CN101927158A - Preparation method of nano ZnO/gamma-Al2O3 composite photocatalyst - Google Patents

Abstract

A preparation method of a nano ZnO/gamma-Al2O3 composite photocatalyst comprises the following steps: selecting the granules with size of 0.2-0.3mm after grinding gamma-Al2O3 and drying the granules at 110-150 DEG C for 3-6h after washing the granules with deionized water to obtain a gamma-Al2O3 carrier; mixing ZnO, ammonium bicarbonate and ammonia water according to the molar ratio of 1:1-3:1-6, stirring the mixture for 2-8h and taking the supernatant after standing for 1-3h to obtain zinc ammonia liquid; after adding the gamma-Al2O3 carrier to the zinc ammonia liquid according to the mass ratio of ZnO to gamma-Al2O3 carrier being 3:1-9, distilling ammonia at 85-95 DEG C for 4-6h, filtering, washing with water and washing with absolute ethyl alcohol to obtain a precursor; and drying the precursor at 110-150 DEG C for 1-6h and then calcining the precursor at 300-600 DEG C for 2-4h, thus obtaining the nano ZnO/gamma-Al2O3 composite photocatalyst. The preparation method has the advantages of simple process, high ZnO utilization ratio, easy change of load ratio and secure load.

Description

Nano-ZnO/γ-Al 2O 3The preparation method of composite photo-catalyst

Technical field

The invention belongs to a kind of preparation method of catalyst, be specifically related to a kind of nano-ZnO/γ-Al ₂O ₃The preparation method of composite photo-catalyst.

Background technology

In various environmental pollutions, the most general, main and what have the greatest impact is chemical contamination.Thereby; controlling and administer various chemical pollutants effectively is emphasis in the comprehensive environmental improvement to the destruction that constitutes human survival the most basic water resource, soil and atmospheric environment, and exploitation can be the innoxious practical technique of various chemical pollutants the key of environmental protection.Traditional pollutant processing method exist to some extent or efficient low, can not be thoroughly that pollutant is innoxious, easily produce secondary pollution; Or the scope of application is narrow, only is fit to specific pollutant; Or the energy consumption height, be not suitable for the defective of aspects such as large-scale promotion.

Photocatalysis technology is meant that semiconductor catalyst produces electronics-hole under visible light or action of ultraviolet light, makes to be adsorbed on its surperficial O ₂, H ₂O and contaminant molecule are accepted light induced electron or hole, thereby a series of redox reaction takes place, make toxic pollutant be degraded to a kind of photochemical method nontoxic or material that toxicity is less, it has that energy consumption is low, oxidability is strong, reaction condition is gentle and characteristics such as non-secondary pollution.Purposes is widely being arranged aspect the toxic pollutant processing.

Early stage researchers mainly are photocatalyst material such as TiO ₂, ZnO etc. directly puts in the solution that needs degraded light-catalyzed reaction take place, but the catalyst granules that suspends tiny, be difficult to reclaim and easily cause the catalyst waste, so photocatalyst is become the emphasis of people's research to some carriers.Seeking good carrier and being easy to industrialized preparation method is wherein the most key part.

Summary of the invention

The object of the invention is to provide a kind of technology simple, ZnO utilization rate height, and load factor is easy to change and load nano-ZnO/γ-Al firmly ₂O ₃The preparation method of composite photo-catalyst.

Nano-ZnO/γ of the present invention-Al ₂O ₃The preparation method of composite photo-catalyst may further comprise the steps:

(1) with γ-Al ₂O ₃Choose the particle that particle diameter is 0.2-0.3mm after the grinding, after the deionized water washing, 110 ℃～150 ℃ lower oven dry 3～6 hours, obtain γ-Al ₂O ₃Carrier;

(2) be 1 in molar ratio with ZnO, carbonic hydroammonium and ammoniacal liquor under the room temperature: (1～3): the ratio of (1～6) is mixed, and stirs 2～8 hours, leaves standstill after 1～3 hour and gets supernatant liquor, obtains the zinc ammoniacal liquor;

(3) press ZnO and γ-Al ₂O ₃The carrier mass ratio is 3: the ratio of (1～9), and with γ-Al ₂O ₃After carrier joined the zinc ammoniacal liquor, 85～95 ℃ of lower ammonia still processs 4～6 hours, filtration, washing, absolute ethanol washing obtained predecessor;

(4) predecessor was dried 1～6 hour under 110～150 ℃, namely obtained nano-ZnO/γ-Al in 2～4 hours in 300～600 ℃ of lower calcinings again ₂O ₃Composite photo-catalyst.

Nano-ZnO/γ of the present invention-Al ₂O ₃The preparation method of composite photo-catalyst has following features:

(1) solved the difficult recovery of floating type catalyst and easily caused the shortcoming of catalyst waste, and can be recycled, catalytic efficiency is still very high.

(2) γ-Al ₂O ₃Carrier is strong to the absorption of ZnO, the firm difficult drop-off of load.

(3) the ZnO particle diameter of load is still nanoscale, the catalytic efficiency height.

(4) this preparation method's cost of material is cheap, and ZnO utilization rate (amount of load accounts for the ratio of growing amount) is high, process is simple, and the cycle weak point is easy to industrialization.

Description of drawings

Fig. 1 is γ-Al ₂O ₃The ESEM of carrier (SEM) picture.

Fig. 2 is ESEM (SEM) picture of embodiment 1.

The ESEM of Fig. 3 embodiment 2 (SEM) picture

The ESEM of Fig. 4 embodiment 3 (SEM) picture

The specific embodiment

Specify the present invention below in conjunction with example

Embodiment 1

With γ-Al ₂O ₃Choose the particle that diameter is 0.2～0.3mm after the grinding, be placed in the baking oven through the deionized water washing and under 110 ℃, dried 6 hours, obtain γ-Al ₂O ₃Carrier, Fig. 1 are its sem photographs.Be that 1: 1: 6 ratio joins 10g ZnO, 9.7g carbonic hydroammonium and 56.4ml ammoniacal liquor in the there-necked flask in ZnO, carbonic hydroammonium and ammoniacal liquor mol ratio under the room temperature, stirred 2 hours, leave standstill after 1 hour and get supernatant liquor, obtain the zinc ammoniacal liquor; Press ZnO and γ-Al ₂O ₃The carrier mass ratio is that 3: 1 ratio is got 9.8ml zinc ammoniacal liquor and 0.5g γ-Al ₂O ₃Carrier, 95 ℃ of lower ammonia still processs 4 hours, filtration, washing, absolute ethanol washing obtained predecessor.The gained predecessor is put into baking oven in 110 ℃ of lower oven dry 6 hours, and the product after will dry is again put into Muffle furnace in 300 ℃ of lower calcinings 4 hours, namely gets mass ratio and be the nano-ZnO/γ of 3: 1 (load factor is 58%)-Al ₂O ₃Composite photo-catalyst, the particle diameter that calculates institute's loading ZnO according to the scherrer formula is 7.4nm.Fig. 2 is the sem photograph of gained catalyst.

Embodiment 2

With γ-Al ₂O ₃Choose the particle that diameter is 0.2～0.3mm after the grinding, be placed in the baking oven through the deionized water washing and under 130 ℃, dried 3 hours, obtain γ-Al ₂O ₃Carrier, Fig. 1 are its sem photographs.Be that 1: 3: 1 ratio joins 10g ZnO, 29.1g carbonic hydroammonium and 9.4ml ammoniacal liquor in the there-necked flask in ZnO, carbonic hydroammonium and ammoniacal liquor mol ratio under the room temperature, stirred 4 hours, leave standstill after 2 hours and get supernatant liquor, obtain the zinc ammoniacal liquor; Press ZnO and γ-Al ₂O ₃The carrier mass ratio is that 2: 1 ratio is got 6.3ml zinc ammoniacal liquor and 0.5g γ-Al ₂O ₃Carrier, 90 ℃ of lower ammonia still processs 5 hours, filtration, washing, absolute ethanol washing obtained predecessor.The gained predecessor is put into baking oven in 120 ℃ of lower oven dry 4 hours, and the product after will dry is again put into Muffle furnace in 400 ℃ of lower calcinings 3 hours, namely gets mass ratio and be the nano-ZnO/γ of 2: 1 (load factor is 57%)-Al ₂O ₃Composite photo-catalyst, the particle diameter that calculates institute's loading ZnO according to the scherrer formula is gained catalyst sem photograph for 6.8nm Fig. 3.

Embodiment 3

With γ-Al ₂O ₃Choose the particle that diameter is 0.2～0.3mm after the grinding, be placed in the baking oven through the deionized water washing and under 150 ℃, dried 3 hours, obtain γ-Al ₂O ₃Carrier, Fig. 1 are its sem photographs.Be that 1: 2: 3 ratio joins 10g ZnO, 19.4g carbonic hydroammonium and 28.2ml ammoniacal liquor in the there-necked flask in ZnO, carbonic hydroammonium and ammoniacal liquor mol ratio under the room temperature, stirred 8 hours, leave standstill after 3 hours and get supernatant liquor, obtain the zinc ammoniacal liquor; Press ZnO and γ-Al ₂O ₃The carrier mass ratio is that 1: 3 ratio is got 3ml zinc ammoniacal liquor and 0.5g γ-Al ₂O ₃Carrier, 85 ℃ of lower ammonia still processs 6 hours, filtration, washing, absolute ethanol washing obtained predecessor.The gained predecessor is put into baking oven in 150 ℃ of lower oven dry 1 hour, and the product after will dry is again put into Muffle furnace in 600 ℃ of lower calcinings 2 hours, namely gets mass ratio and be the nano-ZnO/γ of 1: 3 (load factor is 20%)-Al ₂O ₃Composite photo-catalyst, the particle diameter that calculates institute's loading ZnO according to the scherrer formula is 10.2nm.Fig. 4 is a gained catalyst sem photograph.

Claims (1)

1. nano-ZnO/γ-Al ₂O ₃The preparation method of composite photo-catalyst is characterized in that comprising the steps:

(1) with γ-Al ₂O ₃Choose the particle that particle diameter is 0.2-0.3mm after the grinding, after the deionized water washing, 110 ℃～150 ℃ lower oven dry 3～6 hours, obtain γ-Al ₂O ₃Carrier;

(2) under the room temperature be that 1: 1～3: 1～6 ratio is mixed in molar ratio, stirred 2～8 hours, leave standstill after 1～3 hour and get supernatant liquor, obtain the zinc ammoniacal liquor ZnO, carbonic hydroammonium and ammoniacal liquor;

(3) press ZnO and γ-Al ₂O ₃The carrier mass ratio is 3: 1～9 ratio, with γ-Al ₂O ₃After carrier joined the zinc ammoniacal liquor, 85～95 ℃ of lower ammonia still processs 4～6 hours, filtration, washing, absolute ethanol washing obtained predecessor;

(4) predecessor was dried 1～6 hour under 110～150 ℃, namely obtained nano-ZnO/γ-Al in 2～4 hours in 300～600 ℃ of lower calcinings again ₂O ₃Composite photo-catalyst.

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