Fenton-like advanced oxidation catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a Fenton-like advanced oxidation catalyst and a preparation method and application thereof.The Fenton-like advanced oxidation catalyst is formed by loading oxides-sulfides of iron, copper, zinc and chromium on activated carbon, and the structure of the Fenton-like advanced oxidation catalyst is Fe-Cu-Zn-Cr-S / O-C. The preparation method comprises the following steps that 1, the activated carbon is subjected to acid-base pretreatment, and the pretreated activated carbon is subjected to acid-base pretreatment; washing to be neutral and drying; 2) impregnating the pretreated activated carbon in a metal salt solution in advance, and then impregnating and depositing in an alkaline sulfide solution; and 3) roasting at high temperature under an inert condition. The Fenton-like advanced oxidation catalyst prepared by the method is an activated carbon loaded oxide-sulfide composite nanomaterial, has the characteristics of high catalytic efficiency and reusability, can be applied to Fenton-like reaction to reduce the chemical oxygen demand (COD) of wastewater under the combined action of the Fenton-like advanced oxidation catalyst and hydrogen peroxide, does not generate sludge, and is superior to Fenton advanced oxidation in process.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and specifically relates to a Fenton-like advanced oxidation catalyst, a preparation method and use thereof. Background Art

[0002] In 1894, the Fenton reaction was first reported, and the experimental results showed that divalent iron (Fe 2+ ) can effectively promote H 2 O 2 Oxidative degradation of malic acid. He then proposed the Fenton reagent (H 2 O 2 and Fe 2+ It can effectively oxidize a variety of organic compounds and degrade them into low-toxic organic and inorganic substances in turn, and the organic substances are finally converted into non-toxic CO 2 and H 2 O. Iron and hydrogen peroxide have little impact on the environment, and the homogeneous Fenton reaction can be carried out at room temperature and atmospheric pressure, and the reaction time is relatively short. Therefore, the classic Fenton reaction has received great attention from the industry as a method for treating organic pollutants. However, the acidity and alkalinity of the reaction system have a significant impact on the activity of the homogeneous Fenton reaction catalyst. A large amount of acid needs to be added to the system to adjust the pH of the reaction solution to the optimal value (pH value ≈ 3). The acid neutralization process after the degradation reaction will produce a large amount of iron sludge. The heterogeneous Fenton method has many advantages. The reaction can be carried out at a neutral pH, eliminating the acidification and neutralization steps, thereby avoiding the formation of iron sludge. At the same time, the catalyst is easy to recover and regenerate, simplifying the operation in wastewater treatment. Although the heterogeneous Fenton reaction can solve some of the problems caused by the homogeneous Fenton reaction, its sewage treatment efficiency is still far behind that of the homogeneous Fenton reaction. The reaction substrate can only react on the active sites on the catalyst surface, and the number of active sites on the surface is limited, so the reaction rate is difficult to match that of the homogeneous Fenton reaction.

[0003] CN109908929A discloses a method for preparing a dual-effect catalyst for synergistically catalyzing visible light / Fenton-like advanced oxidation reactions, wherein GO is used to wrap Fe 3 O 4 The magnetic sheet is the base, on which Ag is enriched. 3 PO 4 Nanoparticle composite catalyst. The dual-effect catalyst of the present invention has the dual functions of synergistically catalyzing visible light / Fenton-like advanced oxidation reactions, and can be applied to the synergistic water treatment technology of visible light / Fenton-like advanced oxidation reactions, overcoming the shortcomings of single-function water treatment technology, and having a more superior treatment effect.

[0004] CN118454689A discloses a Fenton-like diatomic catalyst and its preparation method and application method. The diatomic catalyst uses hollow cuprous oxide to load precious metal-transition metal atom pairs, wherein cuprous oxide is used as a carrier, and cuprous oxide and transition metal atoms are both active components, and precious metal atoms are used as auxiliary agents. The precious metal atoms modulate the electronic structure of cuprous oxide, and the transition metal atoms modulate the electronic structure of precious metal atoms. The diatomic catalyst is used in Fenton-like advanced oxidation reactions to degrade dyes, antibiotics or phenolic substances. The problem of secondary pollution and insufficient activation ability of existing catalysts is solved.

[0005] CN118437346A discloses a Bi 2 WO 6 A method for preparing a heterogeneous Fenton-like catalyst comprising: (1) reacting Na 2 WO 4 ·2H 2 O and Bi(NO 3 )·5H 2 O is added into deionized water, and after ultrasonic dispersion and stirring, hexadecyltrimethylammonium bromide is added and stirred to obtain a suspension; (2) the suspension is placed in an autoclave and maintained at 120°C for more than 24 hours. After the reaction is completed, it is cooled to room temperature and centrifuged, and the obtained product is washed and dried to obtain BWO; (3) Fe(NO 3 )·9H 2 After O is added to the suspension containing BWO, anhydrous sodium sulfate solution is added, ultrasonic dispersion is performed for more than 5 minutes, and then heated in a water bath at 50-60°C for 3h-8h; after the reaction is completed, the product is cooled to room temperature, washed three times by centrifugation with deionized water and ethanol, and dried to obtain Bi 2 WO 6 / FeOOH heterogeneous Fenton-like catalyst, the catalyst of the invention can be used for Fenton-like reaction to degrade tetracycline.

[0006] Therefore, it is of great significance to develop a new Fenton-like advanced oxidation catalyst in this field. Summary of the invention

[0007] The purpose of the present invention is to provide a Fenton-like advanced oxidation catalyst and a preparation method and application thereof. The Fenton-like advanced oxidation catalyst has the characteristics of high catalytic efficiency and reusability.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A Fenton-like advanced oxidation catalyst is composed of oxides and sulfides of iron, copper, zinc and chromium supported on activated carbon, and has a structure of Fe-Cu-Zn-Cr—S / O@C.

[0010] A method for preparing a Fenton-like advanced oxidation catalyst comprises the following steps:

[0011] (1) Pre-treating the activated carbon with acid or alkali, washing it to neutrality, and drying it;

[0012] (2) The pretreated activated carbon is pre-impregnated in a metal salt solution and then impregnated in an alkaline sulfide solution for deposition;

[0013] (3) High temperature calcination under inert conditions.

[0014] Wherein, in the step (1), the activated carbon is powdered activated carbon, granular activated carbon or spherical activated carbon; the activated carbon raw material is wood activated carbon, fruit shell activated carbon or coconut shell activated carbon; the activated carbon pore size is 2nm-50nm, preferably 10nm-35nm.

[0015] Wherein, in the step (1), the acid is at least one of sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, acetic acid or nitric acid; the base is at least one of sodium hydroxide, potassium hydroxide or sodium carbonate; and the acid-base pretreatment time is 1-2 hours.

[0016] Wherein, in the step (1), the drying temperature is 80°C-150°C, and the drying time is 3 to 5 hours.

[0017] Wherein, in step (2), the metal salt solution is a nitrate solution of iron, copper, manganese, cobalt, zinc, and chromium; wherein the ratio of the metal ions is: Fe 3+ : 5-15%, Cu 2+ :5-15%, Mn 2+ : 5-15%, Zn 2+ : 5-70%, Cr 2+ :5-65%,Co 2+ : 5-20%.

[0018] Wherein, in step (2), the alkaline sulfide solution is an alkaline solution of sodium sulfide or potassium sulfide, and the pH value is 13.

[0019] Wherein, in the step (2), the sediment is a nanocomposite material of metal sulfide and metal hydroxide, with a size of 10-20 nm; and the loading amount of the nanocomposite material on the surface of the activated carbon is 1-5%.

[0020] Wherein, in the step (3), the inert condition is nitrogen protection, the roasting temperature is 350°C-500°C, and the roasting time is 1-2 hours.

[0021] The Fenton-like advanced oxidation catalyst prepared by the present invention can be used for reducing the chemical oxygen demand of wastewater by a Fenton-like reaction, wherein the wastewater is wastewater such as papermaking wastewater and pharmaceutical wastewater whose COD is difficult to degrade by biochemical processes; the Fenton-like advanced oxidation catalyst of the present invention and hydrogen peroxide can be used together to reduce the chemical oxygen demand of the wastewater by a Fenton-like reaction, and the amount of sludge generated after treatment is 0.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The Fenton-like advanced oxidation catalyst prepared by the present invention is an activated carbon-supported oxide-sulfide composite nanomaterial, which can be used in a Fenton-like reaction to reduce the chemical oxygen demand (COD) of wastewater in combination with hydrogen peroxide, without generating sludge, which is superior to the conventional Fenton reaction. Moreover, the catalytic efficiency is superior to other Fenton-like catalysts, the COD removal rate is high, and the recovery is simple. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1 Fenton-like reaction: Fe-Cu-Zn-Cr-S / O@C, hydrogen peroxide

[0026] A method for preparing a Fenton-like advanced oxidation catalyst, specifically comprising:

[0027] (1) Soak granular (1 mm diameter) coconut shell activated carbon (pore size 30 nm) in dilute sulfuric acid (10%) for 2 hours.

[0028] , and wash to neutral, and dry at 105℃ for 3 hours;

[0029] (2) The activated carbon of step (1) was immersed in a solution containing iron nitrate (20%), copper nitrate (20%), zinc nitrate (30%) and chromium nitrate (30%) for 2 hours, and then immersed in a sodium sulfide (20%) solution with a pH of 13 for 1 hour, washed to neutrality, and dried at 80°C for 1 hour; the size of the obtained precipitate was 16 nm, and the loading amount was 2.8%.

[0030] (3) Calcinate at 400°C for 1 hour in a nitrogen atmosphere.

[0031] The Fenton-like advanced oxidation catalyst prepared by the above method was used together with hydrogen peroxide to reduce the chemical oxygen demand of wastewater in a Fenton-like reaction. The experimental results are shown in Table 1 below.

[0032] Table 1 COD removal effect

[0033] Fe-Cu-Mn-Co@C Hydrogen Peroxide Raw water COD (ppm) Outlet COD (ppm) Sludge 1‰ 1‰ 280 55 0 1.5‰ 1‰ 280 54 0 2‰ 1‰ 280 52 0

[0034] The catalyst prepared by the present invention has a sludge production rate of 0 and a COD removal rate equivalent to that of the Fenton reaction (80%).

[0035] Example 2 Fenton-like reaction: Fe-Cu-Zn-Cr-S / O@C, hydrogen peroxide

[0036] The COD removal effect after the catalyst of Example 1 was reused 10 times is shown in Table 2 below.

[0037] Table 2 COD removal effect

[0038]

[0039] After the catalyst prepared by the present invention is reused 10 times, the sludge generation rate is 0, and the COD removal rate is equivalent to that of the Fenton reaction (80%).

[0040] In order to highlight the beneficial effects of the present invention, the following comparative example experiments are given.

[0041] Comparative Example 1 Conventional Fenton reaction: ferrous sulfate heptahydrate, hydrogen peroxide

[0042] The effects of using ferrous sulfate heptahydrate and hydrogen peroxide are shown in Table 3 below.

[0043] Table 3 COD removal effect

[0044] Ferrous Sulfate Heptahydrate Hydrogen Peroxide Raw water COD (ppm) Outlet COD (ppm) Sludge 1‰ 1‰ 280 54 1‰ 1.5‰ 1‰ 280 53 1.6‰ 2‰ 1‰ 280 54 2‰

[0045] The removal efficiency of conventional Fenton reaction can reach 80%, but the sludge production is relatively large (1%).

[0046] Comparative Example 2 Fenton-like reaction: Fenton-like catalyst (LAT type, Shandong Longantai Environmental Protection), hydrogen peroxide

[0047] The commercially available Fenton-like catalyst and hydrogen peroxide were used, and the effects are shown in Table 4 below.

[0048] Table 4 COD removal effect

[0049] LAT Hydrogen Peroxide Raw water COD (ppm) Outlet COD (ppm) Sludge 1‰ 1‰ 280 108 0 1.5‰ 1‰ 280 97 0 2‰ 1‰ 280 95 0

[0050] The commercially available Fenton-like catalyst has a sludge production rate of 0, but a low COD removal rate (64%).

[0051] Through the above experimental comparison, it can be seen that the Fenton-like advanced oxidation catalyst prepared by the present invention and hydrogen peroxide work together to reduce the chemical oxygen demand (COD) of wastewater in a Fenton-like reaction, without sludge generation, which is better than the conventional Fenton reaction. Moreover, the catalytic efficiency is better than other Fenton-like catalysts, the COD removal rate is high, and the recovery is simple.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A Fenton-like advanced oxidation catalyst, characterized in that: The Fenton-like advanced oxidation catalyst is composed of oxides-sulfides of iron, copper, zinc and chromium supported on activated carbon, and its structure is Fe-Cu-Zn-Cr—S / O@C.

2. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 1, characterized in that: The following steps are involved: (1) Pre-treating the activated carbon with acid or alkali, washing it to neutrality, and drying it; (2) The pretreated activated carbon is pre-impregnated in a metal salt solution and then impregnated in an alkaline sulfide solution for deposition; (3) High temperature calcination under inert conditions.

3. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (1), the activated carbon is powdered activated carbon, granular activated carbon or spherical activated carbon; the activated carbon raw material is wood activated carbon, fruit shell activated carbon or coconut shell activated carbon; the activated carbon pore size is 2nm-50nm.

4. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (1), the acid is at least one of sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, acetic acid or nitric acid; the base is at least one of sodium hydroxide, potassium hydroxide or sodium carbonate; and the acid-base pretreatment time is 1-2 hours.

5. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (1), the drying temperature is 80° C.-150° C., and the drying time is 3 to 5 hours.

6. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (2), the metal salt solution is a nitrate solution of iron, copper, manganese, cobalt, zinc, and chromium; wherein the ratio of the metal ions is: Fe 3+ : 5-15%, Cu 2+ :5-15%, Mn 2+ : 5-15%, Zn 2+ : 5-70%, Cr 2+ :5-65%,Co 2+ : 5-20%.

7. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (2), the alkaline sulfide solution is an alkaline solution of sodium sulfide or potassium sulfide, and the pH value is 13.

8. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (2), the sediment is a nano-composite material of metal sulfide and metal hydroxide, with a size of 10-20 nm; the loading amount of the nano-composite material on the surface of the activated carbon is 1-5%.

9. The method for preparing the Fenton-like advanced oxidation catalyst according to claim 2, characterized in that: In the step (3), the inert condition is nitrogen protection, the roasting temperature is 350° C.-500° C., and the roasting time is 1-2 hours.

10. Use of the Fenton-like advanced oxidation catalyst according to claim 9 in reducing the chemical oxygen demand of wastewater by a Fenton-like reaction, characterized in that: The wastewater is wastewater whose COD is difficult to degrade through biochemical processes, including papermaking wastewater and pharmaceutical wastewater; the Fenton-like advanced oxidation catalyst and hydrogen peroxide can be used together to reduce the chemical oxygen demand of the wastewater through a Fenton-like reaction, and the amount of sludge produced after treatment is 0.

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