3. The process of claim 2 wherein said heavy metals are selected from the group consisting of lead, cadmium, zinc, chromium, arsenic and mercury.

4. The process of claim 1 wherein said amorphous gel is tin silicate.

5. The process of claim 4 wherein said heavy metals are selected from the group consisting of lead, cadmium, zinc, chromium, arsenic and mercury.

6. 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.

7. The process of claim 6 wherein said pH is from 7 to 8.

8. The process of claim 7 wherein the gel is aged for around 24 hours to no longer than 96 hours.

9. The process of claim 8 wherein said amorphous gel is titanium silicate.

10. The process of claim 8 wherein said amorphous gel is tin silicate.