A bactericidal and scale-inhibiting penetrant compounded by anion and cation surfactants and application thereof

Abstract

This invention discloses a bactericidal, scale-inhibiting, and penetrant compounded from anionic and cationic surfactants and its application, belonging to the field of water treatment science. The single-tailed, double-headed quaternary ammonium salt of this invention exhibits highly efficient bactericidal and algicidal properties. At concentrations greater than 100 mg / L, the bactericidal rate can reach over 99.1%; at concentrations greater than 120 mg / L, the algicidal rate can reach 99.8% after three days. Furthermore, this bactericide adsorbs onto the bacterial surface through strong electrostatic attraction, making it less likely for bacteria to develop drug resistance. The bactericidal, scale-inhibiting, and penetrant prepared by compounding the single-tailed, double-headed quaternary ammonium salt surfactant of this invention can adsorb onto the surface of CaCO3 crystals, preventing normal crystal growth and ultimately dispersing them in the water as loose, broken, microcrystalline particles, thus exhibiting excellent scale inhibition effects.

Description

Technical Field

[0001] This invention relates to a bactericidal, scale-inhibiting, and penetrant compounded from anionic and cationic surfactants and its application, belonging to the field of water treatment science. Background Technology

[0002] With rapid economic development and industrialization, water scarcity has become a global problem facing humanity. Many industrial processes, such as thermal power generation and pulp and paper manufacturing, require large amounts of water, further exacerbating the water shortage. The main solution is water recycling. Therefore, circulating cooling water systems are widely used in industrial production to achieve efficient water use and water conservation. However, in long-term use of open-loop circulating cooling water systems, the introduction of airborne microorganisms leads to their proliferation, deteriorating water quality. Simultaneously, as the concentration factor increases, scaling occurs on the system's inner walls and pipes. These factors cause equipment corrosion, reduce heat transfer efficiency, and affect the normal operation of the system. Therefore, selecting appropriate chemical agents to inhibit microbial growth and scaling within the system is crucial for achieving effective water resource utilization.

[0003] Scale inhibitors used in circulating cooling water typically contain electronegative groups, such as phosphonic acid groups, sulfonic acid groups, and carboxyl groups. They can inhibit scaling through one or more inhibition mechanisms, such as chelation, dispersion, lattice distortion, and threshold effects, interacting with calcium scale. Common microorganisms in circulating cooling water systems include bacteria, fungi, and algae. Based on their bactericidal mechanisms, commonly used bactericides are classified into oxidizing bactericides (such as chlorine and active bromine) and non-oxidizing bactericides (such as quaternary ammonium salts). While oxidizing bactericides have good bactericidal effects, they may cause redox reactions with other water treatment agents, thus affecting their effectiveness. Therefore, special attention must be paid to their addition method, sequence, and time intervals. Consequently, people are increasingly turning to quaternary ammonium salt surfactants, which are easier to use and less toxic. Benzalkonium chloride and benzalkonium chloride are the two most commonly used. However, in actual use, because the hydrophilic head group of quaternary ammonium salt surfactants carries a positive charge, when mixed with anionic scale inhibitors, it is easy to strongly combine with the anionic scale inhibitors through electrostatic attraction to form organic precipitates, which will weaken the bactericidal and scale inhibition effects.

[0004] Existing technology CN115124438B describes the preparation and application of a highly efficient natural product-based viscoelastic solution. The disclosed compound structure contains a bis-headed quaternary ammonium salt. However, the technical problem addressed by this technology is increasing the viscoelasticity of the solution at low surfactant concentrations, which differs from the technical field and problem of developing bactericidal and scale-inhibiting cationic surfactants. Existing technology CN115537193B describes a method for preparing and applying a highly efficient clean fracturing fluid, disclosing a bis-headed quaternary ammonium salt surfactant. This compound exhibits good solubility and strong stability and is used to prepare clean fracturing fluids. However, this technology also does not mention the application of bis-headed quaternary ammonium salts in the preparation of bactericidal and scale-inhibiting agents. Therefore, designing and developing a compound bactericidal and scale-inhibiting agent that is highly efficient in bactericidal action, has good scale inhibition performance, is simple to use, and has low toxicity is of great significance for improving the service life of circulating water systems and conserving water resources. Summary of the Invention

[0005] Technical issues:

[0006] Anionic scale inhibitors release electronegative groups from their dissociation in solution, which collide with and adsorb onto the surface of microcrystalline particles. This results in a large negative charge on the microcrystalline surface. Since like charges repel each other, this prevents effective collisions, growth, and deposition between microcrystalline particles, thus achieving scale inhibition. Quaternary ammonium salt bactericides utilize the negatively charged surface of bacteria for adsorption and destruction, making them less prone to resistance. However, in actual circulating cooling water treatment processes, when quaternary ammonium salt bactericides are mixed with anionic penetrants, precipitation easily occurs, weakening both bactericidal and scale-inhibiting effects. Therefore, developing a high-performance compound bactericidal, scale-inhibiting, and penetrant is a key technical challenge in this field.

[0007] Technical solution: To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first objective of this invention is to provide a compound (a single-tailed, double-headed quaternary ammonium salt surfactant) with the following structural formula:

[0009]

[0010] In one embodiment, the synthetic route of the single-tailed, double-headed quaternary ammonium salt surfactant is as follows:

[0011]

[0012] In one embodiment, the synthesis steps of the single-tailed, two-headed quaternary ammonium salt surfactant (C14-N2) are as follows:

[0013] The molar ratio of N,N-dimethyltetradecylamine to 3-bromopropyltrimethylammonium bromide is 1:1 to 1.5:1.

[0014] In one embodiment, the specific synthesis steps of the compound are as follows:

[0015] N,N-dimethyltetradecylamine, 3-bromo-propyltrimethylammonium bromide, and ethanol were placed in a single-necked flask and reacted at 92°C for 48–72 h. After cooling to room temperature, the solvent was removed by vacuum distillation, and the mixture was recrystallized three times with ethanol and acetone. After drying, pure C14-N2 was obtained.

[0016] In one embodiment, the specific synthesis steps of the compound are as follows:

[0017] N,N-dimethyltetradecylamine (5.0 g, 0.02 mol), 3-bromo-propyltrimethylammonium bromide (5.1 g, 0.02 mol), and 200 mL of ethanol were placed in a single-necked flask and reacted at 92 °C for 48–72 h. After cooling to room temperature, the solvent was removed by vacuum distillation, and the mixture was recrystallized three times with ethanol and acetone. After drying, a white powdery solid C14-N2 was obtained.

[0018] A third objective of this invention is to provide a compound bactericidal, scale-inhibiting, and penetrating agent comprising any of the above-mentioned compounds and anionic scale inhibitors.

[0019] In one embodiment, the concentration of the compound is 100 to 300 ppm (ppm is equivalent to mg / L).

[0020] In one embodiment, the anionic surfactant alkyl alcohol polyoxyethylene ether carboxylate (C 14 The concentration of (EO)3-COONa is 200ppm to 800ppm.

[0021] In one embodiment, the ratio of single-tailed double-headed quaternary ammonium salt surfactant to anionic surfactant is in the range of 1:2 to 3:2.

[0022] The present invention also provides the application of the above-mentioned compound or the above-mentioned compound bactericide, scale inhibitor and penetrant in water treatment.

[0023] In one embodiment, the application includes, but is not limited to, industrial water treatment, cooling water systems, and drinking water disinfection.

[0024] Beneficial effects:

[0025] This invention synthesizes a single-tailed, double-headed quaternary ammonium salt surfactant using N,N-dimethyltetradecylamine and 3-bromopropyltrimethylammonium bromide as raw materials. This single-tailed, double-headed quaternary ammonium salt surfactant has a concentrated head group charge, allowing it to strongly bind to bacterial surfaces and algae, exhibiting highly efficient bactericidal and algicidal properties. At concentrations greater than 100 mg / L, the bactericidal rate can reach over 99.1%; at concentrations greater than 120 mg / L, the algae-killing rate can reach 99.8% within three days. Furthermore, this bactericide adsorbs onto bacterial surfaces through strong electrostatic attraction, making it less likely for bacteria to develop drug resistance.

[0026] Meanwhile, this invention combines a single-tailed, two-headed quaternary ammonium salt surfactant with anionic surfactant C 14 A highly efficient bactericidal, scale-inhibiting, and penetrant is obtained by compounding (EO)3-COONa. The two compounds exhibit good compatibility, and the resulting solution remains clear and transparent without precipitation. This compound bactericidal, scale-inhibiting, and penetrant can adsorb onto the surface of CaCO3 crystals, preventing normal crystal growth. The crystals are ultimately dispersed in the water as loose, broken, tiny crystals, exhibiting excellent scale inhibition. Attached Figure Description

[0027] Figure 1 It has the molecular structure of C14-N2.

[0028] Figure 2 The image shows the hydrogen nuclear magnetic resonance spectrum of C14-N2.

[0029] Figure 3 The graph shows the surface tension of C14-N2 aqueous solution as a function of concentration (25℃).

[0030] Figure 4 Different concentrations of C14-N2 and 200 ppm of C 14 Photograph of the appearance of the aqueous solution of (EO)3-COONa after standing for 7 days.

[0031] Figure 5 To determine the concentration of C14-N2 and 200 ppm C in equimolar (5 mmol / L) CaCl2 and Na2CO3 aqueous solutions without / with different concentrations of C14-N2 and C2CO3, respectively. 14 Photographs of the appearance of a mixed aqueous solution of -(EO)3-COONa.

[0032] Figure 6 To determine the concentration of C14-N2 and 200 ppm C in equimolar (5 mmol / L) CaCl2 and Na2CO3 aqueous solutions without / with different concentrations of C14-N2 and C2CO3, respectively. 14 Microscopic comparison images of CaCO3 formed by mixing (EO)3-COONa with aqueous solution.

[0033] Figure 7 Different concentrations of benzalkonium chloride and 200 ppm of C14 Photograph of the appearance of the aqueous solution of (EO)3-COONa after standing for 7 days. Detailed Implementation

[0034] Example 1: Synthesis of a single-tailed, two-headed quaternary ammonium salt compound (C14-N2)

[0035] N,N-dimethyltetradecylamine (5.0 g, 0.02 mol), 3-bromo-propyltrimethylammonium bromide (5.1 g, 0.02 mol), and 200 mL of ethanol were placed in a single-necked flask and reacted at 92 °C for 48 hours. The mixture was cooled to 25 °C and distilled under reduced pressure to remove the solvent. The solution was recrystallized three times with ethanol and acetone. After drying, a white powdery solid C14-N2 was obtained, with a yield of 78%. The molecular structure is shown below. Figure 1 As shown.

[0036] Weigh 10 mg of C14-N2 and place it in an NMR tube, then dissolve it in deuterated reagent DMSO. Perform NMR analysis using an Adulance III NMR spectrometer at 25°C. 1 1H NMR testing, hydrogen nuclear magnetic resonance spectrum as follows Figure 2 As shown. 1 The resonant frequency of H is 400MHz. From... Figure 2 The hydrogen nuclear magnetic resonance spectrum of N2-C12-N2 shows that the chemical shifts of each hydrogen atom are consistent with the target product, and there are no impurity peaks on the spectrum, indicating that the product has reached a very high purity and meets the requirements of subsequent experiments.

[0037] 1H NMR(400MHz,DMSO)δ3.37,3.30(m,6H,C23-3H,C24-3H),3.15(s,9H,C20- 3H,C21-3H,C22-3H),3.08(s,6H,C14-2H,C16-2H,C18-2H),2.21(m,2H,C1 7-2H),1.68(m,2H,C13-2H,),1.24(m,22H,C2-2H,C3-2H,C4-2H,C5-2H,C 6-2H, C7-2H, C8-2H, C9-2H, C10-2H, C11-2H, C12-2H), 0.86 (t, 3H, C1-3H).

[0038] Example 2: C14-N2 Performance Test

[0039] 1. Determination of surface tension in aqueous solutions (25℃)

[0040] Before testing, C14-N2 prepared in Example 1 was used to prepare a series of C14-N2 solutions of varying concentrations, which were then placed in a 25°C incubator for 12 hours to equilibrate. The specific testing method is as follows: First, 16 mL of ultrapure water was added to a weighing dish (φ60×30 mm) to calibrate the ring parameters. Then, a series of C14-N2 solutions of varying concentrations were added sequentially until the concentration in the weighing dish reached the measured value. After equilibration for 10 minutes, the surface tension was measured using the Du Noüy ring method. The test temperature was 25±0.1°C, and the average of three measurements was taken to ensure an error within 0.1 mN·m. -1 Within.

[0041] Figure 3 The graph shows the surface tension of C14-N2 aqueous solution as a function of concentration. It can be seen from the graph that the CMC of C14-N2 is 5 mmol / L, and it can form micelles in solution, which can increase the solubility of metabaric complexes.

[0042] 2. C14-N2 bactericidal performance test

[0043] The C14-N2 prepared in Example 1 was used, and the test water was Yangtze River water. Following GB / T 22595-2008 "Evaluation Method for the Efficiency of Biocides—Heterotrophic Bacteria", a static heterotrophic bacteria sterilization experiment was conducted, and the sterilization effect was evaluated based on the bacterial count. The culture temperature was (29±1)℃, and the total bacterial count was measured after 72 hours of constant temperature. The results showed that when the C14-N2 concentration was greater than 100 mg / L, the sterilization rate could reach over 99.1%, demonstrating highly efficient sterilization performance.

[0044] 3. Algae-killing performance test of C14-N2

[0045] Take the C14-N2 prepared in Example 1, add 50 mL of mixed algal solution to a 500 mL Erlenmeyer flask, then add 20 mL of water. After culturing for two days under a light intensity of 3000 lux and at room temperature, the algal cell content reaches 10. 6 pcs / m 3 The above steps involved adding a certain concentration of C14-N2 solution and observing the changes in algal cell content over time. The results showed that when the concentration of C14-N2 was greater than 120 mg / L, the algae removal rate reached 99.8% after three days, demonstrating a good algae removal effect.

[0046] Example 3: Preparation of compound bactericidal, scale-inhibiting, and penetrant agents

[0047] 100, 200, and 300 ppm of C14-N2 prepared in Example 1 were respectively mixed with 200 ppm of alkyl alcohol polyoxyethylene ether carboxylate (C 14-(EO)3-COONa) were mixed to obtain compound bactericidal, scale-inhibiting and penetrant agents with different C14-N2 concentrations.

[0048] The compound bactericidal, scale-inhibiting, and penetrant agent was placed in a 25°C constant temperature incubator for 7 days, and the precipitation was tested. Figure 4 Different concentrations of C14-N2 and 200 ppm of C 14 Photographs of the aqueous solution of C14-N2 mixed with anionic surfactant C14-COONa after standing for 7 days. The images show that the mixed solutions are clear and transparent, indicating that the C14-N2 and the anionic surfactant C14-COONa are well-reacted. 14 -(EO)3-COONa has good compatibility.

[0049] Example 4: Scale inhibition performance test of compound bactericidal scale inhibitor and penetrant

[0050] Different concentrations of C14-N2 composite bactericidal, scale-inhibiting, and penetrant prepared in Example 3 were added to 5 mmol / L CaCl2, followed by 5 mmol / L Na2CO3. After thorough mixing, macroscopic photographs were taken. (Without the addition of C14-N2 and C...) 14 The mixed solution of -(EO)3-COONa served as the blank group.

[0051] Figure 5 To determine the optimal concentration of CaCl2 and Na2CO3 aqueous solutions at equimolar concentrations (5 mmol / L) without or with varying concentrations of a compound bactericidal, scale-inhibiting, and penetrant agent (C14-N2 and 200 ppm C14-N2)... 14 The image shows the appearance of a mixed aqueous solution of (EO)3-COONa. As can be seen from the image, compared to the control group, the addition of different concentrations of C14-N2 and 200 ppm of C... 14 The system exhibits higher light transmittance after mixing with an aqueous solution of (EO)3-COONa, indicating that less CaCO3 precipitate is formed.

[0052] Example 5: Effect of compound bactericidal, scale-inhibiting, and penetrant agents on the morphology of CaCO3

[0053] Different concentrations of C14-N2 composite bactericidal, scale-inhibiting, and penetrant prepared in Example 3 were added to 5 mmol / L CaCl2, followed by 5 mmol / L Na2CO3. After mixing thoroughly, the mixture was placed in a 70℃ incubator for 4 hours. The resulting CaCO3 precipitate was then photographed using a microscope. (Without the addition of C14-N2 and C...) 14 The mixed solution of -(EO)3-COONa was used as the blank group.

[0054] Figure 6 To determine the concentration of C14-N2 and 200 ppm C in equimolar (5 mmol / L) CaCl2 and Na2CO3 aqueous solutions without / with different concentrations of C14-N2 and C2CO3, respectively. 14Microscopic comparison images of CaCO3 formed after mixing aqueous solution of -(EO)3-COONa. The images show that the CaCO3 crystals in the control group exhibit a regular calcite structure, and the CaCO3 crystals grow and accumulate to form calcium carbonate scale. The addition of C14-N2 and C... 14 After being mixed with (EO)3-COONa solution, the CaCO3 crystals changed from a calcite-shaped structure to an irregular shape. This is because the scale inhibitor and penetrant adsorbed onto the surface of the CaCO3 crystals, preventing them from growing normally. Ultimately, the CaCO3 crystals dispersed in the water as loose, broken, tiny grains. This illustrates the interaction between C14-N2 and C... 14 The compound bactericidal, scale-inhibiting, and penetrant formed by -(EO)3-COONa has a good scale inhibition effect.

[0055] Example 6: Bactericidal performance test of compound bactericidal, scale-inhibiting and penetrant agents

[0056] The composite bactericidal, scale-inhibiting, and penetrant prepared in Example 3 was used. The test water was Yangtze River water. Following GB / T22595-2008 "Evaluation Method for the Efficiency of Biocides—Heterotrophic Bacteria," a static heterotrophic bacteria method was employed for bactericidal experiments, and the bactericidal effect was evaluated based on the bacterial count. The culture temperature was (29±1)℃, and the total bacterial count was measured after 72 hours of constant temperature. The results showed that when the C14-N2 concentration in the composite bactericidal, scale-inhibiting, and penetrant was greater than 100 mg / L, the bactericidal rate of the composite bactericidal, scale-inhibiting, and penetrant could reach over 99.4%, demonstrating highly efficient bactericidal performance.

[0057] Example 7: Algae-killing performance test of compound bactericidal, scale-inhibiting, and penetrant agents

[0058] The composite bactericidal, scale-inhibiting, and penetrant prepared in Example 3 was added to a 500mL Erlenmeyer flask along with 50mL of mixed algal solution and 20mL of water. After two days of incubation at room temperature under a light intensity of 3000 lux, the algal cell content reached 10. 6 The concentration of algae cells was above 120 mg / L. A certain concentration of a compound bactericidal, scale-inhibiting, and penetrant was added, and the change in algae cell content over time was observed. The results showed that when the concentration of N2-Cl2-N2 in the compound bactericidal, scale-inhibiting, and penetrant was greater than 120 mg / L, the algae removal rate reached 99.7% after three days, demonstrating a good algae removal effect.

[0059] Example 8: Application of composite bactericidal, scale-inhibiting, and penetrant agents in water treatment

[0060] The composite bactericidal, scale-inhibiting, and penetrating agent prepared in Example 3 was used. The test water was Yangtze River water. 100 mL of Yangtze River water was added to a 500 mL conical flask, and then a certain concentration of composite bactericidal, scale-inhibiting, and penetrating agent was added to make the final concentration of C14-N2 200 mg / L and the final concentration of sodium polyacrylate 200 mg / L. After being kept at a constant temperature for 72 h, the total number of bacteria and algae cells and the amount of sediment in the water were measured.

[0061] The results showed that the sterilization and algae removal efficiency in the cooling water reached over 99%, and the water was clear with no foam or sediment.

[0062] Comparative Example 1: A composite bactericidal, scale-inhibiting, and penetrant prepared using benzalkonium chloride.

[0063] 100, 200, and 300 ppm of benzalkonium chloride and 200 ppm of anionic surfactant C were respectively added. 14 -(EO)3-COONa were mixed to obtain composite bactericidal, scale-inhibiting, and penetrant agents with different concentrations of benzalkonium chloride.

[0064] Place the bactericidal, scale-inhibiting, and penetrant agent in a 25°C constant temperature chamber for 7 days.

[0065] Figure 7 Different concentrations of benzalkonium chloride and 200 ppm anionic surfactant C 14 Photographs showing the appearance of the aqueous solution of (EO)3-COONa after standing for 7 days. The images show that the mixed solution is turbid and precipitated, indicating that the reaction between benzalkonium chloride and the anionic surfactant C... 14 -(EO)3-COONa does not have good compatibility.

Claims

1. A bactericidal, scale-inhibiting, and penetrating agent, characterized in that, The bactericidal, scale-inhibiting, and penetrating agent contains a compound and an anionic surfactant; wherein the concentration of the compound is 100-300 ppm, and the anionic surfactant C 14 The concentration of -(EO)3-COONa was 200 ppm to 800 ppm; The molecular structure of the compound is as follows: 。 2. The application of the bactericidal, scale-inhibiting, and penetrant agent according to claim 1 in water treatment.

3. The application according to claim 2, characterized in that, The applications include industrial water treatment, cooling water systems, and drinking water disinfection.

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