# US 2019/0314756 A1 · Method and system for filtering formaldehyde from inoor air

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- Number: US 2019/0314756 A1
- Document ID: US20190314756A1
- Status: Published application
- Kind: A1
- Application number: 16/246,247
- Filed: 2019-01-11
- Published: 2019-10-17
- Earliest claimed: 2013-09-16
- Assignees: Enverid Systems, Inc.
- Applicants: enVerid Systems, Inc.
- Inventors: Udi MEIRAV; Israel BIRAN; Karthik RAMASWAMI; Shira ROSENCWAIG
- Web page: https://patentgrep.com/patent/US20190314756A1

## CPC

- B01D 39/06: Inorganic material, e.g. asbestos fibres, glass beads or fibres
- B01D 53/1487: {Removing organic compounds}
- B01D 39/02: Loose filtering material, e.g. loose fibres
- B01D 53/0407: {Constructional details of adsorbing systems}
- B01D 53/1493: {Selection of liquid materials for use as absorbents}
- B01D 53/72: Organic compounds not provided for in groups B01D53/48 - B01D53/70, e.g. hydrocarbons
- B01D 53/80: Semi-solid phase processes, i.e. by using slurries
- B01D 2239/0407: comprising particulate additives, e.g. adsorbents
- B01D 2239/1241: Particle diameter
- B01D 2252/204: Amines
- B01D 2252/20405: Monoamines
- B01D 2252/2041: Diamines
- B01D 2252/20415: Tri- or polyamines
- B01D 2252/20484: with one hydroxyl group
- B01D 2252/20489: with two or more hydroxyl groups
- B01D 2253/102: Carbon
- B01D 2253/104: Alumina
- B01D 2253/106: Silica or silicates
- B01D 2253/11: Clays
- B01D 2253/202: Polymeric adsorbents
- B01D 2253/25: Coated, impregnated or composite adsorbents
- B01D 2253/302: Dimensions
- B01D 2257/708: Volatile organic compounds V.O.C.'s
- B01D 2258/06: Polluted air
- B01D 2259/4508: for cleaning air in buildings
- 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)

## Abstract

Embodiments of the present disclosure are directed to systems and methods for removing formaldehyde from indoor air. Some embodiments include flowing an indoor airflow over and/or through a solid supported amine filtering medium, such that, at least a portion of formaldehyde entrained in the indoor airflow is removed therefrom. Some other embodiments include systems having one or more fans for providing velocity to one and/or another airflows (e.g., airflows to/from a formaldehyde filter).

## Claims

### Claim 1

A method for removing formaldehyde from indoor air comprising flowing an indoor airflow over and/or through a solid supported amine filtering medium, such that, at least a portion of formaldehyde entrained in the indoor airflow is removed therefrom by the amine filtering medium.

### Claim 2 (depends on 1)

The method of claim 1, wherein the filtering medium comprises a material formed from the combination of liquid amine with one or more granular solid support materials selected from the group consisting of: silica, clay, alumina, carbon, polymer, fiber, or combinations thereof.

### Claim 3 (depends on 1)

The method of claim 1, wherein the amine is selected from the group consisting of: 2,4-dinitrophenylhydrazine, monoethanolamine, polyethylenimine, tetraethylenepentamine, pentaethyleneheptamine, and diethanolamine.

### Claim 4 (depends on 1)

The method of claim 1, wherein the filtering medium comprises granular particles ranging in size from about 0.1 mm diameter to about 3 mm diameter.

### Claim 5 (depends on 4)

The method of claim 4, wherein the granular particles of the filtering medium are arranged in one or more filter sheets so as to allow interaction between the formaldehyde in the indoor air flowing through the medium and amines in the medium.

### Claim 6 (depends on 1)

The method of claim 1, wherein the face velocity of the airflow impinging the filtering medium is between about 10 cm/s to about 500 cm/s.

### Claim 7 (depends on 1)

The method of claim 1, wherein the face velocity of the airflow impinging the filtering medium is between about 0.5 cm/s-10 cm/s.

### Claim 8 (depends on 1)

The method of claim 1, wherein the face velocity of the airflow impinging the filtering medium is between about 0.1 cm/s to about 0.5 cm/s.

### Claim 9 (depends on 1)

The method of claim 1, wherein the filtering medium is provided in a form selected from the group consisting of: sheets, films, monoliths, linings of interiors of air ducts, and wall linings.

### Claim 10 (depends on 1)

The method of claim 1, wherein airflow over and/or through the filtering medium is facilitated by at least one of a fan, a blower, a valve, a shutter and a damper.

### Claim 11 (depends on 1)

The method of claim 1, wherein the airflow over and/or through the filtering medium is configured in a parallel slip stream to a main air circulation path of the indoor airflow.

### Claim 12

A system for removing formaldehyde from indoor air comprising:
an indoor air inlet for at least one of receiving and directing an indoor airflow to and/or from an enclosed space; and
a formaldehyde filter configured to receive the indoor airflow prior to the indoor airflow being returned to the enclosed space, the filter including a solid supported amine filtering medium configured to intercept formaldehyde upon the indoor airflow flowing over and/or through the filtering medium.

### Claim 13 (depends on 12)

The system of claim 12, wherein the filtering medium comprises a material formed from the combination of liquid amine with one or more granular solid support materials selected from the group consisting of: silica, clay, alumina, carbon, polymer, fiber, or combinations thereof.

### Claim 14 (depends on 12)

The system of claim 12, wherein the filter medium comprises granular particles ranging in size from about 0.1 mm in diameter to about 3 mm in diameter.

### Claim 15 (depends on 12)

The system of claim 12, wherein:
the amine is selected from the group consisting of: 2,4-dinitrophenylhydrazine, monoethanolamine, polyethylenimine, tetraethylenepentamine, pentaethyleneheptamine, and diethanolamine;
the system further comprises one or more fans configured to provide velocity to the airflow.

### Claim 16

(canceled)

### Claim 17 (depends on 16)

The system of claim 16, wherein:
a face velocity of the airflow impinging the filtering medium is between about 10 cm/s to about 500 cm/s;
a face velocity of the airflow impinging the filtering medium is between about 0.5 cm/s to about 10 cm/s;
or
a face velocity of the airflow impinging the filtering medium is between about 0.1 cm/s to about 0.5 cm/s.

### Claim 18

(canceled)

### Claim 19

(canceled)

### Claim 20 (depends on 12)

The system of claim 12, wherein:
the system further comprises a controller and air quality sensors, wherein the controller activates the system for removing formaldehyde from indoor air based on air quality measurements measured by the air quality sensors;
and/or
the formaldehyde filter comprises one or more filter sheets containing granular particles of the filtering medium.

### Claim 21

(canceled)

### Claim 22 (depends on 21)

The system of claim 21, wherein the one or more filter sheets comprise a plurality of filter sheets arranged in at least one of a v-bank formation and a parallel stacking configuration.

### Claim 23 (depends on 12)

The system of claim 12, wherein the filtering medium is in a form selected from the group consisting of: sheets, films, monoliths, linings of interiors of air ducts, and wall linings.

### Claim 24 (depends on 21)

The system of claim 21, wherein the filter sheet:
comprises a thickness between about 1 cm to 20 cm;
comprises a thickness less than about 1 cm;
is formed as a flat rectangular sheet with permeable screens for enclosing the filtering medium;
or
is formed in a non-planar shape.

### Claim 25

(canceled)

### Claim 26

(canceled)

### Claim 27

(canceled)