Nano-pore mayenite / zirconium oxide / aluminum oxide ceramic composite catalytic membrane for semi-coke wastewater emulsified tar removal process as well as preparation method and application of nano-pore mayenite / zirconium oxide / aluminum oxide ceramic composite catalytic membrane

Abstract

The invention discloses a nano-pore mayenite / zirconium oxide / aluminum oxide ceramic composite catalytic membrane for a semi-coke wastewater emulsified tar removal process and a preparation method and application thereof, and relates to a ceramic composite catalytic membrane and a preparation method and application thereof. The invention aims to solve the problem that a catalytic ceramic membrane with high-efficiency emulsified oil interception and excellent anti-pollution performance is lacked in the prior art, so that the dual requirements of semi-coke wastewater pretreatment and phenol ammonia recovery processes on inlet water quality and operation stability are difficult to meet. The catalytic membrane is formed by sequentially compounding an aluminum oxide tubular ceramic membrane substrate, a zirconium oxide middle layer and a nanopore Ca12Al14O33 catalytic layer. The method comprises the following steps: 1, preparing an alumina tubular ceramic membrane substrate; 2, preparing a zirconium oxide middle layer; and 3, preparation of the Ca12Al14O33 catalyst layer with the nano pore channels. The method is applied to removal of emulsified tar in semi-coke wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to a ceramic composite catalytic membrane and its preparation method and application. BACKGROUND

[0002] As a key process of low-rank coal fractionation utilization, the production of semi-coke produces a large amount of wastewater (also known as semi-coke wastewater or coal pyrolysis wastewater) in the links of coal gas cooling, ammonia evaporation and tar recovery. This wastewater has the typical characteristics of "four high" - high oil, high phenol, high ammonia nitrogen and high chemical oxygen demand (COD), and is complex in composition and difficult to treat. Compared with conventional coking wastewater, the content of emulsified tar in semi-coke wastewater is significantly higher, and especially the emulsified oil is difficult to be effectively demulsified by traditional physical methods due to the wrapping of polar groups on the surface and the formation of stable double electric layer, which becomes a key bottleneck restricting the subsequent resource recovery.

[0003] The current semi-coke wastewater pretreatment process generally adopts the combined process of "grating-gravity sedimentation-air flotation-coagulation", which can remove most of the floating oil and dispersed oil, but the removal rate of emulsified oil is generally less than 60%, which is difficult to meet the strict requirements of the subsequent phenol and ammonia recovery section on the oil content of the influent (≤200 mg / L). Some processes introduce solvent extraction to strengthen oil removal, but there are problems such as large solvent consumption, high operating cost and easy secondary pollution, which limit its industrial application.

[0004] In recent years, ceramic membrane separation technology has been tried to be used for deep oil removal of semi-coke wastewater due to its excellent corrosion resistance and mechanical strength. However, in actual operation, emulsified oil is easy to deposit on the membrane surface to form a dense filter cake layer, and penetrate into the membrane pore channel to cause blockage, resulting in a sharp decrease of more than 50% in membrane flux within 2-4 hours. The conventional cleaning methods (such as water backflushing, acid and alkali cleaning) have limited cleaning effect on this kind of composite pollution, and the membrane flux recovery rate is usually less than 40%, frequent shutdown cleaning seriously affects the treatment efficiency and increases the operation and maintenance cost.

[0005] To overcome the above-mentioned bottleneck, catalytic membrane technology has emerged, which combines membrane separation with in-situ catalytic oxidation to realize the catalytic degradation of pollutants while intercepting them, thereby effectively alleviating membrane pollution. However, there is still a lack of catalytic ceramic membranes with high-efficiency emulsified oil interception and excellent anti-pollution performance in the existing technology, which is difficult to meet the dual requirements of water quality and operation stability of semi-coke wastewater pretreatment and phenol and ammonia recovery process. SUMMARY

[0006] The present application solves the problem in the prior art that there is a lack of catalytic ceramic membranes with high-efficiency emulsified oil interception and excellent anti-pollution performance, which is difficult to meet the dual requirements of water quality and operation stability of semi-coke wastewater pretreatment and phenol and ammonia recovery process, and further provides a nano-pore channel huntite / zirconia / alumina ceramic composite catalytic membrane for semi-coke wastewater emulsified tar removal process and its preparation method and application.

[0007] A nano-porous calcium aluminate / zirconia / alumina ceramic composite catalytic membrane for removing emulsified tar in semi-coke wastewater is prepared by using an alumina tubular ceramic membrane substrate, a zirconia intermediate layer and a nano-porous calcium aluminate / aluminum oxide catalytic layer. 12 Al 14 O 33 The catalytic layer is sequentially compounded; the zirconia intermediate layer is loaded on the surface of the alumina tubular ceramic membrane substrate, and the nano-porous calcium aluminate / aluminum oxide catalytic layer is loaded on the surface of the zirconia intermediate layer. 12 Al 14 O 33 The catalytic layer is sequentially compounded; the zirconia intermediate layer is loaded on the surface of the alumina tubular ceramic membrane substrate, and the nano-porous calcium aluminate / aluminum oxide catalytic layer is loaded on the surface of the zirconia intermediate layer.

[0008] A preparation method of a nano-porous calcium aluminate / zirconia / alumina ceramic composite catalytic membrane for removing emulsified tar in semi-coke wastewater is as follows:

[0009] I. Preparation of an alumina tubular ceramic membrane substrate:

[0010] After the α-alumina powder and the titanium dioxide powder are ball milled, polyvinyl alcohol aqueous solution, carboxymethyl cellulose aqueous solution, glycerol and polyethylene glycol 8000 are added and stirred to obtain a viscous paste, and the viscous paste is sequentially subjected to vacuum paste refining, aging, extrusion molding, gradient drying and high-temperature calcination to obtain the alumina tubular ceramic membrane substrate.

[0011] II. Preparation of a zirconia intermediate layer:

[0012] Zirconia powder, yttrium oxide powder and a dispersant are added to polyvinyl alcohol aqueous solution and ball milled to obtain a uniform system, and then vacuum degassing is performed to obtain a casting solution, the casting solution is loaded on the surface of the alumina tubular ceramic membrane substrate by using a pulling and dipping method, and then drying is performed, the pulling and dipping and drying are repeated multiple times, and finally calcination is performed to obtain the substrate covered with the zirconia intermediate layer.

[0013] III. Preparation of a nano-porous calcium aluminate / aluminum oxide catalytic layer: 12 Al 14 O 33 IV. Preparation of a nano-porous calcium aluminate / aluminum oxide catalytic layer:

[0014] Calcium acetylacetonate, aluminum acetylacetonate, citric acid and polystyrene-b-polyethylene oxide block copolymer are dissolved in tetrahydrofuran, and then a concentrated nitric acid solution is added and heated and stirred to obtain a precursor sol, the precursor sol is loaded on the surface of the substrate covered with the zirconia intermediate layer by using a pulling and dipping method, and then drying is performed, the pulling and dipping and drying are repeated multiple times, and finally calcination is performed to obtain the nano-porous calcium aluminate / aluminum oxide catalytic layer, i.e. the nano-porous calcium aluminate / zirconia / alumina ceramic composite catalytic membrane. 12 Al 14 O 33 The catalytic layer is sequentially compounded; the zirconia intermediate layer is loaded on the surface of the alumina tubular ceramic membrane substrate, and the nano-porous calcium aluminate / aluminum oxide catalytic layer is loaded on the surface of the zirconia intermediate layer. 12 Al 14 O 33Ceramic composite catalytic membrane of / ZrO2 / Al2O3.

[0015] The application of a nano-pore channel mayenite / zirconia / alumina ceramic composite catalytic membrane for the removal of emulsified tar in semi-coke wastewater, which is used for the removal of emulsified tar in semi-coke wastewater.

[0016] The present application has the following advantages:

[0017] (1) High separation efficiency: the Ca 12 Al 14 O 33 The interception rate of the / ZrO2 / Al2O3 ceramic membrane for emulsified oil in semi-coke wastewater is ≥99%, and the oil content in the effluent is ≤10 mg / L, which meets the requirement of the subsequent phenol and ammonia recovery process for the oil content in the influent (≤200 mg / L), avoiding coking and plugging of the tower equipment.

[0018] (2) Strong anti-pollution ability: the membrane flux recovery rate is ≥94% through in-situ catalytic cleaning with ozone, the cleaning cycle is prolonged, and the operation and maintenance cost is reduced;

[0019] (3) No secondary pollution: no flocculant needs to be added in the pretreatment process, and there is no chemical agent residue;

[0020] (4) Excellent stability: the ceramic membrane substrate and the Ca 12 Al 14 O 33 The catalytic layer is combined tightly, and there is no falling off during long-term operation under the condition of semi-coke wastewater pH of 3-11 and room temperature, and the service life is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a flow chart of the nano-pore channel Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane filtering in Example 1, ① is a water tank, ② is a valve, ③ is a membrane device, ④ is a phenol and ammonia recovery device, ⑤ is a water tank, ⑥ is a gas-liquid mixing pump, ⑦ is an ozone generator, ⑧ is a backwashing water tank, and ⑨ is a backwashing pump.

[0022] Figure 2 It is a physical map of the nano-pore channel Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane prepared in Example 1.

[0023] Figure 3 It is a SEM image, a is the zirconia intermediate layer prepared in step two of Example 1, and b is the nano-pore channel Ca 12 Al 14 O 33Cross-sectional view of ZrO2 / Al2O3 ceramic composite catalytic membrane, c is nano-porous Ca 12 Al 14 O 33 Catalytic layer, d is a partial enlarged view of c;

[0024] Figure 4 Nano-porous Ca 12 Al 14 O 33 XRD pattern of catalytic layer;

[0025] Figure 5 Nano-porous Ca 12 Al 14 O 33 Membrane flux and 1-methylnaphthalene removal rate of ZrO2 / Al2O3 ceramic composite catalytic membrane;

[0026] Figure 6 Nano-porous Ca 12 Al 14 O 33 Cleaning efficiency of ZrO2 / Al2O3 ceramic composite catalytic membrane;

[0027] Figure 7 Nano-porous Ca 12 Al 14 O 33 Removal rate of 1-methylnaphthalene by ZrO2 / Al2O3 ceramic composite catalytic membrane under different pH conditions;

[0028] Figure 8 Comparison of catalytic ozone degradation of phenol by different catalysts;

[0029] Figure 9 Rate constant of catalytic ozone decomposition by different catalysts. DETAILED DESCRIPTION

[0030] Embodiment one: a nano-porous Ca 12 Al 14 O 33 Catalytic layer is sequentially compounded; the zirconium oxide intermediate layer is loaded on the surface of the alumina tubular ceramic membrane substrate, and the nano-porous Ca 12 Al 14 O 33 Catalytic layer is loaded on the surface of the zirconium oxide intermediate layer.

[0031] Principle: Calcite (Ca) 12 Al 14 O 33 It has a unique calcium aluminum stone crystal structure, belongs to the hexagonal crystal system, and contains elements composed of Ca. 2+ Al 3+ With O 2- A constructed three-dimensional mesh framework. Among them, Al 3+ Through covalent bonds with O 2- Two coordination structures are formed: [AlO4] tetrahedron and [AlO6] octahedron. The two types of coordination units are interconnected to form a through-hole structure; Ca 2+ It fills the interstitial spaces of the crystal lattice and bonds with the surrounding O through ionic bonds. 2- This combination stabilizes the crystal lattice structure and provides active sites on the crystal surface. The abundant oxygen vacancies on its surface can serve as ozone activation sites; ozone in Ca... 2+ / Al 3+ The active site adsorbs and activates, generating •OH and 1 O2; active species can rapidly oxidize and degrade oil contaminants (such as naphthalene and benzene compounds) on the membrane surface and within the pores, converting them into CO2 and H2O, thus preventing membrane fouling caused by contaminant accumulation. It is used as a catalyst layer on the ceramic membrane surface, enabling in-situ self-cleaning of the membrane with the help of ozone while filtering emulsified oil, thereby maintaining stable operating flux and effluent water quality.

[0032] The beneficial effects of this embodiment are:

[0033] (1) High separation efficiency: The Ca prepared in this embodiment 12 Al 14 O 33 The ZrO2 / Al2O3 ceramic membrane achieves a ≥99% retention rate for emulsified oil in semi-coke wastewater, with an effluent oil content ≤10mg / L, meeting the requirements of subsequent phenol and ammonia recovery processes for influent oil content (≤200mg / L) and preventing coking and clogging of the tower equipment.

[0034] (2) Strong anti-pollution ability: Through ozone in-situ catalytic cleaning, the membrane flux recovery rate is ≥94%, the cleaning cycle is extended, and the operation and maintenance costs are reduced;

[0035] (3) No secondary pollution: No flocculant needs to be added during the pretreatment process, and there is no chemical residue;

[0036] (4) Excellent stability: The ceramic film substrate and Ca 12 Al 14 O 33 The catalyst layer is tightly bonded and does not detach during long-term operation under conditions of pH 3-11 in semi-coke wastewater and room temperature, thus extending its service life.

[0037] Specific embodiment two: the preparation method of the nano-pore Ca

[0038] I. Preparation of the alumina tubular ceramic membrane substrate:

[0039] After ball-milling the α-alumina powder and the titanium dioxide powder, polyvinyl alcohol aqueous solution, carboxymethyl cellulose aqueous solution, glycerol and polyethylene glycol 8000 are added and stirred to obtain a viscous paste. The viscous paste is subjected to vacuum kneading, aging, extrusion molding, gradient drying and high-temperature calcination in sequence to obtain the alumina tubular ceramic membrane substrate.

[0040] II. Preparation of the zirconia intermediate layer:

[0041] Zirconia powder, yttrium oxide powder and a dispersant are added to the polyvinyl alcohol aqueous solution and ball-milled to obtain a uniform system, which is then vacuum-deaerated to obtain a casting solution. The casting solution is loaded on the surface of the alumina tubular ceramic membrane substrate by using the dip-coating method, and then dried. The dip-coating and drying are repeated for multiple times, and finally calcined to obtain the substrate coated with the zirconia intermediate layer.

[0042] III. Preparation of the nano-pore Ca 12 Al 14 O 33 catalytic layer:

[0043] Calcium acetylacetonate, aluminum acetylacetonate, citric acid and polystyrene-b-polyethylene oxide block copolymer are dissolved in tetrahydrofuran, and then a concentrated nitric acid solution is added and heated and stirred to obtain a precursor sol. The precursor sol is loaded on the surface of the substrate coated with the zirconia intermediate layer by using the dip-coating method, and then dried. The dip-coating and drying are repeated for multiple times, and finally calcined to obtain the nano-pore Ca 12 Al 14 O 33 catalytic layer, i.e. the nano-pore Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane.

[0044] In step one, the α-alumina powder and the titanium dioxide powder are ball-milled to ensure that the powders are uniformly mixed and have no obvious agglomeration. In step one, the viscous paste has plasticity and fluidity. In step one, the internal bubbles of the paste are fully removed by vacuum kneading. In step one, the water and various additives are fully diffused and uniformly distributed by aging, so as to avoid defects in the subsequent molding. In step one, the surface state of the green body is monitored in real time during the extrusion process, and the environmental temperature and humidity are controlled to prevent the green body from generating surface cracks or deformation due to rapid water loss. In step one, the alumina tubular ceramic membrane substrate has a uniform pore size distribution and can be used as a stable support carrier for the subsequent coating.

[0045] In the third embodiment, the mass ratio of the α-alumina powder to the titanium dioxide powder in the viscous paste in step one is 85:(1.1-1.3), the mass ratio of the α-alumina powder to polyvinyl alcohol is 85:(2.3-2.6), the mass ratio of the α-alumina powder to carboxymethyl cellulose is 85:(2.6-3.0), the mass ratio of the α-alumina powder to glycerol is 85:(6.5-7.5), the mass ratio of the α-alumina powder to polyethylene glycol 8000 is 85:(0.13-0.16), and the mass ratio of the α-alumina powder to ultrapure water is 85:(21-23); the particle size of the α-alumina powder in step one is 40-90 µm, and the particle size of the titanium dioxide powder is 50-120 nm; the ball milling in step one is specifically carried out at a ball-to-material mass ratio of 1:(0.43-0.46) and a rotation speed of 180-220 rpm for 3-5 h; the vacuum kneading in step one is specifically carried out using a vacuum kneading machine at a vacuum degree of -0.085 to -0.095 MPa for 3-5 times, each time for 8-10 min; the aging in step one is specifically carried out at an ambient temperature of 20-30 °C and an ambient humidity of 60-65% for 24-36 h; the extrusion molding in step one is specifically carried out using a tubular ceramic extruder at an ambient temperature of 20-25 °C, an ambient humidity of 50-60%, an extrusion pressure of 0.6-0.9 MPa, and an extrusion rate of 7-9 cm / min to obtain a tubular ceramic green body, wherein the outer diameter of the tubular ceramic green body is 10.8-11.2 mm, the inner diameter is 6.8-7.2 mm, and the length is 11-11.2 cm; the gradient drying in step one is specifically carried out by first drying at a temperature of 30-35 °C for 6-8 h, then drying at a temperature of 50-55 °C for 12-15 h, and finally drying at a temperature of 70-75 °C for 8-10 h to obtain a dried green body, wherein the water content of the dried green body is reduced to below 0.8%; and the high-temperature calcination in step one is specifically carried out at a heating rate of 6-8 °C / min, the temperature is raised to 1280-1320 °C, and the calcination is carried out at a temperature of 1280-1320 °C for 5-6 h, followed by natural cooling to room temperature. The other steps are the same as in the second embodiment.

[0046] Specific embodiment four: the difference between this embodiment and one of the specific embodiments two or three is that the polyvinyl alcohol aqueous solution in steps one and two is prepared by dissolving polyvinyl alcohol in ultrapure water at a temperature of 80℃ to 90℃ and a rotation speed of 150 rpm to 250 rpm, and the viscosity of the polyvinyl alcohol is 55 mPa.s to 65 mPa.s. The rest is the same as specific embodiments two or three.

[0047] Specific embodiment five: the difference between this embodiment and one of the specific embodiments two to four is that the mass ratio of polyvinyl alcohol to ultrapure water in the polyvinyl alcohol aqueous solution in step two is 1:(90-100); the mass ratio of polyvinyl alcohol to zirconium oxide powder in step two is 1:(20-30); the mass ratio of polyvinyl alcohol to yttrium oxide powder in step two is 1:(1-4); the mass ratio of polyvinyl alcohol to dispersant in step two is 1:(5-15); the dispersant in step two is DARVAN C-N; the particle size of the zirconium oxide powder in step two is 0.1 μm to 5 μm, and the particle size of the yttrium oxide powder is 40 nm to 100 nm; the ball milling in step two is carried out at a ball-to-material mass ratio of 1:(0.3-0.6) and a rotation speed of 150 rpm to 250 rpm for 3 h to 4 h; the vacuum degassing in step two is carried out at a vacuum degree of -0.08 MPa to -0.1 MPa for 15 min to 30 min; the dip-coating method in step two is carried out by first immersing the alumina tubular ceramic membrane substrate in the casting solution at a temperature of 20℃ to 25℃ for 32 s to 38 s, and then pulling the alumina tubular ceramic membrane substrate at a speed of 2.2 mm / s to 2.8 mm / s; the drying in step two is carried out at a temperature of 62℃ to 68℃ for 3 min to 5 min; the dip-coating and drying in step two are repeated 2 to 3 times; the calcination in step two is carried out by increasing the temperature at a rate of 5℃ / min to 10℃ / min to 1100℃ to 1400℃, and then keeping the temperature at 1100℃ to 1400℃ for 5 h to 6 h, and then decreasing the temperature to room temperature at a rate of 3℃ / min to 5℃ / min. The rest is the same as specific embodiments two to four.

[0048] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Two to Five in the following ways: the number average molecular weight of the polystyrene-b-polyethylene oxide block copolymer mentioned in step three is 13,000~14,000; the mass percentage of the concentrated nitric acid solution mentioned in step three is 65%~68%; the molar ratio of citric acid to calcium acetylacetonate in step three is 5:(0.1~0.2); the molar ratio of citric acid to aluminum acetylacetonate in step three is 5:(0.1~0.2); the molar ratio of citric acid to polystyrene-b-polyethylene oxide block copolymer in step three is 5:(0.002~0.006); the molar ratio of citric acid to tetrahydrofuran in step three is 5:(150~200); the molar ratio of citric acid to nitric acid in the concentrated nitric acid solution in step three is 5:(0.3~0.4); the specific steps of adding concentrated nitric acid solution and heating and stirring in step three are... Under conditions of 35℃~40℃ and stirring speed of 200rpm~240rpm, heat and stir for 12h~20h; the dip-coating method described in step three specifically involves first immersing the substrate covered with the zirconia intermediate layer in the precursor sol for 18s~22s at a temperature of 20℃~25℃, and then pulling the substrate covered with the zirconia intermediate layer at a speed of 1.2mm / s~1.4mm / s; the drying described in step three specifically involves drying at a temperature of 80℃~100℃ for 12h~48h; the dip-coating and drying process in step three is repeated 2~3 times; the calcination described in step three specifically involves heating to 800℃~1000℃ at a heating rate of 3℃ / min~6℃ / min, holding at 800℃~1000℃ for 4h~5h, and then cooling to room temperature at a rate of 3℃ / min~6℃ / min. The rest is the same as in specific implementation methods two to five.

[0049] Specific Implementation Method Seven: This implementation method describes the application of a nanoporous calcium aluminum stone / zirconia / alumina ceramic composite catalytic membrane for the removal of emulsified tar from semi-coke wastewater.

[0050] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that it is used for the removal of emulsified tar from semi-coke wastewater, and is carried out according to the following steps:

[0051] ① Wastewater treatment:

[0052] Semi-coke wastewater with a pH of 3-11 and room temperature was fed into a Ca2+ channel with nanoporous structures. 12 Al 14 O 33 The filtered water is then filtered through a ZrO2 / Al2O3 ceramic composite catalytic membrane device and enters a phenol and ammonia recovery unit.

[0053] ② Membrane backwashing:

[0054] After the filtration, the nano-pore Ca 12 Al 14 O 33 The back-flushing is performed on the ZrO2 / Al2O3 ceramic composite catalytic membrane. The other steps are the same as those in the seventh embodiment.

[0055] The ninth embodiment is different from the seventh or eighth embodiment in that the concentration of the ozone water in step ② is 45 mg / L to 55 mg / L; and the back-flushing in step ② is specifically performed under the condition that the pressure is 0.3 bar to 0.5 bar, and the back-flushing time is 4 min to 10 min. The other steps are the same as those in the seventh or eighth embodiment.

[0056] The tenth embodiment is different from the seventh to ninth embodiments in that the nano-pore Ca 12 Al 14 O 33 The ZrO2 / Al2O3 ceramic composite catalytic membrane has a coke waste water emulsified oil interception rate of ≥99% and an effluent oil content of ≤10 mg / L; and the membrane flux recovery rate in step ② is ≥94%. The other steps are the same as those in the seventh to ninth embodiments.

[0057] The following examples are used to verify the beneficial effects of the present application:

[0058] Example 1

[0059] A preparation method of a nano-pore CaO / Al2O3 / ZrO2 ceramic composite catalytic membrane for coke waste water emulsified tar removal process, which is performed according to the following steps:

[0060] I. Preparation of an alumina tubular ceramic membrane substrate:

[0061] The α-alumina powder and the titanium dioxide powder (sintering aid) were ball milled for 3.5 h by using a planetary ball mill under the conditions of a ball-to-material mass ratio of 1:0.45 and a rotation speed of 200 rpm, and then the polyvinyl alcohol (binder) aqueous solution, the carboxymethyl cellulose (plasticizer, CMC) aqueous solution, the glycerol (lubricant), and the polyethylene glycol 8000 (pore-forming agent) were added, and the viscous slip was stirred for 2.5 h under the condition of a stirring speed of 250 rpm, and then the viscous slip was placed in a vacuum slip casting machine, and the slip was cast for 3 times for 8 min each time under the condition of a vacuum degree of -0.085 MPa, and then the cast green body was aged for 36 h under the conditions of an ambient temperature of 24℃ and an ambient humidity of 65%, and then the cast green body was extruded into a tubular ceramic green body by using a tubular ceramic extruder under the conditions of an ambient temperature of 22℃, an ambient humidity of 55%, an extrusion pressure of 0.8 MPa, and an extrusion rate of 8 cm / min, and then the tubular ceramic green body was dried for 7 h at a temperature of 32℃, and then the tubular ceramic green body was dried for 14 h at a temperature of 52℃, and finally the tubular ceramic green body was dried for 9 h at a temperature of 72℃, so as to obtain a dried green body, and the water content of the dried green body was reduced to 0.6%, and finally the dried green body was heated to 1300℃ at a heating rate of 7℃ / min, and then the dried green body was calcined at a temperature of 1300℃ for 5.5 h, and then the dried green body was naturally cooled to room temperature, so as to obtain the alumina tubular ceramic membrane substrate;

[0062] The mass ratio of the α-alumina powder to the titanium dioxide powder in the viscous slip was 85:1.2, the mass ratio of the α-alumina powder to the polyvinyl alcohol was 85:2.5, the mass ratio of the α-alumina powder to the carboxymethyl cellulose was 85:2.8, the mass ratio of the α-alumina powder to the glycerol was 85:7, the mass ratio of the α-alumina powder to the polyethylene glycol 8000 was 85:0.15, and the mass ratio of the α-alumina powder to the ultrapure water was 85:22; the particle size of the α-alumina powder was 40μm-90μm, and the particle size of the titanium dioxide powder was 50nm-120nm; the outer diameter of the tubular ceramic green body was 11mm, the inner diameter was 7mm, and the length was 11cm; the polyvinyl alcohol aqueous solution was prepared by dissolving the polyvinyl alcohol in the ultrapure water under the conditions of a temperature of 85℃ and a rotation speed of 200 rpm, and the viscosity of the polyvinyl alcohol was 55mPa.s-65mPa.s; the solvent in the carboxymethyl cellulose aqueous solution was ultrapure water;

[0063] II. Preparation of the zirconia intermediate layer

[0064] Zirconium oxide powder, yttrium oxide powder and dispersant were added into polyvinyl alcohol aqueous solution, then the system was uniformly grinded for 3 hours under the condition of ball-to-material mass ratio of 1:0.4 and rotation speed of 200 rpm, and vacuum degassing was performed for 15 minutes under the condition of vacuum degree of-0.09 MPa to obtain casting solution; firstly, the alumina tubular ceramic membrane substrate was immersed in the casting solution for 35 seconds under the condition of temperature of 25℃, then the alumina tubular ceramic membrane substrate was pulled up at a speed of 2.5 mm / s, and then drying was performed for 4 minutes under the condition of temperature of 65℃; the pulling and immersing and drying were repeated twice, finally, the temperature was raised to 1200℃ at a rate of 8℃ / min, and calcination was performed for 5 hours under the condition of temperature of 1200℃, and then the temperature was lowered to room temperature at a rate of 5℃ / min to obtain the substrate covered with zirconium oxide intermediate layer;

[0065] The mass ratio of polyvinyl alcohol to ultrapure water is 1:100; the mass ratio of polyvinyl alcohol to zirconium oxide powder is 1:30; the mass ratio of polyvinyl alcohol to yttrium oxide powder is 1:2; the mass ratio of polyvinyl alcohol to dispersant is 1:5; the dispersant is DARVAN C-N; the average particle size of zirconium oxide powder is 0.2 μm, and the average particle size of yttrium oxide powder is 50 nm; the polyvinyl alcohol aqueous solution is prepared by dissolving polyvinyl alcohol in ultrapure water under the condition of temperature of 85℃ and rotation speed of 200 rpm, and the viscosity of polyvinyl alcohol is 55 mPa.s-65 mPa.s;

[0066] III. Nanopore Ca 12 Al 14 O 33 Preparation of the catalytic layer:

[0067] Calcium acetylacetonate, aluminum acetylacetonate, citric acid and polystyrene-b-polyethylene oxide block copolymer (PS-b-PEO) were dissolved in tetrahydrofuran, and concentrated nitric acid solution was added, and then heating and stirring were performed for 16 hours under the condition of temperature of 40℃ and stirring speed of 220 rpm to obtain precursor sol; firstly, the substrate covered with zirconium oxide intermediate layer was immersed in the precursor sol for 20 seconds under the condition of temperature of 25℃, then the substrate covered with zirconium oxide intermediate layer was pulled up at a speed of 1.3 mm / s, and then drying was performed for 12 hours under the condition of temperature of 80℃; the pulling and immersing and drying were repeated twice, finally, the temperature was raised to 800℃ at a rate of 5℃ / min, and calcination was performed for 4 hours under the condition of temperature of 800℃, and then the temperature was lowered to room temperature at a rate of 5℃ / min to obtain nanopore Ca 12 Al 14 O 33 The catalytic layer, namely nanopore Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane;

[0068] The number average molecular weight of the polystyrene-b-polyethylene oxide block copolymer is 13000; the mass percentage of the concentrated nitric acid solution is 65%; the molar ratio of citric acid to calcium acetylacetonate is 5:0.12; the molar ratio of citric acid to aluminum acetylacetonate is 5:0.14; the molar ratio of citric acid to polystyrene-b-polyethylene oxide block copolymer is 5:0.003; the molar ratio of citric acid to tetrahydrofuran is 5:170; and the molar ratio of citric acid to nitric acid in the concentrated nitric acid solution is 5:0.3;

[0069] The specific preparation method of the polystyrene-b-polyethylene oxide block copolymer is as follows:

[0070] ① 30.0 g of polyethylene glycol monomethyl ether PEO5000 is dissolved in 90 mL of THF, then 60 mL of pyridine is added to obtain a uniform solution, the uniform solution is cooled in an ice water bath, then 4.50 g of 2-bromoisobutyryl bromide is added dropwise under stirring, and stirring is performed at a temperature of 30℃ for 12 h; then it is dialyzed in a dialysis bag for 48 h, and finally freeze-dried at -80℃ for 48 h to obtain a white product, i.e., PEO-Br;

[0071] ② 4.50 g of PEO-Br, 0.12 g of CuBr, 0.15 g of pentamethyldiethylene triamine (PMDETA), and 22.5 g of styrene are added to a three-necked flask; then it is immersed in a constant temperature oil bath at 180℃ under the protection of nitrogen, and stirring is performed to polymerize styrene, the reaction lasts for 1.5 h, then the system is cooled to room temperature to obtain a gel-like product, the gel-like product is dissolved in 75 mL of THF, and filtration is performed through a neutral alumina column to remove Cu complex, and finally petroleum ether (300 mL) is poured into the solution to precipitate the PEO-b-PS block copolymer.

[0072] The nano-pore Ca 12 Al 14 O 33 Application of the / ZrO2 / Al2O3 ceramic composite catalytic membrane, which is used for removing emulsified tar in semi-coke wastewater, in combination with Figure 1 Specifically, the following steps are performed:

[0073] ① Wastewater treatment:

[0074] The emulsified tar simulated wastewater with a pH of 10 and at room temperature is sent into the nano-pore Ca 12 Al 14 O 33The filtered water enters a phenol-ammonia recovery device under the condition of a transmembrane pressure difference of 0.3 MPa.

[0075] ②Membrane backwashing:

[0076] After filtration, the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane is backwashed with ozone water under the condition of a pressure of 0.4 bar for 6 min.

[0077] The concentration of the ozone water is 50 mg / L.

[0078] The emulsified tar simulated wastewater in step ① is prepared according to the following steps: 0.1004 g of sodium oleate is dissolved in 250 mL of deionized water to obtain a sodium oleate aqueous solution; 5 g of 1-methylnaphthalene is added to the sodium oleate aqueous solution, which is subjected to high-speed magnetic stirring at a speed of 800 rpm for 60 min, and then subjected to ultrasonic stirring at an ultrasonic power of 300 W for 40 min to obtain a mixed solution; the mixed solution is transferred to a 500 mL volumetric flask, diluted with deionized water to a constant volume and mixed uniformly, and then left to stand for 10 min, and finally the upper liquid is collected to obtain an emulsified tar simulated mother liquor; the concentration of sodium oleate in the emulsified tar simulated mother liquor is 200 mg / L, and the concentration of 1-methylnaphthalene is 9500 mg / L; then the emulsified tar simulated mother liquor is diluted to a 1-methylnaphthalene content of 2500 mg / L to obtain the emulsified tar simulated wastewater; wherein the sodium oleate is a surfactant, and the 1-methylnaphthalene is the main component of the simulated tar.

[0079] Example 2: The difference between this comparative experiment and Example 1 is that the pH value of the emulsified tar simulated wastewater in step ① is 3, 5, 7, 9 or 11, and the others are the same as in Example 1.

[0080] Comparative Experiment 1: The difference between this comparative experiment and Example 1 is that the average particle size of the zirconium oxide powder in step ② is 7 μm, and the others are the same as in Example 1.

[0081] Comparative Experiment 2: The difference between this comparative experiment and Example 1 is that the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane is backwashed with water in step ②, and the others are the same as in Example 1.

[0082] Figure 1 The nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane in Example 1 is backwashed with ozone water.The flow chart of the ceramic composite catalytic membrane filter of / ZrO2 / Al2O3, ① is a water tank, ② is a valve, ③ is a membrane device, ④ is a phenol ammonia recovery device, ⑤ is a water tank, ⑥ is a gas-liquid mixing pump, ⑦ is an ozone generator, ⑧ is a backwashing water tank, and ⑨ is a backwashing pump; the emulsified tar simulation wastewater is loaded into the water tank ①, the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane is placed in the membrane device ③, under the condition of a transmembrane pressure difference of 0.3 MPa, the emulsified tar simulation wastewater is filtered into the membrane device ③, the filtered water is sent into the device ④ for phenol ammonia recovery, and the concentrated water is partially returned to the water tank ① through a circulating pipeline for recycling treatment, or is discharged through a discharge valve. After the filtration is completed, the water tank ⑤ and the ozone generator ⑦ are opened, the mixture is sent to the backwashing water tank ⑧ through the gas-liquid mixing pump ⑥, and then the ozone water is transported to the membrane device ③ through the pipeline by the backwashing pump ⑨ to backwash the membrane.

[0083] Figure 2 The nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane prepared in Example 1.

[0084] Figure 3 The SEM images, a is the zirconium oxide intermediate layer prepared in step two of Example 1, b is the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane, c is the nano-porous Ca 12 Al 14 O 33 catalytic layer prepared in step three of Example 1, d is a local enlarged view of c. As shown in the image a, the zirconium oxide intermediate layer has a nano-porous structure and a high porosity, and the porosity can reach 60% to 66%; as shown in the image b, the upper layer is the nano-porous Ca 12 Al 14 O 33 catalytic layer, and the intermediate layer is the zirconium oxide intermediate layer. As shown in the images c and d, the nano-porous Ca 12 Al 14 O 33 catalytic layer forms a nano-porous structure, and the pore size can reach 25 nm to 35 nm.

[0085] Figure 4 The nano-porous Ca 12 Al 14 O 33XRD pattern of the catalytic layer. It can be seen from the figure that it has very narrow and high characteristic peaks, indicating that the crystallinity is very high. And compared with the PDF standard card of Ca 12 Al 14 O 33 , it is proved that the catalytic layer is the substance of Ca 12 Al 14 O 33 .

[0086] Figure 5 The membrane flux and 1-methylnaphthalene removal rate of the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane prepared in Example 1 and Comparative Experiment 1 are shown in the figure. It can be seen from the figure that the catalytic membrane prepared by using a ceramic membrane substrate of 0.2 μm zirconia in Example 1 has a membrane flux (emulsified tar simulated wastewater) of 270 L·m -2 ·h -1 ·bar -1 , and the removal rate of 1-methylnaphthalene reaches 99%, and the oil content of the effluent is 10 mg / L; the catalytic membrane prepared by using a ceramic membrane substrate of 7 μm zirconia in Comparative Experiment 1 has a membrane flux (emulsified tar simulated wastewater) of 330.1 L·m -2 ·h -1 ·bar -1 , and the removal rate of 1-methylnaphthalene is only 68.9%.

[0087] Figure 6 The cleaning efficiency of the nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane prepared in Example 1 and Comparative Experiment 2 is shown in the figure. After the membrane filters the simulated wastewater solution for 2 h, the backwashing is carried out by using ordinary water and ozone water solution (concentration of 50 mg / L) respectively at a pressure of 0.4 bar from the back side of the membrane for 6 min. It can be seen from the figure that the flux recovery after different cleaning methods, and after four backwashings, the flux recovery rate of the membrane backwashed by ordinary water is low, about 12%, and the flux of the membrane backwashed by ozone water can be recovered to 94%, and the cleaning effect is significant.

[0088] Figure 7 The nano-porous Ca 12 Al 14 O 33The removal rate of 1-methylnaphthalene by the ZrO2 / Al2O3 ceramic composite catalytic membrane under different pH conditions is shown in the figure. As can be seen from the figure, the removal rate of 1-methylnaphthalene by the ceramic composite membrane remains above 99% within the pH range of 3-11, proving that it can operate stably under different pH conditions.

[0089] Ca was prepared according to step three of Example 1. 12 Al 14 O 33 Catalyst: Step 3, including dip-coating and drying, was omitted. The precursor sol prepared in Step 3 of Example 1 was directly dried at 80°C for 12 hours. After drying, it was ground and then heated to 800°C at a rate of 5°C / min. The sol was then calcined at 800°C for 4 hours and then cooled to room temperature at a rate of 5°C / min to obtain Ca. 12 Al 14 O 33 catalyst.

[0090] Using Ca 12 Al 14 O 33 Phenol (50 mg / L) was degraded using catalysts, CaO catalyst, MnO2 catalyst, and Al2O3 catalyst. The specific reaction conditions were: ozone gas concentration of 10 mg / L, gas flow rate of 0.2 L / min, and catalyst dosage of 0.3 g / L. Figure 8 A comparison chart of the performance of different catalysts in catalyzing the degradation of phenol by ozone; as shown in the chart, compared with other catalytic systems, Ca... 12 Al 14 O 33 Phenol (50 mg / L) can be completely degraded within 10 minutes under the O3 system, demonstrating its excellent ozone catalytic oxidation performance.

[0091] By adding Ca to saturated ozone water with a concentration of 5 mg / L 12 Al 14 O 33 The effects of different catalysts (CaO, MnO2, and Al2O3) on the ozone decomposition rate were investigated, with a catalyst dosage of 0.3 g / L. Figure 9 The figures represent the rate constants for ozone decomposition catalyzed by different catalysts; as shown in the figure, Ca... 12 Al 14 O 33 The decomposition rate constant for O3 is 0.866 min. -1 Under catalyst-free conditions (0.188 min) -1 4.60 times that of MnO2 (0.495 min) -1The ratio of the area of the peak of the sample 1 to that of the sample 2 was 1.74 times, reflecting the excellent ozone catalytic decomposition ability.

Claims

1. A nano-channels chabazite / zirconia / alumina ceramic composite catalytic membrane for the removal of emulsified tar from semi-coke wastewater, characterized in that It comprises an alumina tubular ceramic membrane substrate, a zirconia intermediate layer and a nano-pore Ca 12 Al 14 O 33 Catalytic layers are sequentially compounded; the zirconia intermediate layer is loaded on the surface of the alumina tubular ceramic membrane substrate, and the nano-pore Ca 12 Al 14 O 33 Catalytic layer is loaded on the surface of the zirconia intermediate layer.

2. A method for preparing a nano-channel mayenite / zirconia / alumina ceramic composite catalytic membrane for a green coal wastewater emulsified tar removal process according to claim 1, characterized in that It is carried out according to the following steps: I. Preparation of the alumina tubular ceramic membrane substrate: After the alpha-alumina powder and the titanium dioxide powder are ball milled, polyvinyl alcohol aqueous solution, carboxymethyl cellulose aqueous solution, glycerol and polyethylene glycol 8000 are added and stirred to obtain a viscous slip, and the viscous slip is subjected to vacuum slip casting, aging, extrusion molding, gradient drying and high-temperature calcination in sequence to obtain the alumina tubular ceramic membrane substrate; II. Preparation of the zirconia intermediate layer: Zirconia powder, yttrium oxide powder and a dispersant are added to polyvinyl alcohol aqueous solution and ball milled to obtain a uniform system, and then vacuum degassing is performed to obtain a casting solution, the casting solution is loaded on the surface of the alumina tubular ceramic membrane substrate by using a pulling and dipping method, and then drying is performed, the pulling and dipping and drying are repeated for multiple times, and finally calcination is performed to obtain the substrate covered with the zirconia intermediate layer. III. Nanochannel Ca 12 Al 14 O 33 Preparation of the catalytic layer: Calcium acetylacetonate, aluminum acetylacetonate, citric acid, polystyrene-b-polyethylene oxide block copolymer are dissolved in tetrahydrofuran, then concentrated nitric acid solution is added and heated and stirred to obtain a precursor sol, the precursor sol is loaded on the surface of a substrate covered with a zirconia intermediate layer by using a pulling and dipping method, then dried, the pulling and dipping and drying are repeated for multiple times, and finally calcined to obtain a nano-porous Ca 12 Al 14 O 33 catalytic layer, i.e. a nano-porous Ca 12 Al 14 O 33 / ZrO2 / Al2O3 ceramic composite catalytic membrane.

3. The preparation method of a nano-channel hard-berylite / zirconia / alumina ceramic composite catalytic membrane for the removal of emulsified tar from semi-coke wastewater according to claim 2, characterized in that The mass ratio of the α-alumina powder to the titanium dioxide powder in the viscous paste in step one is 85:(1.1-1.3), the mass ratio of the α-alumina powder to the polyvinyl alcohol is 85:(2.3-2.6), the mass ratio of the α-alumina powder to the carboxymethyl cellulose is 85:(2.6-3.0), the mass ratio of the α-alumina powder to the glycerol is 85:(6.5-7.5), the mass ratio of the α-alumina powder to the polyethylene glycol 8000 is 85:(0.13-0.16), and the mass ratio of the α-alumina powder to the ultrapure water is 85:(21-23); the particle size of the α-alumina powder in step one is 40 µm-90 µm, and the particle size of the titanium dioxide powder is 50 nm-120 nm; the ball milling in step one is specifically carried out under the conditions of a ball-to-material mass ratio of 1:(0.43-0.46) and a rotation speed of 180 rpm-220 rpm for 3-5 h; the vacuum kneading in step one is specifically carried out by using a vacuum kneading machine under the conditions of a vacuum degree of -0.085 MPa--0.095 MPa for 3-5 times, each time for 8 min-10 min; the aging in step one is specifically carried out under the conditions of an ambient temperature of 20 °C-30 °C and an ambient humidity of 60%-65% for 24 h-36 h; the extrusion molding in step one is specifically carried out by using a tubular ceramic extruder under the conditions of an ambient temperature of 20 °C-25 °C, an ambient humidity of 50%-60%, an extrusion pressure of 0.6 MPa-0.9 MPa, and an extrusion rate of 7 cm / min-9 cm / min to obtain a tubular ceramic green body, and the tubular ceramic green body has an outer diameter of 10.8 mm-11.2 mm, an inner diameter of 6.8 mm-7.2 mm, and a length of 11 cm-11.2 cm; the gradient drying in step one is specifically carried out by first drying at a temperature of 30 °C-35 °C for 6 h-8 h, then drying at a temperature of 50 °C-55 °C for 12 h-15 h, and finally drying at a temperature of 70 °C-75 °C for 8 h-10 h to obtain a dried green body, and the water content of the dried green body is reduced to 0.8% or less; and the high-temperature calcination in step one is specifically carried out at a heating rate of 6 °C / min-8 °C / min, the temperature is raised to 1280 °C-1320 °C, and then the calcination is carried out at a temperature of 1280 °C-1320 °C for 5 h-6 h, followed by natural cooling to room temperature.

4. The preparation method of the nano-porous chabazite / zirconia / alumina ceramic composite catalytic membrane for the process of removing emulsified tar from semi-coke wastewater according to claim 2, characterized in that The polyvinyl alcohol aqueous solution in steps one and two is specifically prepared by dissolving the polyvinyl alcohol in ultrapure water under the conditions of a temperature of 80 °C-90 °C and a rotation speed of 150 rpm-250 rpm, and the viscosity of the polyvinyl alcohol is 55 mPa.s-65 mPa.s.

5. The method for preparing a nano-channel chabazite / zirconia / alumina ceramic composite catalytic membrane for the process of removing emulsified tar from semi-coke wastewater according to claim 2, characterized in that The mass ratio of polyvinyl alcohol to ultrapure water in the aqueous polyvinyl alcohol solution in step two is 1:(90-100); the mass ratio of polyvinyl alcohol to zirconium oxide powder in step two is 1:(20-30); the mass ratio of polyvinyl alcohol to yttrium oxide powder in step two is 1:(1-4); the mass ratio of polyvinyl alcohol to dispersant in step two is 1:(5-15); the dispersant in step two is DARVAN C-N; the particle size of the zirconium oxide powder in step two is 0.1-5 μm, and the particle size of the yttrium oxide powder is 40-100 nm; the ball milling in step two is specifically carried out under the conditions of a ball-to-material mass ratio of 1:(0.3-0.6) and a rotation speed of 150-250 rpm for 3-4 h; the vacuum defoaming in step two is specifically carried out under the conditions of a vacuum degree of -0.08 to -0.1 MPa for 15-30 min; the dip-coating method in step two is specifically as follows: first, immerse the alumina tubular ceramic membrane substrate in the casting solution at a temperature of 20-25 °C for 32-38 s, and then pull the alumina tubular ceramic membrane substrate at a speed of 2.2-2.8 mm / s; the drying in step two is specifically carried out at a temperature of 62-68 °C for 3-5 min; the dip-coating and drying in step two are repeated for 2-3 times; the calcination in step two is specifically as follows: first, increase the temperature at a rate of 5-10 °C / min to 1100-1400 °C, and then keep the temperature at 1100-1400 °C for 5-6 h, and then decrease the temperature to room temperature at a rate of 3-5 °C / min.

6. The method for preparing a nano-channel chabazite / zirconia / alumina ceramic composite catalytic membrane for the process of removing emulsified tar from semi-coke wastewater according to claim 2, characterized in that The number average molecular weight of the polystyrene-b-polyethylene oxide block copolymer in step three is 13000-14000; the mass percentage of the concentrated nitric acid solution in step three is 65%-68%; the molar ratio of citric acid to calcium acetylacetonate in step three is 5:(0.1-0.2); the molar ratio of citric acid to aluminum acetylacetonate in step three is 5:(0.1-0.2); the molar ratio of citric acid to polystyrene-b-polyethylene oxide block copolymer in step three is 5:(0.002-0.006); the molar ratio of citric acid to tetrahydrofuran in step three is 5:(150-200); the molar ratio of citric acid to nitric acid in the concentrated nitric acid solution in step three is 5:(0.3-0.4); the heating and stirring in step three is specifically under the condition that the temperature is 35-40 DEG C and the stirring speed is 200-240 rpm, and the heating and stirring is performed for 12-20 h; the dip-coating method in step three is specifically that the substrate covered with the zirconia intermediate layer is first dipped into the precursor sol under the condition that the temperature is 20-25 DEG C for 18-22 s, and then the substrate covered with the zirconia intermediate layer is pulled up at a speed of 1.2-1.4 mm / s; the drying in step three is specifically under the condition that the temperature is 80-100 DEG C, and the drying is performed for 12-48 h; the dip-coating and drying in step three are repeated for 2-3 times; the calcination in step three is specifically that the temperature is raised to 800-1000 DEG C at a speed of 3-6 DEG C / min, and then the temperature is kept at 800-1000 DEG C for 4-5 h, and then the temperature is lowered to room temperature at a speed of 3-6 DEG C / min.

7. The use of a nano-channel mayenite / zirconia / alumina ceramic composite catalytic membrane for a green coal wastewater emulsified tar removal process according to claim 1, characterized in that It is used for removing emulsified tar in semi-coke wastewater.

8. The use of a nano-channel meixnerite / zirconia / alumina ceramic composite catalytic membrane for a green coal wastewater emulsified tar removal process according to claim 7, characterized in that It is used for removing emulsified tar in semi-coke wastewater, and the process is as follows: ① wastewater treatment: The low pH and room temperature Lanmei coal tar wastewater is sent into a device with nano-pore Ca 12 Al 14 O 33 The filtered water is sent into a phenol ammonia recovery device. ② membrane backwashing: After the filtration, the nano-porous Ca 12 Al 14 O 33 ZrO2 / Al2O3 ceramic composite catalytic membrane was back-flushed with ozone water.

9. The use of a nano-channel meyerite / zirconia / alumina ceramic composite catalytic membrane for a green charcoal wastewater emulsified tar removal process according to claim 8, characterized in that The concentration of the ozone water in step ② is 45-55 mg / L; the backwashing in step ② is specifically under the condition that the pressure is 0.3-0.5 bar, and the backwashing is performed for 4-10 min.

10. The use of a nano-channel meyerite / zirconia / alumina ceramic composite catalytic membrane for a green charcoal wastewater emulsified tar removal process according to claim 8, characterized in that The nano-porous Ca 12 Al 14 O 33 The interception rate of the ZrO2 / Al2O3 ceramic composite catalytic membrane for the emulsified oil in the coking waste water is ≥99%, the oil content in the effluent is ≤10 mg / L, and the membrane flux recovery rate in step ② is ≥94%.

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