Modified zero-valent iron preparation for sterilization and algae removal in water and preparation method of modified zero-valent iron preparation

Abstract

The invention provides a modified zero-valent iron preparation for sterilization and algae removal in water and a preparation method of the modified zero-valent iron preparation, and relates to the technical field of zero-valent iron modification. The modified zero-valent iron preparation comprises silicate modified zero-valent iron and carbonate modified zero-valent iron, the mass ratio of the silicate modified zero-valent iron to the carbonate modified zero-valent iron is 1: (0.8-1.2); in the silicate modified zero-valent iron, the molar ratio of silicate to zero-valent iron is (3-8): 100; in the carbonate modified zero-valent iron, the molar ratio of carbonate to zero-valent iron is (3-8): 100. The application comprises the application of the modified zero-valent iron preparation in preparation of water microorganism removal products. According to the modified zero-valent iron preparation, adsorption and in-situ oxidation inactivation of microorganisms on the surface of zero-valent iron are achieved, the defects that active oxygen species are short in service life and small in migration distance are overcome, and efficient removal of water microorganisms is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of zero-valent iron modification, and in particular to a modified zero-valent iron preparation for sterilization and algae removal in water and a preparation method thereof. Background Art

[0002] Pathogenic bacteria and algae in water are common microbial pollutants in water bodies, which can cause serious health risks and ecological problems. The large-scale discharge of sewage from production, life, and medical treatment has led to the entry of many pathogenic microorganisms into the environment, seriously threatening public health safety. For example, diarrhea caused by pathogenic Escherichia coli causes a large number of deaths worldwide every year. Algal pollution leads to algal blooms, which can cause aquatic organisms to die due to lack of oxygen, causing black and smelly water bodies. Some algae release algal toxins, which seriously affect water quality safety. The elimination and removal of pathogenic bacteria and algae in water mostly adopts chemical methods, such as chlorine disinfection and copper reagent treatment, but chemical drugs may have toxic effects on water ecology, affect water quality, and easily develop drug resistance. In addition, harmful disinfection by-products may also be generated. Zero-valent iron is one of the hot materials that has attracted much attention in the current environmental field. It has high reducibility and a large specific surface area, and can be used as an adsorbent and reductant to remove harmful substances. Zero-valent iron has a significant killing effect on Gram-negative bacteria, Gram-positive bacteria, algae, etc. Its mechanism mainly includes physical adsorption and redox reactions such as active oxygen inactivation. However, zero-valent iron is easily passivated during use and storage, forming a dense oxide shell on the surface, which reduces the adsorption active sites on the ZVI surface, hinders the outward transfer of iron core electrons, and reduces the generation of reactive oxygen species, resulting in a decrease in its adsorption, redox and other capabilities, limiting the disinfection effect. In addition, the reactive oxygen species generated by zero-valent iron have a short half-life, a small migration distance, a low steady-state concentration, and a low effective utilization rate of free radicals reacting with bacteria. These defects limit the large-scale application of ZVI in the removal of pathogenic microorganisms in water bodies. Therefore, it is necessary to select suitable modifiers to regulate the shell structure of ZVI and improve its reaction activity, while finding effective coupled adsorption-inactivation technology to sterilize at the zero-valent iron interface and enhance the ability of zero-valent iron to remove bacteria.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] In view of this, the present invention proposes a modified zero-valent iron preparation for sterilization and algae removal in water and a preparation method thereof. By combining silicate-modified zero-valent iron with carbonate-modified zero-valent iron, the adsorption of bacteria and the production of reactive oxygen species are simultaneously improved, thereby achieving effective coupling of microbial adsorption on the zero-valent iron surface and in-situ oxidative inactivation, overcoming the defects of short lifespan and small migration distance of reactive oxygen species, and achieving efficient removal of water microorganisms.

[0005] The technical solution of the present invention is implemented as follows: the present invention provides a modified zero-valent iron preparation for sterilization and algae removal in water, comprising silicate-modified zero-valent iron and carbonate-modified zero-valent iron; the mass ratio of the silicate-modified zero-valent iron to the carbonate-modified zero-valent iron is 1:(0.8-1.2);

[0006] In the silicate-modified zero-valent iron, the molar ratio of silicate to zero-valent iron is (3-8):100;

[0007] In the carbonate-modified zero-valent iron, the molar ratio of carbonate to zero-valent iron is (3-8):100.

[0008] The present invention also provides a use of the modified zero-valent iron preparation for sterilization and algae removal in water in the preparation of a water microorganism removal product.

[0009] On the basis of the above technical solution, preferably, the water body microorganism removal product includes an adsorbent for water body microorganisms.

[0010] On the basis of the above technical solution, preferably, the water body microorganism removal product includes a biocide for water body microorganisms.

[0011] The present invention also provides a method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water, comprising the following steps:

[0012] S10, obtaining zero-valent iron powder, carbonate and silicate;

[0013] Add carbonate and zero-valent iron powder into the first ball mill according to a molar ratio of (3-8):100;

[0014] Add silicate and zero-valent iron powder into the second ball mill according to a molar ratio of (3-8):100;

[0015] S20, the first ball mill and the second ball mill are respectively subjected to mechanical ball milling to obtain silicate-modified zero-valent iron and carbonate-modified zero-valent iron, respectively;

[0016] S30, mixing the silicate-modified zero-valent iron and the carbonate-modified zero-valent iron in a mass ratio of 1:(0.8-1.2) to obtain a modified zero-valent iron preparation.

[0017] In this embodiment, reduced iron powder can be used as the main component of zero-valent iron powder, and carbonates and silicates are selected as modification materials. Through functional surface modification, specific functional groups are introduced on the surface of zero-valent iron to optimize the surface modification of the material, so as to improve the selectivity, adsorption capacity and reaction activity of the material for Escherichia coli.

[0018] In this embodiment, in order to prevent the agglomeration of zero-valent iron powder and increase the specific surface area and reaction activity, the zero-valent iron material is modified by mechanical ball milling, and suitable modifiers (carbonates and silicates) are added during the ball milling process to reduce the adhesion between particles, improve dispersibility, and prevent agglomeration. At the same time, starting from the ball milling conditions, the appropriate ball milling speed and time are set to reduce the collision force between particles and reduce the probability of agglomeration. At the same time, the preparation ratio of the ball milling medium is adjusted and reasonably configured to improve the effective collision and grinding ability of the abrasive, ensure the uniform distribution of the modifier on the surface of the iron powder, and thus improve the modification effect.

[0019] On the basis of the above technical solution, preferably, in step S10, carbonate and zero-valent iron powder are added to the first ball mill according to a molar ratio of 5:100;

[0020] Silicate and zero-valent iron powder were added into the second ball mill at a molar ratio of 5:100.

[0021] On the basis of the above technical solution, preferably, the carbonate is sodium carbonate, and the silicate is sodium silicate.

[0022] On the basis of the above technical solution, preferably, in step S20, the first ball mill and the second ball mill are respectively subjected to mechanical ball milling at a rotation speed of 300-800 rpm for 3-6 hours to obtain silicate-modified zero-valent iron and carbonate-modified zero-valent iron, respectively.

[0023] On the basis of the above technical solution, preferably, in step S30, the silicate-modified zero-valent iron and the carbonate-modified zero-valent iron are mixed in a mass ratio of 1:1 to obtain a modified zero-valent iron preparation.

[0024] The present invention also provides a water body sterilization and algae removal device, comprising a sterilization and algae removal filter unit; the filler in the sterilization and algae removal filter unit comprises the above-mentioned modified zero-valent iron preparation.

[0025] The modified zero-valent iron preparation for sterilization and algae removal in water and the preparation method thereof of the present invention have the following beneficial effects compared with the prior art:

[0026] In the present invention, zero-valent iron is modified by using silicate and carbonate to prepare a modified zero-valent iron preparation, so that the modified zero-valent iron has both strong adsorption capacity and stronger oxygen activation capacity for microorganisms. Under the synergistic effect of silicate-modified zero-valent iron and carbonate-modified zero-valent iron, the removal efficiency of polluting microorganisms in water bodies is improved. In addition, the preparation method of the modified zero-valent iron preparation provided by the present disclosure is simple and easy to use, and can simultaneously adsorb and inactivate bacteria and algae, broadening the application of zero-valent iron in the field of water purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 In one embodiment disclosed in the present invention, CO3 2- -ZVI bm 、SiO3 2- -ZVI bm and ZVI bm XRD results of .

[0029] Figure 2 In one embodiment disclosed in the present invention, Na2SiO3, SiO3 2- -ZVI bm and ZVI bm FTIR result diagram.

[0030] Figure 3 In one embodiment disclosed in the present invention, Na2CO3, CO3 2- -ZVI bm and ZVI bm FTIR result diagram.

[0031] Figure 4 In one embodiment disclosed in the present invention, Na2SiO3, Na2SiO3+ZVI bm 、SiO3 2- -ZVI bm and ZVI bm Plate count results for killing E. coli.

[0032] Figure 5 In one embodiment disclosed in the present invention, Na2CO3, Na2CO3+ZVI bm 、CO3 2- -ZVI bm and ZVI bm Plate count results for killing E. coli.

[0033] Figure 6 This is the E. coli fluorescence staining result of a blank control in one embodiment disclosed in the present invention.

[0034] Figure 7 In one embodiment disclosed in the present invention, ZVI bm Fluorescence staining results of E.coli after treatment.

[0035] Figure 8 In one embodiment disclosed in the present invention, SiO3 2- -ZVI bm Fluorescence staining results of E.coli after treatment.

[0036] Fig. 9 In one embodiment disclosed in the present invention, CO3 2- -ZVI bm Fluorescence staining results of E.coli after treatment.

[0037] Fig.10 In one embodiment disclosed in the present invention, blank control, ZVI bm and SiO3 2- -ZVI bm ATR-FTIR test results.

[0038] Fig.11 In one embodiment disclosed in the present invention, ZVI bm and SiO3 2- -ZVI bm The results of the zero-valent iron-OH stretching vibration peak shift before and after the reaction with E. coli.

[0039] Fig.12 In one embodiment disclosed in the present invention, blank control, ZVI bm and SiO3 2- -ZVI bm The results of the ultraviolet absorption signal of C=O transition after reacting with E.coli.

[0040] Fig.13 In one embodiment disclosed in the present invention, CO3 2- -ZVI bm Results of the active species quenching experiment in the system.

[0041] Fig.14 In one embodiment disclosed in the present invention, ZVI bm and CO3 2- -ZVI bm Quantitative results of superoxide radicals ( Fig.14 A) and hydroxyl radical quantitative results ( Fig.14 B).

[0042] Fig.15 In one embodiment disclosed in the present invention, ZVI bm and CO3 2- -ZVI bm The Tafel curve ( Fig.15 A) and changes in dissolved oxygen concentration ( Fig.15 B).

[0043] Fig.16 In one embodiment disclosed in the present invention, ZVI bm Infrared spectrum of E.coli after treatment ( Fig.16 A) and CO3 2- -ZVI bm Infrared spectrum of E.coli after treatment ( Fig.16 B).

[0044] Fig.17 In one embodiment disclosed in the present invention, ZVI bm E.coli count statistics after sand filter column treatment ( Fig.17 A), CO3 2- -ZVI bm E.coli count results after sand filter column treatment ( Fig.17 B), SiO3 2- -ZVI bm E.coli count results after sand filter column treatment ( Fig.17 C), E. coli count results after mixed zero-valent iron sand filter column treatment ( Fig.17 D).

[0045] Fig.18 In one embodiment disclosed in the present invention, ZVI bm Bacterial staining results after sand filter column treatment ( Fig.18 A), Bacterial staining results after mixed zero-valent iron sand filter column treatment ( Fig.18 B).

[0046] Fig.19 In one embodiment disclosed in the present invention, ZVI bm Statistical results of bacterial counts after sand filter column treatment ( Fig.19 A), CO3 2- -ZVI bm Bacterial count results after sand filter column treatment ( Fig.19 B), SiO3 2- -ZVI bm Bacterial count results after sand filter column treatment ( Fig.19 C), Bacterial count results after mixed zero-valent iron sand filter column treatment ( Fig.19 D).

[0047] Fig. 20 In one embodiment disclosed in the present invention, ZVI bm Results of removing Microcystis aeruginosa by sand filter column ( Fig. 20 A), CO3 2- -ZVI bm Results of removing Microcystis aeruginosa by sand filter column ( Fig. 20 B), SiO3 2- -ZVI bmResults of removing Microcystis aeruginosa by sand filter column ( Fig. 20 C), the results of removing Microcystis aeruginosa by mixed zero-valent iron sand filter column ( Fig. 20 D). DETAILED DESCRIPTION

[0048] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] The term "biocide" is an agent that can remove bacteria and microorganisms from water.

[0050] Zero-valent iron has high reducibility and a large specific surface area. It can be used as an adsorbent and reductant to remove harmful substances. It has a significant killing effect on Gram-negative bacteria, Gram-positive bacteria, algae, etc. Its mechanism mainly includes physical adsorption and redox reaction. However, zero-valent iron is easily passivated during use and storage, resulting in a decrease in its adsorption and reduction capabilities, which limits the disinfection effect.

[0051] To solve the above problems, the embodiments of the present disclosure provide a modified zero-valent iron preparation for sterilization and algae removal in water, wherein the modified zero-valent iron preparation includes silicate-modified zero-valent iron and carbonate-modified zero-valent iron; the mass ratio of the silicate-modified zero-valent iron to the carbonate-modified zero-valent iron is 1:(0.8-1.2); in the silicate-modified zero-valent iron, the molar ratio of silicate to zero-valent iron is (3-8):100; in the carbonate-modified zero-valent iron, the molar ratio of carbonate to zero-valent iron is (3-8):100.

[0052] Silicate has a strong affinity with iron and is very easy to coordinate with iron and iron oxides. Silicate modification increases the specific surface area and active sites of zero-valent iron (ZVI), enriches the surface functional groups of ZVI, increases the adsorption sites, and enhances the adsorption between zero-valent iron and bacteria, thereby improving the activity of zero-valent iron in removing bacteria. Carbonate has a strong electron induction ability. Carbonate modification can improve the reduction activity of ZVI, promote iron-nuclear electron transfer, and is conducive to activating O2, producing more active oxygen species, and enhancing the bactericidal activity of zero-valent iron. In this way, based on the strong adsorption capacity of silicate-modified zero-valent iron and the excellent oxygen activation ability of carbonate-modified zero-valent iron, the two modified zero-valent irons are batch-made into composite fillers, which can effectively give play to the advantages of both, make up for the shortcomings of short migration distance and easy self-quenching of active oxygen species, and enhance the adsorption and inactivation coupling of modified zero-valent iron on microorganisms by mixing the two modified zero-valent iron fillers, providing a new option for solving water treatment contaminated by pathogenic microorganisms.

[0053] The modified zero-valent iron preparation provided by the present disclosure is further described below through specific examples.

[0054] Example 1

[0055] This embodiment adopts mechanical ball milling to prepare silicate / carbonate modified zero-valent iron, which includes the following steps:

[0056] S10, 4 g of commercial zero-valent iron powder and 0.379 g of sodium carbonate are added to the first ball mill; 4 g of commercial zero-valent iron powder and 0.435 g of sodium silicate are added to the second ball mill. The first ball mill and the second ball mill are both equipped with 50 small ball mill beads with a diameter of 6 mm and 30 medium ball mill beads with a diameter of 10 mm.

[0057] S20, set the ball mill speed to 500 rpm, the time to 4 hours, mechanical ball milling to obtain 5% molar ratio carbonate modified zero-valent iron, named CO3 2- -ZVI bm , and 5% molar ratio of silicate modified zero-valent iron, named SiO3 2- -ZVI bm .

[0058] The preparation of the control zero-valent iron comprises the following steps:

[0059] S10. Add commercial zero-valent iron powder into a third ball milling jar, wherein the third ball milling jar is filled with 50 small ball milling beads with a diameter of 6 mm and 30 medium ball milling beads with a diameter of 10 mm.

[0060] S20, set the ball mill speed to 500 rpm, the time to 4 hours, mechanical ball milling to obtain unmodified zero-valent iron, named ZVI bm .

[0061] X-ray powder diffraction (XRD) was used to characterize the phase structure of the sample. Figure 1 As shown, CO3 2- -ZVI bm 、SiO3 2- -ZVI bm and ZVI bm The comparison results show that silicate modification and carbonate modification do not change the original crystal structure of zero-valent iron, and the sample composition is still Fe 0 . Use infrared spectroscopy (FTIR) to characterize the functional group information on the sample surface, such as Figure 2 Shown are Na2SiO3, SiO3 2- -ZVI bm and ZVI bm Compare the results, such as Figure 3 Shown are Na2CO3, CO32- -ZVI bm and ZVI bm The comparison results show that silicate and carbonate modify the surface of zero-valent iron, change the structure of the surface oxide layer of zero-valent iron, and regulate the composition and structure of the zero-valent iron shell.

[0062] Example 2

[0063] This example compares the removal of Escherichia coli by CO3 2- -ZVI bm 、SiO3 2- -ZVI bm and ZVI bm Eliminate the activity of microorganisms.

[0064] ZV bm Group: Measure 50 mL of a concentration of 1.2×10 6 CFU / mL (CFU, colony forming unit) of Escherichia coli in a conical flask, add 0.0050g (100mg / L) ZVI bm Afterwards, the conical flask was placed in a constant temperature shaker at 200 rpm and 37°C, and 5 mL of the mixed solution was taken at 20 min, 40 min, and 60 min of reaction time, and the activity effect was tested by the spread plate counting method.

[0065] CO3 2- -ZVI bm Group: Measure 50 mL of a concentration of 1.2×10 6 CFU / mL (CFU, colony forming unit) of Escherichia coli in a conical flask, add 0.0050g of 100mg / L CO3 2- -ZVI bm Afterwards, the conical flask was placed in a constant temperature shaker at 200 rpm and 37°C, and 5 mL of the mixed solution was taken at 20 min, 40 min, and 60 min of reaction time, and the activity effect was tested by the spread plate counting method.

[0066] SiO3 2- -ZVI bm Group: Measure 50 mL of a concentration of 1.2×10 6 CFU / mL (CFU, colony forming unit) of Escherichia coli in a conical flask, add 0.0050g of SiO3 with a concentration of 100mg / L 2- -ZVI bm Afterwards, the conical flask was placed in a constant temperature shaker at 200 rpm and 37°C, and 5 mL of the mixed solution was taken at 20 min, 40 min, and 60 min of reaction time, and the activity effect was tested by the spread plate counting method.

[0067] Control group: 50 mL of 1.2×10 6 CFU / mL (CFU, colony forming unit) of Escherichia coli in a conical flask, add CO3 2- -ZVI bm The same amount of Na2CO3, or add CO3 2- -ZVI bm The same amount of Na2CO3+ZVI bm After the mixture (without ball milling), the conical flask was placed in a constant temperature shaker at 200 rpm and 37°C, and 5 mL of the mixture was taken at 20 min, 40 min, and 60 min of reaction time, and the active effect was tested by the spread plate counting method. bm The test results of the group.

[0068] Take 50mL of a solution with a concentration of 1.2×10 6 CFU / mL (CFU, colony forming unit) of Escherichia coli in a conical flask, add SiO3 2- -ZVI bm The same amount of Na2SiO3, or adding 2- -ZVI bm The same amount of Na2SiO3+ZVI bm After the mixture (without ball milling), the conical flask was placed in a constant temperature shaker at 200 rpm and 37°C. 5 mL of the mixture was taken at 20 min, 40 min, and 60 min of reaction time, and the active effect was tested by the spread plate counting method. bm The test results of the group.

[0069] See also Figure 4 , by comparing the control group and ZVI bm Group data comparison, SiO3 2- -ZVI bm The plate count results of the group showed that the addition of SiO3 2- -ZVI bm After that, the number of Escherichia coli was significantly reduced; Figure 5 As shown, by comparing the control group and ZVI bm Group data comparison, CO3 2- -ZVI bm The plate count results of the group showed that the addition of CO3 2- -ZVI bm After that, the number of E. coli was significantly reduced. In summary, the results show that CO3 2- -ZVI bm and SiO3 2- -ZVIbm Can effectively remove E.coli (Escherichia coli). Figure 4 and Figure 5 In the table, N0 is the initial E. coli count and N is the E. coli count at 60 min.

[0070] Example 3

[0071] This example verifies the adsorption effect of silicate-modified zero-valent iron through specific experiments.

[0072] (1) Use Live / Dead reagent to stain E. coli before and after the reaction, and use an inverted fluorescence microscope without eyepieces to observe ZVI bm 、SiO3 2- -ZVI bm The bacterial aggregation after treatment is compared to determine the strength of the adsorption. The specific operations include:

[0073] A stain solution was prepared by adding 3 μL PI (cell stain, staining dead cells and showing red) and 3 μL SYTO9 (cell stain, staining dead cells and living cells and showing green) into each milliliter of deionized water, and mixing well.

[0074] Take ZVI in Example 2 bm Group, SiO3 2- -ZVI bm The 200 μL bacterial solution after treatment in the group and control group was added with 200 μL dye, mixed, and reacted at room temperature in the dark for 20 minutes. 50 μL of the mixed solution after dyeing was placed on a slide, covered with a cover slip, and placed under an inverted fluorescence microscope without eyepieces. Turn on the fluorescent light source, find bacteria with clear vision, select a suitable area and take pictures, such as Figure 6 , Figure 7 and Figure 8 As shown, the results show that E. coli treated with zero-valent silicate modification exhibits obvious agglomeration phenomenon, indicating that zero-valent silicate modification has strong adsorption capacity and can remove E. coli by adsorbing it.

[0075] (2) Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) equipped with a diamond internal reflection element was used to characterize the interfacial interaction between zero-valent iron and Escherichia coli. The specific operation process includes:

[0076] 1 g of ZVI prepared in Example 1 bm and 1g SiO3 2- -ZVI bm Add 1 mL of anhydrous ethanol and disperse them ultrasonically. Apply the dispersed zero-valent iron suspension to the surface of the diamond crystal and dry it into a film of uniform thickness. Add 50 μL of OD670nm = 0.2 of the E. coli suspension and then the reaction was started, and infrared spectra were collected at preset time intervals. Fig.10 The results showed that sodium silicate-modified zero-valent iron adsorbed on bacterial proteins and caused changes in the protein conformation. Silicate-modified zero-valent iron enhanced the adsorption of E. coli by producing chemical reactions with E. coli surface proteins.

[0077] (3) The FTIR spectra of the silicate-modified zero-valent iron before and after the reaction in Example 2 were tested to verify the interfacial hydrogen bonding.

[0078] The specific process includes: Determination of ZVI using ATR-FTIR spectroscopy bm 、SiO3 2- -ZVI bm The zero-valent iron-OH stretching vibration peaks before and after the reaction with E. coli verify the interfacial hydrogen bond. Fig.11 The results show that compared with ZVI bm , silicate modified zero valent iron 3435cm -1 The -OH stretching vibration peak at 1632 cm -1 The -OH bending vibration peak at is slightly blue-shifted, indicating that there is an interfacial hydrogen bond between sodium silicate-modified zero-valent iron and E. coli.

[0079] (4) The FTIR spectra of the two zero-valent irons before and after the reaction and the UV-visible spectra of E. coli were tested to verify the role of hydrogen bonding.

[0080] Specifically include: measure 50mL OD 670nm = 0.2 Escherichia coli suspension in a conical flask, add 0.0050g ZVI bm and 0.0050g SiO3 2- -ZVI bm After 60 minutes of reaction, 3 mL of bacterial solution was added to a cuvette and the 800-200 nm band was scanned to obtain the absorption wavelength of C=O transition. The untreated bacterial solution was used as a blank control. Fig.12 The results showed that the untreated E. coli showed a UV absorption signal of C=O transition at 266nm. bm After the reaction, the absorption signal blue-shifted to 265nm, which is consistent with SiO3 2- -ZVI bm After the reaction, the absorption signal blue-shifted to 260nm, indicating that SiO3 2- -ZVI bm The adsorption between E. coli can be enhanced through hydrogen bonding.

[0081] Example 4

[0082] This example verifies the bactericidal effect of carbonate-modified zero-valent iron through specific experiments.

[0083] (1) Use Live / Dead reagent to stain E. coli before and after the reaction, and use an inverted fluorescence microscope without eyepieces to observe ZVI bm 、CO3 2- -ZVI bm The damage of bacterial membrane after treatment is compared with the strength of oxidative damage. The specific operations include:

[0084] A stain solution was prepared by adding 3 μL PI (cell stain, staining dead cells and showing red) and 3 μL SYTO9 (cell stain, staining dead cells and living cells and showing green) into each milliliter of deionized water, and mixing well.

[0085] Take ZVI in Example 2 bm Group, CO3 2- -ZVI bm The 200 μL bacterial solution after treatment in the group and control group was added with 200 μL dye, mixed, and reacted at room temperature in the dark for 20 minutes. 50 μL of the mixed solution after dyeing was placed on a slide, covered with a cover slip, and placed under an inverted fluorescence microscope without eyepieces. Turn on the fluorescent light source, find bacteria with clear vision, select a suitable area and take pictures, such as Figure 6 , Figure 7 and Fig. 9 As shown, the results showed that E. coli treated with zero-valent carbonate modification showed a significant increase in dead cells, indicating that zero-valent carbonate modification has a strong killing effect on E. coli.

[0086] (2) Quenching and quantification experiments: Superoxide dismutase (SOD), furfuryl alcohol (FFA), tert-butyl alcohol (TBA), and CAT (catalase) were used as quenchers to evaluate the main active species in the sodium carbonate-modified zero-valent iron system.

[0087] Specifically, 0.0050 g ZVI was added to a conical flask containing 50 mL of E. coli and then the quencher was added. bm , 0.0050g CO3 2- -ZVI bm Start the reaction, take 5 mL of the mixture at 20 min, 40 min, and 60 min, and use the plate count method to count the change in the number of bacteria after adding the quencher. The results are shown in Fig.13 The concentration of superoxide radicals in the quantitative system was detected by UV-visible spectrophotometer, and the concentration of hydroxyl radicals in the quantitative system was detected by high performance liquid chromatography. The results are as follows: Fig.14 shown. Fig.14The results show that superoxide radicals are the main active species in the carbonate-modified zero-valent iron system.

[0088] (3) Tafel curve is used to characterize the electron transfer capacity and verify the CO3 2- -ZVI bm Ability to activate molecular oxygen

[0089] Specifically, a three-electrode system was constructed using a calomel electrode as a reference electrode, a Pt sheet as a counter electrode, and a glassy carbon electrode with zero-valent iron powder dispersed on the surface as a working electrode to measure ZVI. bm and CO3 2- -ZVI bm The Tafel curve of the test results is as follows Fig.15 .CO3 2- -ZVI bm The corrosion potential is more negative, the corrosion current is larger, and the carbonate modification significantly improves the electron release and transmission capacity of ZVI, which is beneficial to the occurrence of O2 activation process.

[0090] A dissolved oxygen meter was used to monitor the concentration of dissolved oxygen in the system during the reaction. The test results were as follows: Fig.15 As shown, during the reaction, CO3 2- -ZVI bm ZVI bm Consumes more dissolved oxygen, the results show that CO3 2- -ZVI bm It is easier to activate O2 and produce reactive oxygen species.

[0091] (4) Characterization of ZVI using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) with diamond internal reflector bm 、CO3 2- -ZVI bm The interface interaction with E. coli, the specific operation is shown in Example 3. The test results are as follows Fig.16 As shown in the figure, the results show that with the increase of reaction time, 1635cm -1 and 1542cm -1 The carbonyl stretching vibration peak and amino bending vibration peak at 1240cm-1, which belong to the cell membrane protein, have weakened, indicating that the protein on the cell membrane is damaged; -1 The antisymmetric vibration peak of the phosphodiester bond at 1086 cm -1 The peak intensity of the phosphate bond stretching vibration is significantly weakened, indicating that CO3 2- -ZVI bm It causes bacterial death by destroying the cell membrane protein and phospholipid bilayer.

[0092] Example 5

[0093] Based on the results verified in the above examples, the sodium silicate-modified zero-valent iron has a stronger adsorption effect on bacteria, and the sodium carbonate-modified zero-valent iron has a stronger oxidative damage ability on bacteria. In order to more effectively exert the advantages of both, effectively couple the adsorption effect and the chemical redox sterilization effect, overcome the weaknesses of the short migration distance and easy self-quenching of active oxygen species, the CO3 prepared in Example 1 is added to the mixture. 2- -ZVI bm , and SiO3 2- -ZVI bm . Mix them in a mass ratio of 1:1 to prepare fillers and construct mixed zero-valent iron sand filter columns, ZVI bm Sand filter column, CO3 2- -ZVI bm Sand filter column, SiO3 2- -ZVI bm Sand filter column.

[0094] (1) The bacterial concentration in the effluent of the mixed zero-valent iron sand filter column was tested by the plate count method to detect the performance of removing E. coli. The test results are as follows Fig.17 As shown, the mixed zero-valent iron sand filter column has better sterilization effect, longer stable operation time, and better performance in removing bacteria. Fig.17 In the figure, N in the vertical axis is the actual live cell count.

[0095] (2) The treated E. coli were stained with Live / Dead reagent, and the bacterial damage after treatment with the mixed zero-valent iron sand filter column was observed using an inverted microscope without an eyepiece. The test results are as follows: Fig.18 As shown, after being treated with the mixed zero-valent iron sand filter column, E. coli exhibited a strong red fluorescence, and the mixed zero-valent iron sand filter column had a strong adsorption and inactivation ability for E. coli.

[0096] (3) The plate count method was used to select water from Wuhan East Lake as the actual water sample to test the removal effect of the mixed zero-valent iron sand filter column on microorganisms in actual water quality. The test results are as follows: Fig.19 As shown, the mixed zero-valent iron sand filter column has a better effect on the removal and inactivation of bacteria in actual river water. Fig.19 In the figure, N in the vertical axis is the actual live cell count.

[0097] (4) The water containing Microcystis aeruginosa (algae concentration of 1×10 6 cells / mL) were subjected to ZVI bm Filter column, CO3 2- -ZVI bm Filter column, SiO3 2- -ZVI bmThe filter column and the mixed zero-valent iron filter column were used. The algae absorbance at 680nm of the effluent at different treatment times was measured by ultraviolet spectrophotometer to detect the performance of removing Microcystis aeruginosa. The test results are as follows Fig. 20 As shown, the mixed zero-valent iron sand filter column also has certain advantages in capturing Microcystis aeruginosa. In addition to removing bacteria in water, the mixed zero-valent iron sand filter column can also be used to treat algae-contaminated water and has a wider range of uses.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A modified zero-valent iron preparation for sterilization and algae removal in water, characterized in that: It includes silicate-modified zero-valent iron and carbonate-modified zero-valent iron; the mass ratio of the silicate-modified zero-valent iron to the carbonate-modified zero-valent iron is 1:(0.8-1.2); In the silicate-modified zero-valent iron, the molar ratio of silicate to zero-valent iron is (3-8):100; In the carbonate-modified zero-valent iron, the molar ratio of carbonate to zero-valent iron is (3-8):

100.

2. Use of the modified zero-valent iron preparation for sterilization and algae removal in water as claimed in claim 1 in the preparation of a water microorganism removal product.

3. The use according to claim 2, wherein the water microorganism removal product comprises an adsorbent for water microorganisms.

4. The use according to claim 2, wherein the water microorganism removal product comprises a biocide for water microorganisms.

5. A method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water according to claim 1, characterized in that: The following steps are involved: S10, obtaining zero-valent iron powder, carbonate and silicate; Add carbonate and zero-valent iron powder into the first ball mill according to a molar ratio of (3-8):100; Add silicate and zero-valent iron powder into the second ball mill according to a molar ratio of (3-8):100; S20, the first ball mill and the second ball mill are respectively subjected to mechanical ball milling to obtain silicate-modified zero-valent iron and carbonate-modified zero-valent iron; S30, mixing the silicate-modified zero-valent iron and the carbonate-modified zero-valent iron in a mass ratio of 1:(0.8-1.2) to obtain a modified zero-valent iron preparation.

6. The method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water according to claim 5, characterized in that: In step S10, carbonate and zero-valent iron powder are added into a first ball mill according to a molar ratio of 5:100; Silicate and zero-valent iron powder were added into the second ball mill at a molar ratio of 5:

100.

7. The method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water according to claim 5 or 6, characterized in that: In step S10, the carbonate is sodium carbonate, and the silicate is sodium silicate.

8. The method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water according to claim 5, characterized in that: In step S20, the first ball mill and the second ball mill are respectively subjected to mechanical ball milling at a rotation speed of 300-800 rpm for 3-6 hours to obtain silicate-modified zero-valent iron and carbonate-modified zero-valent iron, respectively.

9. The method for preparing the modified zero-valent iron preparation for sterilization and algae removal in water according to claim 5, characterized in that: In step S30, silicate-modified zero-valent iron and carbonate-modified zero-valent iron are mixed in a mass ratio of 1:1 to obtain a modified zero-valent iron preparation.

10. A water body sterilization and algae removal device, characterized in that: It comprises a sterilization and algae removal filtration unit; the filler in the sterilization and algae removal filtration unit comprises the modified zero-valent iron preparation for sterilization and algae removal in water as claimed in claim 1.

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