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Process for preparing rare-earth composite porous aluminium oxide loaded Pd catalyst

A composite technology of porous alumina and rare earth, applied in the field of chemical preparation of environmental catalytic materials, can solve the problems of complex components, high catalytic bed temperature, macromolecular size, etc., and achieves easy reaction process, broad application prospects, high temperature resistance, etc. good performance

Inactive Publication Date: 2008-01-30
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These catalysts usually use traditional microporous, low-medium pore materials (such as γ-alumina, natural mordenite, etc.) Derivatives can be eliminated by catalytic oxidation at higher temperatures, but organic pollutants emitted by most industrial sources, such as polycyclic aromatic hydrocarbons, esters and amines, have relatively large molecular sizes, and their concentrations are low and complex Very complicated
Due to steric hindrance, traditional microporous, low-medium pore catalytic materials do not allow these organic pollutants of large molecular size to approach and adsorb; in addition, with the loading of active components, the pore size of the carrier will further decrease
Therefore, the catalytic oxidation treatment of these low-concentration, multi-component organic pollutants requires a higher catalytic bed temperature, which means that energy consumption and operating costs are greatly increased, which is not conducive to the promotion and application of catalytic technology.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Cordierite ceramic honeycomb as carrier (square 100×100×40mm, 250 square holes / in 2 , the hole wall thickness is 0.25mm, the water absorption rate is 22-24%wt), the proportion Al 2 o 3 ·H 2 O:PEG-1000:H 2 O=1:0.03:3 (mass ratio), dried at 120° C. and treated at 350° C. for 1 hour to obtain an alumina hydrate / ceramic honeycomb carrier with a loading capacity of 120 g / liter of alumina hydrate. Take a piece of the above-mentioned carrier and immerse it in a solution containing Ce:Zr at a ratio of 3:1 (molar ratio), CeO 2 and ZrO 2 The total content of 6 grams of cerium and zirconium nitrate aqueous solution (pH=2.0), let stand for 0.5 hours and then heat to boiling, continue heating for 2.0 hours, take out the carrier, and then soak in the aqueous solution containing 1% KOH for 0.5 hours, Then it was washed several times with distilled water until neutral, dried at 120°C and treated at 500°C for 2.0 hours in an air atmosphere. Then the support was soaked in H contain...

Embodiment 2

[0021] With the same operation of embodiment 1, the difference is: the CeO in the cerium and zirconium nitrate aqueous solution 2 and ZrO 2 The total content was changed to 3.0 g; the resulting catalyst contained 0.15 g Pd, 3.0 g CeO 2 +ZrO 2 ; The organic pore-forming agent is PEG-10000, and the mass ratio of hydrated alumina, organic pore-forming agent and water is 1: 0.05: 4.5; the weight percentage concentration of the precipitating agent is 2% NH 3 ·H 2 O; the reducing agent is 0.5% potassium borohydride in weight percent concentration. at 10000~30000h -1 Air velocity, 3~5g / m 3Under the condition of organic matter concentration, the complete oxidation temperature of the catalyst to toluene or ethyl acetate is 180°C and 280°C respectively, and the complete oxidation temperature of the catalyst is 220°C (toluene) and 320°C ( ethyl acetate).

Embodiment 3

[0023] With the same operation of embodiment 1, the difference is: the H 2 PdCl 4 The Pd content in the aqueous solution was changed to 0.2 g; the resulting catalyst contained 0.2 g Pd, 6.0 g CeO 2 +ZrO 2 ; Precipitating agent weight percent concentration is 0.5% NaOH; reducing agent weight percent concentration is 1.5% formaldehyde. at 10000~30000h -1 Air velocity, 3~5g / m 3 Under the condition of organic matter concentration, the complete oxidation temperature of the catalyst to toluene or ethyl acetate is 180°C and 260°C respectively, and the complete oxidation temperature is 200°C (toluene) and 260°C ( ethyl acetate).

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Abstract

The preparation of porous alunina supported compounded compound RE-Pd catalyst adopts honeycomb cordierite ceramic as carrier, and includes sol soaking process to coat alunina hydrate and heat adsorption process to support compound Ce-Zr oxide and Pd catalyst. The catalyst contains Pd 0.2-0.8g / L and CeO2+ZrO2 3.0-15.0 g / L. Under the condition of space velocity of 10000-30000 / hr, the catalyst has complete toluene and ethyl acetate oxidizing temperature of 180-200 deg c and 260-280 deg c separately; and after being treated in air atmosphere at 1000 deg c for 4 hr, the complete oxidizing temperature is raised by 20-40 deg c only. The present invention has the features of simple preparation process, low production cost, high catalytic activity at low temperature and high heat resistance.

Description

technical field [0001] The invention relates to the chemical preparation of environmental catalytic materials, in particular to a preparation method for catalytic oxidation degradation catalysts of CO and volatile organic pollutants (VOCs). Background technique [0002] With the rapid development of my country's industrialization, the volatile organic compounds (VOCs) exhaust gas emitted by industry has become one of the main pollution sources affecting the air quality of my country's cities due to many factors such as its large amount and complex composition. The problem of VOCs pollution from industrial emissions has always been one of the most important environmental issues in the world, and has strict regulations on emissions. For example, the United States lists 189 kinds of air organic pollutants in industry as toxic pollutants, while my country's current atmospheric The Comprehensive Pollutant Discharge Standard (GB16297-1996) stipulates the emission limits of 14 types...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/44B01J32/00B01J37/00
Inventor 周仁贤陈敏
Owner ZHEJIANG UNIV