METHOD FOR TREATING WASTE GASES CONTAINING LOW-CONCENTRATION VOLATILE ORGANIC COMPOUNDS (VOCs) BASED ON COMBINATION OF ADSORPTION AND IN-SITU TEMPERATURE-VARYING CATALYTIC OZONATION

Abstract

A method for treating waste gases containing low-concentration volatile organic compounds (VOCs) based on combination of adsorption and in-situ temperature-varying catalytic ozonation, relating to treatment of organic waste gases. In the method, a VOCs-containing waste gas is fed to an adsorption bed for enrichment, which includes a low-temperature regeneration process and a high-temperature regeneration process. A catalyst with high adsorption capacity and catalytic activity is loaded on the adsorption bed.

Claims

1. A method for treating a volatile organic compounds (VOCs)-containing waste gas, comprising; (S1) feeding the VOCs-containing waste gas to an adsorption bed for enrichment; (S2) when a VOC monitor arranged near an outlet of the adsorption bed detects VOCs, continuously feeding the VOCs-containing waste gas to the adsorption bed; and performing a primary in-situ regeneration; and (S3) when an ozone monitor arranged near an outlet of the adsorption bed detects ozone, performing a secondary in-situ regeneration; and (S4) repeating steps (S1)-(S3) to complete treatment of the VOCs-containing waste gas; wherein the primary in-situ regeneration is performed through a step of: (a) turning on an ozone generator; and feeding ozone-containing oxygen to the adsorption bed to be mixed with the VOCs-containing waste gas for simultaneous adsorption and catalytic ozonation; the secondary in-situ regeneration is performed through steps of: (A) turning on a gas heating device to heat the VOCs-containing waste gas, so as to heat the adsorption bed to 70-90° C.; (B) after a concentration of CO.sub.2 in a tail gas is stable, turning off the ozone generator; (C) turning off the gas heating device to allow the adsorption bed to be cooled.

2. The method of claim 1, wherein in the primary in-situ regeneration, a temperature of the adsorption bed is controlled to be 20-50° C.

3. The method of claim 1, wherein a concentration of VOCs in the VOCs-containing waste gas is lower than 500 mg/m.sup.3.

4. The method of claim 1, wherein a gaseous hourly space velocity of the adsorption bed is 10000-200000 h.sup.−1.

5. The method of claim 1, wherein in step (S2), when a VOC concentration detected by the VOC monitor is larger than or equal to 10% of an initial VOC concentration in the VOCs-containing waste gas, the waste gas is continuously fed to the adsorption bed, and the primary in-situ regeneration is performed.

6. The method of claim 1, wherein in step (a), an ozone concentration at an outlet of the ozone generator is 4000-35000 mg/m.sup.3; and a volume ratio of the ozone-containing oxygen to the VOCs-containing waste gas is 1:(10-50).

7. The method of claim 1, wherein the VOC monitor and the ozone monitor are arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅕-⅓ of a length of the adsorption bed.

8. The method of claim 1, wherein in step (S3), when an ozone concentration detected by the ozone monitor is larger than or equal to 1 mg/m.sup.3, the secondary in-situ regeneration is performed.

9. The method of claim 1, wherein in step (B), when a concentration change of CO.sub.2 is less than 10% within 3-10 min, the concentration of CO.sub.2 in the tail gas is considered to be stable.

10. The method of claim 1, wherein the adsorption bed is filled with a catalyst; the catalyst comprises an inorganic ceramic matrix and a molecular sieve coating; the molecular sieve coating is loaded on the inorganic ceramic matrix; the inorganic ceramic matrix has a specific surface area of 5-150 m.sup.2/g; the molecular sieve coating has a specific surface area of 300-800 m.sup.2/g; a silicon-to-aluminum ratio of the molecular sieve coating is not less than 3; the molecular sieve coating is loaded with a metal oxide; the metal oxide is 0-10% by weight of the molecular sieve coating; and the molecular sieve coating and the inorganic ceramic matrix are both coated with colloidal silica.

11. A system for implementing the method of claim 1, comprising: an adsorption bed; wherein an inlet of the adsorption bed is provided with a first gas distribution support layer; an outlet of the adsorption bed is provided with a second gas distribution support layer; a filler is arranged between the first gas distribution support layer and the second gas distribution support layer; an oxygen-ozone mixture feeding system is arranged between an inlet of an adsorption tower and the first gas distribution support layer; and a temperature sensor, a temperature control device, a VOC monitor, and an ozone monitor are provided near the outlet of the adsorption bed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG. 1 is a flow chart of a method for treating a waste gas with low-concentration VOCs according to an embodiment of the present disclosure;

[0062] FIG. 2 structurally shows a system for treating a waste gas with low-concentration VOCs according to Example 1 of the present disclosure;

[0063] in FIG. 2: 1-1, first valve; 1-2, second valve; 2, gas heating device; 3, oxygen-ozone mixture feeding system; 4, ozone generator; 5, one-way valve; 6, filler loading and unloading port; 7, adsorption bed; 8, gas distribution support layer; 9, VOC monitor; 10, temperature sensor; 11, temperature control device; 12, ozone monitor, and 13, adsorption tower; and

[0064] FIG. 3 shows the ability of a catalyst made in accordance with Example 3 of Chinese patent application No. 202011621185X to decompose ozone respectively at 30° C. and 80° C., where the experimental conditions are as follows: ozone concentration: 1000 ppm; oxygen concentration: 20%; nitrogen concentration: 80%; gaseous hourly space velocity: 300000 h.sup.−1; and water bath temperature control.

DETAILED DESCRIPTION OF EMBODIMENTS

[0065] The present disclosure will be described in detail below with reference to embodiments, but these embodiments are not intended to limit the present disclosure.

Example 1

[0066] Provided herein is a system for treating a waste gas containing low-concentration volatile organic compounds (VOCs).

[0067] As shown in FIG. 2, a first valve 1-1 and a second valve 1-2 are configured to control the system to be turned on or off. A gas heating device 2 is arranged between the first valve 1-1 and an adsorption tower 13, and close to the gas inlet pipe. The oxygen-ozone mixture feeding system 3 is connected to an ozone generator 4, and is controlled by a one-way valve 5 to be connected to the adsorption tower 13. The adsorption tower 13 is provided with an adsorption bed 7. A VOC monitor 9, an ozone monitor 12, a temperature sensor 10 are arranged near an outlet of the adsorption bed 7. The temperature sensor 10 is configured to transmit heat signals to a temperature control device 11. The temperature control device 11 is configured to control the gas heating device 2 for temperature adjustment. Two sides of the adsorption bed 7 are respectively provided with a gas distribution support layer 8, and the gas distribution support layer 8 and the adsorption tower 13 are sealed by a seal ring. The adsorption bed 7 is provided with a filler loading and unloading port 6 corresponding to the adsorption tower 13 for filling fillers.

[0068] The waste gas enters the adsorption tower 13 from the inlet pipe via the first valve 1-1 and the gas heating device 2, and successively passes through the gas distribution support layer 8, the adsorption bed 7, the VOC monitor 9, the ozone monitor 12, the temperature sensor 10, and the gas distribution support layer 8, and is then discharged from the tail gas pipe via the second valve 1-2. During the regeneration process, ozone-containing oxygen is supplied by the oxygen-ozone mixture feeding system 3 connected in series with the ozone generator 4, and is controlled by the one-way valve 5 to enter the adsorption tower 13 to be mixed with the waste gas. Then the gas mixture enters the adsorption area for the catalytic degradation of the adsorbed VOCs to allow the adsorbent to regenerate.

[0069] A method for treating a VOCs-containing waste gas by using the aforementioned system was also provided, which included the following steps.

[0070] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1. After the adsorption, a tail gas contained 2 mg/m.sup.3 of toluene, and the adsorption efficiency reached 98%.

[0071] (S2) After 15 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the low-temperature regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0072] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas. The catalytic ozonation was performed at 29° C., and the temperature was monitored by the temperature sensor. The enriched VOCs in the adsorption bed underwent ozonation.

[0073] (S4) After 5 h of the low-temperature regeneration, the ozone concentration was detected to be 1 mg/m.sup.3 by the ozone monitor 12 arranged near an outlet of the adsorption bed, and then the high-temperature regeneration was performed.

[0074] (S5) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 80° C. under the monitoring of the temperature sensor 10. The remaining toluene and the intermediate products produced during the low-temperature regeneration (such as phenol, benzyl alcohol, benzoic acid, and straight chain hydrocarbons) were completely degraded to CO.sub.2 and water, and the adsorption bed was fully regenerated.

[0075] (S6) When the concentration of CO.sub.2 in the tail gas was basically stable (that is, the concentration change of CO.sub.2 was less than 10% within 5 min), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0076] (S7) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0077] Steps (S1)-(S7) were repeated.

[0078] The catalyst used in herein was prepared with reference to the Example 3 in Chinese patent application No. 202011621185X.

[0079] In this embodiment, the content of each substance in the tail gas was measured in real time by using an autosampler and gas chromatography detection system during use, and the total selectivity of CO and CO.sub.2 was measured to be 95.5%. Toluene in the tail gas was maintained at the emission standard.

[0080] The steps (S1)-(S7) were repeated for ten cycles, and the adsorption penetration was reduced by 4%.

Example 2

[0081] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0082] (S1) A waste gas containing 200 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1. After the adsorption, a tail gas contained 5 mg/m.sup.3 of toluene, and the adsorption efficiency reached 97.5%.

[0083] (S2) After 9 h of the adsorption, the VOC monitor 9 detected 20 mg/m.sup.3 of toluene, and then the low-temperature regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0084] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas. The catalytic process was performed at 27° C., and the temperature was monitored by the temperature sensor. The highly-adsorbed VOCs in the adsorption bed underwent ozonation.

[0085] (S4) After 8 h of the low-temperature regeneration, the ozone concentration was detected to be 1 mg/m.sup.3 by the ozone monitor 12 arranged near an outlet of the adsorption bed, and then the high-temperature regeneration was performed.

[0086] (S5) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 70° C. under the monitoring of the temperature sensor 10. The remaining toluene and the intermediate products produced during the low-temperature regeneration (such as phenol, benzyl alcohol, benzoic acid, and straight chain hydrocarbons) were completely degraded to CO.sub.2 and water, and the catalyst of the adsorption bed was fully regenerated.

[0087] (S6) When the concentration of CO.sub.2 in the tail gas was basically stable (that is, the concentration change of CO.sub.2 was less than 10% within 5 min), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0088] (S7) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0089] Steps (S1)-(S7) were repeated.

[0090] The catalyst used in herein was prepared with reference to the Example 3 in Chinese patent application No. 202011621185X.

[0091] In this embodiment, the content of each substance in the tail gas was measured in real time by using an autosampler and gas chromatography detection system during use, and the total selectivity of CO and CO.sub.2 was measured to be 98%. Toluene in the tail gas was maintained at the emission standard.

[0092] The steps (S1)-(S7) were repeated for ten cycles, and the adsorption penetration was reduced by 2%.

Example 3

[0093] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0094] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1. After the adsorption, a tail gas contained 2 mg/m.sup.3 of toluene, and the adsorption efficiency reached 98%.

[0095] (S2) After 15 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the low-temperature regeneration was started, where the VOC monitor 9 was arranged at ⅓ of the total length of the adsorption bed away from the outlet of the adsorption bed.

[0096] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 20 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas. The catalytic ozonation was performed at 24° C., and the temperature was monitored by the temperature sensor. The enriched VOCs in the adsorption bed were oxidized and decomposed by the ozone.

[0097] (S4) After 9 h of the low-temperature regeneration, the ozone concentration was detected to be 1 mg/m.sup.3 by the ozone monitor 12 arranged near an outlet of the adsorption bed, and then the high-temperature regeneration was performed.

[0098] (S5) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 80° C. under the monitoring of the temperature sensor 10. The remaining toluene and the intermediate products produced during the low-temperature regeneration (such as phenol, benzyl alcohol, benzoic acid, and straight chain hydrocarbons) were completely degraded to CO.sub.2 and water, and the catalyst of the adsorption bed was fully regenerated.

[0099] (S6) When the concentration of CO.sub.2 in the tail gas was basically stable (that is, the concentration change of CO.sub.2 was less than 10% within 5 min), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0100] (S7) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0101] Steps (S1)-(S7) were repeated.

[0102] The catalyst used in herein was prepared with reference to the Example 3 in Chinese patent application No. 202011621185X.

[0103] In this embodiment, the content of each substance in the tail gas was measured in real time by using an autosampler and gas chromatography detection system during use, and the total selectivity of CO and CO.sub.2 was measured to be 94.7%. Toluene in the tail gas was maintained at the emission standard.

[0104] The steps (S1)-(S7) were repeated for ten cycles, and the adsorption penetration was reduced by 5%.

Comparative Example 1

[0105] The method provided in this example was different from Example 1 merely in the filler of the adsorption bed.

[0106] In this example, the filler of the adsorption bed was a Y-zeolite loaded with, where the manganese oxide was loaded by the equal volume impregnation method; and the Y-zeolite was a commercial Y-zeolite without de-alumination.

[0107] The toluene contained in the tail gas after the adsorption process was detected to be 5.3 mg/m.sup.3, the adsorption efficiency was 97.4%, and the total selectivity of CO and CO.sub.2 during the regeneration process was 71%.

[0108] After the whole process was repeated for three cycles and five cycles, the adsorption penetration was reduced by 49%, 78% respectively. Ozone and toluene emissions were detected in the tail gas during the regeneration process and the catalyst was significantly deactivated.

Comparative Example 2

[0109] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0110] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1.

[0111] (S2) After 15 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0112] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas.

[0113] (S4) The gas heating device 2 was switched on to increase the temperature of the waste gas to raise the adsorption bed to 80° C. under the monitoring of the temperature sensor 10.

[0114] (S5) When the concentration of CO.sub.2 in the tail gas was basically stable (after 16 h), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0115] (S6) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0116] Steps (S1)-(S6) were repeated.

[0117] In this embodiment, the total selectivity of CO and CO.sub.2 was measured to be 98%. The total feeding time of ozone was 16 hours, 2.6 times longer than that in Example 1 (370 min).

[0118] The steps (S1)-(S6) were repeated for ten cycles, and the adsorption penetration was reduced by 3%.

Comparative Example 3

[0119] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0120] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1. After the adsorption, a tail gas contained 2 mg/m.sup.3 of toluene.

[0121] (S2) After 5 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0122] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas.

[0123] (S4) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 30° C. under the monitoring of the temperature sensor 10.

[0124] (S5) When the concentration of CO.sub.2 in the tail gas was basically stable (after 8 h), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0125] (S6) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0126] Steps (S1)-(S6) were repeated.

[0127] In this embodiment, the total selectivity of CO and CO.sub.2 was measured to be 70%.

[0128] The steps (S1)-(S6) were repeated for five cycles, and the adsorption penetration was reduced by 42%.

Comparative Example 4

[0129] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0130] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1.

[0131] (S2) After 11 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the low-temperature regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0132] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas. The catalytic process was performed at 25° C., and the temperature was monitored by the temperature sensor.

[0133] (S4) After 5 min of the low-temperature regeneration, the ozone concentration was detected to be 1 mg/m.sup.3 by the ozone monitor 12 arranged near an outlet of the adsorption bed, and then the high-temperature regeneration was performed.

[0134] (S5) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 80° C. under the monitoring of the temperature sensor 10.

[0135] (S6) When the concentration of CO.sub.2 in the tail gas was basically stable (after 20 h), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0136] (S7) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0137] Steps (S1)-(S7) were repeated.

[0138] The catalyst used in herein was prepared with reference to the Example 3 in Chinese patent application No. 202011621185.X, where the addition amount of manganese acetate was reduced such that the mass fraction of manganese in the de-aluminized Y zeolite carrier was 0.1%.

[0139] In this embodiment, the content of each substance in the tail gas was measured in real time by using an autosampler and gas chromatography detection system during use, and

[0140] The total selectivity of CO and CO.sub.2 was measured to be 91%. Toluene in the tail gas was maintained at the emission standard.

[0141] Due to insufficient active sites, the ozone was penetrated quickly and could not be fully consumed during the low-temperature regeneration.

[0142] In the high-temperature regeneration process, the desorbed toluene could not be degraded in time due to the increase in temperature and insufficient active sites, and desorbed toluene was detected in the tail gas with a maximum concentration of 50 mg/m.sup.3.

[0143] During the high-temperature regeneration process, the ozone did not react completely, and the ozone was detected in the tail gas with a maximum concentration in of 14.2 g/m.sup.3.

[0144] The steps (S1)-(S7) were repeated for five cycles, and the adsorption penetration was reduced by 11%.

Comparative Example 5

[0145] Provided herein was a method for treating a VOCs-containing waste gas by using the system of Example 1, which was specifically described below.

[0146] (S1) A waste gas containing 100 mg/m.sup.3 of toluene was fed to the adsorption bed that is filled with 10 kg catalyst for adsorption with a gaseous hourly space velocity of 20000 h.sup.−1.

[0147] (S2) After 21 h of the adsorption, the VOC monitor 9 detected 10 mg/m.sup.3 of toluene, and then the low-temperature regeneration was performed, where the VOC monitor 9 was arranged at a position which is away from the outlet of the adsorption bed at a distance of ⅓ of a length of the adsorption bed.

[0148] (S3) The ozone generator 4 and the oxygen-ozone mixture feeding system 3 were switched on, and oxygen containing 30 g/m.sup.3 of ozone was fed to the waste gas through the one-way valve 5, where a measured flow rate was 1/11 of the flow rate of the waste gas. The catalytic process was performed at 28° C., and the temperature was monitored by the temperature sensor.

[0149] (S4) After 11 h of the low-temperature regeneration, the ozone concentration was detected to be 1 mg/m.sup.3 by the ozone monitor 12 arranged near an outlet of the adsorption bed, and then the high-temperature regeneration was performed.

[0150] (S5) The gas heating device 2 was switched on to increase the temperature of the waste gas to heat the adsorption bed to 80° C. under the monitoring of the temperature sensor 10.

[0151] (S6) When the concentration of CO.sub.2 in the tail gas was basically stable (after 3 h), the ozone generator 4 and the oxygen-ozone mixture feeding system 3 were turned off, the one-way valve 5 was automatically closed, and the waste gas was always kept feeding.

[0152] (S7) The gas heating device 2 was turned off, and the adsorption bed was cooled to room temperature.

[0153] Steps (S1)-(S7) were repeated.

[0154] The catalyst used in herein was prepared with reference to the Example 3 in Chinese patent application No. 202011621185.X, where the addition amount of manganese acetate was increased such that the mass fraction of manganese in the de-aluminized Y zeolite carrier was 20%.

[0155] The toluene in the tail gas after the adsorption was detected to be 1 mg/m.sup.3, and the adsorption efficiency reached 99%.

[0156] The total selectivity of CO and CO.sub.2 was measured to be 94%.

[0157] The duration of the low-temperature regeneration process was longer compared with Example 1, as some of the ozone underwent autolysis, while the total adsorption volume was increased.

[0158] The duration of the high-temperature regeneration process was also longer compared with Example 1, as a large amount of ozone underwent autolysis due to the high temperature and high metal content conditions.

[0159] The steps (S1)-(S7) were repeated for ten cycles, and the adsorption penetration was reduced by 3%.

[0160] In this example, the amount of manganese oxides was more than that in Example 1, but the effects were not improved and the ozone consumption was increased.

[0161] In this application, the removal rate of low-concentration VOCs in the waste gas was more than 95%, the ozone consumption was much lower than the general ozone catalytic process, and the average concentration of the ozone in the tail gas was below 0.2 mg/m.sup.3, which met the emission standards.

[0162] In summary, this application adopts a low-metal content catalyst with high VOC adsorption capacity and desirable catalytic activity for ozonation to achieve the single adsorption bed treatment of continuous flow waste gases containing low-concentration VOCs without replacing the adsorbent, reducing the energy and material consumption and avoiding the secondary pollution.