A digital intelligent multifunctional water treatment agent based on fluorescent tracing and application thereof
Patent Information
- Application Number
- CN202611185087.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-06
- Publication Date
- 2026-09-25
AI Technical Summary
[0011]本发明要解决的第二个技术问题是：现有荧光示踪技术中，惰性荧光示踪剂与水处理剂物理共混的方式存在示踪剂与药剂分离、消耗速率不一致导致信号失真的技术缺陷
[0045]1、实现水处理剂浓度的实时在线监测。
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Figure CN122809658A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water treatment technology, specifically to a digitally intelligent multifunctional water treatment agent for industrial circulating cooling water systems that integrates scale inhibition, corrosion inhibition, and fluorescence tracing functions, and its application. Background Technology
[0002] Industrial circulating cooling water systems are widely used in industries such as petrochemicals, thermal power generation, steel smelting, and central air conditioning, serving as an indispensable heat exchange medium circulation system in industrial production. Circulating cooling water faces three core problems during operation: scaling, corrosion, and microbial growth. To solve these problems, it is usually necessary to add water treatment agents such as scale inhibitors, corrosion inhibitors, and bactericides to the circulating water. However, traditional methods of adding water treatment agents mainly rely on manual timed sampling and offline chemical analysis, which have the following significant technical drawbacks:
[0003] First, the dosing control suffers from severe lag. Traditional methods involve manual, timed sampling (usually 1-2 times daily) and sending samples to the laboratory for analysis, with testing cycles lasting from several hours to several days. The acquisition of water quality parameters lags significantly behind actual operating conditions. By the time the test results are fed back to the dosing operation, the system's water quality conditions have already changed, causing the dosing dosage to deviate from the actual requirements. Under this open-loop control method, the concentration fluctuation of circulating water treatment agents can reach ±30% to 50% of the set value, far exceeding the effective control range.
[0004] Second, there is significant waste of chemicals and high operating costs. Because the actual concentration of chemicals in the circulating water cannot be known in real time, operators often resort to overdosing to ensure water quality meets standards, resulting in chemical consumption exceeding theoretical requirements by 20% to 50%. Overdosing not only increases operating costs but also increases environmental emissions.
[0005] Third, the water treatment effect is unstable. The circulating cooling water system is affected by multiple factors such as changes in makeup water quality, wastewater treatment, system load fluctuations, and seasonal temperature changes, causing the effective concentration of the chemicals to be constantly changing. The lack of real-time monitoring means that frequent fluctuations in chemical concentration lead to unstable scale inhibition, corrosion inhibition, and bactericidal effects, affecting equipment operating safety and system energy efficiency.
[0006] To address the aforementioned issues, fluorescence tracer technology has been gradually introduced into the water treatment field. The core principle of this technology is to introduce a tracer substance with detectable fluorescence signals into the water treatment agent, continuously monitor the intensity of the fluorescence signal in the circulating water using an online fluorescence sensor, and calculate the concentration of the effective agent in the circulating water in real time based on a pre-established fluorescence intensity-reagent concentration standard curve.
[0007] However, existing fluorescent tracer technologies mainly employ the physical blending of inert fluorescent tracers (such as tetrasodium 1,3,6,8-pyrene tetrasulfonate, PTSA) with water treatment agents, which has the following inherent drawbacks: (1) Physical blending relies on the uniform mixing of tracers and agents in circulating water, but components with different molecular weights have different migration and diffusion rates in water. Long-term operation carries the risk of tracer and agent separation, resulting in the fluorescent signal not accurately reflecting the agent concentration. (2) There is no chemical bond between the inert tracer and the agent, and the consumption rate of the tracer may differ from that of the agent, further amplifying the signal deviation. (3) Physical blending tracer systems require precise proportional feeding equipment and strict quality control, increasing system complexity and maintenance costs.
[0008] In recent years, covalent fluorescently labeled polymer technology has provided a new approach to solving the aforementioned problems. Polyaspartic acid (PASP) is a recognized green scale inhibitor, and its molecular chain contains abundant carboxyl groups and terminal amino groups, providing ideal reaction sites for the covalent bonding of fluorescent groups. By covalently linking fluorescent molecules to the PASP molecular chain, a 1:1 stoichiometric correspondence between the fluorescence signal and the PASP molecule can be ensured. However, covalently fluorescently labeled polymers face problems such as complex synthesis processes, insufficient photostability of fluorescent groups, and high industrialization costs. Carbon quantum dots, as an emerging fluorescent nanomaterial, have advantages such as tunable excitation wavelength and good photostability, but the feasibility and economic viability of large-scale industrial applications still need to be verified.
[0009] In summary, existing technologies have not yet provided a digital and intelligent water treatment agent technology solution that balances real-time online monitoring accuracy, signal-concentration correspondence accuracy, and engineering implementation economy. This invention addresses these shortcomings by providing multiple parallel technical approaches to achieve precise dosing and intelligent management of water treatment agents. Summary of the Invention
[0010] The first technical problem that this invention aims to solve is that the concentration of existing water treatment agents cannot be monitored online in real time, and manual sampling and detection are severely delayed, failing to provide timely feedback signals for precise dosing control.
[0011] The second technical problem that this invention aims to solve is that in existing fluorescent tracer technologies, the physical blending of inert fluorescent tracers and water treatment agents has technical defects such as tracer and reagent separation and inconsistent consumption rates leading to signal distortion.
[0012] The third technical problem that this invention aims to solve is that existing water treatment agent products have limited functions and lack multifunctional water treatment agent products that integrate scale inhibition, corrosion inhibition, and fluorescence tracing.
[0013] To address the aforementioned technical problems, this invention provides a digitally intelligent multifunctional water treatment agent based on fluorescence tracing. The water treatment agent comprises a scale and corrosion inhibitor component and a fluorescence tracing component, wherein the fluorescence tracing component is implemented through the following three parallel embodiments:
[0014] (a) Fluorescence Tracing Scheme
[0015] Option A: PASP-FITC covalent fluorescent labeling
[0016] The fluorescent tracer component is a PASP-FITC fluorescently labeled polymer formed by the covalent chemical bonding of fluorescein isothiocyanate (FITC) and polyaspartic acid (PASP). The isothiocyanate group (-N=C=S) in the FITC molecule undergoes a nucleophilic addition reaction with the primary amino group (-NH2) on the side chain or at the end of the PASP molecule, generating a stable thiourea bond (-NH-CS-NH-), thereby achieving covalent fixation of the FITC fluorescent group on the PASP molecular chain. This reaction is carried out under mild conditions, efficiently at pH 8–9 and room temperature. The molecular weight of PASP is 2000–5000 Da, and the molar ratio of FITC to PASP amino groups is 1:1 to 1:10. The fluorescence detection characteristics are: excitation wavelength 495 nm, emission wavelength 519 nm, and fluorescence quantum yield ≥0.7 (determined using a relative method with quinine sulfate (quantum yield 0.54 in 0.1 M H2SO4) as a reference).
[0017] Option B: PASP-carbon quantum dot composite
[0018] The fluorescent tracer component is a PASP-CDs fluorescent composite nanomaterial, consisting of carbon quantum dots (CDs) and PASP covalently bonded via amide bonds. Multiple carboxyl groups on the side chains of the PASP molecular chains are linked to amino groups on the CDs surface via amide condensation reactions, forming multivalent amide bonds. Each CD surface is connected to 2–8 PASP molecular chains. The CDs have a particle size of 2–10 nm and their surface contains functional groups such as carboxyl (-COOH), hydroxyl (-OH), carbonyl (C=O), and amino (-NH2). The fluorescence detection characteristics are: excitation wavelength 360–380 nm, emission wavelength 430–450 nm, exhibiting blue fluorescence.
[0019] Option C: PTSA inert fluorescent tracer blend
[0020] The fluorescent tracer component is tetrasodium 1,3,6,8-pyrenetetrasulfonic acid (PTSA), which is physically blended with the water treatment agent in a fixed ratio as an inert tracer. PTSA has a molecular weight of 606.40 Da (tetrasodium salt form) and a chemical structure with four sulfonic acid groups, giving it extremely high water solubility (>500 g / L). Its fluorescence detection characteristics are: excitation wavelength 373 nm, emission wavelength 404 nm, and Stokes shift 31 nm. The mass percentage of PTSA in the water treatment agent is 0.1% to 5.0% (based on pure PTSA), preferably 0.5% to 2.0%.
[0021] (ii) Scale and corrosion inhibitor components
[0022] In the above three schemes, the scale and corrosion inhibitor components include, but are not limited to, one or more combinations of the following: polyaspartic acid (PASP), molecular weight 2000-5000 Da; polyepoxysuccinic acid (PESA), molecular weight 1000-5000 Da; acrylic acid / hydroxypropyl acrylate copolymer (AA / HPA), molecular weight 2000-8000 Da; 2-phosphono-1,2,4-tricarboxylate butane (PBTCA); hydroxyethylidene diphosphonic acid (HEDP); zinc salt (in the form of Zn) 2+ (Calculation). Preferably, the scale and corrosion inhibitor component is a compound combination of PASP and PESA.
[0023] Preferably, the water treatment agent comprises, by mass percentage: 8%–40% scale and corrosion inhibitor polymer, 0.05%–2% fluorescent tracer component, 1%–10% corrosion inhibitor, 0.5%–5% dispersant, 0.1%–2% pH adjuster, 0.1%–5% bactericide, and the balance being water.
[0024] (III) Preparation method of water treatment agent
[0025] The present invention also provides a method for preparing the above-mentioned water treatment agent, comprising the following steps:
[0026] (1) When using scheme A, polyaspartic acid is dissolved in a buffer solution with pH 7.5 to 9.0, an organic solvent solution of fluorescein isothiocyanate is added, and the reaction is carried out at 20 to 40°C in the dark for 4 to 12 hours. After dialysis purification and freeze drying, the fluorescently labeled polymer is obtained.
[0027] (2) When using scheme B, the carbon quantum dot aqueous dispersion is mixed with polyaspartic acid at a mass ratio of 1:1 to 1:5, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added as condensing agents. The mixture is stirred at 20 to 40°C for 6 to 24 hours and purified by dialysis to obtain the polymer-nano fluorescent complex.
[0028] (3) When using scheme C, dissolve the tetrasodium salt of 1,3,6,8-pyrene tetrasulfonate in deionized water in proportion, add the scale inhibitor and corrosion inhibitor polymer aqueous solution under stirring, stir for 10 to 30 minutes until the mixture is uniform, and obtain the mixed preparation.
[0029] (4) Mix the fluorescent tracer component obtained in step (1), (2) or (3) with corrosion inhibitor, dispersant, pH adjuster, bactericide and the remaining water, mix for 10 to 60 minutes under stirring at 200 to 800 rpm, and adjust the pH value to 6.5 to 9.0 to obtain the fluorescent tracer-based intelligent multifunctional water treatment agent.
[0030] (iv) Application methods of water treatment agents
[0031] This invention also provides a method for applying the above-mentioned water treatment agent in a circulating cooling water system. The water treatment agent is added to the circulating cooling water in a continuous dosing manner, with the dosage ensuring an effective concentration of the scale and corrosion inhibitor polymer in the circulating water of 10–200 ppm, preferably 30–100 ppm. The dosage of the water treatment agent in the circulating cooling water system is controlled by real-time monitoring of the fluorescence intensity in the circulating water using an online fluorescence sensor; the sampling interval of the online fluorescence sensor is 1–10 seconds, and the linear determination coefficient R² of the calibration curve between the fluorescence intensity and the concentration of the scale and corrosion inhibitor polymer is ≥0.998.
[0032] After detecting the fluorescence intensity in the circulating water, the online fluorescence sensor corrects the calibration curve through temperature compensation and photobleaching correction. The temperature compensation is performed in real time based on the temperature-fluorescence intensity relationship model.
[0033] The temperature-fluorescence intensity relationship model is F 25 = F T / [1+α T ·(T-25)], where F T This is the raw fluorescence intensity directly measured by the sensor when the actual circulating water temperature is T, in au F. 25 To standardize the fluorescence intensity to a reference temperature of 25°C, the units are au and α. T α is the temperature coefficient (unit: °C⁻¹), a negative value representing a decrease in fluorescence intensity at the same reagent concentration as water temperature increases; T is the actual temperature of the circulating water (unit: °C). Temperature coefficient α T The determination method is as follows: The fluorescence intensity of a standard solution of the same concentration is measured every 5°C within the range of 15–45°C, with 25°C as the reference temperature. The relative fluorescence intensity (F) is used as the metric. T / F 25 A linear regression was performed on the temperature difference (T-25), and the regression slope is α. T .
[0034] The photobleaching correction adopts a first-order kinetic model F(t)=F0·e -kt To compensate for the attenuation of fluorescence signals during long-term operation, the photobleaching rate constant k was determined by the following method: Under set excitation light intensity and wavelength conditions, the fluorescence intensity of the fluorescent tracer standard solution was continuously monitored over time, and the fluorescence intensity-time data were analyzed according to the first-order exponential decay model F(t) = F0·e -kt A nonlinear fitting is performed to obtain the k value.
[0035] Photobleaching correction compensation formula: F corr =F(t)·e kt
[0036] The parameters in the formula are defined as follows:
[0037] F(t): The original fluorescence intensity measured by the sensor after continuous operation for time t, in au;
[0038] F corr Standard fluorescence intensity after photobleaching correction, in au;
[0039] F0: Initial fluorescence intensity of a freshly prepared, light-attenuated standard reagent solution at 25°C, in au;
[0040] k: First-order decay rate constant of photobleaching, in days -1 The larger the value of k, the faster the fluorescence signal decays over time.
[0041] t: Continuous operating time of the water treatment system, in days (d).
[0042] Final calibration fluorescence F of online fluorescence sensor final =F 25 ·e kt = F T ·e kt / [1+α T (T-25)].
[0043] The circulating cooling water system is at least one of the following: petrochemical circulating cooling water system, thermal power plant circulating cooling water system, iron and steel smelting circulating cooling water system, coal chemical circulating water system, central air conditioning circulating cooling water system, reverse osmosis pretreatment system, boiler water treatment system, or industrial wastewater treatment system.
[0044] Compared with the prior art, the present invention has the following beneficial effects:
[0045] 1. Real-time online monitoring of water treatment agent concentration.
[0046] This invention achieves real-time online monitoring of reagent concentration in circulating water by introducing fluorescent tracer components into the water treatment agent and combining them with an online fluorescence sensor. The sampling interval of the fluorescence sensor is only 3 seconds, representing a significant leap forward compared to traditional manual offline sampling methods. The detection limit is as low as 2.26 ppm, and the quantitation limit is as low as 6.84 ppm.
[0047] 2. The fluorescence signal and the drug concentration have a stable correlation.
[0048] The three fluorescent tracer schemes provided by this invention each have their own advantages: Scheme A directly links the fluorescent group to the scale inhibitor molecule through chemical bonds, achieving a strict 1:1 correspondence between the fluorescent signal and the agent molecule; Scheme B fixes PASP on the CDs surface through polyvalent amide bonds, exhibiting excellent photostability; Scheme C uses mature commercial tracers, which are low in cost, have good linearity, and are convenient for on-site implementation.
[0049] 3. Significantly reduces drug usage and operating costs.
[0050] Through precise online concentration monitoring and intelligent feedback control, the waste of reagents caused by concentration fluctuations and overdosing in traditional methods is avoided, and reagent consumption can be reduced by 20% to 40%.
[0051] 4. Automatic fluorescence attenuation compensation ensures long-term operational reliability.
[0052] This invention employs a fluorescence decay correction method based on an exponential decay kinetic model, which can effectively compensate for fluorescence signal attenuation caused by factors such as photobleaching and chemical degradation. The designed photobleaching half-life is ≥30 days, and after correction, the signal can be restored to more than 95% of its initial intensity during long-term operation.
[0053] 5. Multiple fluorescence schemes are available to meet different needs.
[0054] This invention provides three parallel fluorescence tracing schemes, covering the full spectrum of needs from scientific research verification to engineering implementation, and from high-end applications to economical and practical applications.
[0055] 6. Wide range of applications.
[0056] The water treatment agent of this invention can be applied to various circulating water system scenarios such as petrochemicals, thermal power generation, iron and steel smelting, coal chemical industry, central air conditioning, reverse osmosis pretreatment, boiler water treatment and industrial wastewater treatment. Attached Figure Description
[0057] Figure 1 shows the comparison curves of fluorescence intensity versus scale inhibitor polymer concentration calibration for three fluorescence tracing schemes;
[0058] Figure 2 shows the comparison curves of fluorescence intensity with water temperature before and after temperature compensation;
[0059] Figure 3 shows the curves of measured fluorescence intensity and corrected fluorescence intensity as a function of running time during photobleaching attenuation. Detailed Implementation
[0060] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.
[0061] Example 1: Preparation and application of PASP-FITC covalent fluorescently labeled water treatment agent
[0062] (1) Synthesis of PASP-FITC
[0063] 5.0 g of polyaspartic acid (PASP) with a molecular weight of 3000 Da was dissolved in 100 mL of deionized water, and the pH was adjusted to 8.5 with 0.5 M NaOH solution. Under light-protected stirring, a DMSO solution of FITC (fluorescein isothiocyanate) (10 mg / mL) was slowly added dropwise, with a molar ratio of FITC to PASP amino group of 10:1. After the addition was complete, the reaction was stirred at room temperature (25℃) for 3 hours in the dark. After the reaction was complete, the solution was dialyzed in deionized water for 48 hours using a dialysis bag (MWCO 3500 Da), with the dialysate changed every 8 hours to remove unreacted free FITC and byproducts. The dialyzed PASP-FITC solution was freeze-dried to obtain a yellow solid powder. The labeling rate was determined to be 12.5% by UV-Vis spectrophotometry, based on the molar absorptivity of FITC at 495 nm (ε = 7.2 × 10⁻⁶). 4 L·mol -1 ·cm -1 ) Calculate the FITC content, and calculate the labeling rate based on the amino content of PASP.
[0064] (2) Preparation of water treatment agent
[0065] Weigh the above-mentioned PASP-FITC fluorescently labeled polymer and prepare a working solution containing 100 ppm PASP (based on PASP) with deionized water. Simultaneously, add 30 ppm PESA as a synergistic scale inhibitor and 5 ppm benzotriazole as a corrosion inhibitor. Adjust the pH to 7.5–8.5 to obtain the finished water treatment agent.
[0066] (3) Fluorescence detection parameters
[0067] The detection system uses a 495 nm LED excitation source and a 520 nm bandpass filter (10 nm half-width) for emission detection. Within the PASP concentration range of 0–100 ppm, the fluorescence intensity exhibits a linear relationship with concentration (R² = 0.999), the fluorescence response sensitivity is S = 8.2 au / ppm, and the detection limit is 1.8 ppm.
[0068] (4) Scale inhibition performance test
[0069] The scale inhibition performance of calcium carbonate was tested according to GB / T 16632-2008 standard under an 80℃ water bath. The experimental water quality was: Ca²⁺ concentration 250 mg / L (calculated as CaCO₃), HCO₃⁻ concentration 250 mg / L (calculated as CaCO₃), and the temperature was maintained for 10 hours. The test results showed that PASP-FITC (PASP concentration 100 ppm) achieved a scale inhibition rate of 88.7% for calcium carbonate scale, maintaining good scale inhibition performance compared to unlabeled PASP (scale inhibition rate 90.2%).
[0070] (5) Application methods
[0071] The aforementioned water treatment agent was continuously added to the central air conditioning circulating cooling water system. The fluorescence intensity in the circulating water was monitored in real time using an online fluorescence sensor. The dosage was controlled to maintain an effective PASP concentration of 50–100 ppm in the circulating water. 24-hour continuous operation results showed that the water treatment agent concentration was stable and the scale inhibition effect was good.
[0072] Example 2: Preparation and application of PASP-carbon quantum dot composite water treatment agent
[0073] (1) Preparation of CDs
[0074] Citric acid (2.0 g) and ethylenediamine (1.5 mL) were used as precursors, dissolved in 30 mL of deionized water, and transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The mixture was heated at 200 °C for 6 hours. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a brown CDs solution. The solution was filtered through a 0.22 μm microporous membrane, dialyzed using a dialysis bag (MWCO 1000 Da) for 24 hours, and then freeze-dried to obtain CDs powder. Transmission electron microscopy characterization showed that the CDs particle size was 3–5 nm.
[0075] (2) Synthesis of PASP-CDs complex
[0076] Dissolve 0.5 g of the above-mentioned CDs powder in 50 mL of deionized water, add 0.2 g of EDC and 0.12 g of NHS, and activate the carboxyl groups on the CDs surface for 30 minutes. Then add 1.0 g of PASP (molecular weight 3000 Da), adjust the pH to 7.5, and stir the reaction at room temperature for 6 hours. After the reaction is complete, dialyze through a dialysis bag (MWCO 10000 Da) for 24 hours, and freeze-dry to obtain the PASP-CDs complex.
[0077] (3) Fluorescence property test
[0078] The PASP-CDs complex exhibited blue fluorescence with an excitation wavelength of 365 nm and an emission wavelength of 440 nm. The fluorescence quantum yield was 0.35, determined using a relative method with quinine sulfate (quantum yield 0.54 in 0.1 M H₂SO₄) as a reference. In a circulating cooling water simulation experiment (water temperature 32℃, containing Ca…),… 2+ 250 mg / L, HCO 3- In 250 mg / L, the fluorescence intensity of the 50 ppm PASP-CDs complex decreased by less than 10% after continuous excitation irradiation for 48 hours, demonstrating excellent photostability.
[0079] (4) Scale inhibition performance
[0080] Calcium carbonate scale inhibition tests were conducted according to GB / T 16632-2008 standard. The 50 ppm PASP-CDs complex showed a scale inhibition rate of 86.5% for calcium carbonate scale, meeting the requirements for industrial use.
[0081] (5) Application methods
[0082] The aforementioned water treatment agent was continuously added to the circulating cooling water system of the thermal power plant to achieve an effective concentration of 30–80 ppm for the PASP-CDs complex in the circulating water. An online fluorescence sensor monitored the fluorescence intensity in the circulating water in real time, and temperature compensation and photobleaching correction ensured long-term operational accuracy. After 30 days of continuous operation, the water treatment agent concentration remained stable, demonstrating good scale and corrosion inhibition effects.
[0083] Example 3: Preparation and application of PTSA inert fluorescent tracer blended water treatment agent
[0084] (1) Preparation of water treatment agent
[0085] The water treatment agent solution was prepared according to the following mass percentages: polyaspartic acid (PASP, molecular weight 3000 Da) 8.0%, polyepoxysuccinic acid (PESA, molecular weight 2000 Da) 2.0%, PTSA (tetrasodium 1,3,6,8-pyrenetetrasulfonate) 0.5%, benzotriazole (BTA, corrosion inhibitor) 0.5%, and deionized water as the balance. The preparation method was as follows: PASP and PESA were added sequentially to deionized water and stirred until completely dissolved. Then PTSA and BTA were added, and the mixture was stirred and mixed for another 30 minutes until homogeneous, thus obtaining the concentrated water treatment agent solution.
[0086] (2) Concentration calibration curve
[0087] Within the PASP concentration range of 0–60 ppm (corresponding to PTSA 0–0.6 ppm), the fluorescence intensity showed a good linear relationship with the PASP concentration: F = 7.57 × C + 18.02, R² = 0.9988. C represents the concentration of the scale and corrosion inhibitor polymer PASP (ppm). The detection limit was 2.26 ppm PASP (calculated as PASP), and the quantitation limit was 6.84 ppm.
[0088] (3) Thermal stability and light stability tests
[0089] PTSA solution (10 ppm) was heated in water baths at 40℃, 60℃, and 80℃ for 24 hours, and the fluorescence intensity decay was less than 3% in all cases. Under continuous 365 nm ultraviolet irradiation (power 10 mW / cm²), the fluorescence half-life of PTSA was >30 days. This indicates that PTSA has excellent thermal and photostability.
[0090] (4) Application method
[0091] The aforementioned water treatment agent was continuously added to the petrochemical circulating cooling water system to achieve an effective PASP concentration of 50–100 ppm and a corresponding PTSA concentration of 0.5–1.0 ppm. A fluorescence sensor was used with a 373 nm UV-LED as the excitation source and a 404 nm bandpass filter to detect the emitted fluorescence. Online monitoring results showed minimal fluctuations in the water treatment agent concentration and stable scale and corrosion inhibition effects.
[0092] Figure 1The graphs show a comparison of fluorescence intensity versus scale inhibitor polymer concentration calibration for three fluorescence tracer schemes. The horizontal axis represents the effective concentration of polyaspartic acid in circulating water, and the vertical axis represents the standard fluorescence intensity calibrated to 25°C. Curve A represents the PASP-FITC covalent fluorescent labeling system, curve B represents the PASP-carbon quantum dot composite system, and curve C represents the PTSA inert tracer physical blend system. All three schemes exhibit excellent linear correlation in the commonly used industrial concentration range of 0–100 ppm. Scheme A has the highest fluorescence response sensitivity, the strongest fluorescence signal at the same reagent concentration, and the lowest detection limit. Scheme C has a weak background fluorescence at the baseline, making it suitable for low-cost online monitoring scenarios. Scheme B has a stable linear range and the best photostability.
[0093] Example 4: Verification Experiment of Fluorescence Signal Interference Correction Effect
[0094] This embodiment verifies the temperature interference compensation effect and the long-term attenuation correction effect of photobleaching. The test reagent uses a PTSA physical blending fluorescent tracer system with a fixed concentration of 50 ppm.
[0095] 4.1 Temperature Compensation Effect Verification Test
[0096] The prepared tracer solution was placed in a thermostat, and the water temperature was controlled to vary gradually within the range of 15–45°C. The original fluorescence intensity F directly measured by the sensor at different temperatures was collected. T Using a temperature correction model:
[0097] F 25 =F T / [1+α T [(T−25)] The measured fluorescence was uniformly corrected to a reference temperature of 25℃, α T =-0.015 / ℃.
[0098] The test results are as follows Figure 2 As shown, by Figure 2 As can be seen, without temperature compensation, the fluorescence intensity decreases linearly with increasing water temperature; after temperature model correction, the fluorescence intensity remains stable at a constant value. This correction method can eliminate detection errors caused by fluctuations in circulating cooling water temperature and is suitable for industrial environments with significant temperature variations between winter and summer.
[0099] Figure 2 shows the comparison curves of fluorescence intensity with water temperature before and after temperature compensation; the horizontal axis is the temperature of circulating cooling water, and the vertical axis is the fluorescence intensity; the dashed line is the original measured fluorescence signal without temperature model compensation, which continues to decrease as the water temperature increases; the solid line is the standard fluorescence intensity after correction by the temperature correction model of this invention, which is stable and constant, eliminating the concentration detection error caused by water temperature fluctuations.
[0100] With 25℃ as the reference temperature, the fluorescence intensity at 32℃ (typical circulating water temperature in summer) is about 90% of the reference value, indicating that temperature correction is a necessary step to ensure measurement accuracy.
[0101] 4.2 Verification Experiment of Photobleaching Attenuation Correction Effect
[0102] Maintaining a constant solution temperature of 25℃, the detection light source was continuously turned on for long-term irradiation to simulate on-site online monitoring conditions. The test was conducted continuously for 30 days, with measured fluorescence intensity F collected every 5 days. meas .
[0103] Photobleaching of fluorescent tracers follows a first-order kinetic decay model.
[0104] F meas =F0·e -kt The formula is transformed to obtain the photobleaching correction formula:
[0105] F corr = F meas ·e kt
[0106] In the formula, the rate constant k = 0.0231d -1 The above formula is used to compensate for the attenuation of the collected raw data.
[0107] The test results are as follows Figure 3 As shown in the diagram, the dashed triangular line represents the uncorrected measured fluorescence, while the solid horizontal line represents the fluorescence intensity after kinetic correction. Under uncorrected conditions, the measured fluorescence intensity, affected by photobleaching, decays exponentially with operating time, with a signal attenuation of approximately 50% after 30 days of continuous operation, leading to severely low reagent concentration detection. Using the correction model of this invention, the corrected fluorescence intensity remains stable, effectively eliminating signal drift caused by light source irradiation during long-term monitoring and ensuring the system's long-term online detection accuracy.
[0108] Example 5: Performance Comparison and Application Selection of Different Fluorescence Schemes
[0109] The detection sensitivity of the three fluorescence schemes is compared in Table 1 below within the effective concentration range of 0–100 ppm for PASP:
[0110]
[0111] Table 1
[0112] All three schemes showed good linearity (R²>0.997) in the range of 0–60 ppm, and the detection limits were all below 3 ppm.
[0113] In terms of photostability, scheme B (PASP-CDs) showed the best photostability (half-life > 60 days), followed by scheme C (PTSA blend) (half-life > 30 days), while scheme A (PASP-FITC) had the worst photostability (half-life of about 15 days) and required more frequent attenuation correction.
[0114] Based on different application requirements, the following solution selection strategies are recommended: For high-end application scenarios requiring a strict 1:1 signal-to-concentration ratio, solution A is recommended in conjunction with fluorescence attenuation correction; for scenarios seeking optimal photostability and long-term operational reliability, solution B is recommended; for scenarios prioritizing ease of engineering implementation, economy, and technological maturity, solution C is recommended, which is also the preferred solution for current industrial applications.
[0115] The fluorescent tracer-based intelligent multifunctional water treatment agent provided by this invention has demonstrated the following industrial application feasibility through theoretical analysis and experimental verification:
[0116] 1. Feasibility of the preparation process.
[0117] Both Scheme A and Scheme B involve preparation in an aqueous solution system under mild reaction conditions (room or medium temperature, normal pressure), requiring no complex reaction equipment or special protective measures. Scheme C is the simplest, requiring only the physical mixing of PTSA and the water treatment agent in a conventional stirred tank, and can be fully utilized using existing water treatment agent production lines.
[0118] 2. Feasibility of the method of use.
[0119] The water treatment agent of this invention is simple to use. It is simply added to the circulating cooling water in a continuous dosing manner, and precise dosing control is achieved by real-time monitoring of fluorescence intensity using an online fluorescence sensor. Commercially available online fluorescence sensors already exist, and the hardware investment can be recovered within 1-3 years through cost savings on the reagents.
[0120] 3. Scope of application.
[0121] The technical solution of this invention is applicable to water temperature ranges of 5–60℃ and water quality conditions of pH 6.0–9.0, with circulating water systems ranging from 100 to 50,000 m³, and can achieve long-term continuous and stable operation. This invention can be widely applied to various circulating water system scenarios such as petrochemicals, thermal power generation, steel smelting, coal chemicals, central air conditioning, reverse osmosis pretreatment, boiler water treatment, and industrial wastewater treatment.
[0122] 4. Economic benefits.
[0123] By using precise online concentration monitoring and feedback control, the waste of reagents caused by concentration fluctuations and overdosing in traditional methods is avoided, and reagent consumption can be reduced by 20% to 40%, resulting in significant economic and environmental benefits.
[0124] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A digitally intelligent multifunctional water treatment agent based on fluorescence tracing, characterized in that, The water treatment agent comprises a fluorescent tracer component and a scale and corrosion inhibitor component, wherein the fluorescent tracer component is selected from at least one of the following: (A): Fluorescent dyes are covalently linked to the molecular chains of scale-inhibiting and corrosion-inhibiting polymers to form fluorescently labeled polymers; (B): The surface of fluorescent nanomaterials is covalently modified with scale-inhibiting and corrosion-inhibiting polymers to form polymer-nanofluorescent composites; (C): Inert fluorescent tracer molecules are physically blended with scale and corrosion inhibitor polymers in a fixed ratio to form a mixed formulation; The scale and corrosion inhibitor polymer is selected from at least one of polyaspartic acid, polyepoxysuccinic acid, and polyacrylic acid, or a copolymer of any two or more of the above monomers.
2. The intelligent multifunctional water treatment agent based on fluorescence tracing according to claim 1, characterized in that, The fluorescein dye described in Scheme A is fluorescein isothiocyanate, which is covalently linked to the side chain amino or terminal amino group of polyaspartic acid via thiourea bonds; the weight-average molecular weight of the polyaspartic acid is 3000-5000 Da, and the labeling rate of fluorescein isothiocyanate and polyaspartic acid is 10%-100%.
3. The intelligent multifunctional water treatment agent based on fluorescence tracing according to claim 1, characterized in that, The fluorescent nanomaterial described in Scheme B is carbon quantum dots with a particle size of 1 to 10 nm and a surface containing at least one functional group selected from carboxyl, hydroxyl and amino groups; the scale inhibitor and corrosion inhibitor polymer is covalently modified on the surface of the carbon quantum dots by amide bonds.
4. The intelligent multifunctional water treatment agent based on fluorescence tracing according to claim 1, characterized in that, The inert fluorescent tracer described in Scheme C is tetrasodium 1,3,6,8-pyrenetetrasulfonate, and its mass ratio with the scale and corrosion inhibitor polymer is 1:50 to 1:
200.
5. The intelligent multifunctional water treatment agent based on fluorescence tracing according to any one of claims 1 to 4, characterized in that, By mass percentage, it contains the following components: scale and corrosion inhibitor polymer 8%–40%, fluorescent tracer component 0.05%–2%, corrosion inhibitor 1%–10%, dispersant 0.5%–5%, pH adjuster 0.1%–2%, bactericide 0.1%–5%, and the balance being water.
6. A method for preparing a digitally intelligent multifunctional water treatment agent based on fluorescence tracing as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) When using scheme A, polyaspartic acid is dissolved in a buffer solution with pH 7.5 to 9.0, an organic solvent solution of fluorescein isothiocyanate is added, and the reaction is carried out at 20 to 40°C in the dark for 4 to 12 hours. After dialysis purification and freeze drying, the fluorescently labeled polymer is obtained. (2) When using scheme B, the carbon quantum dot aqueous dispersion is mixed with polyaspartic acid at a mass ratio of 1:1 to 1:5, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added as condensing agents. The mixture is stirred at 20 to 40°C for 6 to 24 hours and purified by dialysis to obtain the polymer-nano fluorescent complex. (3) When using scheme C, dissolve the tetrasodium salt of 1,3,6,8-pyrene tetrasulfonate in deionized water in proportion, add the scale inhibitor and corrosion inhibitor polymer aqueous solution under stirring, stir for 10 to 30 minutes until the mixture is uniform, and obtain the mixed preparation. (4) Mix the fluorescent tracer component obtained in step (1), (2) or (3) with corrosion inhibitor, dispersant, pH adjuster, optional bactericide and the balance water, mix for 10 to 60 minutes under stirring at 200 to 800 rpm, and adjust the pH value to 6.5 to 9.0 to obtain the fluorescent tracer-based intelligent multifunctional water treatment agent.
7. The application of the fluorescent tracer-based intelligent multifunctional water treatment agent according to any one of claims 1 to 5 in a circulating cooling water system, characterized in that, The water treatment agent is added to the circulating cooling water in a continuous dosing manner, and the dosage is such that the effective concentration of the scale inhibitor and corrosion inhibitor polymer in the circulating water is 10-200 ppm.
8. The application according to claim 7, characterized in that, The dosage of the water treatment agent in the circulating cooling water system is monitored in real time by an online fluorescence sensor to detect the fluorescence intensity in the circulating water and to control the dosage based on feedback. The sampling interval of the online fluorescence sensor is 1 to 10 seconds, and the linear determination coefficient R² of the calibration curve between the fluorescence intensity and the concentration of the scale and corrosion inhibitor polymer is ≥0.
998.
9. The application according to claim 8, characterized in that, After detecting the fluorescence intensity in the circulating water, the online fluorescence sensor corrects the calibration curve through temperature compensation and photobleaching correction; the temperature compensation is performed in real time based on the temperature-fluorescence intensity relationship model. The temperature-fluorescence intensity relationship model is F 25 = F T / [1+α T ·(T-25)], where F T F represents the fluorescence intensity measured at temperature T. 25 To correct the fluorescence intensity to 25°C, α T Let α be the temperature coefficient, and T be the actual temperature of the circulating water. T The determination method is as follows: the fluorescence intensity of the standard solution of the same concentration is measured every 5℃ within the range of 15~45℃; The photobleaching correction adopts a first-order kinetic model F(t)=F0·e -kt The fluorescence signal is attenuated and compensated during long-term operation, where F(t) is the measured fluorescence intensity at time t, F0 is the initial fluorescence intensity, t is the running time, and k is the photobleaching rate constant.
10. The application according to claim 7, characterized in that, The circulating cooling water system is at least one of the following: petrochemical circulating cooling water system, thermal power plant circulating cooling water system, iron and steel smelting circulating cooling water system, coal chemical circulating water system, central air conditioning circulating cooling water system, reverse osmosis pretreatment system, boiler water treatment system, or industrial wastewater treatment system.