Preparation method of composite metal oxide catalyst for catalytic decomposition for VOCs (Volatile Organic Compounds)

Abstract

The invention discloses a preparation method of a composite metal oxide catalyst for the catalytic decomposition of VOCs (Volatile Organic Compounds). Nano powder TiO2 is used as a carrier; after a composite metal oxide layer is formed, transition metal salt is added; the composite metal oxide catalyst with multiple active components is formed after heat treatment. The composite metal oxide catalyst has higher catalytic oxidation capacity (more than 98 percent) for ester and benzene organic matters at a low ignition temperature (300 DEG C). The catalyst is prepared by adopting a normal-temperature precipitation method; the method is simple and convenient. The composite metal oxide catalyst does not contain a noble metal element, and is low in cost. The composite metal oxide catalyst is prepared by adopting a two-step precipitation method to ensure that Ce is closely in contact with the TiO2; a solid solution is conveniently formed during roasting; the composite metal oxide catalyst has favorable oxygen supply capacity. Finally, loaded transition metal elements are uniformly distributed on the surface of the catalyst; the adsorption on molecules of the VOCs is facilitated; an active site is provided; the catalytic capacity is increased. The obtained catalyst is used for oxidizing the VOCs into CO2 and H2O, has advantages of high catalytic conversion rate, low ignition temperature, high stability, low price and the like, and has favorable application value and prospect.

Description

technical field

[0001] The invention relates to the technical field of environmental protection, in particular to a preparation method of a composite metal oxide catalyst for catalytic decomposition of VOCs. Background technique

[0002] Volatile organic compounds (VOCs) refer to organic compounds with a saturated vapor pressure greater than 70 Pa at normal temperature and a boiling point below 260°C at normal pressure, or with corresponding volatility at a vapor pressure greater than or equal to 10 Pa at 20°C. of all organic compounds. According to its chemical structure, VOC can be further divided into: alkanes, aromatics, esters, aldehydes and others. More than 300 species have been identified so far. The most common ones are benzene, toluene, xylene, styrene, trichloroethylene, chloroform, trichloroethane, diisocyanate (TDI), diisocyanocresyl, etc. When the concentration of volatile organic compounds in the indoor air is too high, it is easy to cause acute poisoning. ...

Examples

preparation example Construction

[0023] Preparation method of composite metal oxide catalyst for catalytic decomposition of VOCs, using nano-powder TiO 2 As a carrier, a transition metal salt is added after the composite metal oxide layer is formed, and a composite metal oxide catalyst with multiple active components is formed after heat treatment, and the specific steps are as follows:

[0024] Step 1, add an appropriate amount of commercially available nano-TiO 2 The powder (P25) was dissolved in distilled water to make a 0.05 M solution.

[0025] Step two, take a certain amount of Ce (NO 3 ) 3 •6H 2 O was added to the solution obtained in Step 1, and stirred to dissolve 1H. Wherein, the molar ratio Ce / Ti=3 / 1~1 / 5 is controlled.

[0026] Step 3: Take a certain amount of NaOH and NH 3 •H 2 O is prepared as a 0.1M precipitant, and the precipitant is added to the solution in step 2 under vigorous stirring, and the molar ratio of the added amount is controlled to be [OH - ] / [Ce 3+ ]=3 / 1~4 / 1.

[0027] S...

Embodiment 1

[0033] (1) Weigh 3.32 g TiO 2 The powder was placed in a 1000 mL Erlenmeyer flask, and 400 mL of distilled water was added and stirred for 30 min to dissolve.

[0034] (2) Weigh 3.61 g Ce(NO 3 ) 3 •6H 2 Add O to the solution of (1) above, and continue to stir and dissolve for 30 min.

[0035] (3) Weigh 1.6 g NaOH+20 mL NH 3 •H 2 O, add 400 mL of distilled water and stir to dissolve to prepare a precipitant.

[0036] (4) Put the precipitating agent in a separatory funnel, and add the solution obtained in (2) dropwise under vigorous stirring. After the dropwise addition, place the conical flask in an oil bath, and stir for 1 hour at a constant temperature of 80°C. Filtrate while it is hot, and the resulting solid is placed in an oven at 80°C

[0037] Dry for 10H and grind to get Ce / TiO 2 Mixture A.

[0038] (5) Take 0.95 g of the mixture A obtained in (4), add it into 150 mL of distilled water, stir and dissolve for 30 min. Weigh Cu(NO 3 ) 2 0.33 g was added, and st...

Embodiment 2

[0045] (1) Weigh 0.332 g TiO 2 Put the powder in a 250 mL Erlenmeyer flask, add 100 mL of distilled water and stir to dissolve for 30 min.

[0046] (2) Weigh 0.361 g Ce(NO 3 ) 3 •6H 2 Add O to the solution of (1) above, and continue to stir and dissolve for 30 min.

[0047] (3) Weigh 0.16 g NaOH+2 mL NH 3 •H 2 O, add 40mL distilled water and stir to dissolve to prepare a precipitant.

[0048] (4) Put the precipitating agent in a separatory funnel, and add the solution obtained in (2) dropwise under vigorous stirring. After the dropwise addition, place the Erlenmeyer flask in an oil bath, and stir for 1 hour at a constant temperature of 80°C.

[0049] (5) Weigh 0.17 g AgNO 3 Dissolve in 50 mL of distilled water and place in a separatory funnel. After the solution of (4) was lowered to room temperature, it was added dropwise while stirring.

[0050] (6) Weigh 0.16 g NaOH+2 mL NH 3 •H 2 O, add 40 mL of distilled water and stir to dissolve to prepare a precipitant.

[...

technical field

[0001] The invention relates to the technical field of environmental protection, in particular to a preparation method of a composite metal oxide catalyst for catalytic decomposition of VOCs. Background technique

[0002] Volatile organic compounds (VOCs) refer to organic compounds with a saturated vapor pressure greater than 70 Pa at normal temperature and a boiling point below 260°C at normal pressure, or with corresponding volatility at a vapor pressure greater than or equal to 10 Pa at 20°C. of all organic compounds. According to its chemical structure, VOC can be further divided into: alkanes, aromatics, esters, aldehydes and others. More than 300 species have been identified so far. The most common ones are benzene, toluene, xylene, styrene, trichloroethylene, chloroform, trichloroethane, diisocyanate (TDI), diisocyanocresyl, etc. When the concentration of volatile organic compounds in the indoor air is too high, it is easy to cause acute poisoning. ...

Examples

preparation example Construction

[0023] Preparation method of composite metal oxide catalyst for catalytic decomposition of VOCs, using nano-powder TiO 2 As a carrier, a transition metal salt is added after the composite metal oxide layer is formed, and a composite metal oxide catalyst with multiple active components is formed after heat treatment, and the specific steps are as follows:

[0024] Step 1, add an appropriate amount of commercially available nano-TiO 2 The powder (P25) was dissolved in distilled water to make a 0.05 M solution.

[0025] Step two, take a certain amount of Ce (NO 3 ) 3 •6H 2 O was added to the solution obtained in Step 1, and stirred to dissolve 1H. Wherein, the molar ratio Ce / Ti=3 / 1~1 / 5 is controlled.

[0026] Step 3: Take a certain amount of NaOH and NH 3 •H 2 O is prepared as a 0.1M precipitant, and the precipitant is added to the solution in step 2 under vigorous stirring, and the molar ratio of the added amount is controlled to be [OH - ] / [Ce 3+ ]=3 / 1~4 / 1.

[0027] S...

Embodiment 1

[0033] (1) Weigh 3.32 g TiO 2 The powder was placed in a 1000 mL Erlenmeyer flask, and 400 mL of distilled water was added and stirred for 30 min to dissolve.

[0034] (2) Weigh 3.61 g Ce(NO 3 ) 3 •6H 2 Add O to the solution of (1) above, and continue to stir and dissolve for 30 min.

[0035] (3) Weigh 1.6 g NaOH+20 mL NH 3 •H 2 O, add 400 mL of distilled water and stir to dissolve to prepare a precipitant.

[0036] (4) Put the precipitating agent in a separatory funnel, and add the solution obtained in (2) dropwise under vigorous stirring. After the dropwise addition, place the conical flask in an oil bath, and stir for 1 hour at a constant temperature of 80°C. Filtrate while it is hot, and the resulting solid is placed in an oven at 80°C

[0037] Dry for 10H and grind to get Ce / TiO 2 Mixture A.

[0038] (5) Take 0.95 g of the mixture A obtained in (4), add it into 150 mL of distilled water, stir and dissolve for 30 min. Weigh Cu(NO 3 ) 2 0.33 g was added, and st...

Embodiment 2

[0045] (1) Weigh 0.332 g TiO 2 Put the powder in a 250 mL Erlenmeyer flask, add 100 mL of distilled water and stir to dissolve for 30 min.

[0046] (2) Weigh 0.361 g Ce(NO 3 ) 3 •6H 2 Add O to the solution of (1) above, and continue to stir and dissolve for 30 min.

[0047] (3) Weigh 0.16 g NaOH+2 mL NH 3 •H 2 O, add 40mL distilled water and stir to dissolve to prepare a precipitant.

[0048] (4) Put the precipitating agent in a separatory funnel, and add the solution obtained in (2) dropwise under vigorous stirring. After the dropwise addition, place the Erlenmeyer flask in an oil bath, and stir for 1 hour at a constant temperature of 80°C.

[0049] (5) Weigh 0.17 g AgNO 3 Dissolve in 50 mL of distilled water and place in a separatory funnel. After the solution of (4) was lowered to room temperature, it was added dropwise while stirring.

[0050] (6) Weigh 0.16 g NaOH+2 mL NH 3 •H 2 O, add 40 mL of distilled water and stir to dissolve to prepare a precipitant.

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