# US 2014/0150828 A1 · Method for Cleaning Metals, Oils, and Solvents from Contaminated Wipers, Cloths, Towels, and the Same

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- Number: US 2014/0150828 A1
- Document ID: US20140150828A1
- Status: Published application
- Kind: A1
- Application number: 13/692,115
- Filed: 2012-12-03
- Published: 2014-06-05
- Earliest claimed: 2012-12-03
- Inventors: Valentine Asongu Nzengung
- Web page: https://patentgrep.com/patent/US20140150828A1

## CPC

- C11D 7/265: {Carboxylic acids or salts thereof}
- C11D 3/2086: {Hydroxy carboxylic acids-salts thereof}
- C11D 3/3942: {Inorganic per-compounds (C11D3/3902 takes precedence)}
- B08B 3/04: Cleaning involving contact with liquid
- C11D 2111/12: Soft surfaces, e.g. textile
- C11D 2111/16: Metals
- C11D: DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL

## Abstract

Method for cleaning metals and organic solvents adsorbed to tissues. Soiled tissues are placed into a container or specially designed collection and cleaning container. An aqueous reagent formulation solution, not to exceed 15% of reagent in water on mass-mass basis is prepared. The required concentration of reagent as a function of the type and level of contamination of the tissues and the contaminants of concern to be cleaned is determined. The reagent solution of desired concentration to the soiled tissues in the container is then added. The dissolved reagent and soiled tissues are mechanically mixed to create intimate contact at ambient or above ambient temperatures. The container is sealed allowing the cleaning to occur for a period of time. Testing for metals and organics solvents are performed to confirm that the metals are stabilized/immobilized and the volatile organics are degraded. The tissues are then dried for reuse, recycling, or disposal.

## Claims

### Claim 1

A method for cleaning metals and organic solvents adsorbed to tissues comprising the steps of:
placing the soiled tissues into a container or specially designed collection and cleaning container;
preparing an aqueous reagent formulation solution, not to exceed 15% of reagent in water on mass-mass basis;
calculating the required concentration of reagent as a function of the type and level of contamination of the tissues and the contaminants of concern to be cleaned;
adding the reagent solution of desired concentration to the soiled tissues in the container;
mixing the dissolved reagent and soiled tissues mechanically to create intimate contact;
sealing the container and allowing the cleaning to occur for a period of time; and
performing a Toxicity Characteristic Leaching Procedure (TCLP) for metals and organic solvents or other required test to confirm that the metals are stabilized/immobilized and the volatile organics are degraded.

### Claim 2 (depends on 1)

The method of claim 1, wherein the desired reagent formulation is achieved by mixing hydrosulfite with a strong base to achieve an alkaline solution of pH>8.5 immediately after the solution is prepared for use in the cleaning process.

### Claim 3 (depends on 2)

The method of claim 2, wherein the strong base may include alkali and/or alkaline earth metal hydroxides, oxides, carbonate, and bicarbonate.

### Claim 4 (depends on 1)

The method of claim 1, wherein the desired reagent formulation is achieved by mixing persulfate with a strong base to achieve an alkaline solution of pH>10 immediately after the solution is prepared for use in the cleaning process.

### Claim 5 (depends on 4)

The method of claim 4, wherein the strong base may include alkali and/or alkaline earth metal hydroxides, oxides, carbonate, and bicarbonate.

### Claim 6 (depends on 1)

The method of claim 1, wherein the desired reagent formulation is achieved by preparing a cleaning solution of organic acid and persulfate.

### Claim 7 (depends on 6)

The method of claim 6 wherein the organic acid is lemon juice or citric acid.

### Claim 8 (depends on 1)

The method of claim 1, further comprising the step of:
adding an organic surfactant to enhance desorption and solubility of the adsorbed solvents.

### Claim 9 (depends on 8)

The method of claim 8, wherein the concentration of the surfactant is less than 15% (V/V) of the aqueous phase.

### Claim 10 (depends on 8)

The method of claim 8, wherein the surfactant is biodegradable.

### Claim 11 (depends on 8)

The method of claim 8, wherein the surfactant is non-biodegradable.

### Claim 12 (depends on 2)

The method of claim 2, further comprising the step of
controlling the temperature between 60 and 90 degrees Celsius in the absence of air.

### Claim 13 (depends on 2)

The method of claim 2, further comprising the step of
adding the powder form of the reagent to the soiled tissues; and
adding water at or above ambient temperature.

### Claim 14 (depends on 13)

The method of claim 13, further comprising the step of
controlling the temperature between 25 degrees Celsius to 90 degrees Celsius.

### Claim 15 (depends on 8)

The method of claim 8, wherein the cleaning occurs for a maximum period of 72 hours.

### Claim 16 (depends on 2)

The method of claim 2 further comprising the step of
allowing the soiled tissues and hydrosulfite to incubate for a minimum of 72 hours in the absence of air to enhance precipitation of the metals as insoluble metal sulfides for metals decontamination.

### Claim 17 (depends on 1)

The method of claim 1 further comprising the step of
removing the cleaned tissues from the container and rinsing with clean water if the cleaned tissues are to be reused or recycled.

### Claim 18 (depends on 1)

The method of claim 1 further comprising the step of
disposing the cleaned tissues as non-hazardous waste.

### Claim 19 (depends on 1)

The method of claim 1 further comprising the step of
adding trace amounts of metal catalyst to the reagents significantly increasing the efficiency of the reaction at ambient temperature leading to complete oxidation of the solvents.

### Claim 20 (depends on 19)

The method of claim 19 wherein the metal catalyst is a titanium oxide and palladium salts.