Visible light responsive composite photocatalyst and its preparation method and use

A visible light and composite light technology, applied in the field of photocatalysis, can solve the problems of different catalyst reduction performance and photocatalytic oxidation performance, expensive catalyst preparation cost, low solar energy utilization rate, etc., to achieve a wide range of applications, high cost performance, and reduced energy consumption. Effect

Inactive Publication Date: 2013-04-24
ZHEJIANG GONGSHANG UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the photocatalytic reduction of Cr(VI) mainly involves the reduction reaction of photogenerated electrons, the reduction performance of the catalyst is significantly different from the photocatalytic oxidation performance, which cannot be inferred from existing studies.
In addition, at present, silver-based catalysts contain a relatively high amount of Ag (≥15%), the cost of catalyst preparation is high, and the power of the light source used is also high (≥300W), emitting strong light (80-300mW / cm 2 ), much higher than the average power of sunlight radiating to the earth's surface (about 43mW / cm 2 )
The utilization rate of solar energy is very low, which limits the development process of photocatalysis for practical wastewater treatment

Method used

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  • Visible light responsive composite photocatalyst and its preparation method and use
  • Visible light responsive composite photocatalyst and its preparation method and use
  • Visible light responsive composite photocatalyst and its preparation method and use

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Accurately weigh 1.000g of commercial P25 TiO 2 and 0.1025g KI, dispersed in 100mL deionized water, ultrasonically dispersed for 10 minutes. Slowly add AgNO dropwise under magnetic stirring 3 Silver ammonia solution (AgNO 3 : KI molar ratio is 1: 1), stirred for 1 hour, and a bright yellow milky precipitate was obtained. Then filter and dry at 100°C in a blast drying oven to obtain AgI / TiO containing AgI of 5% (molar ratio) 2 . The prepared 5%AgI / TiO 2 Calcined at 250°C, 350°C, 500°C and 700°C for 2 hours to obtain AgI / TiO after heat treatment at different temperatures 2 composite photocatalyst.

[0041] AgI / TiO heat-treated at different temperatures 2 Carry out X-ray diffraction characterization, the specific results are shown in figure 1 , it can be seen from the figure that with the increase of the catalyst preparation temperature, the proportion of β-AgI is greatly increased, and the AgI / TiO prepared at low temperature 2 Coexist in two phases of β-AgI and γ...

Embodiment 2

[0045] Accurately weigh 1.000g of commercial P25 TiO 2 and different quality KI, control KI and TiO 2 The molar ratio is between 1% and 15%. Disperse it in 100mL deionized water and ultrasonically disperse for 10 minutes. Slowly drop a certain concentration of AgNO under magnetic stirring 3 Silver ammonia solution (AgNO 3 : KI molar ratio is 1: 1), stirred for 1 hour, obtained light yellow to bright yellow milky precipitate. Then filter, dry at 100°C in a blast drying oven, and then calcinate at 350°C in a muffle furnace for 2 hours to obtain β-AgI / TiO containing 1% to 15% (molar ratio) AgI 2 -350.

[0046] Accurately weigh 1.000g of commercial P25 TiO 2 And different quality KI, KBr, control K 总 with TiO 2 The molar ratio of KI to KBr is 0.05:1, and the molar ratio of KI to KBr is between 0.11 and 1.50. It is dispersed in 100 mL of deionized water and ultrasonically dispersed for 10 minutes. Slowly drop a certain concentration of AgNO under magnetic stirring 3 Silver...

Embodiment 3

[0048] Add 50mL and 0.5mL of simulated hexavalent chromium-containing wastewater containing potassium dichromate concentration of 20mg / L (calculated by chromium mass) into six glass reactors, respectively. -4 mol / L EDTA, add 50 mg (100°C, 250°C, 350°C, 500°C, 700°C) calcined AgI / TiO 2 Visible light photocatalyst (prepared in Example 1), use perchloric acid to adjust the pH value of the simulated wastewater containing hexavalent chromium to 2, magnetically stir and disperse the catalyst in the dark for 30min, the artificial light source used is a 50W xenon lamp, and configure a 420nm cut-off filter film, turn on the light source and irradiate with weak visible light for 60 minutes.

[0049] Under the irradiation of weak visible light, AgI with excellent visible light response and TiO with electron transport properties 2 Composite made AgI / TiO 2 Reduction of hexavalent chromium Cr(VI) which is soluble, easy to migrate and highly toxic in water to trivalent chromium Cr(III) whi...

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Abstract

The invention discloses a visible light responsive composite photocatalyst and its preparation method and use. The preparation method comprises the following steps of adding TiO2, KBr and KI into deionized water, slowly and dropwisely adding AgNO3 and ammonia water into the solution with stirring to obtain a silver-ammonia solution and to obtain luminous yellow curdy precipitates by the stirring reaction, filtering the luminous yellow curdy precipitates, drying, and carrying out calcination at a specified temperature. The use of the visible light responsive composite photocatalyst comprises taking Cr(VI)-containing waste water, adding a hole trapping agent into the Cr(VI)-containing waste water, adding the visible light responsive composite photocatalyst into the Cr(VI)-containing waste water, adjusting a pH value of the Cr(VI)-containing waste water, carrying out uniform dispersion, and carrying out irradiation by visible light. The visible light responsive composite photocatalyst utilizes weak visible light or directly utilizes sunlight to realize Cr(VI)-containing waste water treatment, greatly improves a solar energy utilization rate and reduces waste water treatment energy consumption.

Description

technical field [0001] The invention relates to the technical field of photocatalysis, in particular to a visible light responsive composite photocatalyst and its preparation method and application. Background technique [0002] The heavy metal chromium is an essential raw material for tanning, printing and dyeing, electroplating and other industries. It is also a carcinogen, an internationally recognized key pollutant, and a key control object in my country. Chromium pollution control is a worldwide environmental protection problem. The core of its technology is to reduce soluble, easily migrated, and highly toxic hexavalent chromium Cr(VI) to trivalent chromium Cr(III) that is 100 times less toxic and easy to coordinate and precipitate. , and make comprehensive use of it. [0003] Photocatalytic technology is an emerging and promising method for the reduction and removal of heavy metal Cr(VI) under ultraviolet light irradiation (Chenthamarakshan C R and Rajeshwar K. Heter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/08C02F1/30C02F1/70C02F101/22
CPCY02W10/37
Inventor 王齐邹钢姜家浩郭丝丝俞柯军徐媛媛
Owner ZHEJIANG GONGSHANG UNIVERSITY
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