Anti-pollution reverse osmosis membrane module for coal chemical industry wastewater, preparation method thereof and application thereof

Abstract

The present invention provides an anti-pollution reverse osmosis membrane module for coal chemical wastewater and a preparation method thereof. The polyamide composite reverse osmosis membrane material is modified, and the configurations of different components in the module are designed. By optimizing the structure and thickness of the desalination layer of the membrane sheet, and constructing a uniform and stable surface protection layer and charge shielding layer, the reverse osmosis membrane material has more excellent anti-organic pollution ability and cleaning resistance. Combined with the design of the internal structure of the membrane module, the inlet water flow rate is increased, the anti-pollution property is improved, the membrane flux is increased, and the service life of the reverse osmosis membrane sheet is extended. Through the method of the present invention, an anti-pollution reverse osmosis membrane module product with good anti-pollution performance and stable desalination rate is developed, meeting the requirements of low-cost deep treatment and reuse, and zero discharge of coal chemical wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of coal chemical wastewater treatment, and particularly relates to an anti-pollution reverse osmosis membrane module for coal chemical wastewater, its preparation and application. Background Art

[0002] At present, the development chain of the coal chemical industry mainly includes coal gasification, coal liquefaction, and coal coking. A large amount of water is required in the coal chemical process, mainly for gas washing and condensation, so corresponding wastewater will be generated, specifically including coking wastewater, coal liquefaction wastewater, and coal gasification wastewater. The pollutants in coal chemical wastewater have a high concentration and complex water quality, and it is an industrial wastewater with high concentration and difficult biodegradation.

[0003] With the development of coal chemical wastewater treatment technology, most technologies are relatively mature, including membrane separation technology, which is widely used in coal chemical wastewater treatment operations and plays a positive role. Membrane separation technology mainly relies on the selective characteristics of the membrane to selectively allow components to pass through, thereby achieving separation of the feed liquid.

[0004] Reverse osmosis, as an advanced water treatment technology, is a membrane separation operation that uses a pressure difference as the driving force to separate the solvent from the solution. Pressure is applied to the feed liquid on one side of the reverse osmosis membrane. When the pressure exceeds its osmotic pressure, the solvent will perform reverse osmosis against the natural osmosis direction. Thus, the permeated solvent, i.e., the permeate, is obtained on the low-pressure side of the reverse osmosis membrane; and the concentrated solution, i.e., the concentrate, is obtained on the high-pressure side. Polyamide composite reverse osmosis membranes are commonly used reverse osmosis membranes, which can effectively remove dissolved salts, colloids, microorganisms, and organic matter in water and have broad application prospects.

[0005] However, there is still great room for improvement in the anti-pollution ability, chemical cleaning resistance, service life, etc. of existing reverse osmosis membranes. Summary of the Invention

[0006] The purpose of the present invention is to provide an anti-pollution reverse osmosis membrane module for coal chemical wastewater and its preparation method in view of the deficiencies of existing reverse osmosis membranes. Through the modification of polyamide composite reverse osmosis membrane materials and the design of module configurations, an anti-pollution reverse osmosis membrane module product with good anti-pollution performance and stable salt rejection rate is developed to meet the requirements of low-cost in-depth treatment, reuse, and zero discharge of coal chemical wastewater.

[0007] According to the first aspect of the purpose of the present invention, a preparation method of an anti-pollution reverse osmosis membrane module for coal chemical wastewater is provided, including the following steps:

[0008] S1. Prepare polyamide membrane sheets

[0009] S11. Coat an aqueous solution containing a compound with multiple amino groups on the surface of the porous support base membrane, and remove the excess aqueous solution on the surface of the porous support base membrane infiltrated by the aqueous solution; wherein, the aqueous solution is a mixed solution of a compound with multiple amino groups, sodium dodecyl sulfonate, carbon nanotubes, graphene, and water.

[0010] S12. Coat an oil-phase solution containing a compound with multiple acyl chloride groups on the surface of the porous support base membrane treated in step S11 for an interfacial polymerization reaction. After the reaction ends, remove the excess oil-phase solution to form a desalination layer on the surface of the porous support base membrane.

[0011] S13. Immerse the porous support base membrane treated in step S12 in the functional layer solution and let it stand until the surface of the porous support base membrane is fully saturated with the functional layer solution. Among them, the functional layer solution is an acidic aqueous solution of o-phenylenediamine, ethoxylated alkylamine, and graphene. Through ultraviolet light initiation, o-phenylenediamine undergoes a polymerization reaction on the surface of the porous support base membrane, and ethoxylated alkylamine and graphene are imprinted in the formed polymer to form a functional layer on the surface of the desalination layer.

[0012] S14. Heat-treat the porous support base membrane treated in step S13 to obtain a polyamide membrane sheet.

[0013] Among them, the carbon nanotubes and graphene in the desalination layer make the desalination membrane have a three-dimensional network pore structure, increase the thickness of the membrane, and combine with the functional layer to reduce the surface potential of the membrane sheet.

[0014] By controlling the concentration of the aqueous solution and the concentration of the oil-phase solution, control the thickness and structure of the desalination layer, and by controlling the concentration of the functional layer solution, control the thickness of the functional layer, so as to obtain polyamide membrane sheets with different desalination rates.

[0015] S2. Assembly of the membrane module

[0016] S21. Sandwich each concentrated water grid between the polyamide membrane sheets obtained in step S1 to form an inlet channel, and obtain a number of first combined membrane sheets and second combined membrane sheets; the desalination rate of the first combined membrane sheet is greater than that of the second combined membrane sheet.

[0017] [[ID=2৪]]Among them, the concentrated water grid is set to be thick at the front end and thin at the rear end along the water flow direction, so as to form a stepped shape, and the concentrated water grid is set into a Z-shaped grid structure to improve the mass transfer efficiency in the flow channel.

[0018] The surface of the concentrated water grid is wrapped with a hydrophilic gel, and the hydrophilic gel contains ethoxylated alkylamine and graphene, which improves the hydrophilicity of the concentrated water grid and reduces the adsorption of pollutants.

[0019] S22. Connect a number of dialysis fluid diversion meshes to the water production central pipe, adhesively bond the first combined membrane sheet and the second combined membrane to the first dialysis fluid diversion mesh, with the position of the first combined membrane sheet close to the water outlet end, and then cover and adhesively bond with the adjacent second dialysis fluid diversion mesh to obtain the third combined membrane sheet. Each group of third combined membrane sheets forms an independent filtration system for multiple cycles of filtration;

[0020] Among them, the first dialysis fluid diversion mesh is set as a honeycomb structure with unequal honeycomb sizes; the second dialysis fluid diversion mesh is set as a zigzag grid structure, causing adjacent dialysis fluid diversion meshes to form a mismatch and increasing the speed of the purified water flowing into the pore positions;

[0021] The water production central pipe is provided with multiple groups of pore positions, and each group of pore positions is composed of a number of hexagonal holes, increasing the flow rate of the dialysis fluid;

[0022] S23. Combine and wind a number of the third combined membrane sheets obtained in step S22 onto the water production central pipe, install end caps at both ends, and wind the outer shell with fiberglass to obtain a coal chemical wastewater anti-pollution reverse osmosis membrane module;

[0023] Among them, the surface of the end cap is pulse-shaped and is provided with pulse-shaped holes for water flow through to promote the flow rate of the inlet water.

[0024] In an alternative embodiment, in the aqueous solution, the mass percentage of the polyamine group-containing compound is 0.1 - 6%, the mass percentage of sodium dodecyl sulfate is 0.01 - 0.05%, the mass percentage of graphene is 1 - 3%, and the mass percentage of carbon nanotubes is 1 - 3%.

[0025] In an alternative embodiment, the graphene is bilayer graphene, and the diameter of the carbon nanotubes is 2 - 20 nm.

[0026] In an alternative embodiment, the polyamine group-containing compound is one or more of triethanolamine, 1,2-ethylenediamine, o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine.

[0027] In an alternative embodiment, the compound containing a polyacyl chloride group is one or more of isophthaloyl chloride, phthaloyl chloride, terephthaloyl chloride, and trimellitic trichloride, and its mass percentage in the oil phase solution is 0.1 - 5%.

[0028] In an alternative embodiment, in the functional layer solution, the mass percentage of o-phenylenediamine is 1 - 5%, the mass percentage of ethoxylated alkylamine is 0.1 - 0.5%, and the mass percentage of graphene is 0.1 - 0.5%.

[0029] In an alternative embodiment, the main component of the hydrophilic gel is sodium alginate.

[0030] In an alternative embodiment, in the hydrophilic gel, the mass percentage of ethoxylated alkylamine is 0.1-0.5%, and the mass percentage of graphene is 0.1-0.5%.

[0031] According to the second aspect of the object of the present invention, there is provided a coal chemical wastewater anti-pollution reverse osmosis membrane module prepared by the foregoing method.

[0032] According to the third aspect of the object of the present invention, there is provided an application of the foregoing coal chemical wastewater anti-pollution reverse osmosis membrane module in the treatment of coal chemical wastewater.

[0033] Compared with the prior art, the remarkable beneficial effects of the present invention are as follows:

[0034] The coal chemical wastewater anti-pollution reverse osmosis membrane module of the present invention optimizes the structure and thickness of the desalination layer of the membrane sheet, and constructs a uniform and stable surface protection layer and charge shielding layer, so that the reverse osmosis membrane material has a more excellent ability to resist organic pollution and cleaning resistance; at the same time, combined with the design of the internal structure of the membrane module, by setting membrane sheets with different desalination rates, the front and rear desalination rates and fluxes are relatively uniform; through the design of the concentrated water grid structure, grid blockage and scaling are reduced, the inlet water flow channel and the effective area of the membrane are increased, and the mass transfer efficiency in the flow channel is improved; and a hydrophilic gel containing ethoxylated alkylamine and graphene is wrapped on the concentrated water grid to improve the hydrophilicity of the concentrated water grid and reduce the adsorption of pollutants; through the design of the dialysis liquid diversion net structure, by setting grids with different shapes and using them mismatched, the water flow velocity is increased; combined with the hole position design of the water production central pipe, each group of hole positions is a combination of several hexagonal holes to form a honeycomb shape, which improves the flow rate of the dialysis liquid; and by designing the surface of the end cap to be pulsed and provided with pulsed holes for water flow to pass through, the inlet water flow velocity is increased.

[0035] Thus, through the design of the membrane sheet and the combination of the design of the internal structure of the membrane module, the anti-pollution performance of the reverse osmosis membrane module is improved, the stability of the desalination rate and the membrane flux is improved, the life of the reverse osmosis membrane sheet is extended, and under standard test conditions, the desalination rate of the membrane module of the present invention for coal chemical wastewater is ≥99.3%, the comprehensive flux decay rate after pollution is ≤15%, the change in desalination rate is ≤0.3%, the comprehensive chemical cleaning recovery rate is ≥95%, and the use cost is reduced by more than 20% compared with imported membrane modules, having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a process flow schematic diagram of the preparation method of the coal chemical wastewater anti-pollution reverse osmosis membrane module of the present invention.

[0037] Figure 2 is a structural schematic diagram of the coal chemical wastewater anti-pollution reverse osmosis membrane module of the present invention.

[0038] Figure 3 It is a top view of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0039] Figure 4 It is an assembled external view of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0040] Figure 5 It is a schematic structural view of the water production central pipe of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0041] Figure 6 It is a schematic structural view of the first combined membrane sheet of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0042] Figure 7 It is a schematic structural view of the first dialysate diversion net of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0043] Figure 8 It is a schematic structural view of the second dialysate diversion net and the concentrated water grid of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0044] Figure 9 It is an exploded schematic structural view of the first combined membrane sheet of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0045] Figure 10 It is a schematic side view of the end cap of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention.

[0046] Figure 11 It is a schematic front view of the end cap of the anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention. Detailed implementation manners

[0047] For a better understanding of the technical content of the present invention, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0048] In the present disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to cover all aspects of the present invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways.

[0049] Preparation Method of Anti-Pollution Reverse Osmosis Membrane Module for Coal Chemical Wastewater

[0050] Combined with Figure 1 the process flow shown, an exemplary preparation method of an anti-pollution reverse osmosis membrane module for coal chemical wastewater of the present invention includes the following steps:

[0051] S1. Prepare polyamide membrane sheets

[0052] S11. Coat an aqueous solution containing a polyamine-based compound on the surface of the porous support substrate membrane, and remove the excess aqueous solution on the surface of the porous support substrate membrane infiltrated with the aqueous solution; wherein, the aqueous solution is a mixed solution of a polyamine-based compound, sodium dodecyl sulfonate, carbon nanotubes, graphene and water.

[0053] It can be understood that the bottom surface of the porous support substrate membrane is non-woven fabric, and there is a support layer on the surface, such as a polysulfone porous support layer.

[0054] The porous support substrate membrane can be directly purchased or prepared according to the existing technology.

[0055] S12. Coat an oil phase solution containing a polyacyl chloride-based compound on the surface of the porous support substrate membrane treated in step S11 for interfacial polymerization reaction. After the reaction is completed, remove the excess oil phase solution to form a desalination layer on the surface of the porous support substrate membrane.

[0056] S13. Immerse the porous support substrate membrane treated in step S12 in the functional layer solution and let it stand until the surface of the porous support substrate membrane is filled with the functional layer solution. Wherein, the functional layer solution is an acidic aqueous solution of o-phenylenediamine, ethoxylated alkylamine and graphene. Through ultraviolet light initiation, o-phenylenediamine undergoes a polymerization reaction on the surface of the porous support substrate membrane, and ethoxylated alkylamine and graphene are imprinted in the formed polymer to form a functional layer on the surface of the desalination layer.

[0057] S14. Heat-treat the porous support substrate membrane treated in step S13 to obtain a polyamide membrane sheet.

[0058] Among them, the carbon nanotubes and graphene in the desalination layer make the desalination membrane have a three-dimensional network pore structure, increase the thickness of the membrane, and combine with the molecular imprinting technology to imprint the antistatic agent and conductive graphene on the surface of the substrate membrane to form a functional layer. The polymerized o-phenylenediamine, and the imprinted components cooperate with the components in the desalination layer to reduce the potential on the surface of the membrane sheet, reduce electrostatic adsorption, and improve the anti-fouling ability of the membrane sheet.

[0059] By controlling the concentration of the aqueous solution and the concentration of the oil phase solution, the thickness and structure of the desalination layer are controlled, and by controlling the concentration of the functional layer solution, the thickness of the functional layer is controlled, so as to obtain polyamide membrane sheets with different desalination rates.

[0060] S2. Assembly of the membrane module

[0061] S21. As Figure 9 shown, sandwich each concentrated water grid in the middle of the polyamide membrane sheet obtained in step S1 to form an inlet channel, and obtain a number of first combined membrane sheets and second combined membrane sheets; the desalination rate of the first combined membrane sheet is greater than that of the second combined membrane sheet.

[0062] Among them, the concentrated water grid is arranged to be thick at the front end and thin at the rear end along the water flow direction, thereby forming a stepped shape, and the concentrated water grid is arranged in a zigzag grid structure, as Figure 8 shown, to improve the mass transfer efficiency in the flow channel. It can be understood that the size and interval shape of the zigzag can be designed according to the actual situation.

[0063] The surface of the concentrated water grid is wrapped with a hydrophilic gel, and the hydrophilic gel contains ethoxylated alkylamine and graphene, which improves the hydrophilicity of the concentrated water grid and reduces the adsorption of pollutants.

[0064] S22. As Figure 6 and Figure 9 shown, a number of dialysate diversion nets are connected to the water production central pipe, the first combined membrane sheet and the second combined membrane are adhesively bonded to the first dialysate diversion net, and the position of the first combined membrane sheet is close to the water outlet end. Then, the adjacent second dialysate diversion net is used to cover and bond, obtaining a third combined membrane sheet. Each group of third combined membrane sheets forms a separate filtration system for multiple cycle filtrations.

[0065] As Figure 7 and Figure 8 shown, among them, the first dialysate diversion net is arranged in a honeycomb structure, and the sizes of the honeycombs are not equal; the second dialysate diversion net is arranged in a zigzag grid structure, so that the adjacent dialysate diversion nets are mismatched, improving the speed of the purified water flowing into the pore positions.

[0066] It should be understood that the size and interval shape of the zigzag of the zigzag grid structure of the second dialysate diversion net can be designed according to the actual situation, which can be the same as or different from the concentrated water grid, and no further limitation is made here.

[0067] As Figure 5 shown, a plurality of groups of pore positions are provided on the water production central pipe, and each group of pore positions is composed of a number of hexagonal holes, improving the flow rate of the dialysate.

[0068] S23. As Figure 2 and Figure 3 shown, a number of third combined membrane sheets obtained in step S22 are combined and wound around the water production central pipe, end caps are installed at both ends, and the outer shell is wound with fiberglass to obtain a coal chemical wastewater anti-pollution reverse osmosis membrane module.

[0069] Among them, as Figure 10 and Figure 11 shown, the surface of the end cap is pulsed and provided with pulsed holes for water flow to pass through, promoting the flow rate of the inlet water.

[0070] ​​​​​​In an alternative embodiment, in the aqueous solution, the mass percentage of the polyamine group-containing compound is 0.1-6%, the mass percentage of sodium dodecyl sulfonate is 0.01-0.05%, the mass percentage of graphene is 1-3%, and the mass percentage of carbon nanotubes is 1-3%.

[0071] In an alternative embodiment, the graphene is bilayer graphene, and the diameter of the carbon nanotubes is 2-20 nm.

[0072] In an alternative embodiment, the polyamine group-containing compound is one or more of triethanolamine, 1,2-ethylenediamine, o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine.

[0073] In an alternative embodiment, the compound containing a polyacyl chloride group is one or more of isophthaloyl chloride, phthaloyl chloride, terephthaloyl chloride, and trimesoyl chloride, and the mass percentage in the oil phase solution is 0.1-5%.

[0074] In an alternative embodiment, in the functional layer solution, the mass percentage of o-phenylenediamine is 1-5%, the mass percentage of ethoxylated alkylamine is 0.1-0.5%, and the mass percentage of graphene is 0.1-0.5%.

[0075] In an alternative embodiment, the main component of the hydrophilic gel is sodium alginate.

[0076] In an alternative embodiment, in the hydrophilic gel, the mass percentage of ethoxylated alkylamine is 0.1-0.5%, and the mass percentage of graphene is 0.1-0.5%.

[0077] Anti-Pollution Reverse Osmosis Membrane Module for Coal Chemical Wastewater

[0078] In another embodiment of the present invention, there is provided a coal chemical wastewater anti-pollution reverse osmosis membrane module prepared by the foregoing method. The diameter of the membrane module is related to the number of membrane sheets, and the number of membrane sheets is designed according to the required water production. The larger the water production, the more the number of membrane sheets.

[0079] Combined Figure 2 - Figure 4 As shown, the exemplary coal chemical wastewater anti-pollution reverse osmosis membrane module of the present invention includes a membrane blank composed of a water production central pipe 1 and a plurality of groups of third combined membrane sheets 2 wound around the water production central pipe, end caps 3 provided at both ends of the membrane blank, and a housing 4 provided outside the membrane blank.

[0080] A plurality of groups of hole positions 11 are provided on the water production central pipe 1, and the purified water enters the water production central pipe through the hole positions for collection and outflow; wherein, as Figure 5 shown, each group of hole positions is preferably set as a combination of several hexagonal holes.

[0081] As Figure 6As shown, each set of third combined diaphragms 2 includes a first dialysate diversion net 21, a second dialysate diversion net 22, and a first combined diaphragm 23 and a second combined diaphragm 24 disposed between the first dialysate diversion net 21 and the second dialysate diversion net 22.

[0082] One side of the first dialysate diversion net 21 and the second dialysate diversion net 22 is connected to the water production central pipe 1, and the three edges not connected to the water production central pipe are adhesively bonded to the edges of the combined diaphragm, thereby forming a first combined diaphragm connected to the central water production pipe.

[0083] As Figure 7 and Figure 8 shown, the first dialysate diversion net 21 is arranged in a honeycomb structure, and the second dialysate diversion net 22 is arranged in a Z-shaped grid structure, so that adjacent dialysate diversion nets are mismatched, improving the speed of purified water flowing into the holes 11.

[0084] In a preferred embodiment, in the honeycomb structure of the first dialysate diversion net 21, there are honeycombs of various sizes.

[0085] In a more preferred embodiment, it is composed of two sizes of honeycombs, one large and one small.

[0086] In other preferred embodiments, honeycombs of different sizes are arranged at intervals to form a mismatch between honeycombs of different sizes, improving the mass transfer efficiency.

[0087] As Figure 6 shown, the first combined diaphragm 23 and the second combined diaphragm 24 are arranged in sequence. The position of the first combined diaphragm 23 is close to the purified water outlet end, and the desalination rate of the first combined diaphragm 23 is higher than that of the second combined diaphragm 24.

[0088] As Figure 9 shown, the first combined diaphragm 23 is composed of a first polyamide diaphragm 231 and a first concentrated water grid 232 sandwiched between the first polyamide diaphragms. The second combined diaphragm 24 is composed of a second polyamide diaphragm and a second concentrated water grid sandwiched between the second polyamide diaphragms, thereby forming an inlet channel, and the desalination rate of the first polyamide diaphragm is higher than that of the second polyamide diaphragm.

[0089] The first concentrated water grid 232 and the second concentrated water grid have the same structure, which is arranged in a Z-shaped grid structure and is set to be thick at the front end and thin at the rear end along the water flow direction, thereby forming a stepped shape and improving the water inlet efficiency.

[0090] As Figure 10 and Figure 11 shown, in a preferred embodiment, the surface of the end cap 3 is pulsed, and the holes are set in a pulsed shape for accelerating the flow rate of the inlet water.

[0091] In the Z-shaped grid structures of the second dialysis liquid diversion net 22 and the first concentrated water grid, the size and interval shape of the Z-shape can be designed according to actual conditions.

[0092] Preferably, the intermediate distance D of each Z-shaped structure is equal.

[0093] Preferably, the intermediate distance D of each Z-shaped structure is equal.

[0094] Preferably, the housing 4 of the anti-pollution reverse osmosis membrane module for coal chemical wastewater is made of fiberglass.

[0095] Preferably, a sealing ring 5 is further provided outside the anti-pollution reverse osmosis membrane module for coal chemical wastewater, and the water flow is blocked by the sealing ring 5 and can only pass through the membrane roll gap.

[0096] In another exemplary embodiment of the present invention, an application of the foregoing anti-pollution reverse osmosis membrane module for coal chemical wastewater in the treatment of coal chemical wastewater is provided.

[0097] Next, specific examples and tests will be used to conduct exemplary tests and comparisons on the foregoing process methods and their effects. Of course, the embodiments of the present invention are not limited thereto.

[0098] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following embodiments can all be obtained from commercial channels.

[0099] In the following examples, the graphene is bilayer graphene, and the diameter of the carbon nanotubes is 2-20 nm.

[0100]

Example 1

[0101] Design a reverse osmosis membrane with a water production rate of 0.25 T / h

[0102] Preparation of Polyamide Membrane Sheet 1

[0103] Coat an aqueous solution on the surface of the polysulfone porous support layer of the base membrane, and remove the excess aqueous solution on the surface of the porous support base membrane after being infiltrated by the aqueous solution. The aqueous solution is: a mixed solution of 2 wt.% o-phenylenediamine, 0.05 wt.% sodium dodecylsulfonate, 1 wt.% carbon nanotubes, 1 wt.% graphene and deionized water.

[0104] Continue to coat an oil phase solution on the surface of the polysulfone porous support layer for an interfacial polymerization reaction. The oil phase solution is: an aqueous solution containing 2 wt.% phthaloyl chloride. After the reaction is completed, the excess oil phase solution is removed, and a desalination layer is formed on the surface of the porous support base membrane.

[0105] 1 wt.% of o-phenylenediamine, 0.1 wt.% of ethoxylated alkylamine, and 0.1 wt.% of graphene were added to deionized water, ultrasonically dispersed, and the pH was adjusted to 4 with 1 M HCl to obtain the functional layer solution.

[0106] The base membrane with the desalination layer was immersed in the functional layer solution and left standing for 24 h until the surface of the base membrane was fully saturated with the functional layer solution. Then, ultraviolet light was irradiated for 30 min to cause the polymerization reaction of o-phenylenediamine on the surface of the porous support base membrane. Through poly-o-phenylenediamine, ethoxylated alkylamine and graphene were imprinted in the formed polymer to form a functional layer on the surface of the desalination layer. After that, it was repeatedly washed with sodium carbonate solution and distilled water until neutral, then rinsed with absolute ethanol and dried at 80 °C for 3 min to obtain polyamide membrane sheet 1 with a desalination rate of 98%.

[0107] Preparation of Polyamide Membrane Sheet 2

[0108] An aqueous solution was coated on the surface of the polysulfone porous support layer of the base membrane, and the excess aqueous solution on the surface of the porous support base membrane infiltrated with the aqueous solution was removed. The aqueous solution was a mixed solution of 6 wt.% of o-phenylenediamine, 0.05 wt.% of sodium dodecyl sulfonate, 3 wt.% of carbon nanotubes, 3 wt.% of graphene and deionized water.

[0109] An oil phase solution was continuously coated on the surface of the polysulfone porous support layer for an interfacial polymerization reaction. The oil phase solution was an aqueous solution containing 5 wt.% of phthaloyl chloride. After the reaction ended, the excess oil phase solution was removed to form a desalination layer on the surface of the porous support base membrane.

[0110] 5 wt.% of o-phenylenediamine, 0.5 wt.% of ethoxylated alkylamine, and 0.5 wt.% of graphene were added to deionized water, ultrasonically dispersed, and the pH was adjusted to 4 with 1 M HCl to obtain the functional layer solution.

[0111] The base membrane with the desalination layer was immersed in the functional layer solution and left standing for 24 h until the surface of the base membrane was fully saturated with the functional layer solution. Then, ultraviolet light was irradiated for 30 min to cause the polymerization reaction of o-phenylenediamine on the surface of the porous support base membrane. Through poly-o-phenylenediamine, ethoxylated alkylamine and graphene were imprinted in the formed polymer to form a functional layer on the surface of the desalination layer. After that, it was repeatedly washed with sodium carbonate solution and distilled water until neutral, then rinsed with absolute ethanol and dried at 80 °C for 3 min to obtain polyamide membrane sheet 2 with a desalination rate of 99.3%.

[0112] Assembly of Membrane Module

[0113] A concentrated water grid with a zigzag grid was used. The concentrated water grid was pretreated: immersed in sodium alginate gel containing 0.2 wt.% of ethoxylated alkylamine and 0.2 wt.% of graphene for 24 h and then air-dried.

[0114] Place the pretreated concentrated water grid in the middle of the polyamide membrane sheet 1 to obtain several combined membrane sheets 1; place the concentrated water grid in the middle of the polyamide membrane sheet 2 to obtain several combined membrane sheets 2. The concentrated water grid is thick at the front end and thin at the rear end along the water flow direction in the membrane sheet, forming a step.

[0115] Connect several dialysis fluid diversion nets to the water production central pipe. One side of the dialysis fluid diversion net is connected to the water production central pipe, bond the combined membrane sheet 1 and the combined membrane 2 to the other three sides of the dialysis fluid diversion net, and the position of the combined membrane sheet 2 is close to the water outlet end. Then use adjacent dialysis fluid diversion nets to cover and bond the same three sides to obtain the combined membrane sheet 3.

[0116] For the adopted dialysis fluid diversion nets, among adjacent dialysis fluid diversion nets, one has a honeycomb structure with different honeycomb sizes; the other is set as a Z-shaped grid to make the dialysis fluid diversion nets form a mismatch. There are multiple groups of hole positions on the water production central pipe, and each group of hole positions is composed of several hexagonal holes.

[0117] Wind several combined membrane sheets 3 around the water production central pipe, install end caps at both ends. The surface of the end cap is pulsed and provided with pulsed holes for water flow to pass through. Wind the outer shell with fiberglass to obtain the reverse osmosis membrane module.

[0118] Select the coal chemical wastewater from coal coking as the application scenario for the pilot test of the anti-pollution reverse osmosis membrane module, investigate the applicability of the anti-pollution membrane module in the deep treatment process of coal chemical wastewater, and investigate the advancement and economy of the anti-pollution reverse osmosis membrane module compared with imported reverse osmosis membranes by continuously monitoring the system water flux, recovery rate, product water quality, desalination rate, etc.

[0119] After testing, under standard test conditions, the desalination rate of the membrane module of the present invention is ≥99.3%. Compared with the anti-pollution products of Dow Chemical in the United States, which have a relatively high technical level in the world currently, the anti-pollution performance of the membrane module of the present invention reaches its level: the comprehensive flux decay rate after pollution ≤15%, the change in desalination rate ≤0.3%, and the comprehensive chemical cleaning recovery rate ≥95% (the anti-pollution performance of the anti-pollution product of Dow Chemical in the United States: for an 8-inch pollution-resistant element, the comprehensive flux decay rate after pollution ≤15%, the change in desalination rate ≤0.3%, and the comprehensive chemical cleaning recovery rate ≥95%); compared with imported membrane modules, the use cost of the membrane module product of the present invention can be reduced by more than 20%.

[0120] When using the anti-pollution reverse osmosis membrane module of the present invention to treat coal chemical wastewater, the anti-pollution performance is improved, and the use cost of the membrane product is reduced by about 20% or more. Calculated according to the three-year replacement cycle of the reverse osmosis membrane, it is estimated that the group's coal chemical sector can save about 15 million yuan per year. If it is promoted to the national coal chemical industry, it can save about 80 million yuan per year.

[0121] The method of the present invention provides support for the application and promotion of domestic anti-pollution membrane products, and is of great significance for improving the localization rate of reverse osmosis membranes. Through the customized research on coal chemical wastewater and exploring the customized production path of products, it can be extended to the research and development of similar topics.

[0122] Although the present invention has been disclosed above in preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims

1. A preparation method of a coal chemical industry wastewater anti-pollution reverse osmosis membrane module, characterized in that, It includes the following steps: S1. Prepare a polyamide membrane sheet S11. Coat an aqueous solution containing a compound with multiple amino groups on the surface of a porous support substrate membrane, and remove the excess aqueous solution on the surface of the porous support substrate membrane infiltrated by the aqueous solution; wherein, the aqueous solution is a mixed solution of a compound with multiple amino groups, sodium dodecyl sulfonate, carbon nanotubes, graphene and water; S12. Coat an oil-phase solution containing a compound with multiple acyl chloride groups on the surface of the porous support substrate membrane treated in step S11 for interfacial polymerization reaction. After the reaction is completed, remove the excess oil-phase solution to form a desalination layer on the surface of the porous support substrate membrane; S13. Immerse the porous support substrate membrane treated in step S12 in the functional layer solution and let it stand until the surface of the porous support substrate membrane is filled with the functional layer solution. Wherein, the functional layer solution is an acidic aqueous solution of o-phenylenediamine, ethoxylated alkylamine and graphene. Through ultraviolet light initiation, o-phenylenediamine undergoes a polymerization reaction on the surface of the porous support substrate membrane, and ethoxylated alkylamine and graphene are imprinted in the formed polymer to form a functional layer on the surface of the desalination layer; S14. Heat-treat the porous support substrate membrane treated in step S13 to obtain a polyamide membrane sheet; Wherein, the carbon nanotubes and graphene in the desalination layer make the desalination membrane have a three-dimensional network pore structure, increase the thickness of the membrane, and combine with the functional layer to reduce the surface potential of the membrane sheet; By controlling the concentration of the aqueous solution and the concentration of the oil-phase solution, the thickness and structure of the desalination layer are controlled, and by controlling the concentration of the functional layer solution, the thickness of the functional layer is controlled, so as to obtain polyamide membrane sheets with different desalination rates; S2. Assembly of the membrane module S21. Clamp each concentrated water grid in the middle of the polyamide membrane sheet obtained in step S1 to form an inlet channel, and obtain a number of first combined membrane sheets and second combined membrane sheets; the desalination rate of the first combined membrane sheet is greater than that of the second combined membrane sheet; Wherein, the concentrated water grid is set to be thick at the front end and thin at the rear end along the water flow direction, so as to form a stepped shape, and the concentrated water grid is set into a Z-shaped grid structure to improve the mass transfer efficiency in the flow channel; The surface of the concentrated water grid is wrapped with a hydrophilic gel, and the hydrophilic gel contains ethoxylated alkylamine and graphene, which improves the hydrophilicity of the concentrated water grid and reduces the adsorption of pollutants; S22. Connect a number of dialysis fluid diversion meshes to the water production central pipe, bond the first combined membrane sheet and the second combined membrane sheet to the first dialysis fluid diversion mesh, and the position of the first combined membrane sheet is close to the water outlet end, and then cover and bond with the adjacent second dialysis fluid diversion mesh to obtain a third combined membrane sheet. Each group of third combined membrane sheets forms a separate filtration system for multiple cycle filtrations; Wherein, the first dialysis fluid diversion mesh is set into a honeycomb structure, and the sizes of the honeycombs are different; the second dialysis fluid diversion mesh is set into a Z-shaped grid structure, so that the adjacent dialysis fluid diversion meshes are mismatched to improve the speed of the purified water flowing into the pore positions; Multiple groups of pore positions are provided on the water production central pipe, and each group of pore positions is composed of a number of hexagonal holes to improve the flow rate of the dialysis fluid; S23. Wind the several third combined diaphragm assemblies obtained in step S22 around the water production central tube, install end caps at both ends, and wind the outer shell with fiberglass to obtain a coal chemical wastewater anti-pollution reverse osmosis membrane module; Among them, the surface of the end cap is wavy and is provided with wavy holes for water flow to promote the flow rate of the influent water.

2. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, wherein, In the aqueous solution, the mass percentage of the compound containing polyamino groups is 0.1 - 6%, the mass percentage of sodium dodecyl sulfonate is 0.01 - 0.05%, the mass percentage of graphene is 1 - 3%, and the mass percentage of carbon nanotubes is 1 - 3%.

3. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, characterized in that, The graphene is bilayer graphene, and the diameter of the carbon nanotubes is 2 - 20 nm.

4. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical industry wastewater according to claim 1, wherein, The compound containing polyamino groups is one or more of triethanolamine, 1,2-ethylenediamine, o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine.

5. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, characterized in that, The compound containing polyacyl chloride groups is one or more of isophthaloyl chloride, phthaloyl chloride, terephthaloyl chloride, and trimellitic trichloride, and its mass percentage in the oil phase solution is 0.1 - 5%.

6. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, characterized in that, In the functional layer solution, the mass percentage of o-phenylenediamine is 1 - 5%, the mass percentage of ethoxylated alkylamine is 0.1 - 0.5%, and the mass percentage of graphene is 0.1 - 0.5%.

7. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, characterized in that, The main component of the hydrophilic gel is sodium alginate.

8. The preparation method of the anti-pollution reverse osmosis membrane module for coal chemical wastewater according to claim 1, characterized in that In the hydrophilic gel, the mass percentage of ethoxylated alkylamine is 0.1 - 0.5%, and the mass percentage of graphene is 0.1 - 0.5%.

9. A coal chemical wastewater anti-pollution reverse osmosis membrane module prepared by any one of the methods in claims 1 - 8.

10. An application of the coal chemical wastewater anti-pollution reverse osmosis membrane module according to claim 9 in the treatment of coal chemical wastewater.

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