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Method for reducing selenite through liquid-phase catalytic hydrogenation

A liquid-phase catalysis and selenite technology, applied in chemical instruments and methods, catalyst activation/preparation, reduced water/sewage treatment, etc., can solve the problems of active component loss, catalyst deactivation, surface pollution, etc., to achieve Improved stability, simple synthesis method, and low equipment requirements

Inactive Publication Date: 2021-05-11
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For liquid-phase catalytic hydrogenation reactions, supported noble metal catalysts are often used, but the catalysts are often deactivated due to the loss of active components, particle agglomeration, and surface pollution during the use of the catalysts.
[0005] A liquid-phase catalytic hydrogenation reduction method capable of effectively treating Se(IV) has not been reported yet

Method used

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  • Method for reducing selenite through liquid-phase catalytic hydrogenation
  • Method for reducing selenite through liquid-phase catalytic hydrogenation
  • Method for reducing selenite through liquid-phase catalytic hydrogenation

Examples

Experimental program
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Effect test

Embodiment 1

[0041] The coating structure Pt catalyst of described liquid phase hydrogenation reduction Se (IV) is prepared as follows:

[0042] (1) Firstly, the supported precursor catalyst Pt / CNT was obtained by impregnation method, and the multi-walled carbon nanotube (CNT) and chloroplatinic acid solution were mixed and stirred, evaporated to dryness in a water bath, and N 2 Baked at 300°C under atmosphere, H 2 Reduction at 200°C for 2h under the condition to obtain Pt / CNT, wherein the Pt loading is 0.76wt.%. The transmission electron microscope image of Pt / CNT is as follows figure 1 As shown in (a), it can be seen that the noble metal Pt particles are uniformly dispersed on the surface of the multi-walled carbon nanotubes. According to the statistics, the average particle size of the noble metal Pt is about 2.96nm.

[0043] (2) Add 1g of Pt / CNT to 50mL of absolute ethanol containing 0.4mL of aniline and 10mL of 1M hydrochloric acid. After fully stirring, add 5mL of 1M ammonium persu...

Embodiment 2

[0053] The Pt / CNT, Pt / CNT@C, and Pt / CNT@CN catalysts prepared above were used for the liquid-phase catalytic reduction of Se(IV). The catalyst concentration was 0.125g / L, the initial concentration of Se(IV) was 30ppm, and the hydrogen flow rate was 200mL / min. The reaction was carried out in 10mM HAc-NaAc buffer salt with a pH of 4.75, and the reaction was carried out at room temperature and pressure for 2h. Response curve such as Figure 6 It can be seen that the catalytic performance of the catalyst Pt / CNT@CN coated with the heteronitrogen carbon layer is the highest, indicating that the carbon layer doped with nitrogen can improve the catalytic activity of the catalyst.

Embodiment 3

[0055] The catalyst Pt / CNT@CN for liquid phase hydrogenation reduction of Se(IV) was prepared according to the method in Example 1. The most catalytically active catalyst, Pt / CNT@CN-600, was used for the liquid-phase hydrogenation reduction reaction of Se(IV), with concentrations of 0.05g / L, 0.075g / L, 0.125g / L and 0.15g / L, respectively, The initial concentration of Se(IV) was 30ppm, the hydrogen flow rate was 200mL / min, and the reaction was carried out in 10mM HAc-NaAc buffer salt with pH 4.75. Response curve such as Figure 7 As shown in (a), as the catalyst concentration increases, the time required for Se(IV) to be completely reduced gradually decreases, but from Figure 7 (b) It can be seen that the initial activity of the catalyst is basically maintained at about 2300 mg / (L g cat h), indicating that there is no mass transfer resistance in the reaction system.

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Abstract

The invention discloses a method for reducing selenite through liquid-phase catalytic hydrogenation, which comprises the following steps: (A) preparation of a catalyst: taking a multi-walled carbon nanotube as a carrier, firstly loading noble metal Pt or Pd through an impregnation method, and then forming a polyaniline coating layer on the surface of the carrier through in-situ oxidative polymerization; roasting to obtain a supported noble metal catalyst with a nitrogen-doped carbon coating layer; and (B) Se (IV) liquid phase hydrogenation reduction: under the action of the catalyst prepared in the step (A), removing Se (IV) in the water body through liquid phase catalytic hydrogenation. The catalyst with a wrapping structure is applied to liquid-phase catalytic hydrogenation reduction to remove selenite in a water body, the catalyst has high activity, and meanwhile the technical problems of loss of active components, poisoning and the like of the catalyst are solved; and the catalyst is easy to synthesize and mild in reaction condition, and has a wide application prospect in the field of water treatment.

Description

technical field [0001] The invention belongs to the technical field of liquid-phase catalysis and industrial waste water treatment, and in particular relates to a method for liquid-phase catalytic hydrogenation reduction of selenite Se(IV). Background technique [0002] Selenium (Se) is an essential trace element for the human body and is very important for human life activities. However, high concentrations of selenium and its compounds have carcinogenic and teratogenic effects on the human body. For this reason, the U.S. Environmental Protection Agency (EPA) stipulates that the maximum discharge concentration (MCL) of selenium in drinking water is 50ppb. Selenium in the environment mainly comes from anthropogenic activities such as mining, smelting, oil refining, coal-fired power generation, and agricultural runoff. In natural water, selenium mainly exists in the form of ionic selenate (Se(VI)) and selenite (Se(IV)). The acute toxicity of selenite is about 10 times that ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/24B01J21/18B01J23/42B01J23/44B01J37/02B01J37/08C02F1/70C02F101/10
CPCB01J27/24B01J21/185B01J23/42B01J23/44B01J37/0201B01J37/082C02F1/705C02F2101/106B01J35/397
Inventor 郑寿荣孙玉菡李明会龙莉余乐孙静雅许昭怡郑长龙
Owner NANJING UNIV
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