Buffering type adsorption / desorption method and device for bicarbonate

Abstract

The invention provides a bicarbonate buffer type adsorption / desorption method and a bicarbonate buffer type adsorption / desorption device. According to the bicarbonate buffer type adsorption / desorption method, bicarbonate slow-release balls are prepared and are filled in a buffer device, the pH value of produced water is adjusted to be not lower than 7.5 by utilizing the combination of the buffer device and an adsorption device before target ion adsorption, a proper adsorption environment is provided for a titanium adsorbent, and the adsorption efficiency of the titanium adsorbent is improved. The titanium adsorbent is successfully applied to extraction of lithium from the produced water of the chloride type oil and gas field; and a specially designed segmented circulation thickening desorption mode is further matched to obtain a high-concentration target ion desorption solution.

Description

Technical Field

[0001] This invention belongs to the field of produced water resource utilization technology, and particularly relates to a bicarbonate buffer adsorption / desorption method and apparatus. Background Technology

[0002] With the increasing importance of lithium resources and rising market demand, lithium extraction from produced water in oil and gas fields is receiving increasing attention both domestically and internationally due to its advantages, including a strong industrial foundation, synergistic effects on pollution and carbon reduction, and good resource utilization. Lithium extraction from produced water in oil and gas fields is still in its early stages. Current pilot-scale examples demonstrate that the feasible and effective technical route for lithium extraction from produced water in oil and gas fields is "pretreatment + enrichment and concentration (adsorption-membrane separation) + precipitation". Adsorption-based lithium extraction generally uses lithium-selective adsorbents, such as resin-based alumina adsorbents, lithium alumina intercalated adsorbents, alumina adsorption ion exchange resins, or alumina-based adsorbents. While aluminum-based adsorbents are the most widely used in industrial applications in my country, they also suffer from insurmountable drawbacks, such as low lithium concentrations and a significant burden on subsequent membrane concentration scale and energy consumption.

[0003] Unlike aluminum-based adsorbents, titanium-based adsorbents have high adsorption capacity and can utilize acid circulation for desorption to achieve high lithium desorption solutions. However, their specific adsorption of lithium depends on Li-H exchange and are generally suitable for alkaline brine systems, but not for chloride-type oil and gas field brines.

[0004] Therefore, in order to apply titanium-based adsorbents to lithium extraction from produced water in chloride-type oil and gas fields and obtain high-lithium desorption solutions, it is urgent to develop a method and supporting equipment that can overcome the shortcomings of titanium-based adsorbents being unsuitable for chloride-type oil and gas fields and can apply titanium-based adsorbents to lithium extraction from produced water in chloride-type oil and gas fields and obtain high-lithium desorption solutions. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of the present invention is to provide a bicarbonate buffer adsorption / desorption method and apparatus. The method and apparatus overcome the defect that titanium-based adsorbents are not suitable for chloride-type oil and gas fields, and realize the efficient extraction of lithium from produced water in chloride-type oil and gas fields to obtain a high-concentration lithium desorption solution.

[0006] To achieve the above objectives, one aspect of the present invention provides a bicarbonate buffer-type adsorption / desorption method, comprising the following steps:

[0007] The extracted water is subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent;

[0008] Prior to the adsorption of the target ion, the pH of the produced water is adjusted to not less than 7.5 using a bicarbonate slow-release ball.

[0009] According to the present invention, the bicarbonate slow-release sphere is a membrane microsphere; wherein the membrane is made of a non-water-soluble cellulose derivative, and the microsphere is made of a natural organic material mixed with bicarbonate particles and pore support material.

[0010] According to the present invention, in the bicarbonate slow-release spheres, the mass ratio of the bicarbonate particles, the natural organic material, and the pore support material is (1-5):1:1; and / or

[0011] The average particle size of the bicarbonate slow-release spheres is 0.8-1.5 cm; and / or

[0012] The particle size of the porous support material is no higher than 0.2 mm.

[0013] According to the present invention, the water-insoluble cellulose derivative is ethyl cellulose and / or methyl cellulose; and / or

[0014] The pore support material is fine-grained activated carbon; and / or

[0015] The natural organic material is selected from any one of paraffin, chitosan and alginate;

[0016] Preferably, the particle size of the fine granular activated carbon is 0.1-0.2 mm.

[0017] According to the present invention, the bicarbonate sustained-release spheres are prepared by the following method:

[0018] The natural organic material is heated until it melts, and the bicarbonate particles and the pore support material are added. After mixing evenly, the mixture is poured into a mold and cooled to form the microspheres.

[0019] The microspheres are immersed in a solution of the insoluble cellulose derivative, removed and dried to form a film of the insoluble cellulose derivative on the surface of the microspheres, thus obtaining the bicarbonate slow-release spheres.

[0020] According to the present invention, the adsorption recovery rate of the target ion is not less than 90%; and / or the concentration of the target ion in the target ion-rich desorption solution is not less than 0.2 g / L.

[0021] According to the present invention, the target ion is adsorbed on the extracted water in the following manner;

[0022] First, the produced water is passed into a buffer device, and the pH of the produced water is adjusted to no less than 7.5 using the bicarbonate slow-release ball. Then, the produced water is passed into an adsorption device to adsorb the target ions, producing adsorption tail liquid.

[0023] The adsorption device, having reached the adsorption endpoint, is desorbed to obtain the target ion-rich desorbent solution.

[0024] According to the present invention, the adsorption device is filled with a target ion selective adsorbent; and / or the buffer device is filled with the bicarbonate slow-release spheres.

[0025] According to the present invention, the concentration of the target ion in the adsorption tail liquid is less than 5 mg / L.

[0026] According to the present invention, the number of adsorption devices is n, where n is an integer ≥1; at least one buffer device is provided before the n adsorption devices along the flow direction of the extracted water.

[0027] Preferably, n is an integer ≥ 2.

[0028] According to the present invention, when n is an integer ≥2, the desorption is segmented cyclic concentration desorption; the segmented cyclic concentration desorption includes surface desorption and internal pore rinsing performed in stages sequentially.

[0029] First, the adsorption device that has reached the adsorption endpoint is subjected to surface desorption once to desorb the target ions adsorbed on the surface of the target ion selective adsorbent.

[0030] Then, the adsorption device is rinsed through its internal pores at least once to allow the residual target ions in the internal pores of the target ion selective adsorbent to migrate down, thus obtaining the target ion-rich desorption solution.

[0031] According to the present invention, the segmented cyclic concentration desorption is performed according to the following steps:

[0032] When n = 2 or n is an integer ≥ 3, the first adsorption device is desorbed once with acid to produce the first-stage desorption liquid; the internal pores of the first adsorption device are rinsed n-1 times with washing liquid, and the rinsing liquid produced each time is collected separately.

[0033] When n is an integer ≥ 3, the eluent generated from the first internal pore rinsing of the (m-1)th adsorption device and the acid are combined, and the surface desorption of the m-th adsorption device is performed once to generate the m-th stage desorption liquid; the eluent generated from the second to n-(m-1)th internal pore rinsing of the (m-1)th adsorption device is used to perform nm rinsing of the internal pores of the m-th adsorption device, and the eluent generated from each rinsing is collected separately; m is an integer from 2 to (n-1).

[0034] When n = 2 or n is an integer ≥ 3, the rinsing liquid generated from the first internal pore rinsing of the (n-1)th adsorption device and the acid solution are combined, and the surface desorption of the nth adsorption device is performed once to generate the nth stage desorption liquid; the internal pore rinsing of the nth adsorption device is performed at least once with the rinsing liquid, and the resulting rinsing liquid is combined into the adsorption tail liquid.

[0035] Collect the desorption solutions from the first to the nth stage to obtain the target ion-rich desorption solution;

[0036] After the internal pores have been rinsed, the adsorption device continues to adsorb the target ions.

[0037] According to the present invention, the assembly method of the n adsorption devices is selected from fixed bed type or continuous ion exchange type; n is an integer ≥2.

[0038] According to the present invention, the rinsing rate of the internal pores is 1 to 5 times the desorption rate of the surface layer;

[0039] Preferably, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, the surface desorption rate is 2 to 4 times the adsorption rate; n is an integer ≥ 2.

[0040] According to the present invention, the target ion includes lithium ions; and / or

[0041] The target ion selective adsorbent includes titanium-based adsorbents or manganese-based adsorbents.

[0042] According to the present invention, in any of the adsorption devices in the second to nth groups, when the surface desorption is performed, the pH of the combined eluent and acid solution produced by the first internal pore rinsing of the previous adsorption device is 1.5-2.0; n is an integer ≥2; and / or

[0043] The pH of the acid solution is 1.5-2.0; and / or

[0044] The washing solution is water.

[0045] The second invention provides a bicarbonate buffer adsorption / desorption device, characterized in that it is used to implement the bicarbonate buffer adsorption / desorption method as described in the first invention, comprising:

[0046] A buffer-adsorption unit is used to adsorb the target ions into the produced water, and before adsorbing the target ions, the pH of the produced water is adjusted to not less than 7.5 using a bicarbonate slow-release ball.

[0047] The desorption unit, connected to the buffer-adsorption unit, is used to perform the desorption to obtain the target ion-rich desorption solution.

[0048] The beneficial effects of this invention are:

[0049] To address the issue that the specific adsorption of lithium by titanium-based adsorbents relies on Li-H exchange and is unsuitable for lithium extraction from produced water in chloride-type oil and gas fields, this invention provides a bicarbonate buffer-type adsorption / desorption method and apparatus. Compared with existing technologies, this invention has at least the following advantages:

[0050] 1. A membrane-bound microsphere, namely the bicarbonate slow-release sphere, is obtained by encapsulating a natural organic material microsphere mixed with bicarbonate particles and a pore support material using a non-water-soluble cellulose derivative as a membrane. Further, this invention fills the bicarbonate slow-release sphere into a buffer device, utilizing the combination of a buffer device and an adsorption device to overcome the limitation of titanium-based adsorbents being unsuitable for lithium extraction from produced water in chloride-type oil and gas fields. Specifically, when the bicarbonate slow-release sphere is in produced water, water molecules pass through the non-water-soluble cellulose derivative membrane into the slow-release sphere. Supported by the pore support material, the water contacts the bicarbonate in the microsphere, dissolving it to form a bicarbonate solution. The bicarbonate solution then passes through the non-water-soluble cellulose membrane into the produced water, adjusting the pH of the produced water to not less than 7.5, providing a suitable adsorption environment for the titanium-based adsorbent. Furthermore, the pore support material in the bicarbonate slow-release sphere is preferably fine-grained activated carbon, which can adsorb any residual oil substances in the produced water, avoiding organic pollution of the titanium-based adsorbent and affecting the adsorption / desorption effect.

[0051] 2. This invention also designs a special desorption method of segmented cyclic concentration desorption. For the adsorption device that has reached the adsorption endpoint, only acid solution is used, or acid solution and the rinsing solution generated from the first internal pore rinsing of the previous adsorption device are used for one surface desorption. A large number of ions adsorbed on the surface of the titanium adsorbent are desorbed into the desorption solution and stored separately. After surface desorption, the internal pores are rinsed at least once with water or the rinsing solution generated from the second to the last internal pore rinsing of the previous adsorption device. The residual lithium ions in the internal pores of the titanium adsorbent migrate down from the pores of the titanium adsorbent using the concentration gradient. In the aforementioned segmented cyclic concentration desorption process, since the acid solution does not contain lithium ions, and the amount of lithium ions in the eluent combined with the acid solution is also very small compared to the desorption solution, there is almost no concentration inhibition effect due to the presence of lithium ions during surface desorption. Therefore, a large number of lithium ions can be desorbed with high efficiency. Furthermore, using the eluent or water as the washing solution for internal pore rinsing allows residual lithium ions in the internal pores of the titanium-based adsorbent to migrate down using the concentration gradient, achieving near-complete desorption of lithium ions. The combination of surface desorption and internal pore rinsing enables highly efficient extraction and high recovery of lithium from produced water in chloride-type oil and gas fields. In addition, combining the eluent and acid solution for surface desorption also allows for the recycling of the eluent, reducing the amount of acid used in the surface desorption process and saving on lithium extraction costs. Attached Figure Description

[0052] Figures 1 to 3 This is a schematic diagram of the steps of the bicarbonate buffer adsorption / desorption method provided in the embodiments of the present invention;

[0053] Figure 4 A schematic flowchart illustrating the preparation method of the bicarbonate sustained-release spheres provided in this embodiment of the invention;

[0054] Figure 5 This is a schematic diagram of the segmented cyclic desorption steps in the bicarbonate buffer adsorption / desorption method provided in this embodiment of the invention;

[0055] Figure 6 The diagram shows the structure of the bicarbonate buffer adsorption / desorption device provided in this embodiment of the invention for adsorption / segmented cyclic concentration and desorption. The adsorption device is assembled in a fixed bed manner, with n groups of adsorption devices connected in parallel and a buffer device connected in series before each group of adsorption devices.

[0056] Figure 7 The diagram shows the structure of the bicarbonate buffer adsorption / desorption device provided in this embodiment of the invention for adsorption / segmented cyclic concentration desorption. The adsorption device is assembled in a fixed bed manner, with n groups of adsorption devices connected in series, and a buffer device connected in series before each group of adsorption devices.

[0057] Figure 8 , 9 Figures 10 and 10 are schematic diagrams of the adsorption zone, desorption zone, and rinsing zone of the bicarbonate buffer adsorption / desorption device provided in the embodiments of the present invention, used for adsorption / segmented cyclic concentration desorption, and the adsorption device adopts continuous ion exchange assembly. The n groups of adsorption devices are connected in parallel. Figure 8 In the displayed adsorption zone, a buffer device is connected in series before each adsorption device.

[0058] Figure 11 , 12 Figures 1 and 13 are schematic diagrams of the adsorption zone, desorption zone, and rinsing zone of the bicarbonate buffer adsorption / desorption device provided in the embodiments of the present invention, used for adsorption / segmented cyclic concentration desorption, and in which the adsorption device adopts continuous ion exchange assembly. The n groups of adsorption devices are connected in series. Figure 11 In the displayed adsorption zone, a buffer device is connected in series before each adsorption device.

[0059] The meanings of the reference numerals in the figure are as follows: 11-buffer device, 12-adsorption device, 13-adsorption tail liquid container, 21-acid container, 22-desorption liquid container, 23-washing liquid container, 24-intermediate container.

[0060] The above figures are not drawn to the actual size and scale. Detailed Implementation

[0061] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0062] The first aspect of the present invention provides a bicarbonate slow-release sphere, wherein the bicarbonate slow-release sphere is a membrane microsphere; wherein the membrane is made of a non-water-soluble cellulose derivative, and the microsphere is made of a natural organic material mixed with bicarbonate particles and a pore support material.

[0063] In one specific embodiment of the present invention, the mass ratio of the bicarbonate particles, the natural organic material and the pore support material in the bicarbonate slow-release sphere is (1-5):1:1, for example, any value in the range of 1:1:1, 2:1:1, 3:1:1, 4:1:1, 5:1:1 or any two values ​​in the range of 5:1:1.

[0064] In a preferred embodiment of the present invention, the mass ratio of the bicarbonate particles, the natural organic material, and the pore support material in the bicarbonate slow-release sphere is (1-3):1:1.

[0065] In one specific embodiment of the present invention, the average particle size of the bicarbonate slow-release spheres is 0.8-1.5 cm.

[0066] In one specific embodiment of the present invention, the particle size of the porous support material is not higher than 0.2 mm.

[0067] In one specific embodiment of the present invention, the non-water-soluble cellulose derivative is ethyl cellulose and / or methyl cellulose.

[0068] In one specific embodiment of the present invention, the pore support material is fine-grained activated carbon; the particle size of the fine-grained activated carbon is 0.1-0.2 mm.

[0069] In one specific embodiment of the present invention, the natural organic material is selected from any one of paraffin, chitosan and alginate.

[0070] like Figure 4 As shown, a second aspect of the present invention provides a method for preparing bicarbonate sustained-release spheres as described in the first aspect of the present invention, comprising the following steps:

[0071] The natural organic material is heated until it melts, and the bicarbonate particles and the pore support material are added. After mixing evenly, the mixture is poured into a mold and cooled to form the microspheres.

[0072] The microspheres are immersed in a solution of the insoluble cellulose derivative, removed and dried to form a film of the insoluble cellulose derivative on the surface of the microspheres, thus obtaining the bicarbonate slow-release spheres.

[0073] Application of the bicarbonate slow-release spheres according to the first aspect of the present invention or the bicarbonate slow-release spheres prepared by the method according to the second aspect of the present invention in bicarbonate buffer adsorption / desorption methods.

[0074] A third aspect of the present invention provides a bicarbonate buffered adsorption / desorption method, comprising the following steps: adsorbing and desorbing target ions into produced water to obtain a target ion-rich desorbent; adjusting the pH of the produced water to not less than 7.5 using bicarbonate slow-release balls before the target ion adsorption; wherein the bicarbonate slow-release balls are slow-release balls as described in the first aspect of the present invention or bicarbonate slow-release balls prepared by the method described in the second aspect of the present invention.

[0075] In one specific embodiment of the present invention, the adsorption recovery rate of the target ion is not less than 90%; and / or the concentration of the target ion in the target ion-rich desorption solution is not less than 0.2 g / L.

[0076] In one specific embodiment of the present invention, such as Figure 1As shown, the target ion is adsorbed onto the extracted water in the following manner;

[0077] First, the produced water is passed into a buffer device, and the pH of the produced water is adjusted to no less than 7.5 using the bicarbonate slow-release ball. Then, the produced water is passed into an adsorption device to adsorb the target ions, producing adsorption tail liquid.

[0078] When the adsorption device reaches the adsorption endpoint, desorption occurs, yielding the target ion-rich desorbent solution.

[0079] In one specific embodiment of the present invention, the adsorption device is filled with a target ion selective adsorbent.

[0080] In one specific embodiment of the present invention, the buffer device is filled with the bicarbonate slow-release spheres.

[0081] In one specific embodiment of the present invention, when the pH of the adsorption tail liquid is measured to be less than 4 after flowing through the buffer device, the adsorption device is determined to have reached the adsorption endpoint.

[0082] In one specific embodiment of the present invention, the concentration of the target ion in the adsorption tail liquid is less than 5 mg / L.

[0083] In one specific embodiment of the present invention, the number of adsorption devices is n, where n is an integer ≥ 1; at least one buffer device is provided before the n adsorption devices along the flow direction of the extracted water; the connection between each adsorption device group is either in series or in parallel.

[0084] Preferably, n is an integer ≥ 2.

[0085] In one specific embodiment of the present invention, the number of adsorption columns in each adsorption device group and the number of buffer columns in each buffer device group are independently at least 1.

[0086] In one specific embodiment of the present invention, the connection method between each adsorption column in each adsorption device and the connection method between each buffer column in each buffer device are independently either series or parallel.

[0087] In one specific embodiment of the present invention, the desorption is acid cyclic desorption.

[0088] It should be noted that the specific steps of the acid circulation desorption (e.g.) Figure 2 The technology shown on the right is existing technology and will not be elaborated here.

[0089] In a preferred embodiment of the present invention, when n is an integer ≥2, the desorption is segmented cyclic concentration desorption; the segmented cyclic concentration desorption includes surface desorption and internal pore rinsing performed in stages sequentially.

[0090] like Figure 3 As shown, firstly, the adsorption device that has reached the adsorption endpoint is subjected to one surface desorption, thereby desorbing the target ions adsorbed on the surface of the target ion selective adsorbent.

[0091] Then, the adsorption device is rinsed through its internal pores at least once to allow the residual target ions in the internal pores of the target ion selective adsorbent to migrate down, thus obtaining the target ion-rich desorption solution.

[0092] In one specific embodiment of the present invention, such as Figure 5 As shown, the segmented cyclic concentration and desorption is performed according to the following steps:

[0093] When n = 2 or n is an integer ≥ 3, the first adsorption device is desorbed once with acid to produce the first-stage desorption liquid; the internal pores of the first adsorption device are rinsed n-1 times with washing liquid, and the rinsing liquid produced each time is collected separately.

[0094] When n is an integer ≥ 3, the eluent generated from the first internal pore rinsing of the (m-1)th adsorption device and the acid are combined, and the surface desorption of the m-th adsorption device is performed once to generate the m-th stage desorption liquid; the eluent generated from the second to n-(m-1)th internal pore rinsing of the (m-1)th adsorption device is used to perform nm rinsing of the internal pores of the m-th adsorption device, and the eluent generated from each rinsing is collected separately; m is an integer from 2 to (n-1).

[0095] When n = 2 or n is an integer ≥ 3, the rinsing liquid generated from the first internal pore rinsing of the (n-1)th adsorption device and the acid solution are combined, and the surface desorption of the nth adsorption device is performed once to generate the nth stage desorption liquid; the internal pore rinsing of the nth adsorption device is performed at least once with the rinsing liquid, and the resulting rinsing liquid is combined into the adsorption tail liquid.

[0096] Collect the desorption solutions from the first to the nth stage to obtain the target ion-rich desorption solution;

[0097] After the internal pores have been rinsed, the adsorption device continues to adsorb the target ions.

[0098] In one specific embodiment of the present invention, the assembly method of the n sets of adsorption devices is selected from fixed bed type or continuous ion exchange type; n is an integer ≥2.

[0099] In one specific embodiment of the present invention, when the n sets of adsorption devices are assembled in a fixed-bed manner, the segmented cyclic concentration and desorption are performed according to the following steps:

[0100] When n = 2 or n is a positive integer ≥ 3, the acid solution is passed into the first adsorption device to perform the surface desorption once, generating the first-stage desorption solution; the washing solution is passed into the first adsorption device to perform the internal pore rinsing n-1 times, and the rinsing solution generated each time is collected separately.

[0101] When n is a positive integer ≥ 3, the eluent generated from the first internal pore rinsing of the (m-1)th adsorption device and the acid are combined and passed into the m-th adsorption device for the first surface desorption to generate the m-th desorption liquid; the eluent generated from the second to n-(m-1)th internal pore rinsing of the (m-1)th adsorption device is passed into the m-th adsorption device to perform nm rinsing of the internal pores of the m-th adsorption device, and the eluent generated from each rinsing is collected, where m is a positive integer from 2 to (n-1);

[0102] When n = 2 or n is a positive integer ≥ 3, the rinsing solution generated from the first internal pore rinsing of the (n-1)th adsorption device and the acid solution are combined and passed into the nth adsorption device for one surface desorption to generate the nth stage desorption solution; the rinsing solution is passed into the nth adsorption device for at least one internal pore rinsing, and the resulting rinsing solution is combined into the adsorption tail liquid.

[0103] Collect the first to nth stage desorption solutions to obtain the target ion-rich desorption solution; the adsorption device, after completing the internal pore rinsing, continues to adsorb the target ions.

[0104] In one specific embodiment of the present invention, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, a buffer-adsorption zone, a surface desorption zone, and an internal pore rinsing zone are provided; wherein, the number of adsorption sites in the buffer-adsorption zone is at least the number of adsorption columns in each adsorption device; the number of desorption sites in the surface desorption zone is at least the number of adsorption columns in each adsorption device / (the ratio of surface desorption rate to adsorption rate); the number of rinsing sites in the internal pore rinsing zone is at least the number of adsorption columns in each adsorption device / (the ratio of internal rinsing rate to adsorption rate); the n sets of adsorption devices cyclically move along the route of adsorption sites, desorption sites, internal pore rinsing sites, and adsorption sites, sequentially performing target ion adsorption, surface desorption, and internal pore rinsing, and then performing target ion adsorption again, continuously and cyclically performing target ion adsorption and segmented cyclic concentration desorption; n is an integer ≥2.

[0105] Based on the above settings, the segmented cyclic concentration and desorption are performed as follows:

[0106] When n = 2 or n is a positive integer ≥ 3, the first adsorption device is moved to the desorption position, and the acid solution is introduced to perform the surface desorption once to generate the first-stage desorption solution; then the first adsorption device is moved to the rinsing position, and the washing solution is introduced to perform the internal pore rinsing n-1 times, and the rinsing solution generated each time is collected separately.

[0107] When n is a positive integer ≥ 3, the m-th adsorption device is moved to the desorption position, and the eluent generated by the first internal pore rinsing of the (m-1)-th adsorption device and the acid solution are combined and introduced to perform the first surface desorption, generating the m-th stage desorption solution; then the m-th adsorption device is moved to the rinsing position, and the eluent generated by the second to n-(m-1) internal pore rinsing of the (m-1)-th adsorption device is introduced to perform nm internal pore rinsing, and the eluent generated by each rinsing is collected; where m is a positive integer from 2 to (n-1);

[0108] When n = 2 or n is a positive integer ≥ 3, the nth adsorption device is moved to the desorption position, and the rinsing solution generated by the first internal pore rinsing of the (n-1)th adsorption device and the acid solution are combined and introduced to perform the surface desorption once, generating the nth stage desorption solution; then the nth adsorption device is moved to the rinsing position, and the rinsing solution is introduced to perform at least one internal pore rinsing, and the resulting rinsing solution is combined with the adsorption tail liquid;

[0109] Collect the first to nth stage desorption solutions to obtain the target ion-rich desorption solution; after completing the internal pore rinsing, the adsorption device moves to the adsorption site to adsorb the target ion.

[0110] In one specific embodiment of the present invention, the rinsing rate of the internal pores is 1 to 5 times the desorption rate of the surface layer.

[0111] In one specific embodiment of the present invention, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, the surface desorption rate is 2 to 4 times the adsorption rate; n is an integer ≥ 2.

[0112] In one specific embodiment of the present invention, the target ion includes lithium ions.

[0113] In one specific embodiment of the present invention, the target ion selective adsorbent includes a titanium-based adsorbent or a manganese-based adsorbent.

[0114] In one specific embodiment of the present invention, the pH of the acid solution is 1.5-2.0.

[0115] In one specific embodiment of the present invention, the washing solution is water.

[0116] In one specific embodiment of the present invention, when any one of the adsorption devices in the second to nth groups performs the surface desorption, the pH of the rinsing solution generated by the first internal pore rinsing of the previous adsorption device and the combined acid solution is 1.5-2.0; n is an integer ≥2.

[0117] For the adsorption device, whether a fixed-bed assembly or a continuous ion exchange assembly is used for the segmented cyclic concentration and desorption, the target ions adsorbed on the surface of the target ion selective adsorbent are first desorbed using acid (or a combination of acid and the eluent generated from the first internal pore rinsing of the previous adsorption device), i.e., surface desorption; then, the residual target ions in the internal pores of the target ion selective adsorbent are migrated out by the concentration gradient using the washing liquid (or the eluent generated from the second to the last internal pore rinsing of the previous adsorption device), i.e., internal pore rinsing; in this way, the target ions adsorbed by the target ion selective adsorbent can be almost completely desorbed. Furthermore, since the surface desorption is performed only once during the segmented cyclic concentration desorption process of a set of adsorption devices, meaning the acid solution is used only once, unlike traditional acid solution cyclic desorption, this significantly reduces the concentration inhibition effect caused by the presence of a certain concentration of already desorbed target ions in the acid solution on subsequent target ion desorption processes. After the surface desorption is performed once, the internal pores are rinsed. With the help of the concentration gradient, the release of residual target ions in the internal pores of the target ion selective adsorbent is promoted, and the residual target ions are migrated down, achieving complete desorption of the target ions.

[0118] It should be noted that the desorption (including acid circulation desorption and segmented circulation concentration desorption) described in this invention are all performed on the adsorption device that has reached the adsorption endpoint; during the desorption process, the fluids used, including but not limited to water and acid, do not flow through the buffer device.

[0119] In one specific embodiment of the present invention, before implementing the bicarbonate buffer adsorption / desorption method, the produced water is first subjected to oil and suspension removal treatment to prevent the oil and suspended matter contained in the produced water from causing organic pollution to the adsorption device or adhering to the adsorption device, thereby reducing the adsorption efficiency of the target ion adsorbent for the target ion and the subsequent desorption efficiency of the target ion.

[0120] The methods and steps for removing oil and suspension from produced water are existing technologies and will not be described in detail here.

[0121] In a preferred embodiment of the present invention, after the oil removal and desuspension treatment of the produced water, monovalent / divalent ion separation treatment and bromine extraction are carried out, and then the bicarbonate buffer adsorption / desorption method is implemented to prevent bromine or other monovalent / divalent ions other than the target ion contained in the produced water from interfering with the subsequent target ion adsorption / desorption, while realizing the extraction of other resources in the produced water other than the target ion.

[0122] In one specific embodiment of the present invention, before implementing the bicarbonate buffered adsorption / desorption method, the target ions in the produced water are pre-concentrated by adsorption / desorption using an adsorption device with at least one stage filled with aluminum-based adsorbent. For example, the target ions in the produced water are adsorbed using an adsorption device with at least one stage filled with aluminum-based adsorbent, and then the adsorption device filled with aluminum-based adsorbent, which has reached the adsorption endpoint, is desorbed with water, and the desorbed liquid is collected; then the bicarbonate buffered adsorption / desorption method is implemented to adsorb / desorb the target ions from the collected desorbed liquid.

[0123] Since the target ions adsorbed on the aluminum-based adsorbent are desorbed using water, the resulting desorbate has a higher pH than the naturally acidic produced water from chloride-type oil and gas fields. This reduces the pressure on the buffer device to adjust the pH during the implementation of the bicarbonate buffer adsorption / desorption method, decreases the amount of bicarbonate slow-release balls in the buffer device, and thus lowers the lithium extraction cost from chloride-type oil and gas field produced water. Furthermore, the higher concentration of the target ions in the desorbate obtained from the aluminum-based adsorbent compared to the produced water also contributes to obtaining a higher concentration of target ion-rich desorbate after implementing the bicarbonate buffer adsorption / desorption method.

[0124] A fourth aspect of the present invention provides a bicarbonate buffer adsorption / desorption device for implementing the bicarbonate buffer adsorption / desorption method as described in the third aspect of the present invention, comprising:

[0125] A buffer-adsorption unit is used to adsorb the target ions into the produced water, and before adsorbing the target ions, the pH of the produced water is adjusted to not less than 7.5 using a bicarbonate slow-release ball.

[0126] The desorption unit, connected to the buffer-adsorption unit, is used to perform the desorption to obtain the target ion-rich desorption solution.

[0127] In one specific embodiment of the present invention, the buffer-adsorption unit includes a buffer device and an adsorption device, which is used to first pass the produced water into the buffer device, adjust the pH of the produced water to not less than 7.5 using the bicarbonate slow-release ball, and then pass the produced water into the adsorption device to adsorb the target ions, thereby generating adsorption tail liquid.

[0128] In one specific embodiment of the present invention, the adsorption device is filled with a target ion selective adsorbent; and / or

[0129] The buffer device is filled with the bicarbonate slow-release spheres.

[0130] In one specific embodiment of the present invention, the desorption unit includes an acid container and an acid replenishment container; the acid container holds the acid and / or the desorption solution; the acid replenishment container holds the acid.

[0131] In a preferred embodiment of the present invention, the desorption unit includes an acid container, a desorption liquid container, a washing liquid container, and an intermediate container; wherein, the acid container is used to hold the acid, the desorption liquid container is used to hold the desorption liquid generated by the surface desorption, the intermediate container is used to hold the washing liquid generated by the internal channel rinsing, and the washing liquid container is used to hold the washing liquid.

[0132] In one specific embodiment of the present invention, the number of adsorption devices is n, where n is an integer ≥ 1; at least one buffer device is provided before the n adsorption devices along the flow direction of the extracted water; the assembly method of the n adsorption devices is selected from fixed bed type or continuous ion exchange type; the connection method between the n adsorption devices is series or parallel.

[0133] Preferably, n is an integer ≥ 2.

[0134] In one specific embodiment of the present invention, the number of adsorption columns in each adsorption device group and the number of buffer columns in each buffer device group are independently at least 1; the connection method between each adsorption column in each adsorption device group and the connection method between each buffer column in each buffer device group are independently either series or parallel.

[0135] It should be noted that, in this invention, provided that the extracted water first flows through a buffer device to adjust the pH to no less than 7.5 before flowing through an adsorption device for target ion adsorption, the configuration of the buffer device can be adjusted as needed. For example, when each buffer device group includes no less than 2 buffer columns and each adsorption device group includes no less than 2 adsorption columns, a buffer column is connected in series before each adsorption column of each adsorption device group, and the buffer columns connected in series before each adsorption column of that adsorption device group constitute a buffer device group; another example is that a buffer device group is connected in series before each adsorption device group; yet another example is that a buffer device group is connected in series only before the first adsorption device group in n adsorption device groups; the above examples are not exhaustive.

[0136] In one specific embodiment of the present invention, the n sets of adsorption devices are assembled in a fixed bed configuration;

[0137] like Figure 6 , Figure 7 As shown, in the buffer-adsorption unit, the liquid phase inlet and outlet of the buffer device are respectively connected to the produced water and at least to the liquid phase inlet of the first group of adsorption devices, so that the produced water is first introduced into the buffer device, and the pH is adjusted to not less than 7.5 by the bicarbonate slow-release ball, and then introduced into n groups of adsorption devices to perform the adsorption of the target ions, generating adsorption tail liquid.

[0138] In one specific embodiment of the present invention, the desorption unit is used to perform acid cyclic desorption on the adsorption device that has reached the adsorption endpoint.

[0139] In one specific embodiment of the present invention, when the n sets of adsorption devices are assembled in a fixed bed manner, n is an integer ≥1; in the desorption unit, the outlet and inlet of the acid container are respectively connected to the liquid phase inlet and outlet of the n sets of adsorption devices, or the outlet and inlet of the acid container are respectively connected to the liquid phase inlet of the first set of adsorption devices and the liquid phase outlet of the nth set of adsorption devices; the outlet of the acid replenishment container is connected to the inlet of the acid container; used to realize the cyclic desorption of the acid solution of the adsorption devices that have reached the adsorption endpoint.

[0140] In one specific embodiment of the present invention, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, n is an integer ≥2; the adsorption unit is used as a buffer-adsorption zone, and the desorption unit is used as a desorption zone; the number of adsorption sites in the buffer-adsorption zone is at least the number of adsorption columns in each set of adsorption devices; the number of desorption sites in the desorption zone is at least the number of adsorption columns in each set of adsorption devices / (the ratio of desorption rate to adsorption rate); after any set of adsorption devices reaches the adsorption endpoint at the adsorption site, it moves to the desorption site to perform acid circulation desorption.

[0141] In a preferred embodiment of the present invention, when n is an integer ≥2, the desorption unit is used to perform segmented cyclic concentration desorption on the adsorption device that has reached the adsorption endpoint.

[0142] like Figure 6 , Figure 7 As shown, in a preferred embodiment of the present invention, when the n adsorption devices are assembled in a fixed-bed manner, in the desorption unit, the washing liquid container is connected to the liquid phase inlet of at least the first and nth adsorption devices in the n adsorption devices; the acid container and the desorption liquid container are respectively connected to the liquid phase inlet and outlet of the n adsorption devices; ni intermediate containers are connected in parallel between the liquid phase outlet of the i-th adsorption device and the liquid phase inlet of the (i+1)-th adsorption device, where i is an integer from 1 to (n-1), and n is an integer ≥2; to achieve the segmented cyclic concentration desorption: when n = 2 or n is a positive integer ≥3, the acid is introduced into the first adsorption device for one surface desorption, generating the first-stage desorption liquid; the washing liquid is introduced into the first adsorption device for n-1 internal pore rinsing, and the rinsing liquid generated each time is collected; when n is a positive integer ≥3, the (m-1)-th adsorption device is introduced into the first adsorption device for n-1 internal pore rinsing, and the rinsing liquid generated each time is collected; when n is a positive integer ≥3, the washing liquid is introduced into the (m-1)-th adsorption device. The eluent generated from the first internal pore rinsing is combined with the acid solution and passed into the m-th adsorption device for one surface desorption, producing the m-th stage desorption solution. The eluent generated from the second to n-(m-1)th internal pore rinsings of the m-1th adsorption device is then passed into the m-th adsorption device for nm rinsing of the internal pores, and the eluent generated from each rinsing is collected, where m is a positive integer from 2 to (n-1). When n = 2 or n is a positive integer ≥ 3, the eluent generated from the first internal pore rinsing of the n-1th adsorption device is combined with the acid solution and passed into the n-th adsorption device for one surface desorption, producing the n-th stage desorption solution. The eluent is passed into the n-th adsorption device for at least one internal pore rinsing, and the resulting eluent is combined with the adsorption tail liquid. The first to n-th stage desorption solutions are collected to obtain the target ion-rich desorption solution.

[0143] like Figures 8 to 13As shown, in a preferred embodiment of the present invention, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, the buffer-adsorption unit is used as the buffer-adsorption zone; the number of adsorption sites in the buffer-adsorption zone is at least the number of adsorption columns in each adsorption device; the desorption unit is provided with a surface desorption zone and an internal pore rinsing zone; the number of desorption sites in the surface desorption zone is at least the number of adsorption columns in each adsorption device / (the ratio of surface desorption rate to adsorption rate); the number of rinsing sites in the internal pore rinsing zone is at least the number of adsorption columns in each adsorption device / (the ratio of internal rinsing rate to adsorption rate); the n sets of adsorption devices cyclically move along the route of adsorption sites, desorption sites, rinsing sites, and adsorption sites, sequentially performing target ion adsorption, surface desorption, and internal pore rinsing, and then performing target ion adsorption again, continuously and cyclically performing target ion adsorption and segmented cyclic concentration desorption; n is an integer ≥2.

[0144] In a preferred embodiment of the present invention, such as Figure 8 , Figure 11 As shown, at the adsorption site, the liquid phase inlet and outlet of the buffer device are respectively connected to the produced water and at least to the liquid phase inlet of the first group of adsorption devices, so that the produced water is first passed into the buffer device, and the pH is adjusted to not less than 7.5 by the bicarbonate slow-release ball, and then passed into n groups of adsorption devices to perform the adsorption of the target ion, generating adsorption tail liquid; n is an integer ≥2;

[0145] At the desorption site, such as Figure 9 , Figure 12 As shown, the liquid inlet and outlet of the first adsorption device are connected to the acid container and the desorption liquid container, respectively, so that the acid is introduced into the first adsorption device to perform the surface desorption once, and the first-stage desorption liquid is generated and collected in the desorption liquid container.

[0146] When n is an integer ≥ 3, in the adsorption devices of groups 2 to n-1, the liquid phase inlet of the m-th adsorption device is connected to the acid container and the intermediate container that holds the eluent generated by the first internal pore rinsing of the m-1-th adsorption device, respectively. The liquid phase outlet of the m-th adsorption device is connected to the desorption container, so as to combine the eluent generated by the first internal pore rinsing of the m-1-th adsorption device and the acid, and pass them into the m-th adsorption device for the first surface desorption; the resulting m-th stage desorption is collected in the desorption container.

[0147] When n is 2 or an integer greater than or equal to 3, the liquid phase inlet of the nth adsorption unit is connected to the acid container and the intermediate container containing the eluent generated by the first internal pore rinsing of the (n-1)th adsorption unit, respectively. The liquid phase outlet of the nth adsorption unit is connected to the desorption container to combine the eluent generated by the first internal pore rinsing of the (n-1)th adsorption unit and the acid, and then introduce them into the nth adsorption unit for the first surface desorption. The resulting nth-stage desorption solution is collected in the desorption container. Wherein, m is an integer from 2 to (n-1).

[0148] At the rinse position, such as Figure 10 , Figure 13 As shown, the liquid inlet of the first adsorption device is connected to the washing liquid container, and the liquid outlet is connected to n-1 intermediate containers to allow the washing liquid to be introduced into the first adsorption device for n-1 rinses of the internal pores; the liquid outlet of the first adsorption device is connected to n-1 intermediate containers to collect the generated rinsing liquid in the n-1 intermediate containers respectively.

[0149] When n is a positive integer ≥3, in the 2nd to n-1th adsorption devices, the liquid phase inlet of the mth adsorption device is connected to nm intermediate containers, each containing the rinsing liquid generated by the (m-1th)th adsorption device through nm rinsing of the internal pores, so as to perform nm rinsing of the mth adsorption device through the internal pores; the liquid phase outlet of the mth adsorption device is connected to nm intermediate containers, so as to collect the generated rinsing liquid in nm intermediate containers respectively.

[0150] When n is 2 or an integer greater than or equal to 3, the liquid inlet of the nth adsorption device is connected to the washing liquid container to allow the washing liquid to be introduced into the nth adsorption device for at least one internal pore rinsing; the liquid outlet of the nth adsorption device is connected to the adsorption tail liquid container to combine the generated rinsing liquid into the adsorption tail liquid.

[0151] In one specific embodiment of the present invention, the target ion includes lithium ions; and / or

[0152] The target ion selective adsorbent includes titanium-based adsorbents or manganese-based adsorbents.

[0153] In one specific embodiment of the present invention, the pH of the acid solution is 1.5-2.0; and / or

[0154] The washing solution is water.

[0155] In one specific embodiment of the present invention, the bicarbonate buffer adsorption / desorption device further includes a pre-concentration unit disposed before the buffer-adsorption unit; the pre-concentration unit includes at least one set of adsorption devices filled with aluminum-based adsorbent for pre-concentrating the produced water. The pre-concentration unit helps reduce the pressure on the buffer-adsorption unit to adjust the pH and reduces the amount of bicarbonate slow-release balls in the buffer device, thus lowering costs.

[0156] The following examples of bicarbonate slow-release sphere preparation and bicarbonate buffer adsorption / desorption methods further illustrate the technical solution of the present invention.

[0157] 1. Preparation of bicarbonate sustained-release beads

[0158] All room temperatures mentioned below refer to 25°C.

[0159] The fine granular activated carbon used in the following examples has a particle size of 0.1-0.2 cm and an average particle size of 0.15 cm.

[0160] Example 1

[0161] Heating paraffin wax until it melts, adding sodium bicarbonate granules and fine granular activated carbon, stirring until evenly mixed, pouring into a mold, and cooling to form microspheres with an average particle size of 1.0 cm; wherein the mass ratio of sodium bicarbonate granules, paraffin wax and fine granular activated carbon is 1:1:1.

[0162] Methylcellulose was dissolved in ethanol to obtain a methylcellulose solution; the prepared microspheres were immersed in the methylcellulose solution, removed and dried at room temperature to form a film of methylcellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 cm.

[0163] Example 2

[0164] Heating paraffin wax until melted, adding sodium bicarbonate granules and fine granular activated carbon, stirring until evenly mixed, pouring into a mold, and cooling to form microspheres with an average particle size of 1.0 cm; wherein the mass ratio of sodium bicarbonate granules, paraffin wax and fine granular activated carbon is 2:1:1;

[0165] Ethyl cellulose was dissolved in ethanol to obtain an ethyl cellulose solution; the prepared microspheres were immersed in the ethyl cellulose solution, removed and dried at room temperature to form a film of ethyl cellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 μm.

[0166] Example 3

[0167] Heating paraffin wax until it melts, adding sodium bicarbonate granules and fine granular activated carbon, stirring until evenly mixed, pouring into a mold, and cooling to form microspheres with an average particle size of 1.0 cm; wherein the mass ratio of sodium bicarbonate granules, paraffin wax and fine granular activated carbon is 3:1:1;

[0168] Ethyl cellulose was dissolved in ethanol to obtain an ethyl cellulose solution; the prepared microspheres were immersed in the ethyl cellulose solution, removed and dried at room temperature to form a film of ethyl cellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 cm.

[0169] Example 4

[0170] Heating chitosan until melted, adding sodium bicarbonate particles and fine granular activated carbon, stirring until evenly mixed, pouring into a mold, cooling and molding at room temperature to obtain microspheres with an average particle size of 1.0 cm; wherein, the mass ratio of sodium bicarbonate particles, chitosan and fine granular activated carbon is 1:1:1;

[0171] Ethyl cellulose was dissolved in ethanol to obtain an ethyl cellulose solution; the prepared microspheres were immersed in the ethyl cellulose solution, removed and dried at room temperature to form a film of ethyl cellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 cm.

[0172] Example 5

[0173] Sodium alginate was heated until melted, sodium bicarbonate granules and fine granular activated carbon were added, and the mixture was stirred until homogeneous. The mixture was then poured into a mold and cooled to form microspheres with an average particle size of 1.0 cm. The mass ratio of sodium bicarbonate granules, sodium alginate and fine granular activated carbon was 1:1:1.

[0174] Ethyl cellulose was dissolved in ethanol to obtain an ethyl cellulose solution; the prepared microspheres were immersed in the ethyl cellulose solution, removed and dried at room temperature to form a film of ethyl cellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 cm.

[0175] Comparative Example 1

[0176] Heating paraffin wax until melted, adding sodium bicarbonate granules, stirring until evenly mixed, pouring into a mold, and cooling to form microspheres with an average particle size of 1.0 cm at room temperature; wherein the mass ratio of sodium bicarbonate granules to paraffin wax is 1:1;

[0177] Methylcellulose was dissolved in ethanol to obtain a methylcellulose solution; the prepared microspheres were immersed in the methylcellulose solution, removed and dried at room temperature to form a film of methylcellulose on the surface of the microspheres, resulting in sodium bicarbonate slow-release spheres with an average particle size of 1.0 cm.

[0178] Test Example 1 - Determination of the sustained-release performance of bicarbonate sustained-release balls

[0179] (1) Weigh 10g of each of the bicarbonate sustained-release balls prepared in Examples 1 to 5 and Comparative Example 1, disperse them in 100mL of water, let them stand at room temperature, and carry out the bicarbonate release experiment.

[0180] (2) The content of bicarbonate in the water containing the bicarbonate slow-release balls prepared in each example / comparative example was determined by ion chromatography every 6 hours. When the detected bicarbonate content remained unchanged, the time point was the release time.

[0181] (3) Convert the bicarbonate content detected at the time point corresponding to the release time into the amount of bicarbonate, which is the amount of bicarbonate released by 10g of bicarbonate sustained-release balls (mol); then calculate the initial content of bicarbonate in 10g of bicarbonate sustained-release balls prepared in each example / comparative example based on the amount of sodium bicarbonate particles added in each example / comparative example, and convert it into the initial amount of bicarbonate, which is the initial amount of bicarbonate in 10g of bicarbonate sustained-release balls (mol); calculate the percentage of bicarbonate released by each type of bicarbonate sustained-release ball to the initial amount of bicarbonate, which is the final release rate (%).

[0182] The results are shown in Table 1.

[0183] Table 1. Sustained-release performance of bicarbonate sustained-release balls

[0184]

[0185] As shown in Table 1, the type of natural organic material affects the duration of sodium bicarbonate release, and the mass percentage of sodium bicarbonate affects the final release rate of bicarbonate. At room temperature, the final release rate of bicarbonate in water by the slow-release bicarbonate balls prepared in Examples 1 to 5 can reach a relatively high range of 60%-80%, and the release time is as long as 4 to 5 days, achieving a stable and efficient bicarbonate release effect, and continuously releasing bicarbonate to adjust the pH of the produced water. In practical applications, the type of natural organic material and the mass percentage of sodium bicarbonate can be adjusted as needed to obtain a suitable release time and amount of bicarbonate released.

[0186] Compared with Example 1, the bicarbonate slow-release balls prepared in Comparative Example 1 did not contain activated carbon as a pore support material, resulting in poor bicarbonate release capacity. Although the release time of bicarbonate into water reached 7 days, the final release rate of bicarbonate was only 40%, which reduced the utilization rate of bicarbonate. In practical applications, this would affect the buffering effect and increase the amount of bicarbonate slow-release balls required, making it difficult to control costs.

[0187] 2. Bicarbonate buffer adsorption / desorption method

[0188] The pH of the dilute hydrochloric acid used in the following examples / comparative examples is 2.

[0189] The titanium-based adsorbents used in the following examples / comparative examples are metatitanic acid type adsorbents.

[0190] Example 6

[0191] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0192] 1. Composition information of produced water / treated produced water

[0193] Initial composition of produced water: lithium 65 mg / L, bromine 230 mg / L, rubidium 56 mg / L, bicarbonate 150 mg / L, oil 2500 mg / L, suspended solids 110 mg / L.

[0194] The components of the produced water to be treated are: lithium 52 mg / L and bicarbonate 50 mg / L.

[0195] 2. Information on bicarbonate buffer adsorption / desorption devices

[0196] Buffer-Adsorption Unit: Includes four sets of adsorption devices assembled in a fixed bed configuration. The first to fourth sets of adsorption devices are connected in parallel. A buffer device is set up for each set of adsorption devices. Each set of adsorption devices includes four adsorption columns connected in series, with a buffer column connected in series before each adsorption column. The four buffer columns constitute a buffer device. Each buffer column is filled with 600g of the bicarbonate slow-release balls prepared in Example 1, and each adsorption column is filled with 1200g of titanium-based adsorbent. During the buffer-adsorption process, the treated effluent is introduced into the buffer-adsorption unit through the buffer column set before the first adsorption column of the first to fourth sets of adsorption devices for buffer-adsorption.

[0197] The desorption unit includes an acid container, a desorption liquid container, a washing liquid container, and an intermediate container. The acid container contains dilute hydrochloric acid, the desorption liquid container contains desorption liquid, the washing liquid container contains water, and the intermediate container contains rinsing liquid. During the desorption process, the washing liquid container is connected to the liquid phase inlet of the first and fourth adsorption units. The acid container and the desorption liquid container are connected to the liquid phase inlet and outlet of the first to fourth adsorption units, respectively. ni intermediate containers are connected in parallel between the liquid phase outlet of the ith adsorption unit and the liquid phase inlet of the (i+1)th adsorption unit. n is 4, and i is an integer from 1 to (n-1).

[0198] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0199] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0200] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0201] Specifically, the treated effluent was first fed through a buffer column placed before the first adsorption column of the first to fourth adsorption units at a flow rate of 35 mL / min to adjust the pH to no less than 7.5 before flowing into the first to fourth adsorption units for lithium ion adsorption. After the buffer-adsorption unit had been running stably for 1 hour, the adsorption tail liquid was collected and the lithium content was found to have decreased to 4 mg / L. Based on the average lithium content of 4.2 mg / L in the adsorption tail liquid after the buffer-adsorption unit had been running stably for 24 hours, the lithium adsorption recovery rate was calculated to be 92%.

[0202] When the pH of the adsorption tail liquid is measured to be <4, it is determined that the adsorption endpoint of the first to fourth adsorption units has been reached, and segmented cyclic concentration desorption is performed: dilute hydrochloric acid in the acid container is introduced into the liquid phase inlet of the first adsorption unit at a flow rate of 70 mL / min (or desorption flow rate) to perform one surface desorption, and the first-stage desorption liquid is collected in the desorption liquid container; water in the washing liquid container is introduced into the liquid phase inlet of the first adsorption unit at a flow rate of 140 mL / min to perform three internal channel rinsings, and the rinsing liquid generated by each rinsing is collected in three intermediate containers connected in parallel between the liquid phase outlet of the first adsorption unit and the liquid phase inlet of the second adsorption unit.

[0203] The dilute hydrochloric acid in the acid container and the eluent from the first internal pore rinsing of the first adsorption unit in the intermediate container (with a combined pH of 1.5-2.0) are combined and introduced into the liquid phase inlet of the second adsorption unit at a flow rate of 70 mL / min for one surface desorption, producing a second-stage desorption solution which is collected in the desorption solution container. The eluent from the second and third internal pore rinsing of the first adsorption unit in the intermediate container is then introduced into the liquid phase inlet of the second adsorption unit sequentially at a flow rate of 140 mL / min for two internal pore rinsings. The eluent from each rinsing is collected in two intermediate containers connected in parallel between the liquid phase outlet of the second adsorption unit and the liquid phase inlet of the third adsorption unit.

[0204] The dilute hydrochloric acid in the acid container and the eluent from the first internal pore rinsing of the second adsorption unit in the intermediate container (with a combined pH of 1.5-2.0) are combined and introduced into the liquid phase inlet of the third adsorption unit at a flow rate of 70 mL / min for one surface desorption. The resulting desorption solution is collected in the desorption solution container. The eluent from the second internal pore rinsing of the second adsorption unit in the intermediate container is introduced into the liquid phase inlet of the third adsorption unit at a flow rate of 140 mL / min for one internal pore rinsing. The resulting eluent is collected in an intermediate container connected in parallel between the liquid phase outlet of the third adsorption unit and the liquid phase inlet of the fourth adsorption unit.

[0205] The dilute hydrochloric acid in the acid container and the eluent from the first internal pore rinsing of the third adsorption unit in the intermediate container were combined (the combined pH was 1.5-2.0). This combined eluent was then introduced into the liquid phase inlet of the fourth adsorption unit at a flow rate of 70 mL / min for one surface desorption. The resulting eluent was collected in the desorption container. Water from the washing container was then introduced into the liquid phase inlet of the fourth adsorption unit at a flow rate of 140 mL / min for one internal pore rinsing. The resulting eluent was combined with the adsorption tail liquid.

[0206] The bicarbonate buffer adsorption / desorption unit operated stably for 5 days to complete the above-mentioned adsorption / segmented cyclic concentration desorption process. The average concentration of lithium ions in the desorption solution (i.e., lithium-rich desorption solution) produced by the surface desorption of the first to fourth adsorption units was 1.15 g / L, and the concentration of lithium ions in the rinsing solution produced by the internal pore rinsing of the first to third adsorption units was 100 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption solution was 95%.

[0207] Example 7

[0208] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0209] 1. Components of produced water / treated produced water

[0210] Same as Example 6.

[0211] 2. Information on bicarbonate buffer adsorption / desorption devices

[0212] Buffer-adsorption unit: Same as in Example 6;

[0213] Desorption unit: includes an acid container and an acid replenishment container; wherein, the acid container contains dilute hydrochloric acid and / or desorption solution, and the acid replenishment container contains dilute hydrochloric acid; during the desorption process, the outlet and inlet of the acid container are connected to the liquid phase inlet and outlet of the first to fourth adsorption devices, respectively, forming a circulation loop; the acid replenishment container is connected to the inlet of the acid container.

[0214] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0215] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0216] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0217] The specific adsorption steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is found to have decreased to 4 mg / L. Based on the average lithium content of the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 4.2 mg / L, the lithium adsorption recovery rate can be calculated to be 92%.

[0218] When the pH of the adsorption tail liquid is measured to be <4, the adsorption endpoint of adsorption devices 1 to 4 is determined to have been reached, and acid circulation desorption is then performed: dilute hydrochloric acid in the acid container is introduced into the liquid phase inlet of adsorption device 1 at a flow rate of 70 mL / min (or desorption flow rate) for the first round of desorption, which lasts for 4 hours. The desorbed liquid flows out from the liquid phase outlet of adsorption device 1, and the lithium content is measured to be 200 mg / L, corresponding to a lithium desorption recovery rate of 67%. The obtained desorbed liquid is then circulated into adsorption device 1 at a desorption flow rate of 70 mL / min for 4 rounds of desorption, each round lasting for 4 hours. During this period, dilute hydrochloric acid is added to the acid container through the acid replenishment container to maintain the pH of the desorbed liquid in the acid container at 1.5-2.0. Adsorption devices 2 to 4 are subjected to acid circulation desorption in the same manner.

[0219] The bicarbonate buffer adsorption / desorption device operated stably for 5 days to complete the above adsorption / acid solution circulation desorption process, and finally obtained a lithium-rich desorption solution with a lithium content of 200 mg / L, with an average lithium desorption recovery rate of 60%.

[0220] Example 8

[0221] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0222] 1. Components of produced water / treated produced water

[0223] Same as Example 6.

[0224] 2. Information on bicarbonate buffer adsorption / desorption devices

[0225] Buffer-Adsorption Unit: In the buffer-adsorption unit of Example 6, the bicarbonate slow-release balls prepared in Example 1 that fill each buffer column are replaced with an equal mass of bicarbonate slow-release balls prepared in Example 2, and the rest is the same as in Example 6;

[0226] Desorption unit: Same as in Example 6.

[0227] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0228] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0229] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0230] The specific steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is measured to be reduced to 2 mg / L. Based on the average lithium content in the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 2.6 mg / L, the lithium adsorption recovery rate can be calculated to be 95%.

[0231] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0232] The specific steps are the same as in Example 6. The bicarbonate buffer adsorption / desorption device was operated stably for 5 days to complete the above adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 1.2 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 100 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption liquid was 95%.

[0233] Example 9

[0234] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0235] 1. Components of produced water / treated produced water

[0236] Same as Example 6.

[0237] 2. Information on bicarbonate buffer adsorption / desorption devices

[0238] Buffer-Adsorption Unit: In the buffer-adsorption unit of Example 6, the bicarbonate slow-release balls prepared in Example 1 that fill each buffer column are replaced with an equal mass of bicarbonate slow-release balls prepared in Example 3, and the rest is the same as in Example 6;

[0239] Desorption unit: Same as in Example 6.

[0240] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0241] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0242] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0243] The specific steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is measured to be reduced to 2 mg / L. Based on the average lithium content in the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 2.1 mg / L, the lithium adsorption recovery rate can be calculated to be 96%.

[0244] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0245] The specific steps are the same as in Example 6. The bicarbonate buffer adsorption / desorption device was operated stably for 5 days to complete the above adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 1.2 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 100 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption liquid was 95%.

[0246] Example 10

[0247] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0248] 1. Components of produced water / treated produced water

[0249] Same as Example 6.

[0250] 2. Information on bicarbonate buffer adsorption / desorption devices

[0251] Buffer-Adsorption Unit: In the buffer-adsorption unit of Example 6, the bicarbonate slow-release balls prepared in Example 1 that fill each buffer column are replaced with an equal mass of bicarbonate slow-release balls prepared in Example 4, and the rest is the same as in Example 6.

[0252] Desorption unit: Same as in Example 6.

[0253] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0254] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0255] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0256] The specific steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is measured to be reduced to 4 mg / L. Based on the average lithium content of the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 4.2 mg / L, the lithium adsorption recovery rate can be calculated to be 92%.

[0257] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0258] The specific steps are the same as in Example 6. The bicarbonate buffer adsorption / desorption device was operated stably for 4.5 days to complete the above adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 1.15 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 100 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption liquid was 95%.

[0259] Example 11

[0260] This embodiment utilizes the bicarbonate buffer adsorption / desorption device provided by the present invention to implement the bicarbonate buffer adsorption / desorption method provided by the present invention. The lithium ions in the bromine extraction tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of the lithium ion solution obtained by sequentially treating the oil suspension and monovalent / divalent ion separation of the produced water are adsorbed / desorbed.

[0261] 1. Components of produced water / treated produced water

[0262] Same as Example 6.

[0263] 2. Information on bicarbonate buffer adsorption / desorption devices

[0264] Buffer-Adsorption Unit: In the buffer-adsorption unit of Example 6, the bicarbonate slow-release balls prepared in Example 1 that fill each buffer column are replaced with an equal mass of bicarbonate slow-release balls prepared in Example 5, and the rest is the same as in Example 6;

[0265] Desorption unit: Same as in Example 6.

[0266] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0267] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0268] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0269] The specific steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is measured to be reduced to 4 mg / L. Based on the average lithium content of the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 4.2 mg / L, the lithium adsorption recovery rate can be calculated to be 92%.

[0270] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0271] The specific steps are the same as in Example 6. The bicarbonate buffer adsorption / desorption device was operated stably for 4 days to complete the above adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 1.15 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 100 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption liquid was 95%.

[0272] Comparative Example 2

[0273] This comparative example demonstrates the adsorption / desorption of lithium ions in the bromine-extracting tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of lithium ion solution obtained from produced water that has undergone oil removal and suspension treatment and monovalent / divalent ion separation treatment.

[0274] 1. Components of produced water / treated produced water

[0275] Same as Example 6.

[0276] 2. Information on bicarbonate buffer adsorption / desorption devices

[0277] Buffer-Adsorption Unit: In the buffer-adsorption unit of Example 6, the bicarbonate slow-release balls prepared in Example 1 that fill each buffer column are replaced with an equal mass of bicarbonate slow-release balls prepared in Comparative Example 1, and the rest is the same as in Example 6.

[0278] Desorption unit: Same as in Example 6.

[0279] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0280] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0281] Before the target ion adsorption, the pH of the treated effluent is adjusted to no less than 7.5 using bicarbonate slow-release balls.

[0282] The specific steps of the adsorption process are the same as in Example 6. After the buffer-adsorption unit has been running stably for 1 hour, the adsorption tail liquid is collected and the lithium content is measured to be reduced to 20 mg / L. Based on the average lithium content in the adsorption tail liquid after the buffer-adsorption unit has been running stably for 24 hours, which is 20.8 mg / L, the lithium adsorption recovery rate can be calculated to be 60%.

[0283] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0284] The specific steps are the same as in Example 6. The bicarbonate buffer adsorption / desorption device was operated stably for 7 days to complete the above adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 0.6 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 50 mg / L. The average desorption recovery rate of lithium corresponding to lithium ions contained in the lithium-rich desorption liquid was 95%.

[0285] Comparative Example 3

[0286] This comparative example demonstrates the adsorption / desorption of lithium ions in the bromine-extracting tailwater (hereinafter referred to as treated produced water) obtained by further electrolytic bromine extraction of lithium ion solution obtained from produced water that has undergone oil removal and suspension treatment and monovalent / divalent ion separation treatment.

[0287] 1. Components of produced water / treated produced water

[0288] Same as Example 6.

[0289] 2. Adsorption / Desorption Device Information

[0290] Adsorption unit: includes 4 sets of adsorption devices assembled in a fixed bed, with the 1st to 4th sets of adsorption devices connected in parallel; each set of adsorption devices includes 4 adsorption columns connected in series; each adsorption column is filled with 1200g of titanium-based adsorbent; during the adsorption process, the treated effluent flows through the 1st to 4th sets of adsorption devices for adsorption.

[0291] Desorption unit: Same as in Example 6.

[0292] 3. Adsorption / desorption of lithium ions in the treated effluent.

[0293] The treated effluent was subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent.

[0294] Specifically, the treated effluent was simultaneously fed into the first to fourth adsorption units at a flow rate of 35 mL / min for lithium ion adsorption. After the adsorption unit had been running stably for 1 hour, the adsorption tail liquid was collected, and the lithium content was found to have decreased to 25 mg / L. Based on the average lithium content of 26 mg / L in the adsorption tail liquid after the adsorption unit had been running stably for 24 hours, the lithium adsorption recovery rate was calculated to be 50%.

[0295] When the pH of the adsorption tail liquid is measured to be <4, the adsorption devices of groups 1 to 4 are determined to have reached the adsorption endpoint, and segmented circulation concentration and desorption are then performed:

[0296] The specific steps are the same as in Example 6. The adsorption / desorption device was operated stably for 5 days to complete the above-mentioned adsorption / segmented cyclic concentration desorption process. It was determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium-rich desorption liquid) generated by the surface desorption of the first to fourth adsorption devices was 0.5 g / L, and the concentration of lithium ions in the rinsing liquid generated by the internal pore rinsing of the first to third adsorption devices was 50 mg / L. The average desorption recovery rate of lithium ions contained in the lithium-rich desorption liquid was 95%.

[0297] Results Evaluation

[0298] The lithium recovery effects of the adsorption / desorption methods implemented in Examples 6 to 11 and Comparative Examples 2 and 3 are summarized in Table 2.

[0299] Table 2. Lithium recovery efficiency of each adsorption / desorption method

[0300]

[0301]

[0302] As shown in Table 2, Examples 6 to 11 utilize the bicarbonate buffer adsorption / desorption device provided by this invention to recover lithium from produced water using the bicarbonate buffer adsorption / desorption method provided by this invention, achieving good recovery results: with a running time of 4 to 5 days, the lithium ion concentration in the lithium-rich desorption solution can reach 1.2 g / L, the lithium adsorption recovery rate is 92% to 96%, and the lithium desorption recovery rate can reach 95%. Furthermore, comparing Example 6 (lithium desorption recovery rate of 95%, lithium concentration in lithium-rich desorption solution of 1.15 g / L) and Example 7 (lithium desorption recovery rate of 60%, lithium concentration in lithium-rich desorption solution of 0.2 g / L), it can be seen that, compared with the acid-based circulating desorption method, the segmented circulating concentration desorption method provided by the present invention has significant advantages in improving the lithium desorption recovery rate and the lithium concentration in the lithium-rich desorption solution. By combining one surface desorption and at least one internal pore rinsing, the concentration inhibition effect caused by the presence of already desorbed lithium ions during the desorption process is avoided. It also enables the recycling of the rinsing solution generated by the internal pore rinsing, thereby reducing the cost of lithium recovery.

[0303] Furthermore, in Comparative Example 6 and Comparative Example 2, the bicarbonate slow-release balls prepared in Comparative Example 1 without activated carbon were used to adjust the pH of the produced water by releasing bicarbonate ions before lithium ion adsorption. However, due to the poor performance of the bicarbonate slow-release balls prepared in Comparative Example 1 in releasing bicarbonate ions, they failed to release enough bicarbonate ions during operation to adjust the pH of the produced water, thus failing to create a suitable adsorption environment for the titanium-based adsorbent. This affected the lithium adsorption recovery rate and the concentration of lithium ions in the lithium-rich desorption solution, resulting in a significantly worse lithium recovery effect in Comparative Example 2. In Comparative Example 3, neither the bicarbonate slow-release balls provided by this invention nor the bicarbonate slow-release balls prepared in Comparative Example 1 were used. No bicarbonate ions were released in the produced water to adjust the pH, resulting in a significant decrease in all lithium recovery indicators, achieving only a 50% lithium adsorption recovery rate, indicating a very poor lithium recovery effect.

[0304] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0305] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0306] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0307] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0308] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0309] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the invention, and all changes and / or modifications made according to embodiments of the invention should be covered within the protection scope of the invention.

Claims

1. A bicarbonate buffer-type adsorption / desorption method, characterized in that, Includes the following steps: The extracted water is subjected to target ion adsorption and desorption to obtain a target ion-rich desorbent; Prior to the adsorption of the target ion, the pH of the produced water is adjusted to not less than 7.5 using a bicarbonate slow-release ball.

2. The method according to claim 1, characterized in that, The bicarbonate slow-release spheres are membrane-bound microspheres; wherein the membrane is made of a non-water-soluble cellulose derivative, and the microspheres are made of a natural organic material mixed with bicarbonate particles and pore support material.

3. The method according to claim 2, characterized in that, In the bicarbonate slow-release spheres, the mass ratio of the bicarbonate particles, the natural organic material, and the pore support material is (1-5):1:1; and / or The average particle size of the bicarbonate slow-release spheres is 0.8-1.5 cm; and / or The particle size of the porous support material is no higher than 0.2 mm.

4. The method according to claim 3, characterized in that, The water-insoluble cellulose derivative is ethyl cellulose and / or methyl cellulose; and / or The pore support material is fine-grained activated carbon; and / or The natural organic material is selected from any one of paraffin, chitosan and alginate; Preferably, the particle size of the fine granular activated carbon is 0.1-0.2 mm.

5. The method according to claim 4, characterized in that, The bicarbonate slow-release spheres are prepared by the following method: The natural organic material is heated until it melts, and the bicarbonate particles and the pore support material are added. After mixing evenly, the mixture is poured into a mold and cooled to form the microspheres. The microspheres are immersed in a solution of the insoluble cellulose derivative, removed and dried to form a film of the insoluble cellulose derivative on the surface of the microspheres, thus obtaining the bicarbonate slow-release spheres.

6. The method according to claim 5, characterized in that, The adsorption recovery rate of the target ion is not less than 90%; and / or the concentration of the target ion in the target ion-rich desorption solution is not less than 0.2 g / L.

7. The method according to claim 6, characterized in that, The target ion is adsorbed onto the extracted water in the following manner: First, the produced water is passed into a buffer device, and the pH of the produced water is adjusted to no less than 7.5 using the bicarbonate slow-release ball. Then, the produced water is passed into an adsorption device to adsorb the target ions, producing adsorption tail liquid. The adsorption device, having reached the adsorption endpoint, is desorbed to obtain the target ion-rich desorbent solution.

8. The method according to claim 7, characterized in that, The adsorption device is filled with a target ion selective adsorbent; and / or the buffer device is filled with the bicarbonate slow-release spheres.

9. The method according to claim 8, characterized in that, The concentration of the target ion in the adsorption tail liquid is less than 5 mg / L.

10. The method according to claim 9, characterized in that, The number of adsorption devices is n, where n is an integer ≥ 1; at least one buffer device is set before the n adsorption devices along the flow direction of the extracted water. Preferably, n is an integer ≥ 2.

11. The method according to claim 10, characterized in that, When n is an integer ≥2, the desorption is segmented cyclic enrichment desorption; the segmented cyclic enrichment desorption includes surface desorption and internal pore rinsing performed in stages sequentially. First, the adsorption device that has reached the adsorption endpoint is subjected to surface desorption once to desorb the target ions adsorbed on the surface of the target ion selective adsorbent. Then, the adsorption device is rinsed through its internal pores at least once to allow the residual target ions in the internal pores of the target ion selective adsorbent to migrate down, thus obtaining the target ion-rich desorption solution.

12. The method according to claim 11, characterized in that, The segmented cyclic concentration and desorption process is performed according to the following steps: When n = 2 or n is an integer ≥ 3, the first adsorption device is desorbed once with acid to produce the first-stage desorption liquid; the internal pores of the first adsorption device are rinsed n-1 times with washing liquid, and the rinsing liquid produced each time is collected separately. When n is an integer ≥ 3, the eluent generated from the first internal pore rinsing of the (m-1)th adsorption device and the acid are combined, and the surface desorption of the m-th adsorption device is performed once to generate the m-th stage desorption liquid; the eluent generated from the second to n-(m-1)th internal pore rinsing of the (m-1)th adsorption device is used to perform nm rinsing of the internal pores of the m-th adsorption device, and the eluent generated from each rinsing is collected separately; m is an integer from 2 to (n-1). When n = 2 or n is an integer ≥ 3, the rinsing liquid generated from the first internal pore rinsing of the (n-1)th adsorption device and the acid solution are combined, and the surface desorption of the nth adsorption device is performed once to generate the nth stage desorption liquid; the internal pore rinsing of the nth adsorption device is performed at least once with the rinsing liquid, and the resulting rinsing liquid is combined into the adsorption tail liquid. Collect the desorption solutions from the first to the nth stage to obtain the target ion-rich desorption solution; After the internal pores have been rinsed, the adsorption device continues to adsorb the target ions.

13. The method according to claim 12, characterized in that, The assembly method of the n adsorption devices is selected from fixed bed type or continuous ion exchange type; n is an integer ≥2.

14. The method according to any one of claims 11 to 13, characterized in that, The rinsing rate of the internal pores is 1 to 5 times the desorption rate of the surface layer; Preferably, when the n sets of adsorption devices are assembled in a continuous ion exchange manner, the surface desorption rate is 2 to 4 times the adsorption rate; n is an integer ≥ 2.

15. The method according to claim 14, characterized in that, The target ion includes lithium ions; and / or The target ion selective adsorbent includes titanium-based adsorbents or manganese-based adsorbents.

16. The method according to claim 15, characterized in that, In the adsorption devices of groups 2 to n, when any group of adsorption devices performs the surface desorption, the pH of the combined eluent and acid solution produced by the first internal pore rinsing of the previous adsorption device is 1.5-2.0; n is an integer ≥2; and / or The pH of the acid solution is 1.5-2.0; and / or The washing solution is water.

17. A bicarbonate buffer type adsorption / desorption device, characterized in that, A method for implementing the bicarbonate buffered adsorption / desorption method as described in any one of claims 1 to 16, comprising: A buffer-adsorption unit is used to adsorb the target ions into the produced water, and before adsorbing the target ions, the pH of the produced water is adjusted to not less than 7.5 using a bicarbonate slow-release ball. The desorption unit, connected to the buffer-adsorption unit, is used to perform the desorption to obtain the target ion-rich desorption solution.

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