A novel method for degrading PPCPs using activated ozone system

Abstract

The present invention relates to the field of environmental protection technology, and in particular to a method for degrading PPCPs using a novel activated ozone system. The present invention provides a green and efficient novel activated ozone system using ozone as the main oxidant and zero-valent silicon as both a reducing agent and an ozone activator. Zero-valent silicon with a reducing effect is used as an activator to activate ozone in an aqueous phase system to generate active oxygen species, thereby reducing and oxidizing PPCPs pollutants, especially pollutants such as atrazine and ibuprofen, to achieve the goal of decontamination and carbon reduction. The present invention achieves deep degradation of pollutants without generating secondary pollution, and only dissolves metasilicic acid (H 2 SiO 3 ), the recycling rate of zero-valent silicon is high, and the reaction system does not need to adjust the pH value, which provides new ideas and methods for the study of efficient activated ozone degradation of PPCPs.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a method for degrading PPCPs using a novel activated ozone system. Background Art

[0002] In recent years, the pollution problem of pharmaceuticals and personal care products (PPCPs) has attracted widespread attention. Atrazine (ATZ) and ibuprofen (IBP) are widely used PPCPs, and their abuse in agriculture and medicine poses a serious threat to human health and ecological stability. Conventional wastewater treatment technology is difficult to efficiently degrade PPCPs. Research on suitable advanced oxidation processes (AOPs) for deep treatment of organic wastewater containing PPCPs has become a research focus in this field.

[0003] Advanced oxidation technology is a method of oxidizing and degrading large molecular refractory organic matter into low-toxic or non-toxic small molecular substances by generating strong oxidizing free radicals. It is one of the important means of treating organic pollutants at this stage. Advanced oxidation technology has many advantages for wastewater containing refractory organic matter, such as high treatment efficiency, high degree of mineralization, and very little secondary pollution. Common advanced oxidation technologies include: photocatalytic oxidation, Fenton oxidation, electrochemical oxidation, and ozone catalytic oxidation. Ozone catalytic oxidation can produce active oxygen with higher oxidizing performance by catalytically activating ozone to rapidly degrade and effectively mineralize organic pollutants, and has broad application prospects in the field of deep water purification.

[0004] The low solubility and instability of ozone result in a low rate of oxidation of organic pollutants, and the effective utilization rate of ozone is also low, which also leads to high energy consumption and low mineralization rate during the reaction. Therefore, it is necessary to improve the method of adding a catalyst.

[0005] Chinese patent document CN117383689A discloses a homogeneous catalytic ozone oxidation method, which treats the water sample to be treated by adding a certain amount of ozone and catalytic ions to each section of the water treatment path containing the electrolyte solution. This patented method effectively avoids the problems of plate scaling and excessive addition of catalytic ions, but requires multi-stage treatment, increases operating costs, and the homogeneous catalytic ozone method is not conducive to the recovery of catalysts, and will cause secondary pollution to the environment.

[0006] Chinese patent document CN117101656A discloses a preparation method and application of a catalyst for catalytic ozone degradation of wastewater, using a sandstone carrier, Fe 2+The ferric oxyhydroxide crystals prepared from wastewater with a pH value of 4-5 catalyze ozone degradation of caprolactam wastewater with a pH value of 6-9. 2+ The loss of H2O2 is large, which increases the cost. In addition, the catalyst is a metal-based catalyst. During the catalytic ozone reaction, metal ions will be dissolved in water to cause secondary pollution. Summary of the invention

[0007] In view of this, the present invention provides a new green and efficient activated ozone system with ozone as the main oxidant and zero-valent silicon as both a reducing agent and an ozone activator. The zero-valent silicon with a reducing effect is used as an activator to activate ozone in an aqueous phase system to generate hydroxyl radicals (·OH) and superoxide radicals (·O2 - ) and singlet oxygen ( 1 O2) and other active oxygen species can reduce and oxidize PPCPs, especially pollutants such as atrazine and ibuprofen, to achieve the goal of decontamination and carbon reduction.

[0008] The present invention is achieved in that:

[0009] The present invention provides a novel method for degrading PPCPs using an activated ozone system, which is characterized by comprising the following steps:

[0010] S1: adding zero-valent silicon to the water phase and mixing them thoroughly with mechanical stirring;

[0011] S2 adds PPCPs aqueous solution and ozone in sequence to react.

[0012] In the step S1, silicon oxide generated on the surface of zero-valent silicon during the reaction process is separated from or dissolved in water to form metasilicic acid.

[0013] The zero-valent silicon in the present invention includes silicon materials with different crystal planes, such as crystal planes (111), (220), and (100).

[0014] The zero-valent silicon in the present invention also includes silicon powder, silicon particles, other doped silicon-based materials, and surface-processed silicon materials.

[0015] The surface treatment includes increasing surface hydroxyl groups and / or Lewis acid sites.

[0016] Furthermore, the particle size of the zero-valent silicon is 40-200 meshes.

[0017] In an optional embodiment, zero-valent silicon is added to the aqueous phase, and after being fully mixed by mechanical stirring, the concentration of the zero-valent silicon is 0.25-2.5 g / L. The concentration of the zero-valent silicon is preferably 1.25-2.50 g / L.

[0018] In an optional embodiment, the ozone is an ozone solution with a concentration of 11.53-115.35 μmol / L. The concentration of the ozone solution is preferably 69.21-115.35 μmol / L.

[0019] In an optional embodiment, the ozone is ozone gas with a flow rate of 1 L / min. In the step S2, the ozone gas is introduced into the reaction solution through a gas diffusion tube for reaction.

[0020] In an optional embodiment, the PPCPs aqueous solution is an atrazine solution with a concentration of 10.15-93.93 μmol / L. The concentration of the atrazine solution is preferably 10.15-29.02 μmol / L.

[0021] In an optional embodiment, the PPCPs aqueous solution is an ibuprofen solution with a concentration of 10.32-103.17 μmol / L. The concentration of the ibuprofen solution is preferably 10.32-20.63 μmol / L.

[0022] In an optional embodiment, in step S1, zero-valent silicon is added to the aqueous phase, which is then placed on a magnetic stirrer and stirred at 500 r / min for 15-60 min at room temperature to be fully mixed.

[0023] In an optional embodiment, the PPCPs aqueous solution is actual sewage containing PPCPs.

[0024] Furthermore, the present invention also provides a novel activated ozone preparation for degrading PPCPs according to the method for degrading PPCPs using the novel activated ozone system.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a novel activated ozone system to remove refractory PPCPs in an aqueous environment by reduction-oxidation synergy and free radical-non-free radical coupling reaction. In the reaction system, ozone is used as the main oxidant, and zero-valent silicon is used as both a reducing agent and an ozone activator. Zero-valent silicon with a reducing effect is used as an activator to activate ozone in an aqueous system to generate hydroxyl radicals (·OH) and superoxide radicals (·O2 - ) and singlet oxygen ( 1 O2) to reduce and oxidize common PPCPs, thereby achieving the goal of decontamination and carbon reduction. The treatment process is simple, and while achieving deep degradation of pollutants, the activator zero-valent silicon only dissolves the necessary component of high-quality mineral water - metasilicic acid (H2SiO3) through reaction. The present invention is a green and efficient treatment technology, providing a new way to develop water treatment technology.

[0027] (2) In the novel activated ozone system provided by the present invention, zero-valent silicon has a significant activation effect on ozone, and exhibits the ability to efficiently remove different types of PPCPs (specifically atrazine and ibuprofen as target pollutants), while maintaining extremely high activity. It has the advantages of reducing secondary pollution, simple ingredients, low price, and easy acquisition. Zero-valent silicon will be very easy to obtain from photovoltaic panel waste in the near future. The zero-valent silicon in the present invention can be recycled and reused multiple times, and the activation efficiency of recycling and reuse remains high. The present invention does not require the pH value of the system to be adjusted, and the effective pH value treatment range is 5-11 with a high pollutant removal rate, providing new ideas and new methods for the study of efficient activated ozone degradation of PPCPs.

[0028] (3) The new activated ozone system provided by the present invention exhibits a significant removal effect on PPCPs. The removal rate of atrazine by the new activated ozone system is 99.71%, which is nearly 6 times higher than the removal rate of atrazine by ozone alone or zero-valent silicon alone; its removal rate of ibuprofen is 5.9 to 95.2 times higher than the removal rate of ibuprofen by ozone alone or zero-valent silicon alone. The new activated ozone system can achieve a removal rate of 99.95% and 99.99% for atrazine or ibuprofen, respectively, in just 1 minute of reaction; after 180 minutes of reaction, deep mineralization of atrazine or ibuprofen is achieved, with TOC removal rates of 99.92% and 99.72%, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the activation effect of zero-valent silicon on ozone, where ZVS stands for zero-valent silicon, ATZ stands for atrazine, and IBP stands for ibuprofen;

[0030] Figure 2 is the dechlorination rate and removal rate of atrazine by zero-valent silicon alone;

[0031] Figure 3 It is the mineralization effect of the novel activated ozone system of the present invention on atrazine;

[0032] Figure 4 It is the mineralization effect of the novel activated ozone system of the present invention on ibuprofen;

[0033] Figure 5 It is the removal effect of different concentrations of zero-valent silicon on atrazine in the novel activated ozone system of the present invention;

[0034] Figure 6 It is the removal effect of different concentrations of zero-valent silicon on ibuprofen in the novel activated ozone system of the present invention;

[0035] Figure 7 It is the removal effect of different concentrations of ozone solution on atrazine in the novel activated ozone system of the present invention;

[0036] Figure 8 It is the removal effect of different concentrations of ozone solution on ibuprofen in the novel activated ozone system of the present invention;

[0037] Fig. 9 It is the removal effect of the novel activated ozone system of the present invention on atrazine of different concentrations;

[0038] Fig.10 It is the removal effect of the novel activated ozone system of the present invention on ibuprofen of different concentrations;

[0039] Fig.11 The effect of stirring time on atrazine removal in the novel activated ozone system of the present invention;

[0040] Fig.12 The effect of stirring time on the removal of ibuprofen in the novel activated ozone system of the present invention;

[0041] Fig.13 It is the TOC removal effect of the novel activated ozone system of the present invention on actual domestic sewage;

[0042] Fig.14 This is the COD removal effect of the novel activated ozone system of the present invention on actual domestic sewage;

[0043] Fig.15 This is the EPR spectrum of the novel activated ozone system of the present invention capturing hydroxyl radicals;

[0044] Fig.16 This is the EPR spectrum of the novel activated ozone system of the present invention capturing superoxide radicals;

[0045] Fig.17 This is the EPR spectrum of the novel activated ozone system of the present invention capturing singlet oxygen. DETAILED DESCRIPTION

[0046] 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.

[0047] The sources of materials in the examples of the present invention are shown in Table 1.

[0048] Table 1

[0049] Reagent name purity Manufacturers Silicon powder 99.99%metalsbasis,40-200 mesh Aladdin Biotechnology Co., Ltd. Atrazine 97％ McLean Biochemical Technology Co., Ltd. Ibuprofen ≥98%(GC) Aladdin Biotechnology Co., Ltd.

[0050] The detection method used in the embodiment of the present invention is as follows:

[0051] 1) Atrazine concentration test method: Atrazine was determined using a high performance liquid chromatograph (1260 InfinityⅡPrime, Agilent Technologies, Inc.). Test conditions: The chromatographic column used was a ZORBAX Eclipse Plus C18 column (pore size 5 μm, 4.6×150 mm), the column temperature was maintained at 25°C, the mobile phase was 50% ultrapure water and 50% acetonitrile, the flow rate was 1 mL / min, the injection volume was 20 μL, and the detector detection wavelength was 223 nm.

[0052] 2) Ibuprofen concentration test method: Ibuprofen was determined using a high performance liquid chromatograph (1260 InfinityⅡPrime, Agilent Technologies, Inc.). Test conditions: The chromatographic column used was a ZORBAX SB C18 column (pore size 5 μm, 4.6×250 mm), the column temperature was maintained at 25°C, the mobile phase was 25% ultrapure water containing 0.1% phosphoric acid and 75% acetonitrile, the flow rate was 0.5 mL·min-1, the injection volume was 20 μL, and the detector detection wavelength was 220 nm.

[0053] 3) The TOC value was measured using a total organic carbon analyzer (TOC-L CSH, Shimadzu Instruments Co., Ltd.).

[0054] 4) The COD value was determined using the rapid digestion method of HJ / T399-2007.

[0055] 5) The active free radicals were tested using an electron paramagnetic resonance spectrometer (EMXnano, Bruker Corporation, USA).

[0056] In the embodiment of the present invention, the pollutant residual rate, pollutant removal rate, dechlorination rate, TOC removal rate, TOC residual rate and COD residual rate are calculated according to the following calculation formulas:

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] Example 1 Removal of PPCPs (atrazine or ibuprofen) by a novel activated ozone system (zero-valent silicon / ozone), ozone alone, and zero-valent silicon alone

[0064] 1.1 Removal of PPCPs (atrazine or ibuprofen) by the new activated ozone system (zero-valent silicon / ozone)

[0065] Zero-valent silicon was added into deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 min, then PPCPs aqueous solution and ozone stock solution were added in sequence to react for 1 min, and samples were taken at regular intervals (reaction parameters were 1.5 g / L ZVS, 115.35 μmol / L O3, 10.15 μmol / L ATZ or 20.63 μmol / L IBP).

[0066] In this embodiment, the reaction parameter 1.5 g / LZVS means that the concentration of zero-valent silicon in the reaction system is 1.5 g / L. The parameters in all embodiments are the same.

[0067] 1.2 Removal of PPCPs (atrazine or ibuprofen) by ozone alone

[0068] The pollutant aqueous solution and ozone stock solution were added to react for 1 min and samples were taken at regular intervals (reaction parameters were 115.35 μmol / L O3, 10.15 μmol / L ATZ or 20.63 μmol / L IBP).

[0069] 1.3 Removal of PPCPs (atrazine or ibuprofen) by zero-valent silicon alone

[0070] Zero-valent silicon was added to deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 minutes, then PPCPs aqueous solution was added to react for 1 minute, and samples were taken at regular intervals (reaction parameters were 1.5 g / L ZVS, 10.15 μmol / L ATZ or 20.63 μmol / L IBP).

[0071] 1.4 Experimental Results

[0072] like Figure 1 As shown, the removal rate of atrazine by ozone alone is 16.94%, the removal rate of atrazine by zero-valent silicon alone is 16.57%, and the removal rate of atrazine by the new activated ozone system (zero-valent silicon / ozone) is 99.71%, which is nearly 6 times higher than the previous two.

[0073] The removal rate of ibuprofen by ozone alone is 16.95%, the removal rate of ibuprofen by zero-valent silicon alone is 1.05%, and the removal rate of ibuprofen by the new activated ozone system (zero-valent silicon / ozone) is 99.96%, which is 5.9 to 95.2 times higher than the previous two.

[0074] The removal effects of ozone alone on atrazine and ibuprofen were similar, mainly contributed by the direct oxidation effect of ozone.

[0075] The removal rate of atrazine by zero-valent silicon alone (16.57%) is higher than that of ibuprofen (1.05%), mainly because the atrazine molecule contains a chlorine atom that can be reduced and dechlorinated by zero-valent silicon, which significantly reduces the concentration of atrazine in the system, reflecting the reducing property of zero-valent silicon. The new activated ozone system (zero-valent silicon / ozone) has significantly improved the removal rates of atrazine and ibuprofen compared with ozone alone and zero-valent silicon alone, reflecting the efficient oxidation of the system. The experiment proved that there is a synergistic reaction between the reducing effect of zero-valent silicon and the oxidative effect of ozone and activated ozone to produce active oxygen species in the zero-valent silicon / ozone system.

[0076] Example 2 Dechlorination and removal effects of zero-valent silicon on atrazine

[0077] Zero-valent silicon was added to deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 minutes, then PPCPs aqueous solution was added and continued to stir for 60 minutes before sampling (reaction parameters were 1.5 g / LZVS, 10.15 μmol / LATZ).

[0078] like Figure 2 As shown, the removal rate of atrazine by zero-valent silicon alone after stirring for 60 minutes was 51.79%, and the dechlorination rate was 47.63%.

[0079] It was further proved that the atrazine molecule contains a chlorine atom which can be reduced and dechlorinated by zero-valent silicon, which significantly reduced the concentration of atrazine in the system, reflecting the reducibility of zero-valent silicon. The reduction effect of zero-valent silicon was confirmed. Its reduction mechanism is: zero-valent silicon is a strong reducing agent. In the zero-valent silicon / water system, the standard reduction potential of the redox coupling formed by zero-valent silicon and silicon dioxide is -0.857V, making zero-valent silicon an electron donor for the reduction and dechlorination of atrazine (the molecule contains a chlorine atom that is easily reduced). The specific reaction is as follows:

[0080] Si 0 +3H2O+2RCl→H2SiO3+2RH+2H + +Cl -

[0081] Example 3 Mineralization reaction of atrazine by a novel activated ozone system (zero-valent silicon / ozone)

[0082] Zero-valent silicon was added to deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 minutes, then an atrazine aqueous solution was added, and ozone was introduced into the reaction solution through a gas diffusion tube for reaction, and samples were taken at regular intervals (reaction parameters were 1.5 g / LZVS, 1 L / min O3, 10.15 μmol / LATZ).

[0083] like Figure 3 As shown, the new activated ozone system (zero-valent silicon / ozone) has a removal rate of up to 99.95% for atrazine in just 1 minute of reaction. Continuously introducing ozone into the reaction solution can achieve a removal rate of more than 99.98% for atrazine, achieving complete removal of atrazine.

[0084] However, the TOC removal rate of the new activated ozone system (zero-valent silicon / ozone) for atrazine solution after 1 minute of reaction was only 47.82%, indicating that atrazine degradation intermediates still existed in the solution. When ozone was continuously introduced into the reaction solution for 15 minutes, 30 minutes, 60 minutes, 120 minutes, and 180 minutes, the TOC removal rates were 56.39%, 59.69%, 74.69%, 91.51%, and 99.92%, respectively. It can be seen that the new activated ozone system (zero-valent silicon / ozone) can basically achieve deep mineralization of atrazine after 180 minutes of reaction.

[0085] It can be seen that although the atrazine body was efficiently removed, the TOC removal rate of the new activated ozone system (zero-valent silicon / ozone) for atrazine solution was only 47.82% when the reaction lasted for 1 minute. This shows that there are still a large number of atrazine degradation intermediates in the solution. As the reaction time increases, the TOC removal rate of the atrazine solution by the new activated ozone system (zero-valent silicon / ozone) gradually increases. The new activated ozone system (zero-valent silicon / ozone) can gradually further oxidize the atrazine degradation intermediates and eventually mineralize them into inorganic substances.

[0086] Example 4 Mineralization reaction of ibuprofen using a novel activated ozone system (zero-valent silicon / ozone)

[0087] Zero-valent silicon was added to deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 minutes, then an ibuprofen aqueous solution was added, and ozone was introduced into the reaction solution through a gas diffusion tube for reaction, and samples were taken at regular intervals (reaction parameters were 1.5 g / L ZVS, 1 L / min O3, 20.63 μmol / L IBP).

[0088] like Figure 4As shown, the removal rate of ibuprofen bulk was as high as 99.99% when ozone was continuously introduced into the reaction solution for only 1 min, achieving complete removal of ibuprofen bulk.

[0089] However, the TOC removal rate of the new activated ozone system (zero-valent silicon / ozone) for ibuprofen solution after 1 minute of reaction was only 47.93%, indicating that ibuprofen degradation intermediates still existed in the solution. When ozone was continuously introduced into the reaction solution for 15 minutes, 30 minutes, 60 minutes, 120 minutes, and 180 minutes, the TOC removal rates were 49.56%, 52.11%, 62.63%, 81.38%, and 99.72%, respectively. It can be seen that the new activated ozone system (zero-valent silicon / ozone) can basically achieve deep mineralization of ibuprofen after 180 minutes of reaction.

[0090] Example 5 Removal effect of different concentrations of zero-valent silicon on PPCPs (atrazine or ibuprofen) in the new activated ozone system (zero-valent silicon / ozone)

[0091] Zero-valent silicon was added into deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 min, then PPCPs aqueous solution and ozone stock solution were added in sequence to react for 1 min, and samples were taken at regular intervals.

[0092] The reaction parameters are as follows:

[0093] ATZ 1: 0.25g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0094] ATZ 2: 0.50g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0095] ATZ 3: 1.50g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0096] ATZ 4: 2.50g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0097] IBP 1: 0.25g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP;

[0098] IBP 2: 0.50g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP;

[0099] IBP 3: 1.50g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP;

[0100] IBP 4: 2.50g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP.

[0101] like Figure 5-6 As shown, when the concentration of zero-valent silicon in the new activated ozone system is 0.25 g / L, the removal rates of atrazine or ibuprofen are 64.01% and 56.66% respectively; when the concentration of zero-valent silicon is 0.50 g / L, the removal rates of atrazine or ibuprofen are 96.11% and 91.57% respectively, which are significantly increased by 50.15% and 61.61% compared with 0.25 g / L; when the concentration of zero-valent silicon reaches 1.25-2.50 g / L, atrazine or ibuprofen can be basically completely removed, and the removal rate is as high as 99.71-99.99%. This shows that the concentration range of zero-valent silicon in the new activated ozone system of the present invention is 0.25-2.50 g / L, preferably 0.50-2.50 g / L, and more preferably 1.25-2.50 g / L.

[0102] Example 6 Removal effect of different concentrations of ozone solution on PPCPs (atrazine or ibuprofen) in the new activated ozone system (zero-valent silicon / ozone)

[0103] Zero-valent silicon was added into deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 min, then PPCPs aqueous solution and ozone stock solution were added in sequence to react for 1 min, and samples were taken at regular intervals.

[0104] The reaction parameters are as follows:

[0105] ATZ 1: 1.50g / L ZVS, 11.53μmol / L O3, 10.15μmol / LATZ;

[0106] ATZ 2: 1.50g / L ZVS, 34.60μmol / L O3, 10.15μmol / LATZ;

[0107] ATZ 3: 1.50g / L ZVS, 69.21μmol / L O3, 10.15μmol / LATZ;

[0108] ATZ 4: 1.50g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0109] IBP 1: 1.50g / LZVS, 11.53μmol / L O3, 20.63μmol / L IBP;

[0110] IBP 2: 1.50g / LZVS, 34.60μmol / L O3, 20.63μmol / L IBP;

[0111] IBP 3: 1.50g / LZVS, 69.21μmol / L O3, 20.63μmol / L IBP;

[0112] IBP 4: 1.50g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP.

[0113] The results are as follows Figure 7-8 As shown, in the novel activated ozone system, the zero-valent silicon activated ozone oxidation reaction lasted for 1 minute. When the concentration of the ozone solution was 11.53 μmol / L and 34.60 μmol / L, the removal rates of atrazine were 48.43% and 87.18%, respectively, and the removal rates of ibuprofen were 22.58% and 66.07%, respectively; when the concentration of the ozone solution was 69.21 μmol / L and 115.35 μmol / L, the removal rates of atrazine were 98.21% and 99.71%, respectively, and the removal rates of ibuprofen were 94.08% and 99.96%, respectively. It can be seen that the ozone concentration range in the novel activated ozone system of the present invention is 11.53-115.35 μmol / L, preferably 69.21-115.35 μmol / L.

[0114] Example 7 Removal effect of the new activated ozone system on PPCPs of different concentrations

[0115] Zero-valent silicon was added into deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 min, then PPCPs aqueous solution and ozone stock solution were added in sequence to react for 1 min, and samples were taken at regular intervals.

[0116] The reaction parameters are as follows:

[0117] ATZ 1: 1.50g / L ZVS, 115.35μmol / L O3, 10.15μmol / LATZ;

[0118] ATZ 2: 1.50g / L ZVS, 115.35μmol / L O3, 19.45μmol / LATZ;

[0119] ATZ 3: 1.50g / L ZVS, 115.35μmol / L O3, 29.02μmol / LATZ;

[0120] ATZ 4: 1.50g / L ZVS, 115.35μmol / L O3, 57.01μmol / LATZ;

[0121] ATZ 5: 1.50g / L ZVS, 115.35μmol / L O3, 93.93μmol / LATZ;

[0122] IBP 1: 1.50g / LZVS, 115.35μmol / L O3, 10.32μmol / L IBP;

[0123] IBP 2: 1.50g / LZVS, 115.35μmol / L O3, 20.63μmol / L IBP;

[0124] IBP 3: 1.50g / LZVS, 115.35μmol / L O3, 30.95μmol / L IBP;

[0125] IBP 4: 1.50g / LZVS, 115.35μmol / L O3, 61.90μmol / L IBP;

[0126] IBP 5: 1.50g / LZVS, 115.35μmol / L O3, 103.17μmol / L IBP.

[0127] The results are as follows Figure 9-10 As shown, the zero-valent silicon activated ozone oxidation reaction in the new activated ozone system lasted for 1 minute, and the removal rates of 10.15 μmol / L, 19.45 μmol / L, 29.02 μmol / L, 57.01 μmol / L and 93.93 μmol / L atrazine solutions were 99.71%, 98.67%, 96.68%, 86.64% and 71.03%, respectively. Therefore, the concentration range of the atrazine solution degraded by the method for degrading PPCPs using the new activated ozone system provided by the present invention is 10.15-93.93 μmol / L, and more preferably 10.15-29.02 μmol / L.

[0128] The zero-valent silicon activated ozone oxidation reaction in the new activated ozone system lasted for 1 minute, and the removal rates of 10.32 μmol / L, 20.63 μmol / L, 30.95 μmol / L, 61.90 μmol / L and 103.17 μmol / L ibuprofen solutions were 99.95%, 99.96%, 99.71%, 90.50% and 75.93%, respectively. Therefore, the concentration range of ibuprofen solution degraded by the method for degrading PPCPs using the new activated ozone system provided by the present invention is 10.32-103.17 μmol / L, and more preferably 10.32-20.63 μmol / L.

[0129] Example 8 Effect of stirring time on atrazine removal in a novel activated ozone system (zero-valent silicon / ozone)

[0130] Experimental steps:

[0131] (1) Zero-valent silicon was added to deionized water, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 15 min, then PPCPs aqueous solution and ozone stock solution were added in sequence for 1 min reaction, and samples were taken at regular intervals (reaction parameters were 1.50 g / L ZVS, 115.35 μmol / L O3, 10.15 μmol / L ATZ or 20.63 μmol / L IBP).

[0132] (2) Replace the stirring time with 30 min, keep the other steps and parameters unchanged, and take samples at regular intervals.

[0133] (3) Replace the stirring time with 60 min, keep the other steps and parameters unchanged, and take samples at regular intervals.

[0134] The results are as follows Figure 11-12 As shown in the figure, in the new activated ozone system, when the initial mechanical stirring time was 15min, 30min and 60min, the removal rates of atrazine were 97.83%, 99.71% and 99.79%, respectively, and the removal rates of ibuprofen were 99.94%, 99.96% and 99.99%, respectively. It can be seen that under the initial mechanical stirring time of 15-60min, the new activated ozone system can effectively remove atrazine or ibuprofen.

[0135] Example 9: Treatment of actual domestic sewage using a novel activated ozone system (zero-valent silicon / ozone)

[0136] In order to investigate the treatment effect of the novel activated ozone system (zero-valent silicon / ozone) on actual sewage, this example uses urban domestic sewage from Futian District, Shenzhen City, which is filtered and used as an experimental water sample to replace deionized water.

[0137] Zero-valent silicon was added to the experimental water sample, placed on a magnetic stirrer and stirred at room temperature at a stirring speed of 500 r / min for 30 minutes, then ozone was introduced into the reaction solution through a gas diffusion tube for reaction, and samples were taken at regular intervals (reaction parameters were 1.5 g / LZVS, 1 L / min O3).

[0138] like Fig.13 As shown, after continuously introducing ozone into the experimental water sample for 180 minutes, the TOC removal rate of the new activated ozone system (zero-valent silicon / ozone) for the sewage sample was 58.05%.

[0139] like Fig.14 As shown in the figure, as the reaction continues, the COD value of actual domestic sewage increases first and then decreases. This is mainly because domestic sewage contains a large amount of refractory organic pollutants. When determining COD, the potassium dichromate method cannot completely decompose the refractory organic matter, resulting in a low COD value. As the activated ozone reaction proceeds, the refractory organic matter in the reaction solution is oxidized and decomposed into substances that can be oxidized by potassium dichromate, resulting in an increase in the detected COD. As the reaction proceeds, the new activated ozone system (zero-valent silicon / ozone) has a COD removal rate of 65.84% for sewage samples after a reaction of 180 minutes.

[0140] Example 10 Electron Paramagnetic Resonance Spectroscopy Detection of Active Oxygen in a Novel Activated Ozone System (Zerovalent Silicon / Ozone)

[0141] 1.1 Capturing hydroxyl radicals

[0142] DMPO was added as a capture agent into a new activated ozone system (zero-valent silicon / ozone) to capture hydroxyl radicals. The samples were detected and analyzed using an electron paramagnetic resonance spectrometer. The results are as follows: Fig.15 As shown, with the extension of reaction time, the signal of hydroxyl radicals captured in the system increased significantly, further proving that the zero-valent silicon / ozone system can produce a large number of hydroxyl radicals.

[0143] 1.2 Capturing superoxide radicals

[0144] DMPO was used as a capture agent to capture superoxide radicals in a new activated ozone system (zero-valent silicon / ozone) with methanol (eliminating the interference of hydroxyl radicals on the capture of superoxide radicals) as a solvent. The samples were detected and analyzed using an electron paramagnetic resonance spectrometer. The results are as follows Fig.16 As shown, with the extension of reaction time, the signal of superoxide radicals captured in the system increased significantly, further proving that the zero-valent silicon / ozone system can produce a large number of superoxide radicals.

[0145] 1.3 Capturing singlet oxygen

[0146] TEMP was added as a capture agent into a new activated ozone system (zero-valent silicon / ozone) to capture singlet oxygen. The sample was detected and analyzed using an electron paramagnetic resonance spectrometer. The results are as follows: Fig.17 As shown, with the extension of reaction time, the signal of singlet oxygen captured in the system gradually increased, further proving that the zero-valent silicon / ozone system can produce singlet oxygen.

[0147] It can be seen that the oxidation of zero-valent silicon with ozone and activated ozone produces active oxygen species (hydroxyl radicals, superoxide radicals, singlet oxygen) in the new activated ozone system (zero-valent silicon / ozone). In the new activated ozone system (zero-valent silicon / ozone), there is a coupling reaction of free radicals and non-free radicals, with hydroxyl radicals as the main component, superoxide radicals and singlet oxygen as the auxiliary components.

[0148] When zero-valent silicon is stirred in water, the oxide film on the surface of the zero-valent silicon gradually wears away and falls off under the action of mechanical stirring. Some amorphous silicon dioxide particles adhere to the surface of the zero-valent silicon, and some dissolve in water to produce orthosilicic acid (the reaction formula is shown below).

[0149] Si 0 +2H2O→SiO2+4H + +4e -

[0150] Si 0 +3H2O→H2SiO3+4H + +4e -

[0151] The dissolution is pollution-free and harmless to drinking water. It is even a necessary component of high-quality mineral water (see "National Food Safety Standard for Drinking Natural Mineral Water", GB 8537-2018). It is also an essential trace element for the human body.

[0152] As the oxide film on the surface of zero-valent silicon falls off, the reaction sites on its surface are exposed. The Lewis acid sites (Si-L) coordinate with water molecules through spontaneous adsorption and dissociate water to form surface hydroxyl groups (the reaction equation is shown below).

[0153] Si-L+H2O→Si-OH

[0154] Ozone molecules in aqueous solution can easily connect to the hydroxyl groups on the surface of zero-valent silicon through hydrogen bonds and / or electrostatic attraction and initiate a series of free radical chain reactions, converting ozone into hydroxyl radicals, superoxide radicals, singlet oxygen and oxygen (the reaction equation is shown below).

[0155] Si-OH+O3→Si-OH-O3

[0156]

[0157]

[0158]

[0159] In addition, zero-valent silicon releases free electrons under mechanical stirring to react with ozone in the solution to generate hydroxyl radicals and oxygen (the reaction equation is shown below).

[0160]

[0161]

[0162] ·HO3→·OH+O2

[0163] In some embodiments of the present invention, zero-valent silicon is used for heterogeneous activated ozone degradation of PPCPs. The zero-valent silicon after the activated ozone reaction can be reused after membrane filtration, centrifugation, and freeze-drying, and the activation efficiency is still high, and can be recycled multiple times.

[0164] In some embodiments of the present invention, when zero-valent silicon is used for heterogeneous activated ozone degradation of PPCPs, there is no need to adjust the pH value of the system, and a high pollutant removal rate is achieved when the effective pH treatment range is 5-11.

[0165] In some embodiments of the present invention, when zero-valent silicon is used for heterogeneous activated ozone degradation of PPCPs, ozone can also be replaced by hydrogen peroxide or ozone / hydrogen peroxide as the oxidant in the reaction system.

[0166] In the novel activated ozone system provided by the present invention, zero-valent silicon has a significant activation effect on ozone, and exhibits the ability to efficiently remove different types of PPCPs (specifically atrazine and ibuprofen as target pollutants), and can also be used to degrade organic pollutants in actual sewage.

[0167] In the reaction system, ozone is used as the main oxidant, and zero-valent silicon is used as both a reductant (zero-valent silicon can serve as an electron donor for the reduction and dechlorination of atrazine) and an ozone activator. Zero-valent silicon with a reducing effect is used as an activator to activate ozone in the aqueous phase system to produce reactive oxygen species.

[0168] 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 novel method for degrading PPCPs using an activated ozone system, characterized in that: The steps include: S1: adding zero-valent silicon to the water phase and mechanically stirring to fully mix; after mixing, the concentration of the zero-valent silicon is 0.25-2.50 g / L; S2 adds PPCPs aqueous solution and ozone in sequence for reaction; the ozone is an ozone solution with a concentration of 11.53-115.35 μmol / L; the PPCPs aqueous solution is an atrazine solution with a concentration of 10.15-93.93 μmol / L, or an ibuprofen solution with a concentration of 10.32-103.17 μmol / L.

2. The method for degrading PPCPs by a novel activated ozone system according to claim 1, characterized in that: The particle size of the zero-valent silicon is 40-200 meshes.

3. The method for degrading PPCPs by a novel activated ozone system according to claim 1 or 2, characterized in that: The ozone is ozone gas with a flow rate of 1 L / min. In the step S2, the ozone gas is introduced into the reaction solution through a gas diffusion tube to react.

4. The method for degrading PPCPs by a novel activated ozone system according to claim 1 or 2, characterized in that: In the step S1, zero-valent silicon is added to the aqueous phase, and then placed on a magnetic stirrer and stirred at 500 r / min for 15-60 min at room temperature for thorough mixing.

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