# US 7,341,667 B2 · Process for reduction of inorganic contaminants from waste streams

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- Number: US 7,341,667 B2
- Document ID: US7341667B2
- Status: Granted
- Kind: B2
- Application number: 10/976,519
- Filed: 2004-10-29
- Published: 2005-09-08
- Granted: 2008-03-11
- Earliest claimed: 2003-10-31
- Assignees: MAR Systems, Inc.; The United States of America as represented by the Administrator of the U.S. Environmental Protection Agency
- Inventors: Claude Kennard; Michael A. Gonzalez; David C. Szlag
- Web page: https://patentgrep.com/patent/US7341667B2

## CPC

- C02F 1/281: {using inorganic sorbents}
- B01D 15/00: Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D 15/267: {using neutral sorbents, e.g. activated carbon or diatomaceous earth}
- B01D 53/02: by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)}
- B01J 20/08: comprising aluminium oxide or hydroxide; comprising bauxite
- B01D 2253/104: Alumina
- B01D 2257/602: Mercury or mercury compounds
- C02F 2101/103: {Arsenic compounds}
- C02F 2101/20: Heavy metals or heavy metal compounds
- Y10S 210/912: Heavy metal
- Y10S 210/914: Mercury
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The invention relates to the use of used alumina to reduce the level of inorganic contaminants, such as mercury and arsenic, from waste fluid streams. The invention further provides a process for reducing the level of mercury or arsenic in fluid streams by contacting the fluid stream with used alumina, such as used Claus catalyst.

## Claims

### Claim 1

A process for reducing the level of arsenic from a liquid stream comprising contacting said liquid stream with used alumina, wherein the used alumina is used Claus catalyst having a sulfur concentration of 0.1% -2.0% by weight, and wherein the liquid stream is an aqueous stream.

### Claim 2

A process for reducing the level of arsenic from a liquid stream containing arsenic, comprising the steps of:
(a) flowing the liquid stream through a bed containing a sorbent, wherein the sorbent comprises used alumina, wherein the used alumina is used Claus catalyst having a sulfur concentration of 0.1% -2.0% by weight, and wherein the liquid stream is an aqueous stream;
(b) sorbing arsenic from the liquid stream onto the surface of the sorbent; and
(c) allowing the arsenic-depleted effluent stream to exit from the outlet of the bed.

### Claim 3 (depends on 1)

The process of claim 1, wherein the used alumina is crushed prior to contacting said liquid stream.

### Claim 4 (depends on 3)

The process of claim 3, wherein the used alumina is heated to remove moisture prior to contacting said liquid stream.

### Claim 5 (depends on 1)

The process of claim 1, wherein at least about 50% of arsenic is removed from said liquid stream.

### Claim 6 (depends on 1)

The process of claim 1, wherein at least about 75% of arsenic is removed from said liquid stream.

### Claim 7 (depends on 1)

The process of claim 1, wherein at least about 90% of arsenic is removed from said liquid stream.

### Claim 8 (depends on 1)

The process of claim 1, wherein the arsenic is elemental arsenic.

### Claim 9 (depends on 1)

The process of claim 1, wherein the arsenic is ionic arsenic.

### Claim 10 (depends on 1)

The process of claim 1, wherein the arsenic is arsenic(V).

### Claim 11 (depends on 2)

The process of claim 2, wherein the used alumina is crushed prior to being loaded on the bed.

### Claim 12 (depends on 11)

The process of claim 11, wherein the used alumina is heated to remove moisture prior to being loaded on the bed.

### Claim 13 (depends on 2)

The process of claim 2, wherein at least about 50% of arsenic is removed from said liquid stream.

### Claim 14 (depends on 2)

The process of claim 2, wherein at least about 75% of arsenic is removed from said liquid stream.

### Claim 15 (depends on 2)

The process of claim 2, wherein at least about 90% of arsenic is removed from said liquid stream.

### Claim 16 (depends on 2)

The process of claim 2, wherein the arsenic is elemental arsenic.

### Claim 17 (depends on 2)

The process of claim 2, wherein the arsenic is ionic arsenic.

### Claim 18 (depends on 2)

The process of claim 2, wherein the arsenic is arsenic(V).