A resin adsorption enrichment device for trace organic matter in salt water

Abstract

The utility model relates to the technical field of brine preparation, specifically is a kind of resin adsorption enrichment device for trace organic matter of brine, by cascade setting primary macroporous adsorption resin column and secondary weak base anion resin column, cooperate PTC temperature control system, three-way electromagnetic valve and nitrogen pulse interface, realize the full spectrum capture and automatic desorption-analysis of organic matter in brine.The device directly uses GC-MS, solves the problems of traditional SPE method complicated operation, low recovery rate.

Description

Technical Field

[0001] This utility model relates to the field of brine preparation technology, specifically a resin adsorption enrichment device for trace organic matter in brine. Background Technology

[0002] In the chlor-alkali industry, ion-exchange membrane electrolysis is currently the mainstream alkali production process. It has extremely high requirements for the purity of the brine entering the tank, and is particularly sensitive to the content of organic matter. Studies have shown that even if the brine contains ppb-level (μg / L) organic impurities (such as phenols, amines, nitriles, organic acids, etc.), they will be adsorbed or polymerized on the surface of the ion-exchange membrane during electrolysis, leading to increased membrane resistance, increased voltage, and decreased current efficiency. In severe cases, this can cause membrane degradation or even perforation, resulting in unplanned shutdowns and huge economic losses.

[0003] Current brine purification processes typically include primary brine sedimentation, filtration, and secondary purification (chelation resin tower for calcium and magnesium ion removal). However, these traditional processes primarily target inorganic impurities and have limited ability to remove trace organic matter, failing to meet the requirements of modern ion-exchange membranes for long-term stable operation.

[0004] Existing methods for detecting trace organic compounds mostly employ direct injection GC-MS or liquid-liquid extraction followed by concentration analysis, but these methods still have the following problems: High-salt matrix interference is severe: high concentrations of NaCl in brine can severely inhibit mass spectrometry ionization efficiency and mask the target analyte signal; insufficient detection limit: the concentration of the target analyte in unenriched samples is too low to reach the instrument's detection limit; cumbersome and time-consuming pretreatment: traditional offline solid-phase extraction (SPE) requires multiple manual steps (including activation, sample loading, rinsing, elution, and concentration), which can easily cause sample loss or contamination. Each treatment session is time-consuming, sometimes exceeding 2 hours; unstable recovery rate: volatilization and adsorption losses during the transfer process affect the accuracy of qualitative and quantitative analysis.

[0005] In view of this, this technical solution designs a resin adsorption enrichment device for trace organic matter in brine. Utility Model Content

[0006] The purpose of this invention is to provide a resin adsorption enrichment device for trace organic matter in brine, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution: A resin adsorption enrichment device for trace organic matter in saline solution includes: The sample injection unit includes a saline inlet and a metering pump; The dual-stage resin column includes a primary macroporous adsorption resin column and a secondary weakly basic anion exchange resin column arranged in series; the dual-stage resin column is connected to the brine inlet through a transmission pipe, the metering pump is installed on the transmission pipe, and a flow control valve is provided. The dual-stage resin column is equipped with a PTC heating and temperature control system, which includes a PTC self-limiting heating film wrapped around the outer wall of the dual-stage resin column, and forms a closed-loop temperature control system in conjunction with the built-in thermocouple. The outlet end of the dual-stage resin column is equipped with a three-way solenoid valve, whose three ports are respectively connected to a waste liquid discharge port, a desorption solvent storage bottle and a GC-M autosampler. The top of the dual-stage resin column is equipped with a nitrogen pulse backflush port, which is connected to a high-pressure nitrogen source with a pressure set to 0.2–0.5 MPa. The control system integrates a PLC or microprocessor and has preset operating programs.

[0008] As a further aspect of this invention: the secondary weak base anion exchange resin column is made of acrylic primary amine anion exchange resin with a wet basis exchange capacity ≥3.8 mmol / g.

[0009] As a further embodiment of this invention: the particle size of the primary macroporous adsorption resin column is set to 100–200 μm; The particle size of the secondary weak base anion exchange resin column is set to 200–300 μm.

[0010] As a further embodiment of this invention: the series connection between the primary macroporous adsorption resin column and the secondary weakly basic anion exchange resin column is made of stainless steel pipeline.

[0011] As a further aspect of this invention, the temperature control range of the PTC heating temperature control system is 40–90℃.

[0012] As a further improvement of this invention, the solvent in the desorption solvent storage bottle is methanol or acetonitrile.

[0013] Compared with the prior art, the beneficial effects of this utility model are: through the synergistic adsorption of two-stage resin columns: the first-stage column captures moderately polar organic compounds, and the second-stage column specializes in anionic organic compounds, achieving full spectrum coverage; The automated "adsorption-desorption-injection" process is used: the GC-MS autosampler is directly connected via a three-way valve to avoid losses from manual transfer; The PTC temperature control system improves desorption efficiency, and the nitrogen pulse backflushing interface extends resin life. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a resin adsorption enrichment device for trace organic matter in brine.

[0015] Figure 2 This is a schematic diagram of the preparation process in Example 1.

[0016] The components include: 1. Saline inlet; 2. Primary macroporous adsorption resin column; 3. Secondary weak base anion exchange resin column; 4. Metering pump; 5. PTC heating and temperature control system; 6. GC-MS autosampler; 7. Waste liquid discharge port; 8. Three-way solenoid valve; 9. Desorption solvent storage bottle; 10. Nitrogen pulse backflush interface. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0018] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model 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 this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] Please see Figure 1 A resin adsorption enrichment device for trace organic matter in saline solution, comprising: The sample injection unit includes a saline inlet 1 and a metering pump 4; the saline inlet 1 is used to input the purified saline sample to be tested, and the metering pump 4 is used to accurately control the input volume of the saline sample. The dual-stage resin column comprises a primary macroporous adsorption resin column 2 and a secondary weakly basic anion exchange resin column 3 arranged in series. The primary macroporous adsorption resin column 1 is used for broad-spectrum adsorption of moderately polar to non-polar organic compounds, such as benzene compounds, phenols, and polycyclic aromatic hydrocarbons. The dual-stage resin column is connected to the brine inlet 1 via a transfer tube. A metering pump 4 is installed on the transfer tube, and a flow control valve is provided to precisely control the input volume of the brine sample, achieving constant flow loading. The secondary weak base anion exchange resin column 3 uses an acrylic primary amine anion exchange resin with a wet-base exchange capacity ≥3.8 mmol / g, which is used to capture anionic organic compounds such as polar organic acids and nitrogen-containing compounds. Specifically, the particle size of the primary macroporous adsorption resin column 2 is set to 100–200 μm; The particle size of the secondary weak base anion exchange resin column 3 was set to 200–300 μm. The series connection between the primary macroporous adsorption resin column 2 and the secondary weakly basic anion exchange resin column 3 is achieved using stainless steel tubing to ensure smooth passage of brine and control the capture of organic matter across the entire spectrum.

[0022] The dual-stage resin column is equipped with a PTC heating and temperature control system 5, which includes a PTC self-limiting heating film wrapped on the outer wall of the dual-stage resin column, and forms a closed-loop temperature control system with the built-in thermocouple. The temperature control range is 40–90℃, preferably 60℃, in order to improve the solubility of organic matter in the desorption solvent and prevent the decomposition of heat-sensitive substances. The outlet end of the dual-stage resin column is equipped with a three-way solenoid valve 8, whose three ports are respectively connected to the waste liquid discharge port 7, the desorption solvent storage bottle 9 and the GC-M autosampler 6. The solvent in the desorption solvent storage bottle 7 is methanol or acetonitrile 6; That is, by adsorption of the two-stage resin column, desorption of the solvent storage bottle 7 and injection of the GC-M autosampler 6, the automatic switching of the "adsorption-desorption-injection" mode is realized, avoiding the loss caused by intermediate transfer.

[0023] In this embodiment of the invention, a nitrogen pulse backflush port 10 is provided at the top of the dual-stage resin column, which is connected to a high-pressure nitrogen source with a pressure set to 0.2–0.5 MPa. Periodic pulse purging is achieved by controlling the solenoid valve through a program, which loosens the resin bed, removes residual salts and impurities, and extends the resin life.

[0024] The control system integrates a PLC or microprocessor, with preset operating programs to achieve fully automated control of the entire process, including: setting the sample loading volume, for example: typical value for inputting saline samples: 100–500 mL; The adsorption flow rate is typically set to 1–30 mL / min. The volume of the desorption solvent is typically set to 1–5 mL. Temperature setting and monitoring, valve switching timing control, and regeneration cycle management.

[0025] The specific operation process and principles of the control system are conventional technologies and will not be elaborated here.

[0026] See Figure 2 As a preferred embodiment 1 of the present invention, an online monitoring application in a chlor-alkali plant. (1) Install this device at the brine sampling point after the chelation resin tower, and use PLC to control the peristaltic pump to extract 500 mL of refined brine at a flow rate of 3 mL / min; (2) The brine is passed sequentially through XAD-4 type, 100–200 μm primary macroporous adsorption resin 2 and D301 type, acrylic primary amine type, 200–300 μm secondary weak base anion exchange resin 3. (3) After adsorption for 30 minutes, the three-way solenoid valve 8 is switched to desorption mode, the PTC heating temperature control system 5 is started to raise the temperature to 60°C, and 2 mL of chromatographically pure methanol is used to elute at a flow rate of 1 mL / min. (4) The eluent is directly introduced into the GC-MS autosampler 10 via the three-way solenoid valve 8 for full-scan qualitative analysis. (5) After the analysis is completed, switch to regeneration mode and purge with 0.3 MPa nitrogen gas for 5 minutes to restore resin activity.

[0027] Test results: The simulated saline samples containing phenol (0.5 ppb), p-chlorophenol (0.3 ppb), and adiponitrile (0.2 ppb) were processed, and the average recovery rate was 96.7%, the relative standard deviation (RSD) was <5% (n=6), and the limit of detection was 0.08 ppb, which meets the requirements for trace analysis.

[0028] The working principle of this utility model is as follows: In the idle position of this device, all the aforementioned driving components (representing power elements, electrical devices, and compatible power supplies) are connected via wires. The electrical connections are completed in sequence between the working components. The detailed connection methods are well-known in the field. The following mainly describes the working principle and process, without further explanation of the electrical control. It should be understood that in this application, all rotating, sliding, meshing, belt-driven and other moving parts are well lubricated and not prone to slippage or wear, and each part is provided with a corresponding protective shell. However, in the accompanying drawings of this application, the connection state of each moving part is not shown. It should also be understood that each part in this application is made of metal or plastic material with suitable strength in the relevant field to ensure that its structural rigidity meets the actual requirements.

[0029] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A resin adsorption and enrichment device for trace organic matter in brine, characterized in that, include: The sample injection unit includes a saline inlet (1) and a metering pump (4). The dual-stage resin column includes a primary macroporous adsorption resin column (2) and a secondary weak base anion exchange resin column (3) arranged in series; the dual-stage resin column is connected to the brine inlet (1) through a transmission pipe, the metering pump (4) is installed on the transmission pipe, and is equipped with a flow control valve. The dual-stage resin column is equipped with a PTC heating temperature control system (5), which includes a PTC self-limiting heating film wrapped on the outer wall of the dual-stage resin column, and forms a closed-loop temperature control system with the built-in thermocouple. The outlet end of the dual-stage resin column is equipped with a three-way solenoid valve (8), whose three ports are respectively connected to a waste liquid discharge port (7), a desorption solvent storage bottle (9), and a GC-M autosampler (6). The top of the dual-stage resin column is provided with a nitrogen pulse backflush port (10), which is connected to a high-pressure nitrogen source with a pressure set to 0.2-0.5 MPa; The control system integrates a PLC or microprocessor and has preset operating programs.

2. The resin adsorption and enrichment device for trace organic matter in brine according to claim 1, characterized in that, The secondary weak base anion exchange resin column (3) is an acrylic primary amine anion exchange resin with a wet base exchange capacity ≥3.8 mmol / g.

3. The resin adsorption and enrichment device for trace organic matter in brine according to claim 1, characterized in that, The particle size of the primary macroporous adsorption resin column (2) is set to 100-200 μm; The particle size of the secondary weak base anion exchange resin column (3) is set to 200-300 μm.

4. The resin adsorption and enrichment device for trace organic matter in brine according to claim 1, characterized in that, The series connection between the primary macroporous adsorption resin column (2) and the secondary weak base anion exchange resin column (3) is made of stainless steel pipeline.

5. The resin adsorption and enrichment device for trace organic matter in brine according to claim 1, characterized in that, The temperature control range of the PTC heating temperature control system (5) is 40-90℃.

6. The resin adsorption and enrichment device for trace organic matter in brine according to claim 1, characterized in that, The solvent in the desorption solvent storage bottle (9) is methanol or acetonitrile.

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