Universal iron-carbon heterogeneous catalyst for advanced oxidation process as well as preparation method and application of universal iron-carbon heterogeneous catalyst

Abstract

The invention belongs to the technical field of heterogeneous catalysts, and particularly discloses a universal iron-carbon heterogeneous catalyst for an advanced oxidation process as well as a preparation method and application of the universal iron-carbon heterogeneous catalyst. The preparation method of the universal iron-carbon heterogeneous catalyst for the advanced oxidation process comprises the following steps: mixing and granulating 50-60 parts of an iron source, 20-30 parts of a carbon source, 10-15 parts of a transition metal source, 5-10 parts of a rare earth metal source and 5-10 parts of a binder, and calcining to obtain the universal iron-carbon heterogeneous catalyst for the advanced oxidation process. According to the invention, the transition metal and the rare earth metal are added, so that the synergistic effect among the metals is increased, the oxidation-reduction reaction can be accelerated through electron transfer among different metals, and ozone can be effectively decomposed into rich active oxygen such as hydroxyl free radicals, superoxide free radicals and singlet oxygen; decomposing the hydrogen peroxide into hydroxyl radicals in the Fenton reaction; and catalysis is carried out through valence change of the loaded metal in micro-electrolysis.

Description

Technical Field

[0001] The present invention relates to the technical field of heterogeneous catalysts, and in particular to a universal iron-carbon heterogeneous catalyst for advanced oxidation processes and a preparation method and application thereof. Background Art

[0002] In recent years, as my country attaches great importance to environmental protection, the control of wastewater has gradually increased, and the requirements for discharge have become more stringent. The types of organic matter in wastewater are increasing, and the difficulty of wastewater treatment has increased dramatically. The water quality of some water samples cannot be directly entered into biochemical treatment, and pre-oxidation methods are needed to improve the water quality and improve the biodegradability of wastewater. The pre-oxidation process mainly includes micro-electrolysis, ozone oxidation and Fenton oxidation. However, at present, relying solely on traditional biochemical treatment, the indicators of effluent are far from meeting the emission standards. Therefore, deep treatment after biochemical treatment to ensure that the water quality of the effluent meets the standards is a widely used method. Advanced oxidation technology mainly produces hydroxyl radicals (·OH) with strong oxidizing properties to improve the removal efficiency of wastewater by the reaction system. At present, the most widely used deep treatments (advanced oxidation processes) on the market include ozone oxidation and catalytic ozone oxidation, Fenton oxidation, and Fenton-like oxidation.

[0003] As long as it involves a multiphase catalytic oxidation process, the heterogeneous catalyst in the system is crucial. The catalyst should not only have a relatively large specific surface area and porosity, but also have abundant active sites to ensure the catalytic efficiency and stability of the catalyst. Iron-carbon catalysts are mainly used in micro-electrolysis, using the potential difference (1.2V) generated by themselves to treat sewage, but different advanced oxidation processes have different requirements for catalysts. Therefore, how to disclose a catalyst that can demonstrate good catalytic effects in different advanced oxidation processes and reduce the waste of time and resources caused by replacing equipment or adjusting processes to meet different project requirements is a difficult problem that needs to be solved in this field. Summary of the invention

[0004] In view of this, the present invention provides a universal iron-carbon heterogeneous catalyst for advanced oxidation processes and a preparation method and application thereof, so as to solve the problem that catalysts used in existing different types of advanced oxidation technologies are not universal.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A universal iron-carbon heterogeneous catalyst for advanced oxidation processes is prepared from raw materials including the following parts by weight: 50-60 parts of iron source, 20-30 parts of carbon source, 10-15 parts of transition metal source, 5-10 parts of rare earth metal source and 5-10 parts of binder.

[0006] Preferably, the iron source includes one or more of iron oxide, iron salt and iron powder.

[0007] Preferably, the carbon source includes one or more of activated carbon, coal powder and biochar.

[0008] Preferably, the transition metal source includes one or more of manganese salts, nickel salts, copper salts and cobalt salts.

[0009] Preferably, the rare earth metal source comprises cerium salt and / or lanthanum salt.

[0010] Preferably, the binder includes one or more of bentonite, coal tar pitch, polypropylene alcohol and lime.

[0011] Preferably, the particle size of the universal iron-carbon heterogeneous catalyst for advanced oxidation processes is 3 to 6 mm.

[0012] Another object of the present invention is to provide a method for preparing a universal iron-carbon heterogeneous catalyst for an advanced oxidation process, comprising the following steps: An iron source, a carbon source, a transition metal source, a rare earth metal source and a binder are mixed and granulated, and then calcined to obtain a universal iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0013] Preferably, the calcination temperature is 600-800° C., and the calcination time is 3-5 hours.

[0014] Another object of the present invention is to provide a method for preparing a universal iron-carbon heterogeneous catalyst for advanced oxidation processes, and to use the obtained universal iron-carbon heterogeneous catalyst for advanced oxidation processes in ozone oxidation processes, catalytic ozone oxidation processes, Fenton-like processes, micro-electrolysis processes and Fenton processes.

[0015] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects: The present invention adds transition metals and rare earth metals, both of which have relatively unique electronic structures, which can promote the generation rate of hydroxyl radicals in processes such as ozone oxidation and Fenton oxidation, thereby improving the effect of the reaction system. The application of multiple metals increases the synergistic effect between metals. Specifically, the redox reaction can be accelerated through the transfer of electrons between different metals. The increase of transition metals can also enrich the specific surface area of ​​the material to a certain extent and increase the amount of active sites on the surface of the material.

[0016] The catalyst decomposes ozone into abundant reactive oxygen species such as hydroxyl radicals, superoxide radicals and singlet oxygen in the ozone oxidation process; decomposes hydrogen peroxide into hydroxyl radicals in the Fenton reaction; and catalyzes micro-electrolysis through changes in the valence state of the loaded metal. DETAILED DESCRIPTION

[0017] The present invention provides a universal iron-carbon heterogeneous catalyst for advanced oxidation processes, which is prepared from raw materials including the following parts by mass: 50~60 parts of iron source, 20~30 parts of carbon source, 10~15 parts of transition metal source, 5~10 parts of rare earth metal source and 5~10 parts of binder; preferably 52~58 parts of iron source, 22~28 parts of carbon source, 12~14 parts of transition metal source, 6~9 parts of rare earth metal source and 6~9 parts of binder; further preferably 55 parts of iron source, 25 parts of carbon source, 13 parts of transition metal source, 8 parts of rare earth metal source and 8 parts of binder.

[0018] In the present invention, the iron source includes one or more of iron oxide, iron salt and iron powder.

[0019] In the present invention, the iron salt may specifically be ferric nitrate, ferric sulfate, ferric chloride, or ferrous chloride.

[0020] In the present invention, the carbon source includes one or more of activated carbon, coal powder and biochar.

[0021] In the present invention, the transition metal source includes one or more of manganese, nickel, copper, cobalt and their corresponding salts and oxides.

[0022] In the present invention, the transition metal source is preferably one or more of manganese salt, nickel salt, copper salt and cobalt salt.

[0023] In the present invention, the rare earth metal source includes cerium salt and / or lanthanum salt.

[0024] In the present invention, the binder includes one or more of bentonite, coal tar pitch, polypropylene alcohol and lime.

[0025] In the present invention, the particle size of the universal iron-carbon heterogeneous catalyst for advanced oxidation processes is preferably 3-6 mm, specifically 3.5 mm, 4 mm, 4.5 mm, 5 mm, or 5.5 mm.

[0026] In the present invention, the universal iron-carbon heterogeneous catalyst for advanced oxidation processes is preferably spherical or ellipsoidal.

[0027] In the present invention, the universal iron-carbon heterogeneous catalyst for advanced oxidation processes can be applied to advanced oxidation processes such as ozone oxidation processes, catalytic ozone oxidation processes, Fenton-like processes, micro-electrolysis processes and Fenton processes.

[0028] The present invention also provides a method for preparing a universal iron-carbon heterogeneous catalyst for an advanced oxidation process, comprising the following steps: An iron source, a carbon source, a transition metal source, a rare earth metal source and a binder are mixed and granulated, and then calcined to obtain a universal iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0029] In the present invention, the mixing method is preferably rotating centrifugal mixing or mechanical stirring mixing.

[0030] In the present invention, the granulation method is preferably direct bonding granulation, extrusion granulation and rotary centrifugal granulation.

[0031] In the present invention, the calcination temperature is 600-800°C, specifically 620°C, 640°C, 650°C, 680°C, 700°C, 720°C, 740°C, 750°C, 780°C; the calcination time is 3-5h, specifically 3.2h, 3.5h, 3.8h, 4h, 4.2h, 4.5h, 4.8h.

[0032] The present invention also provides a method for preparing a universal iron-carbon heterogeneous catalyst for advanced oxidation processes, and the application of the prepared universal iron-carbon heterogeneous catalyst for advanced oxidation processes in ozone oxidation processes, catalytic ozone oxidation processes, Fenton-like processes, micro-electrolysis processes and Fenton processes.

[0033] 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.

[0034] Example 1

[0035] Preparation of universal iron-carbon heterogeneous catalyst for advanced oxidation processes The iron oxide: coal powder: manganese nitrate: cerium nitrate: coal tar pitch binder = 60:20:12:6:10 ratio was mechanically stirred and mixed, and then extruded into granules. After completion, the granules were calcined at 650 ° C for 3.5 h to obtain a 3-5 mm general-purpose iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0036] The above-mentioned iron-carbon heterogeneous catalyst was used to catalyze ozone oxidation of photovoltaic wastewater. The specific conditions were as follows: inlet ozone concentration of 40 mg / L, inlet air volume of 0.2 L / min, reaction time of 60 min, test water sample volume of 10 L, and the volume dosage of the iron-carbon heterogeneous catalyst was 10% of the total volume of the treated water sample. The same iron-carbon heterogeneous catalyst was repeated 4 times, and the experimental results are shown in Table 1.

[0037] Table 1 Experimental results of iron-carbon heterogeneous catalytic ozone oxidation of photovoltaic wastewater

[0038] It can be seen from Table 1 that the iron-carbon heterogeneous catalyst prepared by the present invention has an excellent catalytic effect. After 4 consecutive repeated tests, the iron-carbon catalytic efficiency did not decrease significantly. The COD removal rates at 45 min were 67.74%, 67.74%, 63.49% and 67.19%, respectively, and the COD of the effluent reached the Class A emission standard.

[0039] The above-mentioned iron-carbon heterogeneous catalyst was used to catalyze high-salinity wastewater with micro-electrolysis. The specific conditions were as follows: micro-electrolysis aeration for 1 hour (pH value was 3.5), iron-carbon catalyst dosage was 500g, and the experimental water sample volume was 2L. The same iron-carbon heterogeneous catalyst was repeated for 3 cycles, and the experimental results are shown in Table 2.

[0040] Table 2 Experimental results of iron-carbon heterogeneous catalytic micro-electrolysis of high-salinity wastewater

[0041] It can be seen from Table 2 that the COD removal rates after three cycles are 39.59%, 35.87% and 38.42% respectively. The B / C of the raw water is 0.11, and the B / C ratios of the micro-electrolysis effluent are 0.38, 0.39 and 0.41, and the B / C of the effluent meets the requirements of the biochemical pool.

[0042] The above-mentioned iron-carbon heterogeneous catalyst was used to treat the landfill leachate after biochemical treatment as the treatment target, and the conventional Fenton process was used for the experiment. The experimental parameters were as follows: iron-carbon heterogeneous catalyst dosage: 0.5g / L, coagulation precipitation: 2mL / LPAC (polyaluminium chloride), 1mL / L PAM (polyacrylamide), pH=3.4, ferrous sulfate: 0.2mol / L; hydrogen peroxide: 0.5mol / L and then reacted for 2h; then adjusted to neutral and allowed to stand (recorded as the experimental group); and a control group without adding the iron-carbon heterogeneous catalyst was set at the same time. The COD removal rate after 30 minutes of reaction was recorded. The COD removal rate of the control group was only 35.48%, while the COD removal rate increased to 56.44% after the addition of the iron-carbon catalyst, indicating that the iron-carbon heterogeneous catalyst disclosed in the present invention can effectively catalyze the Fenton catalytic oxidation reaction.

[0043] It can be seen from the above test results that the iron-carbon heterogeneous catalyst prepared by the present invention has excellent catalytic effects on a variety of different advanced oxidation processes.

[0044] Example 2

[0045] Preparation of universal iron-carbon heterogeneous catalyst for advanced oxidation processes The iron oxide: coal powder: manganese oxide: cerium nitrate: bentonite binder = 60:25:10:5:10 ratio was mechanically stirred and mixed, and then extruded into granules. After completion, the mixture was calcined at 600°C for 4 h to obtain a 3-5 mm general-purpose iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0046] The above-mentioned iron-carbon heterogeneous catalyst was used to catalyze the ozone oxidation of petrochemical wastewater. The specific conditions were as follows: inlet ozone concentration 50 mg / L, inlet air volume 0.3 L / min, reaction time 60 min, test water sample volume 3 L, and the volume of the iron-carbon heterogeneous catalyst was 10% of the total volume of the treated water sample. The same iron-carbon heterogeneous catalyst was repeated 4 times, and the experimental results are shown in Table 3.

[0047] Table 3 Experimental results of iron-carbon heterogeneous catalytic ozone oxidation of petrochemical wastewater

[0048] It can be seen from Table 3 that the iron-carbon heterogeneous catalyst prepared by the present invention also has excellent catalytic effect on petrochemical wastewater. After 4 consecutive repeated tests, the iron-carbon catalytic efficiency did not decrease significantly. At 45 min, the COD removal rates were 40.00%, 48.98%, 49.52% and 51.40% respectively. Due to the large fluctuation of the influent water quality, the effluent COD was stable at about 50 mg / L, which is much higher than the efficiency of catalytic ozone oxidation of catalysts with different substrates sold on the market (under the same experimental conditions, Shandong Senyang Environmental Protection Technology Co., Ltd. catalyst: COD removal rate of 24.74% after one cycle; Shandong Xiguan Alumina Technology Co., Ltd. catalyst: COD removal rate of 28.57% after one cycle; Yixing Feiran Technology FR-OA-1: COD removal rate of 22.47% after one cycle).

[0049] Example 3

[0050] Preparation of universal iron-carbon heterogeneous catalyst for advanced oxidation processes The iron oxide: coal powder: copper chloride: lanthanum nitrate: bentonite binder were mechanically stirred and mixed in a ratio of 50:30:15:10:8, and then extruded and granulated. After completion, the mixture was calcined at 500°C for 3 h to obtain a 4-6 mm general-purpose iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0051] Example 4

[0052] Preparation of universal iron-carbon heterogeneous catalyst for advanced oxidation processes Ferric chloride: coal powder: copper carbonate: cerium nitrate: polypropylene alcohol binder = 50:20:10:10:5 are mechanically stirred and mixed, and then extruded into granules. After completion, the granules are calcined at 800°C for 4 hours to obtain a 3-5 mm general-purpose iron-carbon heterogeneous catalyst for advanced oxidation processes.

[0053] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes, It is characterized in that It is prepared from the following raw materials in parts by weight: 50-60 parts of iron source, 20-30 parts of carbon source, 10-15 parts of transition metal source, 5-10 parts of rare earth metal source and 5-10 parts of binder.

2. A general-purpose iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 1, It is characterized in that The iron source includes one or more of iron oxide, iron salt and iron powder.

3. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 2, It is characterized in that The carbon source includes one or more of activated carbon, coal powder and biochar.

4. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 3, It is characterized in that The transition metal source includes one or more of manganese salt, nickel salt, copper salt and cobalt salt.

5. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 4, It is characterized in that The rare earth metal source includes cerium salt and / or lanthanum salt.

6. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 5, It is characterized in that The binder includes one or more of bentonite, coal tar pitch, polypropylene alcohol and lime.

7. A universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to any one of claims 1 to 6, It is characterized in that The particle size of the universal iron-carbon heterogeneous catalyst for the advanced oxidation process is 3-6 mm.

8. A method for preparing a universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to any one of claims 1 to 7, It is characterized in that The steps include: An iron source, a carbon source, a transition metal source, a rare earth metal source and a binder are mixed and granulated, and then calcined to obtain a universal iron-carbon heterogeneous catalyst for advanced oxidation processes.

9. The method for preparing a universal iron-carbon heterogeneous catalyst for advanced oxidation processes according to claim 8, It is characterized in that The calcination temperature is 600-800° C., and the calcination time is 3-5 hours.

10. Application of a universal iron-carbon heterogeneous catalyst for advanced oxidation processes prepared by the preparation method of a universal iron-carbon heterogeneous catalyst for advanced oxidation processes as described in any one of claims 8 to 9 in ozone oxidation processes, catalytic ozone oxidation processes, Fenton-like processes, micro-electrolysis processes and Fenton processes.

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