CN110698666A - Composite catalyst and application thereof in preparation of polyphenol by oxidative polymerization of phenol-containing wastewater - Google Patents

Abstract

The invention discloses a composite catalyst and its application for preparing polyphenol by oxidative polymerization of phenol-containing wastewater. The composite catalyst is prepared by taking Cu(NO ₃ ) ₂ , Na ₂ SiO ₃ , FeCl ₂ , MnSO ₄ and Na ₂ CO ₃ Add absolute ethanol to obtain mixed solution 1; mix the NaOH aqueous solution and the mixed solution 1 to obtain a mixed solution 2; add the sodium citrate aqueous solution to the mixed solution 2, stir evenly, and within 2 min, raise the reaction temperature to 300-500 ° C , calcined for 12-18 hours, naturally cooled to room temperature, poured off the supernatant, washed the remaining solid with distilled water, centrifuged, freeze-dried, and ground into powder. The composite catalyst of the present invention can selectively oxidize phenol in waste water and reuse it repeatedly. The raw materials are cheap and easy to obtain and environmentally friendly. Polyphenol is generated, which can be used for the subsequent preparation of coatings, adhesives, thermal insulation materials, etc., which not only treats sewage, but also realizes the reuse of resources.

Description

A kind of composite catalyst and its method for preparing polyphenol by oxidative polymerization of phenol-containing wastewater use

technical field

The invention belongs to the field of wastewater treatment, and relates to a composite catalyst and its use for preparing polyphenol by oxidative polymerization of phenol-containing wastewater.

Background technique

Phenol is a toxic organic pollutant. Phenol-containing wastewater can cause harm to humans, animals, and crops. It can damage human nerves, kidneys, liver, etc. Long-term drinking of phenol-contaminated water sources will lead to chronic poisoning. Headache, dizziness, insomnia, tinnitus, leukopenia, anemia and memory loss and other symptoms. Phenol degrades slowly in water, coupled with the wide sources and high toxicity of industrial phenol-containing wastewater. Efficient, economical and environmentally friendly treatment of phenol-containing wastewater is a practical problem that needs to be solved at home and abroad, and has great practical significance.

At present, the treatment methods of phenol-containing wastewater mainly include extraction method (eg patent CN107399779A), adsorption method (eg CN107774232A), catalytic oxidation method (eg CN1017987B), activated sludge method (eg CN105585114A), electrochemical method (eg CN105858823A), etc. , only the mineralization and degradation of phenol in wastewater can not achieve resource recovery. For phenol recovery, traditional methods include extraction recovery (such as CN105399174B), membrane separation method (such as CN105540718B), electrochemical method (such as CN101362677B), etc., which have the disadvantages of high energy consumption, complicated operation and high cost; Meng Xiaorong et al. (Chinese patent: CN105540718B, a liquid membrane and its application for the enrichment and recovery of phenolic organics) Using a solid-phase liquid membrane to recover phenol in wastewater, although the operation is simple and the cost is low, it is not suitable for neutral and alkaline wastewater treatment , with the increase of wastewater pH, the recovery rate of phenol decreased significantly.

Based on HO·[E°(HO·/H ₂ O)=1.8-2.7V vs. NHE] and SO ₄ ⁻ ·[E°(SO ₄ ⁻ ·/SO ₄ ²⁻ )=2.5-3.1V vs. NHE ] advanced oxidation technology can non-selectively oxidize or even completely mineralize phenolic pollutants through reactions such as hydroxylation and ring opening of the benzene ring. However, the oxidative capacity of these oxidizing species tends to decrease rapidly with increasing pH. In addition, as the organic content increases and the carbon chain grows, the amount of oxidant required to fully mineralize it increases significantly, thereby greatly increasing operating costs. Therefore, the search for a more efficient, economical and safe new oxidation technology for phenolic wastewater treatment should become an important goal of the development of oxidation technology.

The oxidative polymerization of phenolic pollutants into polyphenol is a green oxidation technology with potential application value. Since polyphenol is not only an important organic semiconductor material, but also a good substitute for anti-corrosion materials and phenolic resins, this oxidation technology can "turn waste into treasure" of phenolic pollutants in wastewater. Although the system of horseradish peroxidase and H ₂ O ₂ can polymerize phenolic substances in wastewater into insoluble polymers, however, the sensitivity of enzymes to industrial wastewater, the inhibitory effect of phenol radicals on enzyme activities, and the relatively low levels of enzymes The high price and limited service life limit the wide application of this technology in the treatment of phenolic wastewater. Therefore, the idea of "turning waste into treasure" by seeking a cheaper and more durable catalytic system to convert phenolic pollutants in wastewater into polyphenol should become an important development direction for phenol-containing wastewater treatment.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a composite catalyst.

The second object of the present invention is to provide a preparation method of the composite catalyst.

The third object of the present invention is to provide the use of a composite catalyst for preparing polyphenol by oxidative polymerization of phenol-containing wastewater.

The technical scheme of the present invention is summarized as follows:

A preparation method of composite catalyst, comprising the steps:

(1) Take 0.1-0.3mol Cu(NO ₃ ) ₂ , 0.1-0.2 mol Na ₂ SiO ₃ , 0.1-0.3 mol FeCl ₂ , 0.2-0.3 mol MnSO ₄ and 0.1-0.25 mol Na ₂ CO ₃ in proportion to add absolute ethanol to 1L, get mixed solution one;

(2) be 1.5-2.5:1 ratio by volume, mix the NaOH aqueous solution of 10M and described mixed solution one to obtain mixed solution two; add the sodium citrate aqueous solution of 1M in mixed solution two, described mixed solution two with The volume ratio of 1M sodium citrate aqueous solution is 150:0.5-1.5, stir evenly, within 2min, raise the reaction temperature to 300-500°C, calcinate for 12-18 hours, naturally cool to room temperature, pour off the supernatant, The remaining solids are washed with distilled water, centrifuged, freeze-dried, ground or pulverized to a fine powder.

Preferably, step (1) is to take 0.2 mol Cu(NO ₃ ) ₂ , 0.1 mol Na ₂ SiO ₃ , 0.3 mol FeCl ₂ , 0.2 mol MnSO ₄ and 0.2 mol Na ₂ CO ₃ in proportion to add anhydrous ethanol to 1 L to obtain mixed solution one.

The reaction temperature was 500°C.

The composite catalyst prepared by the above method.

The above-mentioned composite catalyst is used for the purposes of preparing polyphenol by oxidative polymerization of phenol-containing wastewater, comprising the following steps:

(1) prepare the composite catalyst aqueous suspension with concentration of 3-5g/L, adjust pH=9-13 to obtain suspension a; prepare aqueous potassium persulfate solution with concentration of 6-24mM, adjust pH=9-13, obtain Solution b; take phenol-containing wastewater with a concentration range of 3-15mM, adjust pH=9-13, and obtain solution c;

(2) According to the volume ratio of (0.5-2): (0.5-2): 1, mix the suspension a, the solution b and the solution c, and at 25-35 ℃, the shaking speed of the shaking table is 100-300r/ Under the condition of min, the oxidative polymerization reaction is carried out for 1-1.5 hours, centrifuged, and the solid is washed with 0.5-1M aqueous hydrochloric acid solution to obtain polyphenol.

Preferably, step (1) is as follows: preparing a composite catalyst aqueous suspension with a concentration of 5g/L, adjusting pH=10-12, to obtain suspension a; preparing an aqueous potassium persulfate solution with a concentration of 12mM, adjusting pH=10-12 , to obtain solution b; take phenol-containing wastewater with a concentration range of 12 mM, adjust pH=10-12, and obtain solution c.

Step (2) is as follows: according to the volume ratio of 1:1:1, the suspension a, the solution b and the solution c are mixed uniformly, and the oxidative polymerization reaction 1 is carried out at 25 ° C and the shaking speed of the shaking table is 150 r/min. h, centrifuged, and the solids were washed with 1M aqueous hydrochloric acid to yield polyphenol.

Advantages of the present invention:

The composite catalyst of the present invention can selectively oxidize phenol in wastewater, and the composite catalyst can be reused. The raw materials are cheap and easily available, the reaction does not depend on the pH value of the system, and the heterogeneous catalytic reaction is more efficient and environmentally friendly. No other intermediate products are produced in the process, and polyphenol, which is insoluble in acids, alkalis and organic solvents, is completely formed, which can be used for the subsequent preparation of coatings, adhesives, thermal insulation materials, etc., which not only treats sewage, but also realizes the reuse of resources. .

Description of drawings

Fig. 1 shows that the composite catalyst prepared in Examples 1-4 adopts the method of Example 5 to remove phenol by oxidative polymerization of phenol-containing wastewater.

Fig. 2 is the phenol-removing effect of the phenol-containing wastewater oxidative polymerization of Examples 6-8.

Fig. 3 is the effect diagram of the catalytic performance of the composite catalyst reused.

Figure 4 is a photo of the product polyphenol obtained in Example 5 washed with 1M EDTA aqueous solution and 1M hydrochloric acid aqueous solution; a. polyphenol after washing with 1M hydrochloric acid aqueous solution; b. polyphenol obtained after washing with 1M EDTA aqueous solution.

Figure 5 is a solid infrared analysis effect diagram of polyphenol. (a: 1M aqueous hydrochloric acid solution dissolves the polyphenol obtained in Example 5; b: 1M EDTA aqueous solution dissolves the polyphenol obtained in Example 5)

FIG. 6 is a graph showing the results of the SSNMR test of polyphenol obtained in Example 5. FIG.

FIG. 7 is a flight mass spectrometry detection diagram of the soluble polyphenol (dissolved in methanol) obtained in Example 5. FIG.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Example 1

A preparation method of composite catalyst, comprising the steps:

(1) Add 0.1 mol Cu(NO ₃ ) ₂ , 0.2 mol Na ₂ SiO ₃ , 0.2 mol FeCl ₂ , 0.3 mol MnSO ₄ and 0.2 mol Na ₂ CO ₃ to anhydrous ethanol to 1L to obtain mixed solution one;

(2) be 2:1 ratio by volume, the NaOH aqueous solution of 10M and described mixed solution one are mixed to obtain mixed solution two; In mixed solution two, add the sodium citrate aqueous solution of 1M, described mixed solution two and 1M The volume ratio of the sodium citrate aqueous solution is 150:1, stir evenly, transfer to the muffle furnace, raise the reaction temperature to 500 °C within 2 minutes, calcine for 12 hours, naturally cool to room temperature, discard the supernatant, and put the remaining The solid was washed with distilled water, centrifuged, lyophilized, and ground to a fine powder.

Example 2

A preparation method of composite catalyst, comprising the steps:

(1) Add 0.2mol Cu(NO ₃ ) ₂ , 0.1 mol Na ₂ SiO ₃ , 0.3 mol FeCl ₂ , 0.2 mol MnSO ₄ and 0.2 mol Na ₂ CO ₃ to anhydrous ethanol to 1L to obtain mixed solution one;

(2) be 1.5:1 ratio by volume, mix the NaOH aqueous solution of 10M and described mixed solution one to obtain mixed solution two; add the sodium citrate aqueous solution of 1M in mixed solution two, described mixed solution two and 1M of The volume ratio of the sodium citrate aqueous solution is 150:0.5, stir evenly, transfer to the muffle furnace, within 2 minutes, raise the reaction temperature to 500 ° C, calcine for 12 hours, naturally cool to room temperature, pour off the supernatant, and put the remaining The solid was washed with distilled water, centrifuged, freeze-dried, and pulverized to a fine powder.

Example 3

A preparation method of composite catalyst, comprising the steps:

(1) Add 0.25mol Cu(NO ₃ ) ₂ , 0.2 mol Na ₂ SiO ₃ , 0.25 mol FeCl ₂ , 0.2 mol MnSO ₄ and 0.1 mol Na ₂ CO ₃ to anhydrous ethanol to 1L to obtain mixed solution one;

(2) be 2.5:1 ratio by volume, the NaOH aqueous solution of 10M and described mixed solution one are mixed to obtain mixed solution two; In mixed solution two, add the sodium citrate aqueous solution of 1M, described mixed solution two and 1M The volume ratio of sodium citrate aqueous solution is 150:1.5, stir evenly, transfer to the muffle furnace, within 2 minutes, raise the reaction temperature to 500 ° C, calcine for 12 hours, naturally cool to room temperature, pour off the supernatant, and put the remaining The solid was washed with distilled water, centrifuged, lyophilized, and ground to a fine powder.

Example 4

A preparation method of composite catalyst, comprising the steps:

(1) Add 0.3mol Cu(NO ₃ ) ₂ , 0.1 mol Na ₂ SiO ₃ , 0.1 mol FeCl ₂ , 0.25 mol MnSO ₄ and 0.25 mol Na ₂ CO ₃ to anhydrous ethanol to 1L to obtain mixed solution one;

(2) be 2:1 ratio by volume, the NaOH aqueous solution of 10M and described mixed solution one are mixed to obtain mixed solution two; In mixed solution two, add the sodium citrate aqueous solution of 1M, described mixed solution two and 1M The volume ratio of sodium citrate aqueous solution is 150:1, stir evenly, transfer to the muffle furnace, raise the reaction temperature to 300 ℃ within 2 minutes, calcine for 18 hours, naturally cool to room temperature, pour off the supernatant, and put the remaining The solid was washed with distilled water, centrifuged, lyophilized, and ground to a fine powder.

Example 5

The use of the composite catalyst for oxidative polymerization of phenol-containing wastewater to prepare polyphenol includes the following steps:

(1) the composite catalyst (prepared by using embodiment 1, 2, 3, and 4) with a concentration of 5g/L in water suspension, adjust pH=10 to obtain suspension a; the preparation concentration is an aqueous potassium persulfate solution of 12mM, Adjust pH=10 to obtain solution b; take phenol-containing wastewater with a concentration of 12 mM, adjust pH=10 to obtain solution c;

(2) Mix suspension a, solution b and solution c in a volume ratio of 1:1:1, conduct oxidative polymerization for 1 hour at 25°C and a shaking speed of 150 r/min, and centrifuge. , the solid was washed with 1M aqueous hydrochloric acid to obtain polyphenol. The appearance and characterization of the product are shown in Figure 4, Figure 5, Figure 6 and Figure 7.

The degradation of the phenol-containing wastewater by the composite catalyst prepared in Examples 1-4 is shown in Figure 1, and the reaction basically reaches equilibrium within 1 h.

Repeated use of composite catalysts:

After centrifugation in step (2) of this embodiment, the composite catalyst with polyphenol is separated and reused. Finally, the solid is washed with 1M aqueous hydrochloric acid solution to obtain polyphenol. The composite catalyst is reused for many times. The catalytic performance is shown in the figure 3.

Example 6

The use of the composite catalyst for oxidative polymerization of phenol-containing wastewater to prepare polyphenol includes the following steps:

(1) The aqueous suspension of the composite catalyst (prepared in Example 2) with a concentration of 5 g/L was prepared, and the pH was adjusted to 12 to obtain the suspension a; the aqueous potassium persulfate solution with a concentration of 12 mM was prepared, and the pH was adjusted to 12 to obtain the solution b ; Get the phenol-containing waste water of concentration 12mM, adjust pH=12, obtain solution c;

(2) Mix suspension a, solution b and solution c in a volume ratio of 1:1:1, conduct oxidative polymerization for 1 hour at 25°C and a shaking speed of 150 r/min, and centrifuge. , the solid was washed with 1M aqueous hydrochloric acid to obtain polyphenol.

The phenol removal effect of phenol-containing wastewater by oxidative polymerization is shown in Figure 2.

Example 7

The use of the composite catalyst for oxidative polymerization of phenol-containing wastewater to prepare polyphenol includes the following steps:

(1) The aqueous suspension of the composite catalyst (prepared in Example 3) with a concentration of 3 g/L was prepared, and pH=9 was adjusted to obtain suspension a; the aqueous potassium persulfate solution with a concentration of 6 mM was prepared, and pH=9 was adjusted to obtain solution b ; Get the phenol-containing waste water of concentration 3mM, adjust pH=9, obtain solution c;

(2) According to the volume ratio of 0.5:0.5:1, the suspension a, the solution b and the solution c were mixed uniformly, and the oxidative polymerization reaction was carried out for 1 hour at 25 ° C and the shaking speed of the shaking table was 100 r/min, and centrifuged. , the solid was washed with 0.5M aqueous hydrochloric acid to obtain polyphenol.

The phenol removal effect of phenol-containing wastewater by oxidative polymerization is shown in Figure 2.

Example 8

The use of the composite catalyst for oxidative polymerization of phenol-containing wastewater to prepare polyphenol includes the following steps:

(1) The aqueous suspension of the composite catalyst (prepared in Example 4) with a concentration of 5 g/L was prepared, and pH=13 was adjusted to obtain suspension a; the aqueous potassium persulfate solution with a concentration of 24 mM was prepared, and pH=13 was adjusted to obtain solution b ; Get the phenol-containing waste water of concentration 15mM, adjust pH=13, obtain solution c;

(2) According to the volume ratio of 2:2:1, the suspension a, the solution b and the solution c were mixed evenly, and the oxidative polymerization reaction was carried out for 1.5 hours at 35 ° C and the shaking speed of the shaking table was 300 r/min, and centrifuged. , the solid was washed with 1M aqueous hydrochloric acid to obtain polyphenol.

The phenol removal effect of phenol-containing wastewater by oxidative polymerization is shown in Figure 2.

Detection of phenol: The specific detection method refers to the national standard method 4-aminoantipyrine to detect phenol, and the concentration of phenol can be obtained. After the reaction started, samples were taken from the reaction system every hour for UV spectrophotometric detection, and the consumption of phenol was judged by the decrease in concentration, and it could be inferred whether the reaction had carried out selective oxidation of phenol.

Solid infrared analysis: The reacted solid was dissolved with sufficient 1M hydrochloric acid aqueous solution (a) and 1M EDTA aqueous solution (b) to obtain the remaining undissolved solid, which was then tested and analyzed on an infrared spectrometer after drying, as shown in Figure 5.

SSNMR (Solid State Nuclear Magnetic Resonance) analysis: Dissolve the reacted solid with enough hydrochloric acid to obtain the remaining insoluble solid, and test it with a nuclear magnetic resonance apparatus after drying to obtain the carbon spectrum of the substance to be tested, and use this for structural identification. , see Figure 6.

Flight mass spectrometry detection: polyphenol was dissolved in methanol, the supernatant was thoroughly mixed with CHCA matrix, and the flight mass spectrometry data was recorded on Bruker Autoflex tof/tofIII in linear mode at 337 nm, as shown in Figure 7.

Claims (7)

1. The preparation method of the composite catalyst is characterized by comprising the following steps:

(1) taking 0.1-0.3mol of Cu (NO) according to the proportion₃)₂、0.1-0.2molNa₂SiO₃、0.1-0.3molFeCl₂、0.2-0.3molMnSO₄And 0.1 to 0.25mol Na₂CO₃Adding absolute ethyl alcohol to 1L to obtain a mixed solution I;

(2) mixing a 10M NaOH aqueous solution with the mixed solution I according to the volume ratio of 1.5-2.5:1 to obtain a mixed solution II; adding a 1M sodium citrate aqueous solution into a mixed solution II, wherein the volume ratio of the mixed solution II to the 1M sodium citrate aqueous solution is 150: 0.5 to 1.5, stirring evenly, raising the reaction temperature to 500 ℃ within 2min, calcining for 12 to 18 hours, naturally cooling to room temperature, pouring out supernatant, washing the residual solid with distilled water, centrifuging, freeze drying, grinding or crushing into fine powder.

2. The method as set forth in claim 1, wherein the step (1) is to take 0.2mol of Cu (NO) in proportion₃)₂、0.1molNa₂SiO₃、0.3molFeCl₂、0.2molMnSO₄And 0.2mol Na₂CO₃Adding absolute ethyl alcohol to 1L to obtain a mixed solution I.

3. The process according to claim 1 or 2, characterized in that the reaction temperature is 500 ℃.

4. A composite catalyst prepared by the process of any of claims 1 to 3.

5. The use of the composite catalyst of claim 4 for the preparation of polyphenol by oxidative polymerization of phenol-containing wastewater, characterized by comprising the steps of:

(1) preparing a composite catalyst water suspension with the concentration of 3-5g/L, and adjusting the pH value to 9-13 to obtain a suspension a; preparing a potassium persulfate aqueous solution with the concentration of 6-24mM, and adjusting the pH value to 9-13 to obtain a solution b; taking phenol-containing wastewater with the concentration range of 3-15mM, and adjusting the pH value to 9-13 to obtain a solution c;

(2) according to the volume ratio of (0.5-2): (0.5-2): 1, mixing the suspension a, the solution b and the solution c, carrying out oxidative polymerization reaction for 1-1.5 hours at the temperature of 25-35 ℃ and the shaking speed of a shaking table of 100-300r/min, centrifuging, and washing the solid with 0.5-1M hydrochloric acid aqueous solution to obtain the polyphenol.

6. Use according to claim 5, characterized in that said step (1) is: preparing a composite catalyst water suspension with the concentration of 5g/L, and adjusting the pH value to 10-12 to obtain a suspension a; preparing a potassium persulfate aqueous solution with the concentration of 12mM, and adjusting the pH value to 10-12 to obtain a solution b; the phenol-containing wastewater with the concentration range of 12mM is taken, and the pH value is adjusted to 10-12, so as to obtain a solution c.

7. Use according to claim 5, characterized in that said step (2) is: according to the volume ratio of 1: 1: 1, mixing the suspension a, the solution b and the solution c uniformly, carrying out oxidative polymerization reaction for 1 hour at the temperature of 25 ℃ and the shaking speed of a shaking table of 150r/min, centrifuging, and washing the solid with 1M hydrochloric acid aqueous solution to obtain the polyphenol.

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