CN112517079B

CN112517079B - Copper-phenolic hydroxyl complexed Fenton-like catalyst and preparation method and application thereof

Info

Publication number: CN112517079B
Application number: CN202011482767.4A
Authority: CN
Inventors: 胡春; 廖威翔; 吕来
Original assignee: Guangzhou University
Current assignee: Guangzhou University
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2022-11-01
Anticipated expiration: 2040-12-15
Also published as: CN112517079A

Abstract

The invention discloses a copper-phenolic hydroxyl complexed Fenton-like catalyst and a preparation method and application thereof, and relates to the technical field of water treatment. The preparation method of the copper-phenolic hydroxyl complexed Fenton-like catalyst disclosed by the invention comprises the following steps of: (1) Dispersing cyclodextrin and a copper source into a solvent to obtain a suspension, (2) evaporating the suspension in a water bath kettle to obtain a solid product A; (3) Drying the solid product A, and then uniformly grinding to obtain a solid product B; (4) And roasting, cooling, washing and drying the solid product B to obtain the copper-phenolic hydroxyl complexed Fenton-like catalyst. The copper-phenolic hydroxyl complexed Fenton-like catalyst has a good degradation effect on organic pollutants in water, has low requirements on pH, has good stability, can be recycled, has low consumption of hydrogen peroxide, and is suitable for wide application.

Description

Copper-phenolic hydroxyl complexed Fenton-like catalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of water treatment, in particular to a copper-phenolic hydroxyl complexed Fenton-like catalyst and a preparation method and application thereof.

Background

Persistent aromatic pollutants are widely present in wastewater from the pharmaceutical, dye, pesticide, paper and plastic industries. These compounds are present in aquatic environments and cause adverse ecotoxicological effects. Most of these compounds cannot be completely eliminated by conventional drinking water treatment, and the process of degrading these compounds may produce more toxic by-products.

Fenton and fenton-like reactions are effective methods for eliminating many recalcitrant organic contaminants from water. The Fenton reaction is carried out with hydrogen peroxide (H)₂O₂) With Fe²⁺Or other reducing transition metals to generate hydroxyl radicals (. OH) for oxidation removal of contaminants. To meet these challenges, heterogeneous Fenton catalysts have been used, which have high pH requirements and can only react under acidic conditions, and high iron sludge yields resulting in secondary pollution and catalyst lossHave been developed as alternatives to the homogeneous Fenton process. However, the current multiphase Fenton process has low efficiency and low activity under neutral conditions and has H resistance₂O₂The consumption is large. Therefore, under the condition of neutral pH, the research and development of a high-efficiency Fenton catalyst become the focus of the research in the present stage.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a copper-phenolic hydroxyl complex Fenton-like catalyst which has wide application range and does not generate secondary pollution in the using process, and a preparation method and application thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a preparation method of a copper-phenolic hydroxyl complexed Fenton-like catalyst comprises the following steps:

(1) Dispersing cyclodextrin and a copper source into a solvent, and stirring to obtain a suspension A;

(2) Evaporating the suspension A to dryness to obtain a solid product A;

(3) Drying the solid product A, and uniformly grinding to obtain a solid product B;

(4) And roasting, cooling, washing and drying the solid product B to obtain the copper-phenolic hydroxyl complex Fenton-like catalyst.

Preferably, in the step (1), the copper source is at least one of copper chloride, copper nitrate, copper acetate and copper sulfate, and the molar ratio of copper ions in the copper source to cyclodextrin is (0.2-5): 1, the solvent is methanol or ethanol.

Preferably, in the step (1), the molar ratio of copper ions in the copper source to cyclodextrin is 2. The applicant of the invention verifies through multiple experiments that the copper-phenolic hydroxyl complex Fenton-like catalyst prepared according to the proportion has the best degradation effect in the process of treating organic pollutants in water.

Preferably, in the step (2), the evaporating temperature is 60-90 ℃.

Preferably, in the step (2), the evaporation temperature is 80 ℃.

Preferably, in the step (3), the drying temperature is 50-80 ℃, and the drying time is 8-24h.

Preferably, in the step (3), the drying temperature is 60 ℃ and the drying time is 12h.

The temperature is too low, the time and cost required by drying are high, the temperature is too high, and thermal stress is easily generated in the material to influence the formation of a special structure of the catalyst.

Preferably, in the step (4), the solid product B is roasted under inert gas or nitrogen, and the roasting is divided into two stages, namely a first stage: the roasting temperature is 300-600 ℃, the roasting time is 1-5h, and the second stage is as follows: the roasting temperature is 600-1000 ℃, the roasting time is 1-5h, and the roasting temperature rise rate is 5 ℃.

Preferably, in the step (4), the first-stage roasting temperature is 500 ℃, and the roasting time is 2 hours; the second stage roasting temperature is 800 ℃, and the roasting time is 2h.

The organic framework can collapse when the roasting temperature is too high, and the special structure required by the invention can not be formed when the temperature is too low.

Preferably, in the step (4), the furnace is cooled, washed with deionized water and ethanol respectively for three times, and dried for 6-24h at 30-60 ℃.

Meanwhile, the invention discloses the copper-phenolic hydroxyl complex Fenton-like catalyst prepared by the preparation method.

In addition, the invention discloses an application of the copper-phenolic hydroxyl complexed Fenton-like catalyst in the field of water treatment, and the application method comprises the step of adding the copper-phenolic hydroxyl complexed Fenton-like catalyst and hydrogen peroxide into waste water containing organic pollutants to oxidize and decompose the organic pollutants.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a preparation method and application of a novel copper-phenolic hydroxyl complexed graphene-like coated zero-valent copper nanoparticle fenton-like catalyst, and the preparation method is simple and has low equipment requirement. A Cu-O-C bond bridge connection is formed in a similar graphene structure of the copper-phenolic hydroxyl complexed Fenton-like catalyst, a metal Cu site forms an electron-rich center due to the generation of the bond bridge, an electron-deficient center is formed at a similar graphene C site, and different types of active centers can undergo different redox reactions.

The copper-phenolic hydroxyl complex Fenton-like catalyst with the graphene-like coated zero-valent copper nanoparticle structure can reduce the contact of zero-valent copper with pollutants and hydrogen peroxide, reduce the consumption of zero-valent copper nanoparticles, and electrons on the zero-valent copper can be transferred to the graphene-like layer, so that a double reaction center is further strengthened, and the catalytic effect is improved.

The catalyst disclosed by the invention can utilize electrons of dissolved oxygen and pollutants in water to generate OOH free radicals in situ to degrade the pollutants; organic matters which are difficult to biodegrade can be degraded under the conditions of neutrality and room temperature, and the consumption of hydrogen peroxide in the degradation process is small; the catalyst has stable structure and low metal ion dissolution, is easy to separate from water and is recycled. In addition, the catalyst of the invention does not produce solid products such as iron mud and the like in the reaction process, and does not need to be additionally provided with a foreign matter removing device.

Drawings

FIG. 1 is a scanning electron micrograph of example 1;

FIG. 2 is the XRD pattern for example 1;

FIG. 3a is an Auger spectrum of copper of example 1, b is an O1s XPS map without doped copper, and c is an O1s XPS map of example 1O;

FIG. 4 is a graph of the degradation profile of ibuprofen, bisphenol A, phenytoin, ciprofloxacin, and diphenhydramine of example 1;

FIG. 5 is a graph of the cyclic recycle activity evaluation of example 1 for BPA degradation;

FIG. 6 is a graph showing the consumption of hydrogen peroxide measured using example 1 in degrading contaminants in water;

FIG. 7 is a graph of the EPR signal of OOH in suspension of example 1.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to the accompanying drawings and specific embodiments.

Example 1

The embodiment of the invention discloses a copper-phenolic hydroxyl complexed Fenton-like catalyst, and the preparation method comprises the following steps:

(1) Dispersing 2g of beta-cyclodextrin and 0.6307g of copper chloride dihydrate into 60mL of methanol, and stirring for 15min to obtain a suspension A;

(2) Evaporating the suspension A in a water bath kettle at 80 ℃ to obtain a solid product A;

(3) Drying the solid product A in an oven at 60 ℃, and uniformly grinding to obtain a solid product B;

(4) Roasting the solid product B under the protection of nitrogen, wherein the first-stage roasting temperature is 500 ℃, and the roasting time is 2 hours; and the second stage of roasting at 800 ℃ for 2h at the heating rate of 5 ℃/min, naturally cooling, washing with deionized water and ethanol for 3-4 times, and then drying in vacuum at 60 ℃ to obtain the copper-phenolic hydroxyl complex Fenton-like catalyst.

Example 2

(1) Dispersing 2g of beta-cyclodextrin and 0.5045g of copper chloride dihydrate into 60mL of methanol, and stirring for 15min to obtain a suspension A;

(3) Drying the solid product A in a drying oven at 60 ℃, and uniformly grinding to obtain a solid product B;

Example 3

(1) Dispersing 2g of beta-cyclodextrin and 0.7568g of copper chloride dihydrate into 60mL of methanol, and stirring for 15min to obtain a suspension A;

(2) Evaporating the suspension A to dryness in a water bath kettle at 80 ℃ to obtain a solid product A;

(4) Roasting the solid product B under the protection of nitrogen, wherein the first-stage roasting temperature is 500 ℃, and the roasting time is 2 hours; and the second-stage roasting temperature is 800 ℃, the roasting time is 2h, the heating rate is 5 ℃/min, the second-stage roasting process is carried out, the second-stage roasting process is naturally cooled, deionized water and ethanol are used for washing for 3 to 4 times, and then vacuum drying is carried out at the temperature of 60 ℃ to obtain the copper-phenolic hydroxyl complex Fenton-like catalyst.

Performance testing

1. Topography and Structure testing

FIG. 1 is a scanning electron micrograph of example 1, from which it can be seen that example 1 is a porous material. Fig. 2 is an XRD spectrum of example 1, and from fig. 2, it can be found that there are diffraction peaks in the XRD spectrum which coincide with the characteristic diffraction peaks (111), (200) and (220) of elemental copper. Fig. 3 (a) is a Cu LM2 auger spectrum of example 1, fig. 3 (b) is a O1s diagram of a material prepared without adding a copper source, and fig. 3 (c) is an O1s diagram of example 1. From FIG. 3 (a), a peak of 569.8eV can be seen, which is found by referring to the manual of X-ray photoelectron spectroscopy⁺The binding energy of (a) is consistent, indicating that only monovalent copper, and no zero-valent copper, is present on the surface of the catalyst. From fig. 3 (b), it can be seen that without the addition of a copper source, there are two peaks at 531.8eV and 532.9eV, corresponding to C = O and the peak of the hydroxyl group on the aromatic ring, respectively; from FIG. 3 (C), it can be seen that the addition of the copper source results in an additional peak of 530.8eV, which is attributed to the formation of the copper oxide lattice, and an additional peak of 533.4eV, which corresponds to the C-O-Cu bond created by the combination of copper with the hydroxyl peak on the aromatic ring.

2. Test for catalytic Performance

0.01g of each of examples 1 to 3 was put into 50mL of a 10mg/L organic contaminant solution, 50. Mu.L of hydrogen peroxide was added thereto, and the mixture was continuously stirred in a water bath at 35 ℃ and then sampled at different time points to determine the contaminant concentration. The organic pollutant solution contains Ibuprofen (IBU), bisphenol A (BPA), phenytoin (PHT), ciprofloxacin (CIP) and Diphenhydramine (DP). FIG. 4 is a graph of the degradation profile of ibuprofen, bisphenol A, phenytoin, ciprofloxacin, and diphenhydramine of example 1; as can be seen from FIG. 4, the degradation rates of BPA and PHT reached 100% in 90 minutes of reaction, 63.7% in IBU and 100% in CIP at 120 minutes. The degradation effect on organic contaminants when treated for 90 minutes in examples 1 to 3 is shown in Table 1.

TABLE 1 degradation ratio of organic contaminants (%)

3. Stability test

The stability of the copper-phenolic hydroxyl complexed fenton-like catalyst disclosed in the present invention in the water treatment process was investigated in example 1, with the following steps:

(1) 0.01g of example 1 was put into 50mL of a 10mg/L BPA solution, and 50. Mu.L of a hydrogen peroxide solution was added thereto, and the mixture was continuously stirred in a water bath at 35 ℃;

(2) After reacting for 90 minutes, detecting the concentration of BPA in the solution;

(3) After the step (2) was completed, the catalyst was taken out, dried, and then the above operation was repeated 6 times.

Fig. 5 is a graph for evaluating the recycling activity of example 1 for BPA degradation, and it can be found from fig. 5 that after repeating for 6 times, the degradation activity of example 1 for BPA is still maintained above 99%, indicating that the copper-phenolic hydroxyl group complexed fenton-like catalyst disclosed by the invention has good stability in the water treatment process, and can be widely applied to the actual water treatment process.

4. Hydrogen peroxide consumption test

Fig. 6 is a graph showing a test of the consumption of hydrogen peroxide in example 1 when the contaminants in water are degraded, and it can be seen from fig. 6 that the consumption of hydrogen peroxide is significantly slowed down after the contaminants BPA are added.

5. Determination of free radicals

FIG. 7 is a plot of the EPR signal for OOH in suspension from example 1, and from FIG. 7 it can be seen that the catalyst can utilize dissolved oxygen in water to produce OOH without the addition of hydrogen peroxide, and that more OOH is produced after the addition of BPA. By combining with the consumption diagram of hydrogen peroxide, the method can obtain that the pollutants also have a certain effect in the Fenton catalytic reaction.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a copper-phenolic hydroxyl complex Fenton-like catalyst is characterized by comprising the following steps:

(2) Evaporating the suspension A to dryness to obtain a solid product A;

(4) Roasting, cooling, washing and drying the solid product B to obtain the copper-phenolic hydroxyl complex Fenton-like catalyst;

in the step (1), the copper source is at least one of copper chloride, copper nitrate, copper acetate and copper sulfate, and the molar ratio of copper ions in the copper source to cyclodextrin is (0.2-5): 1; in the step (2), the evaporation temperature is 60-90 ℃; in the step (3), the drying temperature is 50-80 ℃, and the drying time is 8-24h; in the step (4), the solid product B is roasted under inert gas or nitrogen, the roasting is divided into two sections, the first section is that: the roasting temperature is 300-600 ℃, the roasting time is 1-5h, and the second stage is as follows: the roasting temperature is 600-1000 ℃, and the roasting time is 1-5h.

2. The method according to claim 1, wherein in the step (1), the molar ratio of copper ions in the copper source to cyclodextrin is 2.

3. The method according to claim 1, wherein in the step (2), the temperature for evaporating to dryness is 80 ℃.

4. The method according to claim 1, wherein in the step (4), the solid product B is calcined under an inert gas or nitrogen, and the calcination is divided into two stages, a first stage: the roasting temperature is 500 ℃, the roasting time is 2 hours, and the second stage: the roasting temperature is 800 ℃, and the roasting time is 2h.

5. A copper-phenolic hydroxyl complexed fenton-like catalyst prepared by the method of claim 1.

6. The use of the copper-phenolic hydroxyl group complexed fenton-like catalyst according to claim 5 in the field of water treatment technology, wherein during the use, the copper-phenolic hydroxyl group complexed fenton-like catalyst and hydrogen peroxide are dispersed together in wastewater containing organic pollutants to oxidatively decompose the organic pollutants.