Method for optimizing DOM photosensitization degradation typical PPCPs based on chlorine disinfection process

Abstract

The invention relates to the technical field of sewage treatment, in particular to a method for optimizing DOM photosensitization degradation of typical PPCPs based on a chlorine disinfection process. The method comprises the following steps: 1) collecting humus (HS) and effluent organic matters (EfOM), unifying TOC, and adding sodium hypochlorite into a DOM sample to simulate a chlorine disinfection process; 2) under simulated sunlight irradiation, measuring the generation condition of an active substance (3DOM *, 1O2,. OH) by using a chemical probe; and 3) adding typical PPCPs into the pretreated DOM sample, performing illumination sampling, and analyzing a degradation mechanism by using a quenching experiment and a competitive dynamics experiment. Through chlorine disinfection, the capability of photosensitively degrading ranitidine (RAN) and promethazine (PRO) by DOM is improved, process parameters are optimized, generation of active substances can be regulated and controlled, the active substances are provided for degradation of the PPCPs, different DOM sources and water quality characteristic differences are considered, the process adaptability and stability are enhanced, reliable technical support is provided for efficient removal of the PPCPs in the water environment, and the method is suitable for industrial production. The application prospect in the field of water environment restoration is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to a method for optimizing the DOM photosensitized degradation of typical PPCPs based on a chlorine disinfection process. Background Art

[0002] Pharmaceuticals and personal care products (PPCPs), as a recognized class of emerging pollutants in the world, can be detected in surface water, groundwater, sewage treatment plants, and drinking water effluents, with their concentrations ranging from 20 μg / L to 1 ng / L. Sewage treatment plants are the main pathways for PPCPs to enter the natural water environment. As emerging pollutants, most PPCPs have characteristics such as pseudo-persistence, ecological toxicity, low biodegradability, high water solubility, and low adsorption. The incomplete treatment in sewage treatment plants exacerbates the environmental accumulation of PPCPs. Through processes such as the global water cycle and food chain cycle, their accumulation and enrichment in organisms pose potential toxicity to non-target organisms. Therefore, it is necessary to study the environmental fate of PPCPs.

[0003] The effluent organic matter (EfOM) from sewage treatment plants is an important component of natural water dissolved organic matter (DOM). EfOM has photosensitivity and can generate excited triplet states ( 3 DOM * ), singlet oxygen ( 1 O 2 ), and hydroxyl radicals (·OH) and other reactive substances under sunlight irradiation, which play an important role in the fate of refractory PPCPs in sewage.

[0004] Chlorine disinfection is widely used in large and medium-sized sewage treatment plants due to its advantages such as persistence, high efficiency, and low cost. Chlorine disinfectants can affect the structure of EfOM and thus change its photochemical properties. The effluent from water plants becomes an important component of water body DOM after being discharged into the water environment as a supplementary water source, greatly affecting the physical and chemical removal of pollutants in water by DOM.

[0005] The photoactive substances of EfOM can effectively degrade typical PPCPs in natural water bodies. In the research on the chlorine disinfection process in water plants, more attention has been paid to the generation and degradation of disinfection by-products, but there is a lack of systematic research on the influence of the chlorine disinfection process on the structure, photochemical activity of EfOM, and the effect of degrading typical PPCPs. Therefore, it is urgently needed to be solved.

[0006] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is the closest prior art. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for optimizing the photosensitized degradation of typical PPCPs by DOM based on the chlorination disinfection process. This method deeply analyzes the influence law of the chlorination disinfection process on the physical and chemical properties and photochemical activity of DOM, clarifies its role in the photosensitized degradation mechanism of typical PPCPs (such as ranitidine and promethazine), and accordingly optimizes the parameters of the chlorination disinfection process to enhance the degradation efficiency of PPCPs mediated by DOM, providing reliable technical support for the efficient removal of PPCPs in the water environment.

[0008] To achieve the above object, the technical solution of the present invention is realized as follows: a method for optimizing the photosensitized degradation of typical PPCPs by DOM based on the chlorination disinfection process; the method includes the following steps:

[0009] Step 1) Sample collection and treatment:

[0010] 11) Weigh samples of fulvic acid and humic acid, dissolve them in deionized water respectively, adjust the pH to 7.0 and 10.0, stir continuously until dissolved, and store them in brown bottles to obtain stock solutions; use the stock solutions to prepare FA and HA samples with TOC = 5.0 mg / L respectively;

[0011] 12) Collect the effluent organic matter from the sewage treatment plant. After filtering the effluent organic matter through a 0.45 μm water-based filter membrane, adjust the TOC to 5.0 mg / L and store it in a brown bottle to obtain the EfOM sample;

[0012] Step 2) Chlorination disinfection simulation:

[0013] Add sodium hypochlorite to the FA, HA, and EfOM samples prepared in Step 1) respectively to simulate the chlorination disinfection process and obtain DOM samples;

[0014] Step 3) Determination of active substances:

[0015] Add probe compounds to the DOM samples obtained in Step 2). Through simulated sunlight irradiation, use high-performance liquid chromatography to detect the generation or degradation of the probe compounds in the water samples, thereby reflecting the generation of 3 DOM * 、 1 O 2 and ·OH in the DOM samples;

[0016] Step 4) PPCPs degradation experiment:

[0017] Add 10.0 μM of typical PPCPs to the DOM samples pretreated by chlorination disinfection in Step 2). After irradiation under simulated sunlight, take samples and use high-performance liquid chromatography to detect the degradation of pollutants in the DOM samples;

[0018] Step 5) Analysis of degradation mechanism:

[0019] Through quenching experiments and competitive kinetics experiments, deeply analyze the degradation mechanism and degradation pathway of RAN and PRO in DOM samples after chlorination disinfection treatment, clarify their roles in the photosensitized degradation mechanism of typical PPCPs, and optimize the chlorination disinfection process parameters accordingly.

[0020] Preferably, the simulated chlorination disinfection process in step 2) includes: adding 5.0 mg / L of available chlorine and continuously monitoring the residual chlorine until the residual chlorine < 0.05 mg / L.

[0021] Preferably, the pH of all reaction solutions in step 3) is adjusted to 7.0 with phosphate buffer solution (5.0 mM), and the reaction temperature is maintained at 20 - 25 °C.

[0022] Preferably, in step 3), 2,4,6 - trimethylphenol (TMP), furfuryl alcohol (FFA), and disodium terephthalate (TPA) are selected as the 3 DOM * , 1 O 2 and ·OH probe compounds respectively.

[0023] Preferably, the typical PPCPs in step 4) include ranitidine (RAN) or promethazine (PRO).

[0024] Preferably, under the simulated sunlight irradiation environment in step 4), HS and EfOM after chlorination disinfection pretreatment carry out photosensitized degradation on ranitidine (RAN) and promethazine (PRO) in the polluted water body.

[0025] Preferably, in step 5), sorbic acid, isopropanol, and sodium azide (NaN 3 ) are used as the 3 DOM * , ·OH and 1 O 2 quenching agents respectively during the photodegradation process of PPCPs.

[0026] Preferably, during the photosensitized degradation of ranitidine (RAN) and promethazine (PRO) in the polluted water body by HS and EfOM, 1 O 2 is the active substance for degrading RAN; in humus, 3 HS * is the active substance for degrading PRO; in the effluent organic matter, ·OH and 3EfOM plays a leading role in the degradation of PRO in air and nitrogen environments respectively.

[0027] The beneficial effects of the present invention are embodied in:

[0028] The method provided by the present invention changes the DOM structure and photochemical activity through an optimized chlorine disinfection process, improving the ability of DOM to photosensitize the degradation of RAN and PRO. By optimizing the chlorine disinfection process parameters, the regulation of the generation of 3 DOM * , 1 O 2 and ·OH is realized, providing sufficient active substances for the degradation of PPCPs and improving the degradation efficiency and resource utilization efficiency. At the same time, the present invention fully considers the differences in DOM from different sources and water quality characteristics, enhancing the process adaptability and stability, and ensuring that the method is stable and effective in a variety of actual water environments. Description of the Drawings

[0029] Figure 1 is a schematic diagram of the laboratory-simulated sunlight device in the examples of the present invention;

[0030] Figure 2 is a schematic diagram of the degradation of TMP in DOM treated by the chlorine disinfection process under simulated sunlight in the examples of the present invention (in the figure, Figure a is the FA system, Figure b is the HA system, and Figure c is the EfOM system);

[0031] Figure 3 is a schematic diagram of the degradation of FFA in DOM treated by the chlorine disinfection process under simulated sunlight in the examples of the present invention (in the figure, Figure a is the FA system, Figure b is the HA system, and Figure c is the EfOM system);

[0032] Figure 4 is a schematic diagram of the generation of hTPA in DOM treated by the chlorine disinfection process under simulated sunlight in the examples of the present invention (in the figure, Figure a is the FA system, Figure b is the HA system, and Figure c is the EfOM system);

[0033] Figure 5 is a schematic diagram of the influence of the chlorine disinfection process treatment on the photosensitized degradation of RAN by DOM in the examples of the present invention (in the figure, Figure a is the FA system, Figure b is the HA system, and Figure c is the EfOM system);

[0034] Figure 6 is a schematic diagram of the influence of the quencher on the photosensitized degradation of RAN by HS in the examples of the present invention (in the figure, Figure a is the FA system, Figure b is the HA system);

[0035] Figure 7 is a schematic diagram of the influence of the quencher on the photosensitized degradation of RAN by EfOM in the examples of the present invention;

[0036] Figure 8 is the schematic diagram of the effect of quencher (N 2 ) on the photosensitized degradation of RAN by DOM;

[0037] Figure 9 is the schematic diagram of the effect of chlorination disinfection process on the photosensitized degradation of PRO by HS (in the figure, figure a is the FA system in air, figure a1 is the FA system in nitrogen, figure b is the HA system in air, and figure b1 is the HA system in nitrogen);

[0038] Figure 10 is the schematic diagram of the effect of chlorination disinfection process on the photosensitized degradation of PRO by EfOM (in the figure, figure a is the EfOM system in air, and figure b is the EfOM system in air);

[0039] Figure 11 is the schematic diagram of the effect of quencher on the photosensitized degradation of PRO by HS (in the figure, figure a is the FA system in air, figure a1 is the FA system in nitrogen, figure b is the HA system in air, and figure b1 is the HA system in nitrogen);

[0040] Figure 12 is the schematic diagram of the effect of quencher on the photosensitized degradation of PRO by EfOM (in the figure, figure a is the EfOM system in air, and figure b is the EfOM system in air). Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] As Figures 1 - 12 shown:

[0043] Example 1

[0044] Weigh 1 g of FA and HA powders respectively and dissolve them in 1 L of deionized water. After stirring and dissolving, store them in a brown bottle, and then prepare a solution with TOC = 5.0 mg / L for standby; all reaction solutions are adjusted to pH = 7.0 with phosphate buffer solution (10.0 mM).

[0045] Precisely add 5.0 mg / L of available chlorine to the DOM samples (FA, HA), continuously stir during this period and monitor the residual chlorine until the residual chlorine < 0.05 mg / L to obtain the DOM samples after chlorination disinfection treatment.

[0046] Select 2,4,6-trimethylphenol (TMP), furfuryl alcohol (FFA), and disodium terephthalate (TPA) as probe compounds. Under a simulated sunlight device (see Figure 1 ), measure the generation of FA and HA in two DOM samples before and after the chlorination disinfection process for 3 DOM * , ·OH, and 1 O 2 .

[0047] After the chlorination disinfection treatment of the three DOM samples (FA, HA, and EfOM), under simulated sunlight, the generation rates of photoactive substances ( 3 DOM * , ·OH, and 1 O 2 ) increase. Under simulated sunlight, the degradation of TMP in the DOM treated by the chlorination disinfection process is shown in Figure 2 . Further calculation of the degradation rate constant (kTMP) of TMP in the DOM samples shows that in FA, kTMP increases from 0.01606 min-1 to 0.01739 min-1; in HA, kTMP increases from 0.00330 min-1 to 0.00594 min-1; in EfOM, kTMP increases from 0.00279 min-1 to 0.00302 min-1. The reason for this phenomenon may be that the oxidation of NaClO reduces the components in DOM that quench 3 DOM * , and this effect is greater than the influence brought by the decrease in the aromaticity of DOM, resulting in an increase in the generation rate of 3 DOM * .

[0048] Under simulated sunlight, the degradation of FFA in the DOM treated by the chlorination disinfection process is shown in Figure 3 . Further calculation of the degradation rate constant (kFFA) of FFA and the 1 O 2 steady-state concentration in the DOM samples shows that in FA, kFFA increases from 0.01169 min-1 to 0.01637 min-1, and the 1 O 2 steady-state concentration increases by 40.0%; in HA, kFFA increases from 0.00152 min-1 to 0.00353 min-1, and the 1 O 2The steady-state concentration increased by 132.4%; kFFA in EfOM increased from 0.00181 min-1 to 0.00184 min-1, 1 O 2 The steady-state concentration increased by 1.7%. The chlorination process caused an intramolecular charge transfer (CT) in phenols and quinones (an important source of generation 1 O 2 in DOM), resulting in a significant reduction in quinones, which in turn caused 1 O 2 a decrease in the generation rate. Chlorination made the DOM sample 1 O 2 generation rate increase. The reason may be that the oxidation of NaClO promoted the generation of 3 DOM * more than the influence of charge transfer (CT), so finally it showed that 1 O 2 the generation rate increased.

[0049] Under simulated sunlight, the generation of hTPA in DOM treated by the chlorination process is shown in Figure 4 . For further comparison, by calculating the generation rate constant (khTPA) of hTPA and the steady-state concentration of ·OH in the EfOM system, it can be obtained that khTPA in FA increased from 0.00425 μM / min to 0.00766 μM / min, and the steady-state concentration of ·OH increased by 80.3%; khTPA in HA increased from 0.00178 μM / min to 0.01099 μM / min, and the steady-state concentration of ·OH increased by 5 times; khTPA in EfOM increased from 0.01811 μM / min to 0.03674 μM / min, and the steady-state concentration of ·OH increased by 15.7%. Previous studies have shown that with the increase of the chlorination dose, the contents of carboxyl and phenolic hydroxyl groups (important sources of ·OH) in DOM will continuously increase. Therefore, in this invention, the generation rate of ·OH in the DOM sample after pretreatment by the disinfection process will be accelerated.

[0050] Example 2

[0051] RAN with an initial concentration of 10.0 μM was added to phosphate buffer (5.0 mM, pH = 7.0) and chlorination-pretreated DOM (FA, HA, and EfOM) water samples (pH = 7.0) respectively, and the reaction solution was irradiated using a simulated sunlight device. During the irradiation, 0.5 mL of the sample was taken out from the reaction solution at appropriate times, filtered, and the concentration decay of RAN was detected using high-performance liquid chromatography.

[0052] Isopropanol was used to quench the generated ·OH, and NaN 3 was used to quench the generated1 O 2 , Sorbic acid is used to quench the generated 3 DOM * , and high-purity N 2 is used to exclude the dissolved oxygen in the system to distinguish 1 O 2 and 3 DOM * effects. Quenchers were added to the reaction solution of the indirect photodegradation experiment of RAN respectively, and samples were taken after illumination for the corresponding time, and the process was repeated three times.

[0053] Method for preparing phosphate in the mobile phase: Prepare a 0.01 M potassium dihydrogen phosphate solution, and adjust the pH = 2.5 with phosphoric acid. The solution is filtered through a 0.22 μm aqueous filter membrane before mixing with chromatographically pure acetonitrile.

[0054] The effect of chlorination disinfection process on the photosensitized degradation of RAN by DOM is shown in Figure 5 . Under simulated sunlight, the ability of DOM to photosensitize the degradation of RAN after chlorination disinfection treatment is enhanced. By calculating the photodegradation rate of RAN, it is obtained that the photodegradation rate of RAN in the FA system increases from 3.22 h-1 to 3.89 h-1; in the HA system, the photodegradation rate increases from 0.35 h-1 to 0.76 h-1; in the EfOM system, the photodegradation rate increases from 0.17 h-1 to 0.22 h-1.

[0055] The effect of quenchers on the photosensitized degradation of RAN by HS is shown in Figure 6 . Adding isopropanol (quenching ·OH) and sorbic acid (quenching 3 HS * ) has little effect on the photosensitized degradation of RAN, while adding sodium azide (quenching 1O2) will significantly inhibit the photodegradation of RAN. Therefore, in the FA and HA systems, ·OH and 3 DOM * do not play a role in the indirect photodegradation of RAN, and the main role is played by 1 O 2 .

[0056] The effect of quenchers on the photosensitized degradation of RAN by EfOM is shown in Figure 7 . Adding isopropanol has little effect on the photodegradation of RAN, while adding sodium azide and sorbic acid will significantly inhibit the photodegradation of RAN.

[0057] The effect of quenchers (N 2 ) on the photosensitized degradation of RAN by DOM is shown in Figure 8 , in this experiment, based on the principle that O 2 will quench 3 DOM * in the system, N is introduced into the reaction solution.2 significantly inhibited the photodegradation of RAN. Through this phenomenon, the 3 EfOM * degradation effect on RAN was excluded, and then it was confirmed that 1 O 2 was the main reactive oxygen species for degrading RAN.

[0058] Comparing Figure 6 and Figure 7 it was found that quenching 3 DOM * in the FA and HA systems did not affect the degradation of RAN. The following speculation was made: The quenching rate of 3 HS * was slower than that of quenching 3 EfOM * Therefore, there was enough 1 O 2 generated in the HS system during the quenching reaction, while in the EfOM system, due to the faster quenching of 3 EfOM * by sorbic acid, insufficient 1 O 2 could not be generated, thus inhibiting the degradation of RAN.

[0059] In summary, after the chlorination disinfection process, the mechanism of the photosensitized degradation of RAN by the DOM sample was the same, that is, RAN reacted with 1 O 2 generated by the photosensitization of HS, causing its indirect photodegradation.

[0060] Example 3

[0061] PRO with an initial concentration of 10.0 μM was added to phosphate buffer (5.0 mM, pH = 7.0) and the DOM (FA, HA, and EfOM) water samples pretreated by chlorination disinfection (pH = 7.0), respectively. The reaction solution was irradiated using a simulated sunlight device. During the irradiation, 0.5 mL of the sample was taken from the reaction solution at appropriate times, filtered, and the concentration decay of PRO was detected using high-performance liquid chromatography.

[0062] Isopropanol was used to quench the generated ·OH, NaN 3 was used to quench the generated 1 O 2 Sorbic acid was used to quench the generated 3 DOM * High-purity N 2 was used to exclude the dissolved oxygen in the system to distinguish 1 O 2 and 3 DOM* Function. Quenchers were added to the reaction solution of the indirect photodegradation experiment of PRO, and samples were taken after irradiation for the corresponding time, and the process was repeated three times.

[0063] Method for preparing phosphate in the mobile phase: Prepare a 0.01 M potassium dihydrogen phosphate solution, and adjust the pH = 2.5 with phosphoric acid. The solution is filtered through a 0.22 μm aqueous filter membrane before mixing with chromatographically pure acetonitrile.

[0064] The effect of chlorination disinfection process on the photosensitized degradation of PRO by HS is shown in Figure 9 . Under simulated sunlight, whether in air or in a deoxygenated environment, the ability of HS to photosensitize the degradation of PRO after chlorination disinfection treatment is enhanced. By calculating the photodegradation rate of PRO, in the FA system, the photodegradation rate of PRO in air increased from 0.076 h-1 to 0.086 h-1, and the photodegradation rate in nitrogen increased from 3.277 h-1 to 4.293 h-1; in the HA system, the photodegradation rate of PRO in air increased from 0.027 h-1 to 0.037 h-1, and the photodegradation rate in nitrogen increased from 0.224 h-1 to 0.540 h-1. By comparing the change trends of the photosensitized degradation of PRO in the FA and HA systems after chlorination disinfection treatment with those of 3 FA* and 3 HA * in the same system, it was found that they were highly consistent, and the degradation rate in nitrogen was much faster than that in air, indicating that 3 HS * is the main factor for the degradation of PRO. Humic substances (HS) generate humic triplet excited states ( 3 HS * ) under simulated sunlight, which undergo electron transfer reactions with PRO, thus carrying out indirect photodegradation.

[0065] The effect of chlorination disinfection process on the photosensitized degradation of PRO by EfOM is shown in Figure 10 . Under simulated sunlight: The ability of EfOM to photosensitize the degradation of PRO after disinfection treatment in air and nitrogen is enhanced compared with the initial state, and the degradation rate in nitrogen is much faster than that in air. In the EfOM system, the photodegradation rate of PRO in air increased from 0.038 h-1 to 0.049 h-1, and the photodegradation rate in nitrogen increased from 0.169 h-1 to 0.193 h-1. Similar to HS, there is also an 3 EfOM * electron transfer reaction between EfOM and PRO. After chlorination disinfection treatment, by comparing the trend of the photosensitized degradation of PRO in the EfOM system with that of 3 EfOM *The generation trend was found, and it was found that their change trends in nitrogen were consistent. At the same time, the degradation rate of PRO in nitrogen was much faster than that in air. It is speculated that in the nitrogen environment, because the disinfection process pretreatment affected 3 EfOM * the generation rate, so it would affect the degradation rate of PRO.

[0066] The effect of the quencher on the photosensitized degradation of PRO by HS is shown in Figure 11 . In air, adding 1 O 2 quencher sodium azide and ·OH quencher isopropanol had little effect on the photodegradation of PRO, while adding 3 HS * quencher sorbic acid would significantly inhibit the photodegradation of PRO; in the nitrogen environment, adding isopropanol had a minimal effect on the photodegradation of PRO, while adding sorbic acid would significantly inhibit the photodegradation of PRO. At the same time, due to the quenching effect of oxygen on 3 HS * , the photodegradation rate of PRO in the deoxygenated environment was significantly accelerated. Therefore, for the HS system, 3 HS * played a major role in the indirect photodegradation of PRO.

[0067] The effect of the quencher on the photosensitized degradation of PRO by EfOM is shown in Figure 12 . In air, adding 1 O 2 quencher sodium azide had little effect on the photodegradation of PRO, while adding ·OH quencher isopropanol and 3 EfOM * quencher sorbic acid would significantly inhibit the photodegradation of PRO, and after 3 EfOM * quenching, the inhibitory effect on PRO degradation was more obvious. This indicates that the generation of ·OH in the EfOM system also contributed by 3EfOM*. Therefore, quenching 3 EfOM * would also reduce the degradation of PRO by ·OH, so quenching 3 EfOM * had a greater impact on PRO degradation than quenching ·OH in air conditions. In the nitrogen environment, the addition of isopropanol and sorbic acid both inhibited the photodegradation of PRO, and the quenching effect of sorbic acid was greater than that of isopropanol, that is, 3 EfOM * the degradation contribution was much greater than that of ·OH.

[0068] In summary, in the HS system, the main contributor to the degradation of PRO is 3 HS * ; in the EfOM system,1 O 2 has no effect on the indirect photodegradation of PRO, while ·OH and 3 EfOM * both affect the photodegradation of PRO. In nitrogen, 3 EfOM * plays a dominant role, while in air, ·OH plays a major role.

[0069] In the above Examples 2 and 3, the chlorine disinfection process pretreatment accelerated the rates of DOM-sensitized degradation of typical PPCPs (RAN and PRO), revealed the degradation mechanism, and identified the dominant photoactive substances during the degradation process.

[0070] The method of optimizing DOM-sensitized degradation of typical PPCPs based on the chlorine disinfection process according to the present invention is feasible and has remarkable effects. Chlorine disinfection enhances the ability of DOM to sensitize the degradation of ranitidine (RAN) and promethazine (PRO). Optimizing process parameters can regulate the generation of active substances, provide dominant active substances for the degradation of PPCPs, improve the efficiency and resource utilization rate, and take into account the differences in different DOM sources and water quality characteristics, enhancing the process adaptability and stability, providing reliable technical support for the efficient removal of PPCPs in the water environment, and having broad application prospects in the field of water environment restoration.

[0071] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process, characterized in that: The method comprises the following steps: Step 1) Sample collection and processing: 11) Weigh fulvic acid and humic acid samples, dissolve them in deionized water, adjust the pH to 7.0 and 10.0, stir them continuously to dissolve them, and store them in brown bottles to obtain reserve solutions; use the reserve solutions to prepare FA and HA samples with TOC = 5.0 mg / L respectively; 12) Collect organic matter from the effluent of the sewage treatment plant, filter the effluent organic matter through a 0.45 μm water filter membrane, adjust the TOC to 5.0 mg / L, and store it in a brown bottle to obtain an EfOM sample; Step 2) Chlorine disinfection simulation: Sodium hypochlorite was added to the FA, HA and EfOM samples prepared in step 1) respectively to simulate the chlorine disinfection process to obtain DOM samples; Step 3) Determination of active substances: The probe compound is added to the DOM sample obtained in step 2), and the generation or degradation of the probe compound in the water sample is detected by high performance liquid chromatography by simulating sunlight irradiation, thereby reflecting the 3 DOM * , 1 The generation of O2 and OH; Step 4) PPCPs degradation experiment: 10.0 μM typical PPCPs were added to the DOM sample pretreated with chlorine disinfection in step 2), and samples were taken after illumination under simulated sunlight, and the degradation of pollutants in the DOM sample was detected by high performance liquid chromatography; Step 5) Analysis of degradation mechanism: Through quenching experiments and competitive kinetic experiments, the degradation mechanism and degradation pathway of RAN and PRO in DOM samples after chlorine disinfection were deeply analyzed, their effect on the photosensitized degradation mechanism of typical PPCPs was clarified, and the chlorine disinfection process parameters were optimized accordingly.

2. According to claim 1, a method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process, characterized in that: The simulated chlorine disinfection process in step 2) includes: adding 5.0 mg / L of available chlorine and continuously monitoring the residual chlorine until the residual chlorine is <0.05 mg / L.

3. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 1, characterized in that: In step 3), all reaction solutions were adjusted to pH 7.0 with phosphate buffer, and the reaction temperature was maintained at 20-25°C.

4. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 3, characterized in that: The probe compounds in step 3) are: 2,4,6-trimethylphenol, furanol, and disodium terephthalate are selected as detection compounds. 3 DOM * , 1 Probe compounds for O2 and ·OH.

5. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 1, characterized in that: Typical PPCPs in step 4) include ranitidine or promethazine.

6. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 5, characterized in that: Step 4) simulating the sunlight irradiation environment includes: photosensitizing and degrading ranitidine and promethazine in the contaminated water by HS and EfOM after chlorine disinfection pretreatment.

7. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 6, characterized in that: In the quenching experiment of step 5), sorbic acid, isopropanol and sodium azide are selected as the quenching agents in the photodegradation process of PPCPs. 3 DOM * , OH and 1 O2 quencher.

8. The method for optimizing DOM photosensitization degradation of typical PPCPs based on chlorine disinfection process according to claim 7, characterized in that: During the photosensitized degradation of ranitidine and promethazine in polluted water by HS and EfOM, 1 O2 is the active substance for degrading RAN; in humus, 3 HS * It is the active substance for PRO degradation; in the effluent organic matter, ·OH and 3 EfOM* plays a dominant role in PRO degradation in air and nitrogen environments, respectively.

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