CN114516674B - Method for inactivating bacteria in water body by using sunlight to activate periodate - Google Patents

Abstract

The application discloses a method for inactivating bacteria in a water body by utilizing sunlight to activate periodate, which relates to the technical field of water body bacteria inactivation. Therefore, the solar energy water purification device can excite periodate to generate strong oxidizing free radicals by utilizing sunlight to attack cell membranes so as to inactivate bacteria in water bodies, can be applied to natural water bodies such as tap water, river water, seawater and the like to achieve the purpose of water body purification, does not need to introduce an exciting agent, saves energy and reduces secondary pollution at the same time.

Description

Method for inactivating bacteria in water body by using sunlight to activate periodate

Technical Field

The application relates to the technical field of inactivation of water body bacteria, in particular to a method for inactivating bacteria in a water body by utilizing sunlight to activate periodate.

Background

With the development of science and technology, aquatic pathogenic microorganism pollution is more and more concerned by people. Traditional water treatment sterilization and disinfection methods comprise chlorination disinfection, chlorine dioxide disinfection, ozone disinfection and ultraviolet disinfection, wherein the chlorination disinfection has the risks of incomplete removal of microorganisms and disinfection by-products; the chlorine dioxide disinfection has the problems of higher cost and unstable toxicity; the ozone disinfection and the ultraviolet disinfection are not strong in persistence and high in production cost.

In order to solve the increasingly prominent problems of energy and environmental pollution, more and more novel technologies are applied to environmental governance and new energy development. For example, periodate, which exists in solid form at ordinary temperatures, is attracting attention in the field of water treatment because of its convenience in transportation and storage, however, studies of periodates in the direction of water treatment have been limited to the degradation of Organic pollutants, for example, the prior art discloses that Fe (II) can excite periodates to produce Fe (IV) and hydroxyl radicals for the degradation of emerging Organic pollutants (Zong, Y.; shao, Y.; zeng, Y.; shao, B.; xu, L.; zhao, Z.; liu, W.; wu, D., enhanced Oxidation of Organic pollutants by Iron (II) -Activated Periodote: the signalicicane of High-Valent Iron-Oxo specifices [ J ]. Environ. Sci. Technol.2021,55, (11), 7634-7642.) also, for example, the prior art discloses that Co single atoms dispersed in N-doped graphene can excite periodate to degrade various organic contaminants including organic dyes in a non-radical route ((Long, Y, the number of the Dai, J, the ratio of Zhao, S, the sum of Su, Y, the flow rate of Wang, Z, zhang, Z, an Organic Dispersed Cobalt on graphics as Efficient period Activators for Selective Organic polutant Degradation [ J ]. Environ. Sci. Technol.2021,55, (8), 5357-5370.). There are few reports on the use of Periodate in the inactivation of bacteria in water, among these, the prior art discloses that water-soluble hydroxylamines can excite periodate to produce hydroxyl, superoxide and singlet oxygen for inactivating bacteria in water (Sun, H, the ratio of He, F, choi, W., production of Reactive Oxygen Species by the Reaction of period and Hydroxylamine for Rapid Removal of Organic contaminants and Waterborn bacterium [ J ]. Environ.Sci.Technol.2020.2020, 54, (10), 6427-6437 ].

However, the above-mentioned method for inactivating bacteria in water may release ions or other components on the catalyst by additionally adding an activator to water, thereby causing secondary pollution. The photocatalytic technology is considered as one of the most promising technologies in the water body bacteria inactivation technology due to its advantages in reducing secondary pollution and saving energy, wherein solar radiation (with wavelength more than 300 nm) is used as a renewable energy source, and the research on exciting periodate to inactivate bacteria in the water body has not been reported.

Disclosure of Invention

The method for inactivating the bacteria in the water body by using the solar light to activate the periodate can reduce secondary pollution and save energy.

The method for inactivating bacteria in a water body by utilizing solar light to activate periodate comprises the following steps:

dissolving periodate in a water body containing bacteria to be treated to form a mixed system;

and reacting the mixed system under the sunlight illumination condition to realize bacterial inactivation.

Preferably, the sunlight irradiation condition is natural sunlight irradiation or xenon lamp simulated sunlight irradiation.

Preferably, the illumination intensity of the sunlight illumination condition is 20 to 50 milliwatts per square centimeter.

Preferably, the illumination time under the sunlight illumination condition is 10 to 40 minutes.

Preferably, the periodate is one or both of potassium periodate and sodium periodate.

Preferably, the periodate concentration of the mixed system is 0.1 to 0.4 mmol/l.

Preferably, the bacteria-containing water body is a water body containing escherichia coli or bacillus subtilis.

Preferably, the bacteria concentration of the bacteria-containing water body is 1 × 10 ⁷ Total number of colonies/ml.

Preferably, the temperature is controlled at 25 ℃ during the reaction.

The beneficial effect of this application lies in, compares with prior art, and this application has following advantage:

(1) The solar energy water disinfection device can be used for disinfecting and sterilizing water by exciting periodate through sunlight for the first time;

(2) The method provided by the application has the advantages that the needed chemical reagents and equipment are easy to obtain, the operation is simple and convenient, the application value is high, and the popularization is easy;

(3) The method provided by the application can quickly and effectively inactivate bacteria in the water body;

(4) The method provided by the application is safe and stable, does not need to introduce an excitant, and has no risk of releasing ions or other excitant components;

(5) The method provided by the application can be applied to disinfection and purification of natural water bodies such as tap water, river water, seawater and the like.

Drawings

FIG. 1 is a schematic diagram of disinfection of Escherichia coli in water by different reaction systems;

FIG. 2 is a schematic diagram of disinfection of Bacillus subtilis in water by different reaction systems;

FIG. 3 is a schematic view of the disinfection of E.coli in different water bodies by a simulated sunlight/periodate reaction system;

FIG. 4 is an Electron Spin Resonance (ESR) spectrum simulating the analysis of superoxide radicals during the solar photoactivation periodate reaction;

FIG. 5 is a schematic diagram showing the change in superoxide dismutase (SOD) activity during the inactivation of E.coli by simulated solar light-activated periodate;

FIG. 6 is a schematic illustration of disinfection of a natural sunlight/periodate reaction system in river water;

FIG. 7 is a schematic illustration of disinfection of a natural sunlight/periodate reaction system in seawater;

FIG. 8 is a schematic representation of the disinfection of E.coli under varying concentrations of periodate in a simulated sunlight/periodate reaction system.

Detailed Description

The sunlight is a continuous spectrum, the wavelength reaching the earth surface is more than 300nm, two illumination conditions of natural sunlight and simulated sunlight are adopted in the embodiment of the application, wherein a xenon lamp is adopted in a laboratory to simulate the sunlight, the xenon lamp is a light source generated by ionizing xenon by high voltage, an AM1.5G optical filter is configured, the spectral distribution of the optical filter is closest to that of the natural sunlight, and the optical filter has good optical characteristics.

The present application is further illustrated by the following examples, which are provided by way of illustration only and are not intended to be limiting.

Example 1

Simulated solar photoactivation periodate inactivated escherichia coli in water body

Taking 50mL of initial bacteria with the concentration of 1X 10 ⁷ And (3) filling the total colony count/milliliter (CFU/mL) of the Escherichia coli (E.coli) dispersion liquid into a 100mL double-layer beaker, and regulating the initial pH value of the dispersion liquid to be 7.0 by using 1mol/L of NaOH solution to obtain the Escherichia coli-containing water body to be treated. Adding sodium periodate into the water containing the escherichia coli to enable the concentration of the sodium periodate to be 0.2mmol/L, and fully and uniformly mixing under the action of a magnetic stirrer to obtain a mixed system. Placing the mixed system in a xenon lamp to simulate the irradiation of sunlight for photocatalytic reaction, wherein the illumination intensity is 50 milliwatts per square centimeter (mW/cm) ² ) The mixed system is maintained at a constant temperature of 25 ℃ by a circulating water system.

In the reaction process, samples are respectively taken at fixed reaction time points of 0, 10, 20, 30 and 40 minutes to obtain bacterial suspensions, the obtained bacterial suspensions are sequentially diluted by different times, 100 mu L of diluent is coated on a culture medium, the culture medium is placed in a constant-temperature incubator to be cultured for 24 hours at 37 ℃, the culture medium is taken out and counted after the culture is finished, and the sterilization curve is obtained, wherein the result is shown in figure 1.

As a comparative example to example 1, the procedure of example 1 was repeated except that the water containing Escherichia coli was treated with simulated sunlight alone without adding sodium periodate, and the results are shown in FIG. 1.

As another comparative example of example 1, the procedure of example 1 was repeated except that hydrogen peroxide (H) was used in the same amount concentration as that of the substance ₂ O ₂ ) The results are shown in FIG. 1 instead of sodium periodate.

As another comparative example of example 1, the procedure of example 1 was repeated except that potassium Peroxodisulfate (PDS) was used in place of sodium periodate in the same amount concentration as that of example 1, and the results are shown in FIG. 1.

As another comparative example of example 1, the procedure of example 1 was repeated except that sodium iodate was used in place of sodium periodate at the same quantitative concentration of the substance, and the results are shown in FIG. 1.

As another comparative example to example 1, the procedure of example 1 was repeated except that the mixed system was placed in the dark instead of being placed under simulated solar irradiation of a xenon lamp to conduct the reaction, and the results are shown in FIG. 1.

FIG. 1 shows that 40 minutes after the start of the reaction, E.coli in the E.coli-containing water was completely inactivated by the simulated sunlight/periodate reaction system. Hydrogen peroxide (H) with the same amount and concentration of substance under simulated solar radiation ₂ O ₂ ) Potassium Peroxodisulfate (PDS) and sodium iodate were not effective in inactivating e. Under dark conditions without sunlight, periodate reaction systems also do not effectively inactivate E.coli.

Example 2

Simulation of solar photoactivation of bacillus subtilis in periodate inactivated water body

Example 1 was repeated with the following differences: bacillus subtilis dispersion was used instead of escherichia coli (e.coli) dispersion, and the fixed reaction time points of sampling were changed to 0, 30, 60, 90 and 120 minutes during the reaction, and the results are shown in fig. 2.

As a comparative example of example 2, the procedure of example 2 was repeated except that the water containing Escherichia coli was treated with simulated sunlight alone without adding sodium periodate, and the results are shown in FIG. 2.

As another comparative example of example 2, the procedure of example 2 was repeated except that hydrogen peroxide (H) was used in the same amount concentration as the substance ₂ O ₂ ) The results are shown in FIG. 2 instead of sodium periodate.

As another comparative example of example 2, the procedure of example 2 was repeated except that potassium Peroxodisulfate (PDS) was used in place of sodium periodate in the same amount concentration as that of example 2, and the results are shown in FIG. 2.

As another comparative example of example 2, the procedure of example 2 was repeated except that sodium iodate was used in place of sodium periodate at the same quantitative concentration of the substance, and the results are shown in FIG. 2.

As another comparative example to example 2, the procedure of example 2 was repeated except that the mixed system was placed in the dark instead of being placed under simulated solar irradiation with a xenon lamp to carry out the reaction, and the results are shown in FIG. 2.

FIG. 2 shows that after 120 minutes from the start of the reaction, bacillus subtilis in a water body containing Bacillus subtilis is completely and effectively inactivated by a simulated sunlight/periodate reaction system. Hydrogen peroxide (H) with the same mass concentration under simulated solar radiation ₂ O ₂ ) Potassium Peroxodisulfate (PDS) and sodium iodate were not effective in inactivating bacillus subtilis. Under dark conditions without sunlight irradiation, the periodate reaction system can not effectively inactivate the bacillus subtilis.

Example 3

Simulated solar light-activated periodate inactivated escherichia coli in tap water

50mL of tap water was taken and added to the stock solution of Escherichia coli to give an initial bacterial concentration of 1X 10 ⁷ And filling the CFU/mL into a 100mL double-layer beaker to obtain the natural water body containing the escherichia coli to be treated. And adding sodium periodate into the natural water containing the escherichia coli to enable the concentration of the sodium periodate to be 0.2mmol/L, and fully and uniformly mixing under the action of a magnetic stirrer to obtain a mixed system. Placing the mixed system in a xenon lamp to simulate the irradiation of sunlight for photocatalytic reaction, wherein the illumination intensity is 50 milliwatts per square centimeter (mW/cm) ² ) Mixing and blendingThe system was maintained at a constant temperature of 25 ℃ by a circulating water system.

In the reaction process, samples are respectively taken at fixed reaction time points of 0, 20, 40, 60, 80, 100, 120 and 140 minutes to obtain bacterial suspensions, the obtained bacterial suspensions are sequentially diluted by different times, 100 mu L of diluent is coated on a culture medium, the culture medium is placed in a constant-temperature incubator to be cultured for 24 hours at 37 ℃, the culture medium is taken out after the culture is finished and counted to obtain a sterilization curve, and the result is shown in figure 3.

Example 4

Simulated solar light-activated periodate inactivated escherichia coli in river water

Example 3 was repeated with the following differences: 50mL of tap water was replaced with 50mL of river water, and the results are shown in FIG. 3.

Example 5

Simulated solar photoactivation periodate inactivated escherichia coli in seawater

Example 3 was repeated with the following differences: 50mL of seawater was used instead of 50mL of tap water, and the results are shown in FIG. 3.

FIG. 3 shows 1X 10 in tap water, river water and sea water ⁷ CFU/mL of e.coli was completely inactivated by simulated sunlight/periodate systems in 80 min, 100 min and 140 min, respectively.

Example 6

Detection of superoxide radical in simulated solar photoactivation periodate reaction process

A mixture of 5. Mu.L of 5,5-dimethyl-1-pyrrolidine-N-oxide (DMPO) and 0.5mL of 1mM periodate in dimethyl sulfoxide was drawn into a capillary and placed in an electron spin resonance spectrometer (ESR; bruker EMX/Plus, germany) and tested in simulated sunlight, the results of which are shown in FIG. 4, and FIG. 4, which shows that the signal intensity increases with time.

In the process of inactivating escherichia coli in tap water by using simulated sunlight to activate periodate, 2mL of samples were taken at fixed reaction time points of 0, 20, 40, 60, 80 and 100 minutes, respectively, extracted by using a bacterial protein extraction kit (C600596, sangon biochemical company), and tested by using a total superoxide dismutase (SOD) kit (S0101, cloudy day), and the results are shown in fig. 5.

Fig. 5 shows that the superoxide dismutase activity of the periodate/dark group and the simulated sunlight group did not change much during the reaction. The superoxide dismutase activity of the periodate/simulated sunlight group increases sharply within 20 minutes for combating external free radicals, and then decreases with free radical attack and bacterial apoptosis.

Example 7

Natural solar light-activated periodate inactivated escherichia coli in river water

Adding Escherichia coli stock solution into 1L river water to make initial bacteria concentration 1 × 10 ⁷ And (5) filling the CFU/mL into an organic glass water tank with the volume of about 1.6L to obtain the natural water body containing the escherichia coli to be treated. Adding sodium periodate into the natural water containing the escherichia coli to enable the concentration of the sodium periodate to be 0.2mmol/L, and fully and uniformly mixing under the action of a magnetic stirrer to obtain a mixed system. The mixed system is placed outdoors, namely, the photocatalysis reaction is carried out under the irradiation of natural sunlight, the experimental places are E116 degrees at east longitude, N39 degrees at north latitude, 59 degrees, the starting time of the experimental reaction is 10 am, and the natural light illumination intensity in the reaction process is measured to be 45-51 mW/cm ² 。

In the reaction process, samples are respectively taken at fixed reaction time points of 0, 10, 20, 30 and 40 minutes to obtain bacterial suspensions, the obtained bacterial suspensions are sequentially diluted by different times, 100 mu L of diluent is coated on a culture medium, the culture medium is placed in a constant temperature incubator for 24 hours at 37 ℃, and the culture medium is taken out for counting after the culture is finished, so that a sterilization curve is obtained, and the result is shown in figure 6.

Example 8

Natural solar light-activated periodate inactivated escherichia coli in river water

Example 7 was repeated with the following differences: the starting time of the experimental reaction is 3 pm, and the natural light illumination intensity is 29-35 mW/cm in the measured reaction process ² The results are shown in FIG. 6.

As a comparative example to example 7 and example 8, the procedure of example 7 was repeated except that the mixed system was placed in the dark instead of being exposed to natural sunlight for reaction, and the results are shown in FIG. 6.

As another comparative example of example 7 and example 8, the procedure of example 7 was repeated except that the water containing Escherichia coli was treated with only natural sunlight without adding sodium periodate, and the results are shown in FIG. 6.

Referring to FIG. 6, under natural sunlight irradiation, 1X 10 in river water ⁷ The CFU/mL escherichia coli is completely inactivated by a natural sunlight/periodate system within 40 minutes, so that the periodate can be effectively excited by the natural sunlight, and the method is applied to disinfection of actual water bodies.

Example 9

Natural sunlight-activated periodate inactivated escherichia coli in seawater

Adding Escherichia coli stock solution into 1L seawater to make initial bacteria concentration 1 × 10 ⁷ And (5) filling the CFU/mL into an organic glass water tank with the volume of about 1.6L to obtain the natural water body containing the escherichia coli to be treated. Adding sodium periodate into the natural water containing the escherichia coli to enable the concentration of the sodium periodate to be 0.2mmol/L, and fully and uniformly mixing under the action of a magnetic stirrer to obtain a mixed system. The mixed system is placed outdoors, namely, the photocatalysis reaction is carried out under the irradiation of natural sunlight, the experimental places are E116 degrees at east longitude and E18 degrees, N39 degrees at north latitude and N59 degrees, the starting time of the experimental reaction is 11 degrees at morning, and the natural light illumination intensity is 44-47 mW/cm in the measuring reaction process ² 。

In the reaction process, bacterial suspensions are obtained by sampling at fixed reaction time points of 0, 10, 20, 30, 40 and 50 minutes respectively, the obtained bacterial suspensions are sequentially diluted by different times, 100 mu L of diluent is coated on a culture medium, the culture medium is placed in a constant-temperature incubator for 24 hours at 37 ℃, and after the culture is finished, the culture medium is taken out and counted to obtain a sterilization curve, and the result is shown in figure 7.

Example 10

Natural sunlight-activated periodate inactivated escherichia coli in seawater

Example 9 was repeated with the following differences: the experimental reaction is started at 2 pm, and the natural light illumination intensity is 31-37 mW/cm in the reaction process ² The results are shown in FIG. 7.

As a comparative example to example 9 and example 10, the procedure of example 9 was repeated except that the mixed system was placed in the dark instead of being exposed to natural sunlight for reaction, and the results are shown in FIG. 7.

As another comparative example between example 9 and example 10, the procedure of example 9 was repeated except that the E.coli-containing water body was treated only with natural sunlight without adding sodium periodate, and the results are shown in FIG. 7.

Referring to FIG. 7, under natural sunlight irradiation conditions, 1X 10 in seawater ⁷ The CFU/mL escherichia coli is completely inactivated by a natural sunlight/periodate system within 50 minutes, so that the periodate can be effectively excited by the natural sunlight, and the method is applied to disinfection of actual water bodies.

Example 11

Example 1 was repeated with the following differences: when sodium periodate was added to the water containing Escherichia coli, the concentration of sodium periodate was reduced to 0.1mmol/L, and the results are shown in FIG. 8.

Example 12

Example 1 was repeated with the following differences: when sodium periodate was added to the E.coli-containing water, the concentration of sodium periodate was increased to 0.3mmol/L, and the results are shown in FIG. 8.

Example 13

Example 1 was repeated with the following differences: when sodium periodate was added to the E.coli-containing water, the concentration of sodium periodate was increased to 0.4mmol/L, and the results are shown in FIG. 8.

Referring to fig. 8, the higher the periodate concentration, the better the sterilization of the simulated sunlight/periodate system, where 0.1mmol/L failed to completely inactivate the bacteria in 50 minutes and 0.2mmol/L was able to completely inactivate the bacteria in 40 minutes.

According to the method for inactivating bacteria in the water body by utilizing solar light to activate periodate, periodate is dissolved in the water body containing the bacteria to be treated to form a mixed system, and the mixed system reacts under the sunlight illumination condition to realize bacterial inactivation. The embodiment of the application uses the solar light to excite the periodate to sterilize and disinfect the water body for the first time,under the condition of using 0.2mmol/L periodate dosage, 1X 10 can be completely inactivated by irradiating for 40 minutes by sunlight ⁷ CFU/mL Escherichia coli shows that the solar light can excite periodate to generate strong oxidative free radicals, such as superoxide free radicals, to attack cell membranes, so that the superoxide dismutase in bacteria is increased firstly, and the activity of the superoxide dismutase is reduced along with the continuous oxidative stress, and the substances in the bacteria are destroyed, thereby inactivating the bacteria in the water body. According to the method provided by the embodiment of the application, on one hand, the needed chemical reagents and equipment are easy to obtain, the operation is simple and convenient, the application value is high, the popularization is easy, on the other hand, the method is safe and stable, no excitant is required to be introduced, and no risk of releasing ions or other excitant components exists. In addition, the method can be applied to disinfection and purification of natural water bodies such as tap water, river water, seawater and the like.

The above-mentioned embodiments are further described in detail for the purpose of illustrating the invention, and it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not to be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. A method for inactivating bacteria in a water body by using sunlight to activate periodate is characterized by comprising the following steps:

dissolving periodate in a water body containing bacteria to be treated to form a mixed system;

and reacting the mixed system under the sunlight illumination condition to realize bacterial inactivation.

2. The method for inactivating bacteria in a water body by using solar photoactivated periodate according to claim 1, wherein the sunlight irradiation condition is natural sunlight irradiation or simulated sunlight irradiation of a xenon lamp.

3. The method for inactivating bacteria in a water body by sunlight activated periodate of claim 2, wherein the sunlight irradiation conditions have an irradiation intensity of 20 to 50 mw/cm.

4. The method for inactivating bacteria in a water body by using sunlight activated periodate according to claim 2, wherein the illumination time of the sunlight illumination condition is 10 to 40 minutes.

5. The method of inactivating bacteria in a water body using solar-activated periodate of claim 1 where the periodate is one or both of potassium periodate and sodium periodate.

6. The method for inactivating bacteria in a body of water using solar photoactivation periodate as in claim 1, wherein the periodate concentration of the mixed system is 0.1 to 0.4 mmol/l.

7. The method for inactivating bacteria in a water body by using solar photoactivation periodate as claimed in claim 1, wherein the bacteria-containing water body is a water body containing escherichia coli or bacillus subtilis.

8. The method for inactivating bacteria in a water body using solar photoactivated periodate according to claim 6, wherein the bacteria concentration of the bacteria-containing water body is 1 x 10 ⁷ Total number of colonies/ml.

9. The method for inactivating bacteria in a water body using solar photoactivated periodate as in claim 6, wherein the temperature during the reaction is controlled at 25 ℃.

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