A method for degrading water pollutants based on colloidal calcium peroxide

Abstract

The application discloses a kind of water body pollutant degradation methods based on colloidal calcium peroxide, the water body pollutant degradation methods based on colloidal calcium peroxide include the following steps: colloidal calcium peroxide is mixed with the water body to be treated containing pollutant, forms mixed water body, and the pollutant is degraded by reaction.This application utilizes homogeneous nucleation method to prepare colloidal calcium peroxide, then utilizes colloidal calcium peroxide in water body by the active site of surface calcium ion and combines with pollutant, and utilizes direct electron transfer of its surface peroxide group, realizes the efficient oxidative degradation to various refractory pollutants.This application colloidal calcium peroxide degradation pollutant mechanism is mainly dominated by non-radical effect, avoids the problem that traditional free radical oxidation path is easily interfered by water body matrix, can keep efficient degradation performance in wide pH range, has good anti-interference ability.

Description

Technical Field

[0001] This invention belongs to the field of water pollution control technology, and in particular relates to a method for degrading water pollutants based on colloidal calcium peroxide. Background Technology

[0002] With the rapid development of industrial production and the widespread use of daily necessities, new pollutants such as chlorophenols and endocrine disruptors continue to enter the aquatic environment. These new pollutants are persistent, bioaccumulative, and potentially toxic, posing a serious threat to ecosystem stability and human health, and have become a key and challenging issue in the field of water pollution control. Currently, methods for treating new pollutants in water include physical adsorption, chemical oxidation, and biodegradation. Among these, chemical oxidation has received widespread attention due to its high treatment efficiency and fast reaction speed, and research on water pollution control based on peroxides such as hydrogen peroxide and persulfate is currently a key focus and frontier in this field. However, water pollution control technologies based on peroxides such as hydrogen peroxide and persulfate still have many key limitations: on the one hand, the peroxides themselves have limited oxidation activity and require Fe2+ oxidation. 2+ Only external activation methods such as light and electricity can efficiently generate reactive oxygen species. However, these methods are not only energy-intensive and costly, but also have a narrow applicable pH range. Furthermore, the activation process is prone to producing byproducts such as iron sludge and high salt content. In addition, peroxides have problems such as low utilization rate and high residual risk, which can easily cause secondary pollution.

[0003] Calcium peroxide (CaO2), as a novel clean oxidant, has been widely studied in the field of water treatment in recent years as a slow-release agent for oxygen and hydrogen peroxide. It can directly oxidize and decompose organic pollutants by releasing hydrogen peroxide through its own redox reaction. However, powdered calcium peroxide has obvious limitations in practical applications: it is prone to agglomeration, resulting in poor powder flowability, limited effective specific surface area in actual reactions, reduced effective reactive sites, and low contact efficiency between pollutants and active sites, affecting degradation effects; at the same time, its low solubility and density (greater than water) make it prone to rapid sedimentation after entering water bodies, making it difficult to fully contact and react with organic pollutants.

[0004] In existing studies, the optimal experimental conditions for the degradation of 2,4-dichlorophenol (2,4-DCP) only resulted in 50% degradation in one day and complete degradation of the pollutant in five days. Furthermore, the high concentration of nano-calcium peroxide (10 g / L) used in these studies significantly increased the cost of the reagents, making it difficult to meet the requirements for large-scale application. In addition, high concentrations of nCaO2 tend to agglomerate in groundwater, reducing its dispersibility and mobility, which further reduces the actual degradation efficiency.

[0005] Another study disclosed a Fe(II) / PDA@nCP heterogeneous Fenton system composed of polydopamine (PDA)-coated nano-calcium peroxide (nCP) for degrading groundwater pollutants. Its working principle is as follows: the decomposition rate of nCP is regulated by the PDA shell, achieving controlled release of H2O2 and inhibiting a sudden increase in system pH. Simultaneously, the phenol-quinone conversion of catechol groups on the PDA surface promotes the Fe(II) / Fe(III) cycle, enhancing the continuous generation of hydroxyl radicals. This solves the problems of H2O2 transport risk in traditional Fenton systems and catalyst passivation caused by pH increases when using bare nCP. Ultimately, 96.8% nitrobenzene degradation is achieved within the pH range of 3.0–9.0. However, this system still has significant technical shortcomings. Its preparation requires two steps: nCP synthesis and PDA coating, which is complex, and dopamine increases the preparation cost. Reliance on exogenous Fe(II) catalysts easily leads to heavy metal residues and secondary pollution. The controlled release characteristics of PDA also sacrifice the initial reactivity of nCP. Furthermore, high concentrations of HCO3... - Humic acid can quench free radicals and compete for reaction sites, significantly reducing degradation efficiency and making it difficult to meet the demand for efficient removal of pollutants in complex water bodies. Summary of the Invention

[0006] In order to overcome at least one of the problems of the above-mentioned existing technologies, such as complex preparation process, high cost, reliance on external iron source leading to heavy metal residue, and poor anti-interference ability, the purpose of this invention is to provide a method for the degradation of water pollutants based on colloidal calcium peroxide. This method utilizes the good colloidal stability and slow release of active oxygen species of colloidal calcium peroxide, and binds to pollutants through the active sites of calcium ions on its surface, so as to achieve efficient removal of pollutants in complex water bodies.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a method for degrading water pollutants based on colloidal calcium peroxide, comprising the following steps: mixing colloidal calcium peroxide with water containing pollutants to form a mixed water body, and reacting to degrade the pollutants.

[0008] This invention utilizes the properties of colloidal calcium peroxide (CaO2), which can be uniformly dispersed in water, exhibits good colloidal stability, and slowly releases reactive oxygen species. This allows the colloidal CaO2 to bind to pollutants through the active sites of calcium ions on its surface, achieving the following effects: 1) Highly efficient oxidative degradation of pollutants is achieved through direct electron transfer from surface peroxide groups, with non-toxic and harmless reaction products; 2) The non-radical action is the dominant mechanism, avoiding the problem of free radicals being easily affected by environmental interference in traditional advanced oxidation processes. Furthermore, the method of this invention maintains a relatively stable pH in the system before and after degradation, avoiding impact on the aquatic ecological environment and reducing the cost and difficulty of water quality control in practical applications. It features convenient operation, strong applicability, low energy consumption, and high treatment efficiency. In addition, the degradation mechanism of colloidal calcium peroxide in this invention mainly relies on the self-oxidation of calcium peroxide, avoiding the introduction of heavy metal catalysts and the risk of secondary pollution in traditional advanced oxidation processes.

[0009] In some embodiments of the present invention, the colloidal calcium peroxide coordinates with the pollutant to form an intermediate complex.

[0010] The calcium ion active sites on the surface of colloidal calcium peroxide coordinate with electron-rich functional groups in pollutant molecules to form intermediate complexes, and the target pollutants are degraded through electron transfer mediated by these intermediate complexes.

[0011] In some embodiments of the present invention, the colloidal calcium peroxide is prepared by a method comprising the following steps: mixing a soluble calcium salt, an alkaline compound and water to obtain a calcium salt solution; adding an aqueous solution of hydrogen peroxide to the calcium salt solution and reacting to obtain the colloidal calcium peroxide.

[0012] This invention prepares colloidal CaO2 by optimizing liquid-phase synthesis process parameters. The stepwise addition sequence of "pre-alkalization of calcium salt solution followed by the addition of hydrogen peroxide" effectively inhibits excessively rapid crystal growth and aggregation compared to the traditional one-step mixing method. The entire process requires no organic coating layer, exogenous stabilizers, or exogenous catalysts; simply by optimizing reaction conditions, nano / submicron-sized colloidal CaO2 that is uniformly dispersed in water without significant aggregation or precipitation can be obtained. This simplifies the preparation process, reduces costs, and avoids the risk of secondary pollution from the introduction of organic matter or heavy metals.

[0013] In some embodiments of the present invention, the reaction temperature in the method for preparing colloidal calcium peroxide is 25℃±2℃.

[0014] The synthesis process was carried out at room temperature (25℃±2℃), which avoided high-temperature-induced grain coarsening.

[0015] In some embodiments of the present invention, the addition rate of the hydrogen peroxide aqueous solution is 1~3 mL / min; in some specific embodiments of the present invention, the addition rate of the hydrogen peroxide aqueous solution is 1.5~2.5 mL / min.

[0016] Adding hydrogen peroxide solution gradually at a slow rate can inhibit excessive crystal growth and aggregation, resulting in well-dispersed colloidal CaO2.

[0017] In some embodiments of the present invention, the molar ratio of the soluble calcium salt to the alkaline compound is 1:(1.5~3); in some specific embodiments of the present invention, the molar ratio of the soluble calcium salt to the alkaline compound is 1:(1.8~2.2).

[0018] By controlling the molar ratio of soluble calcium salt to alkaline compound, CaO2 precursor is generated under alkaline conditions and further reacts to form stable colloidal particles. A suitable calcium-alkali ratio helps to regulate the surface charge of particles and enhance colloidal stability.

[0019] In some embodiments of the present invention, the soluble calcium salt includes at least one of calcium chloride, calcium nitrate, or calcium chlorate; in some specific embodiments of the present invention, the soluble calcium salt is selected from calcium chloride.

[0020] In some embodiments of the present invention, the alkaline compound includes at least one of sodium hydroxide, potassium hydroxide, or ammonia water; in some specific embodiments of the present invention, the alkaline compound is selected from potassium hydroxide.

[0021] In some embodiments of the present invention, the concentration of the hydrogen peroxide aqueous solution is 1~5 mol / L; in some embodiments of the present invention, the concentration of the hydrogen peroxide aqueous solution is 2~4 mol / L.

[0022] In some embodiments of the present invention, the volume ratio of the calcium salt solution to the hydrogen peroxide aqueous solution is 1:(0.3~0.6); in some specific embodiments of the present invention, the volume ratio of the calcium salt solution to the hydrogen peroxide aqueous solution is 1:(0.4~0.5).

[0023] In some embodiments of the present invention, the average particle size of the colloidal calcium peroxide is 300-600 nm; in some specific embodiments of the present invention, the average particle size of the colloidal calcium peroxide is 400-500 nm.

[0024] The colloidal calcium peroxide prepared by this invention has significant advantages. Its extremely small particle size allows for uniform dispersion in water without significant aggregation or precipitation. It exhibits good stability in water, forming a nanocolloid solution with excellent colloidal stability, enabling it to continuously exert its degradation effect using its own active sites. Simultaneously, it can fully contact new pollutants in water, significantly improving reaction efficiency. Furthermore, colloidal CaO2 itself is environmentally friendly, the degradation process does not produce secondary pollution, and the post-reaction products have no adverse effects, perfectly aligning with the concept of green and environmentally friendly governance.

[0025] In some embodiments of the present invention, the concentration of the colloidal calcium dioxide in the mixed water is 0.03~1 mol / L; for example, it can be any value or a range between any two of 0.03 mol / L, 0.05 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L or 1 mol / L; in some specific embodiments of the present invention, the concentration of the colloidal calcium dioxide in the mixed water is 0.05~0.1 mol / L.

[0026] The colloidal calcium dioxide of the present invention can achieve good degradation effect with a low dosage, requires less reagent, and can balance degradation efficiency and cost.

[0027] In some embodiments of the present invention, the contaminants include phenolic contaminants, chlorinated contaminants, or combinations thereof.

[0028] In some embodiments of the present invention, the contaminant includes at least one of phenol, 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), nitrobenzene (NB), or bisphenol A (BPA).

[0029] The method of this invention can be widely applied to the removal of various recalcitrant water pollutants, especially to the effective removal of various chlorinated pollutants and phenolic pollutants that are difficult to degrade in groundwater treatment, and is highly practical.

[0030] In some embodiments of the present invention, the concentration of pollutants in the water body to be treated is 0.03~0.5 g / L; in some embodiments of the present invention, the concentration of pollutants in the water body to be treated is 0.05~0.2 g / L.

[0031] In some embodiments of the present invention, the pH of the water to be treated is 2 to 12; for example, it can be any value of 2, 3, 4, 6, 8, 10 or 12 or a range between any two; in some specific embodiments of the present invention, the pH of the water to be treated is 3 to 10.

[0032] The method of this invention maintains high degradation performance over a wide pH range, has good anti-interference ability, and can achieve high-efficiency degradation without frequent acid-base adjustment of the water body, which significantly improves its applicability and ease of operation in actual water treatment.

[0033] In some embodiments of the present invention, the water to be treated contains coexisting ions and natural organic matter (NOM); the coexisting ions include at least one of chloride ions, nitrate ions, carbonate ions, hydrogen phosphate ions, iron ions, zinc ions, or magnesium ions.

[0034] The method of this invention can maintain stable degradation efficiency even in the presence of multiple coexisting ions and natural organic matter, demonstrating good anti-interference ability. It is applicable to the treatment of various recalcitrant pollutants in complex aquatic environments, significantly reducing the application threshold for actual water pollution treatment and showing significant practical application prospects.

[0035] In some embodiments of the present invention, the concentration of coexisting ions in the water to be treated is 1~10 mmol / L; in some specific embodiments of the present invention, the concentration of coexisting ions in the water to be treated is 3~7 mmol / L.

[0036] In some embodiments of the present invention, the concentration of natural organic matter in the water body to be treated is 1~10 mg / L; in some specific embodiments of the present invention, the concentration of natural organic matter in the water body to be treated is 3~7 mg / L.

[0037] The beneficial effects of this invention are: This invention utilizes colloidal calcium peroxide to bind to pollutants in water through the active sites of calcium ions on its surface, and leverages the direct electron transfer of its surface peroxide groups to achieve highly efficient oxidative degradation of various recalcitrant pollutants. Furthermore, the mechanism by which colloidal calcium peroxide degrades pollutants is primarily based on non-radical action, avoiding the problem of traditional free radical oxidation pathways being easily interfered with by the water matrix. It also maintains highly efficient degradation performance over a wide pH range and exhibits excellent anti-interference capabilities. Attached Figure Description

[0038] Figure 1 The image shows the XRD pattern of the colloidal CaO2 material prepared in Example 1 of this invention.

[0039] Figure 2 The graph shows the removal efficiency of colloidal CaO2 prepared in Examples 1-2 of this invention for various pollutants.

[0040] Figure 3 The graphs show the removal efficiency of 2,4-DCP by different materials in Comparative Examples 1-5 of this invention.

[0041] Figure 4The diagram shows the pH changes before and after the removal of 2,4-DCP by different materials in Example 1 and Comparative Examples 1-5 of this invention.

[0042] Figure 5 The graph shows the removal efficiency of 2,4,6-TCP by colloidal CaO2 of different concentrations prepared in Examples 1-2 of this invention.

[0043] Figure 6 The graph shows the removal efficiency of colloidal CaO2 prepared in Examples 1 and 3 of this invention for BPA under different initial pH conditions.

[0044] Figure 7 The figure shows the experimental results of reactive oxygen species quenching in the degradation of BPA by colloidal CaO2 prepared in Example 1 of this invention.

[0045] Figure 8 The graph shows the removal efficiency of colloidal CaO2 prepared in Example 1 of this invention for BPA under different conditions of coexisting ions and natural organic matter in water.

[0046] Figure 9 This is a graph showing the change in sedimentation effect of colloidal CaO2 prepared in Example 1 of the present invention over time.

[0047] Figure 10 This is a Tyndall effect diagram of the colloidal CaO2 prepared in Example 1 of the present invention. Detailed Implementation

[0048] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0049] The reagents and instruments used in the embodiments and comparative examples of this invention are described below: Experimental reagents and instruments: target pollutants (phenol, 4-CP, 2,4-DCP, 2,4,6-TCP, NB, BPA, purity ≥98%); colloidal CaO2 (self-made); calcium chloride (CaCl2), hydrogen peroxide (H2O2), calcium hydroxide (Ca(OH)2), commercial calcium peroxide (CaO2) (analytical grade, micron level); high performance liquid chromatograph (HPLC); electronic balance; thermostatic magnetic stirrer; pH meter.

[0050] Preparation of simulated polluted water bodies: simulated water bodies containing phenol, 4-CP, 2,4-DCP, 2,4,6-TCP, BPA, and NB pollutants at concentrations of 0.1 g / L were prepared respectively.

[0051] Example 1 A method for degrading water pollutants based on colloidal calcium peroxide, comprising the following specific steps: S1. Preparation of colloidal calcium peroxide (CaO2): This was achieved using a liquid-phase synthesis method, with the specific steps as follows: At a temperature of 25℃±2℃, 11.1g of soluble calcium chloride solid was weighed and dissolved in 50mL of high-purity water to obtain a calcium salt solution, which was then poured into a 100mL beaker. Simultaneously, 11.2g of potassium hydroxide was weighed and dissolved in 20mL of high-purity water to obtain an alkaline solution. The alkaline solution was added dropwise to the calcium salt solution at a rate of 2mL / min, and the reaction was stirred under magnetic stirring. After the addition was complete, the reaction was allowed to proceed for 10min to ensure complete reaction. Then, a 3.33M hydrogen peroxide aqueous solution (diluted from 30% hydrogen peroxide aqueous solution) was added dropwise to the system at the same dropping rate. After the addition was complete, a colloidal CaO2 dispersion was obtained.

[0052] S2. Degradation Experiment Procedure: (1) Prepare simulated water bodies containing phenol, 4-CP, 2,4-DCP, 2,4,6-TCP, NB, and BPA at a concentration of 0.1 g / L. Take 2 mL of the simulated polluted water body and place it in a 50 mL beaker. Place the beaker in a thermostatic magnetic stirrer and control the temperature at 25 °C and the stirring speed at 500 r / min.

[0053] (2) Add colloidal CaO2 dispersion to a beaker to make the concentration of colloidal CaO2 in water 0.05M, start timing, and use it as the experimental group.

[0054] (3) Samples were taken at 0 min, 20 min, 40 min and 60 min of reaction, filtered through a 0.22 μm filter membrane, and the residual concentration of the target pollutant in the water sample was detected by HPLC.

[0055] Example 2 A method for degrading pollutants in water, which differs from Example 1 in that the concentration of colloidal CaO2 in the water is adjusted to 0.5M, 0.1M, and 0.005M, respectively, while all other conditions are the same as in Example 1.

[0056] Example 3 A method for degrading water pollutants, which differs from Example 1 in that the initial pH is adjusted to 3, 6, 8, and 10, while other conditions are the same as in Example 1.

[0057] Comparative Example 1 A method for degrading water pollutants, which differs from Example 1 in that colloidal calcium peroxide is replaced with CaCl2 of equal concentration, while all other conditions are the same as in Example 1.

[0058] Comparative Example 2 A method for degrading water pollutants, which differs from Example 1 in that colloidal calcium peroxide is replaced with H2O2 of equal concentration, while all other conditions are the same as in Example 1.

[0059] Comparative Example 3 A method for degrading water pollutants, which differs from Example 1 in that colloidal calcium peroxide is replaced with Ca(OH)2 of equal concentration, while all other conditions are the same as in Example 1.

[0060] Comparative Example 4 A method for degrading water pollutants, which differs from Example 1 in that colloidal calcium peroxide is replaced with solid CaO2 (commercially available) of equal concentration, while all other conditions are the same as in Example 1.

[0061] Comparative Example 5 A method for degrading water pollutants, which differs from Example 1 in that colloidal calcium peroxide is replaced with an equal concentration of CaCl2:H2O2 = 1:1 system (calcium chloride to hydrogen peroxide molar ratio is 1:1), while all other conditions are the same as in Example 1.

[0062] Performance testing (1) The particle size of the colloidal CaO2 dispersion prepared in the example was analyzed using a multi-angle particle size analyzer and a high-sensitivity Zeta potential analyzer.

[0063] The results showed that the average particle size of colloidal CaO2 at a concentration of 0.05 M was 438.84 nm, confirming that the obtained material reached the nano / submicron scale and had good dispersibility in water.

[0064] (2) After solid-liquid separation and drying of the colloidal CaO2 dispersion prepared in the example, the resulting solid was analyzed by X-ray diffraction (XRD).

[0065] Figure 1 This is the XRD pattern of the colloidal CaO2 material prepared in Example 1 of the present invention. Figure 1 As shown, the XRD test results of the obtained material are different from those of the calcium carbonate and calcium hydroxide composite materials. The diffraction peak of this material at 2θ=35.6° corresponds to the characteristic crystal plane of CaO2 in the standard spectrum, confirming the successful synthesis of CaO2 material.

[0066] (3) In order to investigate the degradation effect of the materials in the embodiments on pollutants, experimental studies were conducted on various chlorinated pollutants and phenolic pollutants that are difficult to degrade in groundwater treatment.

[0067] Figure 2 The diagrams show the removal efficiency of colloidal CaO2 prepared in Examples 1-2 of this invention for various pollutants; wherein, (A) is the removal efficiency of 0.05M colloidal CaO2 from Example 1 for phenol, 4-CP, 2,4-DCP, 2,4,6-TCP, and BPA at an initial pH of 10.5; (B) is the removal efficiency of 0.1M colloidal CaO2 from Example 2 for phenol, 4-CP, 2,4-DCP, 2,4,6-TCP, and BPA at an initial pH of 10.5; and (C) is the removal efficiency of 0.05M colloidal CaO2 from Example 1 for NB at an initial pH of 10.5. Figure 2 As can be seen, the colloidal CaO2 prepared in Examples 1-2 of this invention has a high removal rate for a variety of pollutants, which proves that the colloidal CaO2 has a good pollutant degradation effect and can be widely used for the removal of water pollutants. In particular, it can effectively remove a variety of chlorinated pollutants and phenolic pollutants that are difficult to degrade in groundwater treatment, and has strong practicality.

[0068] Figure 3 The graphs show the removal efficiency of 2,4-DCP by different materials in Comparative Examples 1-5 of this invention. Figure 4 This is a graph showing the pH changes before and after the removal of 2,4-DCP by different materials in Example 1 and Comparative Examples 1-5 of this invention. From... Figures 3-4 As can be seen, the pH of the materials in Comparative Examples 1-5 fluctuated significantly before and after the degradation reaction. This increases the cost and difficulty of water quality control in practical applications and affects the aquatic ecological environment. The experimental results directly confirm the limitations of traditional materials in the degradation of new pollutants in water bodies, and also highlight the advantages of the colloidal CaO2 of this invention in pollutant degradation, providing direct experimental evidence for its subsequent application in the treatment of new pollutants in water bodies. Furthermore, the colloidal CaO2 prepared in the embodiments of this invention can effectively degrade pollutant 2,4-DCP in the reaction system, and the pH of the system remains relatively stable after the reaction, further demonstrating that this colloidal CaO2 has the characteristics of convenient operation and strong applicability in the actual degradation of new pollutants in water bodies.

[0069] Figure 5This is a graph showing the removal efficiency of 2,4,6-TCP by colloidal CaO2 of different concentrations prepared in Examples 1-2 of this invention; wherein the initial pH of 2,4,6-TCP is 10.5. From... Figure 5 It is evident that using colloidal CaO2 of different concentrations to degrade 2,4,6-TCP, a typical recalcitrant chlorophenol pollutant, can achieve good degradation results at a concentration of 0.05M, requiring a small amount of reagent and balancing degradation efficiency and cost. This provides precise experimental data support for selecting the optimal dosage of colloidal CaO2 for the degradation of new pollutants in water bodies.

[0070] Figure 6 This is a graph showing the BPA removal efficiency of colloidal CaO2 prepared in Examples 1 and 3 of this invention under different initial pH conditions. Figure 6 It is evident that colloidal CaO2 maintains a high pollutant removal rate within an initial pH range of 3, 6, 8, and 10, indicating that the material has wide pH adaptability and can achieve efficient degradation without frequent acid-base adjustments to the water body, significantly improving its applicability and ease of operation in actual water treatment.

[0071] Figure 7 This image shows the experimental results of reactive oxygen species quenching in the degradation of BPA by colloidal CaO2 prepared in Example 1 of this invention. Under the condition of an initial pH of 10.5, quenchers such as 10 mM methanol (MeOH), furfuryl alcohol (FFA), and p-benzoquinone (PBQ) were added respectively, and a control group (without quenchers) was set up to investigate the contribution of different reactive oxygen species to the degradation process. Figure 7 It can be seen that, due to the dissociation of CaO2 in the system, Ca... 2+ It can coordinate with p-benzoquinone, competitively capturing electrons / active intermediates in the system and interfering with... 1 The formation process of O2 is significantly inhibited, and furfuryl alcohol (a quencher of singlet oxygen) also shows a significant inhibitory effect on the degradation reaction, indicating that the main reactive oxygen species in the degradation of new pollutants by colloidal CaO2 is singlet oxygen. 1 O2), rather than hydroxyl radicals or superoxide anion radicals, reveals its non-radical-dominated oxidation mechanism.

[0072] Figure 8This diagram shows the removal efficiency of colloidal CaO2 prepared in Example 1 of this invention for BPA under different conditions of coexisting ions and natural organic matter (NOM) in water. The coexisting ions included chloride, nitrate, carbonate, hydrogen phosphate, iron, zinc, and magnesium ions, with a concentration of 5 mM; the concentration of natural organic matter was 5 mg / L; and the initial pH of the water was 10.5. The results show that, under the conditions of the above-mentioned ion coexistence and natural organic matter (NOM), colloidal CaO2 can still maintain highly efficient and stable degradation performance, indicating that this material has good anti-interference ability, is suitable for complex aquatic environments, and has strong practical application potential.

[0073] Figure 9 This is a graph showing the sedimentation effect of colloidal CaO2 prepared in Example 1 of the present invention over time; where (A) is the initial state; (B) is after 3 hours; (C) is after 16 hours; and (D) is after 21 hours. Figure 9 As can be seen, the colloidal CaO2 dispersion remained uniform and stable at different time points, indicating that the material has good colloidal stability, which is beneficial for maintaining long-term degradation effect in actual water treatment.

[0074] Figure 10 This image shows the Tyndall effect of the colloidal CaO2 prepared in Example 1 of this invention; where (A) is the initial state; and (B) is after 24 hours. The sample was illuminated from the right side using a laser pointer. Figure 10 As can be seen, the colloidal CaO2 dispersion exhibits a light beam path, confirming that the prepared sample possesses typical colloidal optical properties. CaO2 is uniformly dispersed in the aqueous phase at the nanoscale, forming a stable colloidal system, and it can still maintain colloidal optical properties after 24 hours, indicating that the colloidal system has good stability.

[0075] In summary, this invention utilizes a homogeneous nucleation method to prepare colloidal calcium peroxide. This colloidal calcium peroxide then binds to pollutants in water through the active sites of calcium ions on its surface, and achieves efficient oxidative degradation of various recalcitrant pollutants through direct electron transfer from its surface peroxide groups. Furthermore, the pollutant degradation mechanism of this invention's colloidal calcium peroxide is primarily based on non-radical action, avoiding the problem of interference from the water matrix in traditional free radical oxidation pathways. It also maintains high degradation efficiency over a wide pH range and exhibits good anti-interference capabilities.

Claims

1. A method for degrading water pollutants based on colloidal calcium peroxide, characterized in that, Includes the following steps: Colloidal calcium peroxide is mixed with water containing pollutants to form a mixed water body, which then reacts to degrade the pollutants.

2. The method for degrading water pollutants according to claim 1, characterized in that, The colloidal calcium peroxide is prepared by a method comprising the following steps: mixing a soluble calcium salt, an alkaline compound and water to obtain a calcium salt solution; adding an aqueous solution of hydrogen peroxide to the calcium salt solution and reacting to obtain the colloidal calcium peroxide.

3. The method for degrading water pollutants according to claim 2, characterized in that, The hydrogen peroxide aqueous solution was added at a rate of 1-3 mL / min; And / or, the molar ratio of the soluble calcium salt to the basic compound is 1:(1.5~3). And / or, the concentration of the hydrogen peroxide aqueous solution is 1~5 mol / L; And / or, the volume ratio of the calcium salt solution to the hydrogen peroxide aqueous solution is 1:(0.3~0.6).

4. The method for degrading water pollutants according to claim 2, characterized in that, The soluble calcium salt includes at least one of calcium chloride, calcium nitrate, or calcium chlorate; And / or, the alkaline compound includes at least one of sodium hydroxide, potassium hydroxide, or ammonia water.

5. The method for degrading water pollutants according to claim 1, characterized in that, The average particle size of the colloidal calcium peroxide is 300~600 nm; And / or, the concentration of the colloidal calcium dioxide in the mixed water is 0.03~1 mol / L.

6. The method for degrading water pollutants according to claim 1, characterized in that, The pollutants include phenolic pollutants, chlorinated pollutants, or combinations thereof.

7. The method for degrading water pollutants according to claim 6, characterized in that, The contaminants include at least one of phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, nitrobenzene, or bisphenol A.

8. The method for degrading water pollutants according to claim 1, characterized in that, The concentration of pollutants in the water to be treated is 0.03~0.5g / L.

9. The method for degrading water pollutants according to claim 1, characterized in that, The pH of the water to be treated is 2-12.

10. The method for degrading water pollutants according to claim 1, characterized in that, The water to be treated contains coexisting ions and natural organic matter; the coexisting ions include at least one of chloride ions, nitrate ions, carbonate ions, hydrogen phosphate ions, iron ions, zinc ions, or magnesium ions.

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