# US 11,298,681 B2 · Urea-impregnated zeolite sorbents and method for making the same

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- Number: US 11,298,681 B2
- Document ID: US11298681B2
- Status: Granted
- Kind: B2
- Application number: 16/955,262
- Filed: 2019-02-26
- Published: 2021-11-25
- Granted: 2022-04-12
- Earliest claimed: 2018-03-01
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: Himanshu Jasuja; Michael S. Wendland; Michael W. Kobe
- Web page: https://patentgrep.com/patent/US11298681B2

## CPC

- B01J 20/3204: {Inorganic carriers, supports or substrates}
- B01D 53/02: by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)}
- B01J 20/186: {Chemical treatments in view of modifying the properties of the sieve, e.g. increasing the stability or the activity, also decreasing the activity}
- B01J 20/28028: {Particles immobilised within fibres or filaments}
- B01J 20/2808: {being less than 2 nm, i.e. micropores or nanopores}
- B01J 20/3251: {comprising at least two different types of heteroatoms selected from nitrogen, oxygen or sulphur}
- B01J 20/3255: {comprising a cyclic structure containing at least one of the heteroatoms nitrogen, oxygen or sulfur, e.g. heterocyclic or heteroaromatic structures}
- B01D 2251/2067: Urea
- B01D 2253/1085: characterized by a silicon-aluminium ratio
- B01D 2253/25: Coated, impregnated or composite adsorbents
- B01D 2253/308: Pore size
- B01D 2257/708: Volatile organic compounds V.O.C.'s
- B01D 2258/06: Polluted air
- B01D 2259/4508: for cleaning air in buildings
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- 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

A sorbent suitable for sorbing aldehydes includes acidified zeolite impregnated with a urea-based compound, the acidified zeolite having a pore opening of 5 Å or greater and a molar ratio of silicate to aluminate of at least 1.1:1. The sorbent may be prepared by impregnating acidified zeolite with a solution of a urea-based compound, where the acidified zeolite includes proton counterions. The sorbent may be supported on a filter support to provide an air filter.

## Claims

### Claim 1

A sorbent comprising:
acidified zeolite impregnated with a urea-based compound, the acidified zeolite having a pore opening of 5 Å or greater and a molar ratio of SiO2 to Al2O3 of at least 1.1:1.

### Claim 2 (depends on 1)

The sorbent of claim 1, wherein the acidified zeolite has a pore opening of 7 Å to 14 Å.

### Claim 3 (depends on 1)

The sorbent of claim 1, wherein the molar ratio of SiO2 to Al2O3 is from 1.1:1 to 130:1.

### Claim 4 (depends on 1)

The sorbent of claim 1, wherein the acidified zeolite has a faujasite-type structure.

### Claim 5 (depends on 1)

The sorbent of claim 1, wherein the acidified zeolite is an X-type zeolite.

### Claim 6 (depends on 1)

The sorbent of claim 1, wherein the urea-based compound comprises a cyclic urea selected from ethyleneurea, hydantoin, allantoin, alloxanic acid, oxazolylurea, 5,5-dimethylhydantoin, urazole, malonylurea, mesoxalylurea, hydroxymalonylurea, uramil, dilituric acid, violuric acid, pseudouric acid, uracil, thymine, isocyanuric acid, uric acid, and alloxanthine.

### Claim 7 (depends on 1)

The sorbent of claim 1, wherein the urea-based compound is ethyleneurea.

### Claim 8 (depends on 1)

The sorbent of claim 1, wherein the sorbent comprises 1% to 60% of the urea-based compound by weight of the sorbent.

### Claim 9 (depends on 1)

The sorbent of claim 1, wherein the sorbent is prepared by acidifying zeolite to produce acidified zeolite with a proton counterion and impregnating the acidified zeolite with a solution of the urea-based compound.

### Claim 10 (depends on 9)

The sorbent of claim 9, wherein the solution of the urea-based compound comprises from 5% to 40% of the urea-based compound by weight of the solution.

### Claim 11 (depends on 1)

The sorbent of claim 1, wherein the sorbent has an aldehyde capacity of at least 0.25 mmol/g.

### Claim 12

A method for making a sorbent, the method comprising:
impregnating acidified zeolite with a solution of a urea-based compound, the acidified zeolite comprising proton counterions and having a pore opening of 5 Å or greater and a molar ratio of SiO2 to Al2O3 of at least 1.1:1.

### Claim 13 (depends on 1)

An air filter comprising:
a filter support; and
the sorbent of claim 1 supported on the filter support.

### Claim 14 (depends on 13)

The filter of claim 13, wherein the filter comprises at least 100 g/m2 of the sorbent.

### Claim 15 (depends on 1)

A method of sorbing an aldehyde on a sorbent of claim 1, the method comprising:
contacting the aldehyde with the sorbent, the aldehyde being of Formula (I):
R—(CO)—H (I)
wherein R is hydrogen, alkyl, vinyl, or aryl, and wherein the molecular weight of the aldehyde of Formula (I) is no greater than 200 grams/mole.