A method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation

Abstract

The present application relates to a kind of method based on interface microenvironment regulation and control of heavy metal in-situ activation and organic pollutant synergic treatment, comprising the following steps: adding alkaline nanomaterial to wastewater containing heavy metal ions and organic pollutants, and inducing heavy metal ions in wastewater to form active species precursor in-situ;Oxidizing agent is added to wastewater, and under the action of oxidizing agent, active species precursor generates high-valence metal active species;Under the action of high-valence metal active species, organic pollutants occur polymerization reaction, and finally form stable inorganic-organic composite product with heavy metal species;The recovery of inorganic-organic composite product in wastewater is realized by solid-liquid separation.Compared with prior art, the present application avoids secondary pollution by using nanometer alkaline material instead of traditional pH regulator, and deeply couples the alkali precipitation process of heavy metal with the oxidation polymerization process of organic pollutants, to realize the synergic removal of two types of pollutants in the same system.

Description

Technical Field

[0001] This invention relates to the field of wastewater pollutant technology, and in particular to a method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation. Background Technology

[0002] With the acceleration of industrialization, the global water crisis is further exacerbated by the combined pollution of various pollutants in industrial and urban wastewater. Among these, wastewater containing heavy metals generated by industries such as metallurgy, electroplating, chemicals, and machinery manufacturing exhibits typical toxicity and recalcitrant degradation. Particularly in the flotation and mineral processing of the metallurgical industry, large quantities of flotation reagents are often used, and their degradation or transformation products readily generate various organic compounds. This results in the simultaneous enrichment of high or low concentrations of heavy metal ions and organic pollutants in metal ore beneficiation wastewater. The toxicity of such combined pollution systems is significantly enhanced, and even at low concentrations, they can cause serious and irreversible damage to ecosystems and human health. Therefore, how to efficiently remove heavy metals and organic pollutants from wastewater is a pressing issue that the water treatment industry needs to address.

[0003] Currently, the industry generally adopts a "step-by-step decoupling" strategy to solve the aforementioned complex pollution problems. This approach is not only complex but also suffers from high reagent consumption, high treatment costs, and low resource utilization. In recent years, advanced oxidation technologies have been widely used for the removal of organic pollutants due to their advantages such as fast reaction speed and high treatment efficiency. However, their ability to synergistically remove heavy metal pollutants is limited, and they also suffer from problems such as high catalyst preparation costs and poor system applicability.

[0004] In practical applications, to promote the precipitation and removal of heavy metal ions, it is usually necessary to adjust the overall pH of the system to alkaline conditions by adding strong alkalis such as NaOH. However, the addition of large amounts of alkaline solution not only increases operating costs but also easily causes secondary pollution, and ignores the potential for resource utilization of heavy metals in wastewater. In addition, in advanced oxidation processes, organic pollutants often produce intermediate byproducts due to incomplete mineralization, causing secondary pollution and failing to achieve synergistic transformation between pollutants and resource recovery.

[0005] Patent CN107324587A discloses a method for simultaneously removing heavy metals and organic matter from wastewater, comprising four steps: anoxic reaction, incubation reaction, aerobic reaction, and precipitation reaction. This method addresses the difficulties and shortcomings of existing industrial wastewater treatment technologies that address the coexistence of heavy metals and organic matter. The invention, through the regulation of heavy metal ions in wastewater, generates a catalyst in situ with the function of activating molecular oxygen. This catalyst catalyzes the production of strong oxidizing species from molecular oxygen, achieving the removal of heavy metals through crystallization and precipitation while simultaneously catalytically oxidizing and degrading organic pollutants. This innovative approach utilizes waste to treat waste, achieving green oxidation, shortening treatment processes, improving treatment efficiency, reducing economic costs, and promoting the industrial application of the technology. However, this method requires the additional addition of ferrous species to the wastewater for catalyst synthesis, and the treatment process involves multiple pH adjustments, which can easily cause secondary pollution. Summary of the Invention

[0006] The purpose of this invention is to provide a method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation. By constructing a local alkaline microenvironment to replace the traditional overall pH regulation strategy, the in-situ activation of heavy metal ions and treatment of organic pollutants can be achieved.

[0007] The objective of this invention can be achieved through the following technical solution: a method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation, comprising the following steps: S1: Add alkaline nanomaterials to wastewater containing heavy metal ions and organic pollutants to induce the heavy metal ions in the wastewater to form active species precursors in situ. S2: Adding an oxidant to the wastewater causes the precursors of active species to undergo directional evolution under the action of the oxidant, generating high-valence metal active species; S3: Under the influence of high-valence metal active species, organic pollutants undergo selective oxidative polymerization or coupling polymerization reactions, and eventually form stable inorganic-organic complex products with heavy metal species. S4: Recover inorganic-organic composite products from wastewater through solid-liquid separation.

[0008] Preferably, in step S1, alkaline nanomaterials are added to wastewater containing heavy metal ions and organic pollutants to induce the heavy metal ions in the wastewater to form active species precursors in situ at the interface region. In step S2, an oxidant is added to the wastewater. Under the action of the oxidant, the active species precursors formed at the interface region undergo directional evolution to generate high-valence metal active species.

[0009] Preferably, the alkaline nanomaterial is a functional material with the ability to release alkali slowly.

[0010] More preferably, the functional material includes one or more of nano-magnesium oxide, magnesium hydroxide, calcium oxide, bimetallic layered hydroxide, and other alkaline mineral materials.

[0011] More preferably, the functional material includes nano-magnesium oxide.

[0012] Preferably, the alkaline nanomaterial has a 2-10 nm mesoporous structure and a specific surface area of ​​5-20 m². 2 / g.

[0013] Preferably, the heavy metal ions are transition metal ions that can precipitate in situ to generate precursors of active species in the interfacial microenvironment constructed by alkaline nanomaterials.

[0014] In this invention, high-valence metal active species are formed by in-situ conversion of heavy metal ions in wastewater, without the need for additional metal catalysts.

[0015] More preferably, the transition metal ion includes one or more of cobalt ions, nickel ions, and copper ions.

[0016] Preferably, the active species precursor includes one or more of metal hydroxides, metal oxides, bimetallic hydroxides, and amorphous hydrated oxides.

[0017] Preferably, the high-valence metal active species includes hydroxyl metal oxides.

[0018] More preferably, the high-valence metal active species includes one or more of cobalt hydroxyoxide, nickel hydroxyoxide, and copper hydroxyoxide. Preferably, the organic pollutant is an organic pollutant with an aromatic structure.

[0019] More preferably, the organic pollutants include one or more of phenolic compounds, bisphenolic compounds, aromatic amine pollutants, dye pollutants, and antibiotics.

[0020] More preferably, the organic pollutant includes phenolic compounds.

[0021] More preferably, the organic pollutant includes phenol.

[0022] Preferably, the oxidant in step S2 is a persulfate oxidant.

[0023] More preferably, the persulfate oxidant includes one or both of permonosulfate and perdisulfate.

[0024] More preferably, the persulfate includes potassium permonosulfate, and the perdisulfate includes potassium perdisulfate.

[0025] Preferably, the oxidant in step S2 is potassium peroxymonosulfate.

[0026] Preferably, the molar ratio of the oxidant to the organic pollutant in step S2 is not less than 1.72:1.

[0027] Preferably, the concentration of heavy metals in the wastewater in step S1 is in the range of 0.1 ~ 8000 mg / L.

[0028] Preferably, the total organic carbon content of the wastewater in step S1 ranges from 1 to 4500 mg / L, and the chemical oxygen demand ranges from 1 to 22000 mg / L.

[0029] Preferably, the molar ratio of the alkaline nanomaterial to the total organic matter in step S1 is not less than 25:1.

[0030] Preferably, the wastewater in step S1 includes electroplating wastewater, metallurgical wastewater, mining wastewater, chemical wastewater, pharmaceutical wastewater, printing and dyeing wastewater, and landfill leachate.

[0031] Preferably, the inorganic-organic composite product recovered in step S4 is used as a precursor for catalytic materials, adsorbent materials, electrode materials or other functional composite materials for resource utilization.

[0032] More preferably, the inorganic-organic composite product includes heavy metals and organic polymers coated on the surface of the heavy metals.

[0033] To address the limitations of traditional stepwise removal methods, as well as the constraints on heavy metal ion removal efficiency due to heavy metal dissolution equilibrium, poor selectivity in the mineralization of organic pollutants, and high oxidant requirements, this invention differs from traditional approaches that rely on developing novel functional materials, increasing oxidant dosage, or introducing strong alkalis to adjust pH. It leverages the inherent heavy metals in wastewater as an advantage, constructing an interfacial microenvironment to transform them into active species in situ as a chemical resource. This couples the precipitation of heavy metal ions in the interfacial microenvironment with the polymerization and removal of organic pollutants, achieving a synergistic resource-based transformation of pollutants.

[0034] This invention utilizes native heavy metal resources in wastewater as a premise, and achieves synergistic removal and resource utilization of heavy metal ions and organic pollutants by constructing an interfacial microenvironment that evolves into active species in situ. The method induces structural and oxidation state transformations of heavy metal alkaline precipitation products via persulfate, coupling the removal pathways of heavy metal hydroxides and organic pollutants, thereby generating a synergistic removal effect.

[0035] The key features of this invention are: (1) Alkaline nanomaterials construct a local alkaline microenvironment at the liquid-solid interface, which can induce the in-situ generation of active precursors of heavy metal ions in wastewater without adjusting the overall pH conditions of the system, and without the need to add an external catalyst; (2) Under the action of persulfate, the precursors can be oxidized in-situ into high-valence active species with high oxidizing power, so that the system can obtain continuous and strong oxidizing activity; (3) High-valence active species can selectively oxidize organic pollutants into phenoxy radicals, thereby undergoing polymerization reaction, and finally generating highly hydrophobic polyphenylene ether polymers, which are separated from the solution by precipitation in a solid phase manner to achieve efficient removal; (4) The oxidizing power of high-valence active species can attack the organic ligands that complex heavy metals, causing the complex structure to break, and the released metal ions are further precipitated, thereby achieving deep removal of complex heavy metals.

[0036] This invention primarily targets complex wastewater containing heavy metal ions and organic pollutants, achieving enhanced in-situ synergistic remediation. Its core mechanism lies in utilizing a locally alkaline microenvironment at the liquid-solid interface constructed with alkaline nanomaterials. This microenvironment induces interfacial alkaline precipitation of heavy metals in the wastewater, acting as a precursor. Persulfate and organic pollutants can then undergo highly selective oxidation reactions at these active sites, driving an inorganic-organic co-precipitation process. In the system constructed in this invention, organic pollutants are oxidized to generate phenoxy radicals, which further polymerize into hydrophobic polymers, resulting in solid-phase sedimentation removal. Conversely, the organic polymers coat the surface of the heavy metal precipitates, further altering the chemical equilibrium of the alkaline precipitation and promoting deeper destabilization and sedimentation of the heavy metals. This achieves an enhanced removal effect through "mutually driven and synergistic transformation of the two types of pollutants." This invention constructs a novel wastewater treatment method suitable for the simultaneous enhanced removal of heavy metals and organic pollutants, fully embodying the concept of "treating waste with waste and turning waste into treasure." It not only possesses significant reaction efficiency and environmental friendliness but also demonstrates excellent engineering scale-up potential.

[0037] Compared with the prior art, the present invention has the following technical advantages: 1) This invention uses heavy metal ions naturally present in wastewater to form active species precursors, which are then precipitated in an alkaline environment and further converted in situ into high-valence active species. This achieves the construction of catalytic activity throughout the entire process, without the need to add external catalysts, significantly reducing material costs and avoiding the problems of catalyst separation and recovery.

[0038] 2) To achieve an alkaline environment in the system, a method of using interfacial microenvironment regulation strategy to replace the overall pH regulation of the system was proposed for the first time. This method can induce in-situ activation of heavy metal ions without large-scale addition of alkaline solution, thus improving the greenness and economy of the technology.

[0039] 3) Under the combined action of the interfacial microenvironment and persulfate, the precipitation of heavy metal alkaline substances and the polymerization of organic matter can occur synergistically in the same system. The oxidizing properties of high-valence active species of metals not only promote the polymerization and precipitation of organic pollutants, but also destroy the organic complex structure of heavy metals, causing heavy metal ions to precipitate further, effectively improving the deep removal efficiency of heavy metals, and realizing the efficient synchronous liquid-solid phase transfer removal of the two types of pollutants.

[0040] 4) The reaction conditions of this invention are mild, the reagent requirements are low, it is green and environmentally friendly, and it treats waste with waste. It is suitable for the efficient treatment of industrial wastewater containing heavy metals and organic pollutants.

[0041] 5) This invention avoids secondary pollution by using nano-alkaline materials to replace traditional pH adjusters, and deeply couples the alkaline precipitation process of heavy metals with the oxidative polymerization process of phenolic pollutants to achieve synergistic removal of the two types of pollutants in the same system. The reaction conditions are mild, the reagent requirements are low, it is green and environmentally friendly, and it treats waste with waste. It is suitable for the efficient treatment of industrial wastewater containing heavy metals and phenolic organic pollutants.

[0042] 6) This invention develops a new technology that can achieve in-situ activation of heavy metals and further realize the synergistic resource transformation of heavy metals and organic pollutants without adjusting the overall pH of the system, simply by constructing a local interface microenvironment. This technology is of great significance for improving the treatment efficiency and resource utilization value of complex wastewater. Attached Figure Description

[0043] Figure 1 The graphs show the phenol removal effects of the system of the present invention and the Fenton system described in Example 1 and Comparative Example 1. Figure 2 The graphs show the effects of the present invention system and the Fenton system described in Example 1 and Comparative Example 1 on the removal of total organic carbon content; Figure 3 The graphs show the effect of the pH adjustment system of the present invention in Example 2 and Comparative Example 2 on the removal of phenol compared to the direct pH adjustment system. Figure 4 The graph shows the effect of the pH adjustment system of the present invention in Example 2 and Comparative Example 2 on the removal of total organic carbon content compared with the system of direct pH adjustment. Figure 5 The graphs show the effects of alkaline precipitation on the removal of nickel ions in the systems of the present invention described in Example 3 and Comparative Example 3. Figure 6 The graph shows the effect of the pH adjustment system of the present invention in Example 4 and Comparative Example 4 on the removal of nickel ions; Figure 7 The graph shows the effect of the system of the present invention described in Example 5 on the removal of phenol under different heavy metal conditions; Figure 8The graph shows the effect of the system of the present invention described in Example 6 on the removal of phenol under different persulfate application conditions; Figure 9 The molecular weight distribution diagram of the phenol polymerization product in the system of the present invention described in Example 7 is shown. Figure 10 This is a comparison graph showing the Zeta potential of the product of the system described in Example 7 of the present invention with that of commercially available magnesium oxide. Figure 11 These are scanning electron microscope images of different reaction mechanisms in the system of the present invention described in Example 8; Figure 12 X-ray diffraction patterns of different reaction mechanisms in the system of the present invention described in Example 8; Figure 13 Raman spectra of different reaction mechanisms in the system of the present invention described in Example 8; Figure 14 The diagram shows the effect of the system of the present invention described in Example 9 in removing various organic pollutants; Figure 15 The graph shows the phenol removal effect of the system of the present invention described in Example 10 under different magnesium oxide dosages. Figure 16 The graph shows the COD content of different batches of actual wastewater treated by the system of the present invention described in Example 11. Figure 17 The graph shows the TOC content of different batches of actual wastewater treated by the system of the present invention described in Example 11. Figure 18 The system of the present invention described in Example 11 was used to treat Ni in the same batch of actual wastewater. 2+ Removal rate graph. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] A method for in-situ activation of heavy metals and synergistic resource-based transformation of organic pollutants based on interface microenvironment regulation includes the following steps: S1: Add alkaline nanomaterials to wastewater containing heavy metals and organic pollutants to induce heavy metal ions in the wastewater to form active species precursors in situ in local areas; S2: Adding an oxidant to the wastewater causes the active precursors formed at the interface to evolve in a directed manner under the action of the oxidant, generating high-valence metal active species with high catalytic activity. S3: Under the influence of highly active species, organic pollutants undergo selective oxidative polymerization or coupling polymerization reactions, and eventually form stable inorganic-organic complex products with heavy metal species. S4: Achieve the recovery of inorganic-organic composite products through simple solid-liquid separation, and further utilize them as precursors for catalytic materials, adsorption materials, electrode materials or other functional composite materials for resource utilization, thereby realizing the synergistic unity of pollutant treatment and resource recovery.

[0046] As a preferred technical solution, the alkaline nanomaterial is nano-magnesium oxide, but it can also be further extended to magnesium hydroxide, calcium oxide, bimetallic layered hydroxide, alkaline mineral materials or other functional materials with slow-release alkali capabilities.

[0047] As a preferred technical solution, the heavy metal ions are transition metal ions that can be precipitated in situ in an interfacial microenvironment constructed from alkaline nanomaterials to generate precursors of active species.

[0048] As a preferred technical solution, the heavy metal ions include one or more of cobalt ions, nickel ions, and copper ions.

[0049] As a preferred technical solution, the active species precursor includes, but is not limited to, metal hydroxides, metal oxides, bimetallic hydroxides, and amorphous hydrated oxides.

[0050] As a preferred technical solution, the high-valence metal active species include one or more of cobalt hydroxyoxide, nickel hydroxyoxide, and copper hydroxyoxide.

[0051] As a preferred technical solution, the organic pollutants include phenolic compounds, bisphenolic compounds, aromatic amine pollutants, dye pollutants, antibiotics, and other organic pollutants with aromatic structures.

[0052] As a preferred technical solution, the oxidant in step S2 is a persulfate oxidant.

[0053] As a preferred technical solution, the persulfate oxidant includes permonosulfate, perdisulfate, and combinations thereof.

[0054] As a preferred technical solution, the molar ratio of the oxidant to the phenolic pollutant in step S2 is not less than 1.72:1.

[0055] As a preferred technical solution, the concentration of heavy metals in the wastewater in step S1 ranges from 0.1 to 8000 mg / L.

[0056] As a preferred technical solution, the wastewater in step S1 includes electroplating wastewater, metallurgical wastewater, mining wastewater, chemical wastewater, pharmaceutical wastewater, printing and dyeing wastewater, landfill leachate, and other wastewater containing heavy metals and organic pollutants.

[0057] The following detailed description is based on specific embodiments.

[0058] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0059] Table 1. Main testing instruments and equipment High performance liquid chromatography test conditions: At predetermined time intervals, 500 μL of sample was dispensed via syringe, filtered through a 0.22 μm membrane, and immediately mixed with methanol at a 1:1 volume ratio. The phenol concentration was then determined by high-performance liquid chromatography (HPLC, Shimadzu LC20A) at 270 nm. The HPLC procedure for organic pollutant detection was set as follows: C18 column (4.6 × 250 mm); injection volume 10 μL; flow rate 1 mL / min; column temperature 40°C; UV-Vis detector. Degradation experiments were performed in triplicate to ensure reproducibility, and the mean with standard deviation was reported. HPLC procedures for other pollutants are shown in Table 2.

[0060] Table 2. High-performance liquid chromatography (HPLC) analysis conditions for different pollutants Example 1 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol to potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added. Take samples at different time points (1, 3, 5, 7, and 10 minutes), and then use a high-performance liquid chromatograph to detect the phenol concentration and a total organic carbon analyzer to detect the total organic carbon content.

[0061] Comparative Example 1 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L ferrous sulfate monohydrate, and a 1 mol / L dilute sulfuric acid reaction solution; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: After adjusting the pH of the reaction solution in Step 2 to 3 by adding dilute sulfuric acid, add hydrogen peroxide with a molar ratio of phenol:hydrogen peroxide of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) and keep it stirred throughout the reaction. Start timing the reaction time from the addition of hydrogen peroxide. Take samples at different time points (1, 3, 5, 7, and 10 minutes), and then use a high performance liquid chromatograph to detect the phenol concentration and a total organic carbon analyzer to detect the total organic carbon content.

[0062] See Figure 1 The figure shows the effect of the present invention system and the Fenton system in Example 1 and Comparative Example 1 on the removal of phenol. It can be seen from the figure that under the same and lower oxidant dosage, the phenol removal rate of the present invention system can be close to 100% after 10 minutes; while the phenol removal rate of the Fenton system only reaches 56%.

[0063] See Figure 2 The figure shows the effect of the system of the present invention and the Fenton system in Example 1 and Comparative Example 1 on the removal of total organic carbon content. It can be seen from the figure that under the same and lower oxidant dosage, the removal rate of total organic carbon content of the system of the present invention can reach 80% in 10 minutes; while the total organic carbon content of the Fenton system is almost not removed.

[0064] Example 2 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol to potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added. Take samples at different time points (1, 3, 5, 7, and 10 minutes), and then use a high-performance liquid chromatograph to detect the phenol concentration and a total organic carbon analyzer to detect the total organic carbon content.

[0065] Comparative Example 2 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: After adjusting the pH of the reaction solution in Step 2 to 10 by adding sodium hydroxide, add potassium persulfate in a molar ratio of phenol:potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added. Take samples at different time points (1, 3, 5, 7, and 10 minutes), and then use a high-performance liquid chromatograph to detect the phenol concentration and a total organic carbon analyzer to detect the total organic carbon content.

[0066] See Figure 3 The figure shows the effect of the pH adjustment system of the present invention in Example 2 and Comparative Example 2 on the removal of phenol. It can be seen from the figure that the method of directly adjusting the pH of the system and the method of constructing the interfacial microenvironment have similar phenol removal rates.

[0067] See Figure 4 The figure shows the effect of the pH adjustment system of the present invention in Example 2 and Comparative Example 2 on the removal of total organic carbon content. As can be seen from the figure, the method of directly adjusting the pH of the system and the method of constructing the interfacial microenvironment have similar total organic carbon removal rates.

[0068] Example 3 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol to potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25°C) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added, and take a sample after 10 minutes. Then, use an inductively coupled plasma atomic emission spectrometer to determine the nickel ion content.

[0069] Comparative Example 3 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Add sodium hydroxide to adjust the pH of the reaction solution in step 2 to 10.

[0070] Step 4: Place the mixture from Step 3 at room temperature (25°C) for reaction, keeping it stirred throughout. Start timing the reaction after adjusting the pH, and take a sample at 10 minutes. Then, use an inductively coupled plasma atomic emission spectrometer to determine the nickel ion content.

[0071] See Figure 5 The figure shows the effect of the present invention system and alkaline precipitation in removing nickel ions in Example 3 and Comparative Example 3. It can be seen from the figure that within the same 10 min time, the removal rate of nickel ions in the present invention system is 98.7%, while the removal rate of nickel ions by alkaline precipitation is 76.1%.

[0072] Example 4 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol to potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25°C) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added, and take a sample after 10 minutes. Then, use an inductively coupled plasma atomic emission spectrometer to determine the nickel ion content.

[0073] Comparative Example 4 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: After adjusting the pH of the reaction solution in Step 2 to 10 by adding sodium hydroxide, add potassium persulfate in a molar ratio of phenol:potassium persulfate of 1:1.89, and keep the final pH at 10. Step 4: Place the mixture from Step 3 at room temperature (25°C) for reaction, keeping it stirred throughout. Start timing the reaction time when potassium persulfate is added, and take a sample after 10 minutes. Then, use an inductively coupled plasma atomic emission spectrometer to determine the nickel ion content.

[0074] See Figure 6The figure shows the effect of the pH adjustment system of the present invention in Example 4 and Comparative Example 4 on the removal of nickel ions. It can be seen from the figure that within the same 10 min time, the method of directly adjusting the pH of the system and the method of constructing the interfacial microenvironment have similar nickel ion removal rates.

[0075] Example 5 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate, 20 mg / L phenol and 100 mg / L cobalt chloride hexahydrate, and 20 mg / L phenol and 100 mg / L copper chloride hexahydrate. Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol:potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) for 10 minutes. The reaction time is started from the addition of potassium persulfate. Samples are taken at different time points (1, 3, 5, 7, and 10 minutes), and the phenol concentration is then detected using a high-performance liquid chromatograph.

[0076] See Figure 7 The figure shows the effect of the system of the present invention described in Example 5 on the removal of phenol under different heavy metal conditions. It can be seen from the figure that under the same and lower oxidant dosage, the removal rate of phenol in the nickel ion system is close to 100% at 10 min, the cobalt ion system is 86%, and the copper ion system is 49%.

[0077] Example 6 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate with a molar ratio of phenol: potassium persulfate of 1:1.89. Take another 10 mg of nano magnesium oxide from the reaction solution in Step 2 and add it to the reaction solution. Then add potassium persulfate with a molar ratio of phenol: potassium persulfate of 1:1.89. Step 4: Place the two types of mixtures from Step 3 at room temperature (25℃) for reaction, keeping the mixture stirred throughout. Start timing the reaction time when potassium peroxymonosulfate and potassium peroxymonosulfate are added. Take samples at different time points (1, 3, 5, 10, 20, and 30 minutes), and then use high performance liquid chromatography to detect the phenol concentration.

[0078] See Figure 8 The figure shows the effect of the system of the present invention described in Example 6 on the removal of phenol under different persulfate application conditions. It can be seen from the figure that under the same and lower oxidant dosage, the system of the present invention has good phenol removal activity. Under the condition of potassium persulfate, the phenol removal rate of the system of the present invention can be close to 100% after 30 minutes, and under the condition of potassium persulfate, the removal rate is 66% after 30 minutes.

[0079] Example 7 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate in a molar ratio of phenol:potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25℃) for 10 min while stirring. Filter and collect the product after the reaction. Wash it three times with deionized water, then dry it at 80℃ and collect it. Dissolve it in tetrahydrofuran and analyze the solution using gel permeation chromatography.

[0080] Step 5: Analyze the surface zeta potential of the product collected in step 4 using a zeta potential analyzer.

[0081] See Figure 9 The figure shows the molecular weight distribution of the phenol polymerization product of the present invention described in Example 7. It can be seen from the figure that the phenol polymer has a large molecular weight and a wide distribution.

[0082] See Figure 10 The figure shows a comparison between the Zeta potential of the product of the system described in Example 7 and the Zeta potential of commercially available nano magnesium oxide. After the reaction, the Zeta potential decreased from 18.6 mV to 7.3 mV, which is more conducive to sedimentation and separation, and thus promotes the shift of the equilibrium of heavy metal alkali precipitation.

[0083] Example 8 Step 1: Prepare a reaction solution with a concentration of 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the reaction solution prepared in Step 1 to simulate wastewater containing only heavy metals; Step 3: Weigh 10 mg of nano magnesium oxide, add it to the reaction solution in Step 2, and sonicate for 20 min. Then add 10 mg of potassium peroxymonosulfate. Step 4: Place the mixture from Step 3 at room temperature (25℃) for 10 minutes while stirring. Filter and collect the reaction product, wash it three times with deionized water, and then dry it at 80℃.

[0084] Step 5: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 6: Take 50 mL of the mixed reaction solution prepared in Step 5 to simulate wastewater containing heavy metals and organic pollutants; Step 7: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in step 6. After sonicating for 20 min, add 10 mg of potassium persulfate. Step 8: Place the mixture from Step 7 at room temperature (25℃) for 10 minutes while stirring. Filter and collect the reaction product, wash it three times with deionized water, and then dry it at 80℃. Step 9: After washing away the surface polymerization products by dissolving them in toluene, the product collected in step 8 is filtered and dried at 80°C.

[0085] Step 10: The microstructure of the products collected in Steps 4, 8, and 9, as well as pure nano-magnesium oxide, is observed and compared using a scanning electron microscope.

[0086] Step 11: Analyze the crystal state of the products collected in Steps 4 and 8, as well as pure nano-magnesium oxide, using an X-ray diffractometer.

[0087] Step 12: Use Raman spectroscopy to analyze and compare the evolution of surface species in the products collected in Steps 4 and 8, as well as pure nano-magnesium oxide.

[0088] See Figure 11 The images show scanning electron microscope (SEM) images of different reaction processes in the system of the present invention described in Example 8. The images show that, without phenol, the smooth magnesium oxide surface exhibits wrinkles, mainly due to nickel species deposition. With the presence of phenol, uniform particles grow on the magnesium oxide surface. After removing the organic components with toluene, the number of surface particles decreases, indicating that the particles mainly originate from organic polymers.

[0089] See Figure 12 The figure shows the X-ray diffraction patterns of different reaction processes of the system of the present invention described in Example 8. It can be seen from the figure that the sample before and after the reaction maintains the crystalline phase of magnesium oxide, which suggests that the reaction mainly occurs on the surface of magnesium oxide.

[0090] See Figure 13 The figures show the Raman spectra of different reaction mechanisms in the system of the present invention described in Example 8. It can be seen from the figures that in the phenol-free system, the 3646 cm⁻¹ of the magnesium oxide surface... -1 The characteristic peak disappeared, and a 479 cm⁻¹ peak belonging to Ni(III)-O appeared. -1 and 553 cm -1 The peak indicates that PMS participated in Ni 2+ The transformation process occurs on the MgO surface, forming high-valence nickel species. In phenol-containing systems, the spectrum is mainly observed at 1536 cm⁻¹. -1 and 1592 cm -1 The D and G bands at the location indicate that organic carbon species are enriched on the MgO surface and form a capping layer.

[0091] Example 9 Step 1: Prepare mixed reaction solutions containing 20 mg / L organic pollutants (phenol, enrofloxacin (ENR), sulfamethoxazole (SMX), sulfadiazine (SD), p-chlorophenol, p-hydroxybenzoic acid) and 100 mg / L nickel chloride hexahydrate. Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 10 mg of nano magnesium oxide and add it to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate with a molar ratio of organic pollutant to potassium persulfate of 1:1.89. Step 4: Place the mixture from Step 3 at room temperature (25°C) and keep it stirred throughout. Start timing the reaction time when potassium persulfate is added. Take samples every 20 minutes and then use high performance liquid chromatography to detect the concentration of each organic pollutant.

[0092] See Figure 14 The figure shows the effect of the system of the present invention in Example 9 in removing organic pollutants. It can be seen from the figure that under the same and lower oxidant dosage, the removal rate of phenol, enrofloxacin, p-chlorophenol, and p-hydroxybenzoic acid in the system of the present invention can reach 100% after 20 minutes, the removal rate of sulfamethoxazole can reach 95% after 20 minutes, and the removal rate of sulfadiazine can reach 96% after 20 minutes.

[0093] Example 10 Step 1: Prepare a mixed reaction solution containing 20 mg / L phenol and 100 mg / L nickel chloride hexahydrate; Step 2: Take 50 mL of the mixed reaction solution prepared in Step 1 to simulate wastewater containing heavy metals and organic pollutants; Step 3: Weigh 5 mg of nano magnesium oxide and 10 mg of nano magnesium oxide and add them to the reaction solution in Step 2. After sonicating for 20 min, add potassium persulfate with a molar ratio of phenol to potassium persulfate of 1:1.89. Step 4: Place the two types of mixtures from Step 3 at room temperature (25℃) for reaction, keeping the mixture stirred throughout. Start timing the reaction time when potassium persulfate is added. Take samples at different time points (1, 3, 5, 7, and 10 minutes), and then use high performance liquid chromatography to detect the phenol concentration.

[0094] See Figure 15 The figure shows the effect of the system of the present invention described in Example 10 on the removal of phenol under different dosages of nano-magnesium oxide. It can be seen from the figure that different dosages of nano-magnesium oxide can provide different local alkaline environment capabilities.

[0095] Example 11 A sample of wastewater from a coal chemical plant was taken. The initial concentrations of pollutants in the sample are shown in Table 3. Step 1: Take 50 mL of the wastewater, weigh 1 g of nano magnesium oxide and sonicate for 20 min; Step 2: Add potassium persulfate to the wastewater from Step 1 in a molar ratio of 1:1.89 (total organic matter content: potassium persulfate). Add the potassium persulfate in 5 equal batches, reacting for 10 minutes after each batch is added, while keeping the mixture stirred throughout. Step 3: Analyze the Ni ion concentration, total organic matter content, and chemical oxygen demand in the liquid after each batch of potassium persulfate has been added and reacted. See Figure 16 The figure shows the COD content of different batches of wastewater treated by the system of the present invention described in Example 11. It can be seen from the figure that the reduction in COD and the amount of PMS added have a good linear relationship.

[0096] See Figure 17 The figure shows the TOC content of different batches of wastewater treated by the system of the present invention described in Example 11. It can be seen from the figure that the reduction of TOC and the amount of PMS added also show a good linear relationship.

[0097] See Figure 18 The system of the present invention described in Example 11 was used to treat different batches of Ni in actual wastewater. 2+ The removal rate graph shows that as the number of processing batches increases, Ni... 2+ The removal rate increased from 73.1% to 99.7%, which may be related to the system's ability to break down metal complexes.

[0098] This invention achieves synergistic removal of both types of pollutants within the same system by deeply coupling the alkaline precipitation process of heavy metals with the oxidative polymerization process of organic pollutants. By constructing an alkaline microenvironment and adding persulfate, this invention achieves efficient removal of heavy metals and simultaneous removal of organic pollutants and total organic carbon in the solution without the need for external pre-synthesized catalysts. Under the influence of the alkaline microenvironment, heavy metal ions undergo in-situ oxidation with sulfate to form metal hydroxyl oxides, which selectively oxidize organic pollutants to generate polymers. The polymers then coat the heavy metal precipitates, promoting the stable separation of the inorganic-organic composite solid phase. This invention features mild reaction conditions, low reagent requirements, and is environmentally friendly, utilizing waste to treat waste, making it suitable for the efficient treatment of industrial wastewater containing both heavy metals and organic pollutants.

[0099] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation, characterized in that, Includes the following steps: S1: Add alkaline nanomaterials to wastewater containing heavy metal ions and organic pollutants to induce the heavy metal ions in the wastewater to form active species precursors in situ. S2: Adding an oxidant to the wastewater causes the precursors of active species to undergo directional evolution under the action of the oxidant, generating high-valence metal active species; S3: Under the influence of high-valence metal active species, organic pollutants undergo selective oxidative polymerization or coupling polymerization reactions, and eventually form stable inorganic-organic complex products with heavy metal species. S4: Recover inorganic-organic composite products from wastewater through solid-liquid separation.

2. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The alkaline nanomaterial is a functional material with the ability to release alkali slowly; The functional material includes one or more of nano-magnesium oxide, magnesium hydroxide, calcium oxide, or bimetallic layered hydroxides.

3. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The heavy metal ions are transition metal ions that can precipitate in situ in the interfacial microenvironment constructed by alkaline nanomaterials to generate precursors of active species. The transition metal ions include one or more of cobalt ions, nickel ions, and copper ions.

4. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The active species precursor includes one or more of metal hydroxides, metal oxides, bimetallic hydroxides, and amorphous hydrated oxides; The high-valence metal active species include hydroxyl metal oxides.

5. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The organic pollutant is an organic pollutant with an aromatic structure; The organic pollutants include one or more of the following: phenolic compounds, bisphenolic compounds, aromatic amine pollutants, dye pollutants, and antibiotics.

6. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The oxidant mentioned in step S2 is a persulfate oxidant; The persulfate oxidant includes one or both of permonosulfate and perdisulfate.

7. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The molar ratio of the oxidant to the organic pollutant in step S2 is not less than 1.72:

1.

8. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The concentration of heavy metals in the wastewater in step S1 ranges from 0.1 to 8000 mg / L.

9. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The wastewater mentioned in step S1 includes electroplating wastewater, metallurgical wastewater, mining wastewater, chemical wastewater, pharmaceutical wastewater, printing and dyeing wastewater, and landfill leachate.

10. The method for in-situ activation of heavy metals and synergistic treatment of organic pollutants based on interface microenvironment regulation according to claim 1, characterized in that, The inorganic-organic composite product recovered in step S4 can be used as a precursor for catalytic materials, adsorption materials, electrode materials or other functional composite materials for resource utilization.

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