Mesoporous manganese ferrite Fenton-like catalyst and preparation method and application thereof

Abstract

The invention discloses a mesoporous manganese ferrite Fenton-like catalyst and a preparation method and application thereof and belongs to the field of preparation of Fenton-like catalysts. A mesoporous manganese ferrite catalyst is synthesized by using KIT-6 as a hard template agent. A Fenton-like system oxidized wastewater treatment system is formed by prepared mesoporous manganese ferrite and hydrogen peroxide and is used for carrying out efficient removal and mineralization on organic pollutants in wastewater. According to the mesoporous manganese ferrite Fenton-like catalyst and the preparation method and application thereof, the preparation method is simple and efficient, the prepared Fenton-like catalyst has a mesoporous structure and relatively large specific surface area, can be used for providing more adsorption loci and catalysis loci and can be used for efficiently degrading contaminants in a relatively wide pH range (acidic, neutral and even alkaline), and thus, the problems that the traditional Fenton reaction can only occur under acidic conditions and secondary pollution is easily caused due to a large volume of iron mud produced during the reaction are solved; the catalyst can be recycled and is easily separated from an aqueous solution after the catalyst is used so as to recover the catalyst.

Description

[0001] Technical field: [0002] The present invention relates to a Fenton-like catalyst, in particular to a mesoporous manganese ferrite Fenton-like catalyst material and its preparation method and application, using mesoporous molecular sieve KIT-6 (porous silicon Porous Si) as a hard template, through the impregnation method Synthesis of Mesoporous MnFe 2 o 4 Fenton-like catalysts. [0003] Background technique: [0004] Fenton-like technology is an advanced oxidation water treatment technology that has been studied more in recent years. The hydroxyl radicals generated in the reaction system are second only to fluoride oxides in water. They are highly active and non-selective, and can effectively degrade A variety of biodegradable organic pollutants. Many scholars have carried out a lot of research on Fe-based metal oxides as Fenton-like catalysts, and made great progress. However, the existing research and application of iron-based metal oxides have the following defect...

AI Technical Summary

Problems solved by technology

[0005] (1) Existing literature reports that the rate of degradation of pollutants by iron ore-based Fenton-like catalysts is much lower than that of traditional Fenton processes under the same conditions

[0006] (2) Many unmodified iron oxides can only oxidatively degrade organic matter in the acidic pH range, and are not suitable for wastewater at neutral or alkaline pH

[0009] (1) The morphology of the double metal oxide Fenton reagent prepared by the existing synthesis method is characterized by fewer pores and a smaller specific surface area, which is not conducive to the promotion of catalytic efficiency;

[0010] (2) Iron-based oxides doped with certain transition metals have a negative impact on the actual catalytic performance. It has been reported in the literature that doping Ni(II) and Ti(Ⅴ) can inhibit hydroxyl radicals to a certain extent. production rate;

[0011] (3) Most doped double metal oxides cannot effectively broaden the pH range of Fenton-like catalytic reactions, and still need to be used under acidic conditions

But this patent has the following defects: (1) the pH value of the reaction must be strictly controlled in the catalyst preparation process, and the operating conditions are relatively complicated

(2) The amount of hydrogen peroxide added in the reaction process is relatively high, and the operating cost is relatively high; (3) The pH control range of the reaction process in this patent is about 2.0±0.5. During the process, a large amount of iron sludge will be precipitated, which will reduce the active ions of the catalyst and affect the reusability of the catalyst.

However, there are two obvious defects in the above preparation process: (1) The precursors are simply mixed in the form of salt solution, and it is difficult to form a uniform and uniform mesoporous structure through subsequent steps such as stirring, aging, and calcination, and it is difficult to make Cu-doped The good distribution is in the channel, and the supported Cu may occupy the MnO 2 The original adsorption catalytic active sites, thus affecting the catalytic degradation effect; (2) The dosage of the prepared catalyst in the catalytic degradation reaction process is relatively high, which makes the processing cost higher, which is not conducive to practical engineering application

This patent has the following deficiencies in the actual use process: (1) The essence of the synthesis method is to precipitate the active metal oxides on the inner surface of the sepiolite pores by the impregnation method. As the catalytic degradation reaction proceeds, the Fe-Co oxides are easily It falls off from the sepiolite channel, resulting in poor catalyst stability; (2) Since the hardness of sepiolite decreases after absorbing water, it becomes soft, and the hardness recovers after drying, and the structure of the supported Fe-Co oxide is prone to occur before and after the reaction. change, the dispersion is reduced, and the deactivation of the catalyst is accelerated to a certain extent

This patent has the following defects: (1) in the actual degradation process, the dosage of hydrogen peroxide is relatively large, which is not conducive to the application in actual engineering

(2) The synthesized Fe-Na oxide is loaded in the pores of the molecular sieve, and as the reaction progresses, the oxides fall off from the surface of the molecular sieve and the pores, which reduces the stability of the catalyst

Although the heterogeneous catalyst synthesized in this patent effectively reduces the dissolution of iron ions during the reaction process, the reaction conditions for degrading quinoline and phenol need to be carried out in a system with a pH value of about 3, which cannot be close to neutral in actual wastewater. The defect of catalytic effect under the condition of pH value needs to adjust the acidity of the water sample, which increases the cost of neutral and alkaline wastewater treatment; in addition, the preparation process of graphene oxide is more complicated and the cost is higher

Furthermore, with the progress of the reaction and the repeated use of the catalyst, the graphene loaded on the MCM-41 channel will fall off, which will affect the uniform distribution of hematite, and then affect the catalytic effect in the later stage.

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