Method for co-processing perfluorinated / polyfluoroalkyl compound polluted water based on industrial high-temperature process and industrial symbiotic treatment system

Abstract

The invention relates to the field of industrial environmental protection and resource circulation, in particular to a method for co-processing perfluorinated / polyfluoroalkyl compound polluted water based on an industrial high-temperature process and an industrial symbiotic treatment system. The method comprises the following steps: taking the polluted water containing perfluoro and / or polyfluoroalkyl compounds as a water source of an original process in an industrial high-temperature production process, and introducing the polluted water into a raw material system in the industrial high-temperature production process through a liquid adding process node so as to mix the polluted water with raw materials; and feeding the raw material mixed with the polluted water into a high-temperature treatment process section of an industrial high-temperature production process for pyrolysis treatment. The PFAS polluted water is seamlessly embedded into the production process of the main product by searching and utilizing inherent process conditions of high temperature, alkali metal / alkaline earth metal and acceptable liquid which can be shared in the existing high-energy-consumption industrial process, so that the PFAS polluted water is seamlessly embedded into the production process of the main product on the premise of no negative influence on the quality of the main product. The efficient removal of PFAS pollutants and the in-situ fixation of fluorine elements are synchronously realized.

Description

Technical Field

[0001] This invention relates to the field of industrial environmental protection and resource recycling, and in particular to a method and industrial symbiotic treatment system for the co-treatment of perfluorinated / polyfluorinated alkyl compound contaminated water based on industrial high-temperature processes. Background Technology

[0002] Perfluorinated and polyfluoroalkyl substances (PFAS), represented by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), have become emerging persistent organic pollutants of global concern due to their extreme chemical stability, bioaccumulation, and potential health risks. Traditional water treatment technologies, such as adsorption, coagulation, and biological treatment, are unable to break their strong carbon-fluorine bonds (C–F bonds), typically only achieving phase transfer and producing concentrated wastewater enriched with PFAS, whose final disposal remains a challenge.

[0003] High-temperature incineration is currently the most reliable technological approach for the complete destruction of PFAS concentrates or high-concentration wastewater. Efficient PFAS removal requires temperatures exceeding 1000°C and sufficient residence time. However, constructing and operating dedicated high-temperature hazardous waste incinerators involves huge investments, extremely high energy consumption, expensive operating costs, and the need for strict control of potential secondary pollution from fluorinated acid gases (such as HF), which significantly limits the large-scale application of this technology.

[0004] Therefore, developing a synergistic technology that can achieve efficient, economical, and safe treatment of PFAS wastewater is an urgent practical need and has broad application prospects. Summary of the Invention

[0005] This invention provides a method and industrial symbiotic treatment system for the co-treatment of perfluorinated / polyfluoroalkyl (PFAS) contaminated water using high-temperature industrial processes. The core idea of ​​this invention is not treatment, but integration—that is, identifying and utilizing inherent, shareable high-temperature, alkali / alkaline earth metal, and acceptable liquid process conditions in existing high-energy-consuming industrial processes to seamlessly embed the treatment of PFAS contaminated water into the production process of the main product. Through precise process control, efficient removal of PFAS pollutants and in-situ fixation of fluoride are simultaneously achieved without negatively impacting the quality of the main product, ultimately achieving the maximum balance between environmental and economic benefits.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for the co-treatment of perfluorinated / polyfluorinated alkyl compound contaminated water based on an industrial high-temperature process, comprising the following steps: (1) Polluted water containing perfluorinated and / or polyfluorinated alkyl compounds is used as a complete or partial replacement water source for the original process water in the industrial high-temperature production process. It is introduced into the raw material system of the industrial high-temperature production process through the liquid addition process node in the industrial high-temperature production process, so that the polluted water is mixed with the raw materials. (2) The raw materials mixed with polluted water are sent to the high-temperature treatment section of the industrial high-temperature production process to pyrolyze the perfluorinated and / or polyfluoroalkyl compounds. Wherein, the temperature of the high-temperature treatment process section is ≥900℃, and the time of the high-temperature treatment process section is ≥3min; The raw materials used in the industrial high-temperature production process include alkali metal compounds and / or alkaline earth metal compounds.

[0007] In some specific embodiments, the industrial high-temperature production process includes at least one of sintering, chain grate-rotary kiln pellet roasting, and vertical shaft furnace.

[0008] In some specific embodiments, the alkali metal compound includes at least one of alkali metal oxides, alkali metal carbonates, and alkali metal hydroxides. The alkaline earth metal compound includes at least one of an oxide of an alkaline earth metal, a carbonate of an alkaline earth metal, and a hydroxide of an alkaline earth metal.

[0009] In some specific embodiments, the total mass content of alkali metal elements and alkaline earth metal elements in the raw materials of the industrial high-temperature production process is ≥1%.

[0010] In some specific embodiments, the amount of contaminated water containing perfluorinated and / or polyfluoroalkyl compounds introduced accounts for 1 wt% to 100 wt% of the water used in industrial high-temperature production processes.

[0011] In some specific embodiments, the temperature of the high-temperature treatment process section is 1000~1600℃, and the time of the high-temperature treatment process section is 10min~2h.

[0012] In some specific embodiments, the method further includes: monitoring and treating the exhaust gas generated during the pyrolysis process.

[0013] The present invention also provides an industrial co-processing system for the above-described method, comprising: A contaminated water supply unit for storing and transporting the contaminated water containing perfluorinated and / or polyfluorinated alkyl compounds; The high-temperature processing unit is an inherent production equipment in the industrial high-temperature production process, used to pyrolyze raw materials mixed with polluted water.

[0014] In some specific implementations, it also includes a quantitative dispensing unit, a main control system, and an exhaust gas purification unit; The quantitative dispensing unit is connected to the polluted water supply unit and is used to add the polluted water containing perfluorinated and / or polyfluoroalkyl compounds to the raw material system of the industrial high-temperature production process in a preset ratio. The quantitative dispensing unit is connected to the main control system of the industrial high-temperature production process and can dynamically adjust the amount of polluted water added according to the raw material feed amount. The exhaust gas purification unit is connected to the flue gas outlet of the high-temperature treatment unit and is used to purify the exhaust gas generated during the treatment process.

[0015] In some specific embodiments, a safety monitoring unit is also included, which includes: sampling interfaces installed at the polluted water addition point, the feed point of the high-temperature treatment unit, and the discharge point of the high-temperature treatment unit, and instruments for online monitoring of the temperature of the high-temperature treatment process section and the components of the exhaust gas at the outlet of the exhaust gas purification unit.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) No investment is required to construct a dedicated high-temperature incinerator, nor is it necessary to pay high fuel and operating costs separately. This invention utilizes existing industrial processes and idle high-temperature capacity, transforming disposal costs from a major cost item into near-marginal costs, thus achieving extremely low cost per ton of water treated.

[0017] (2) The industrial high-temperature process (usually >1000℃) on which it is based far exceeds the decomposition temperature of PFAS (decomposition begins at about 600℃). Combined with a strong oxidizing atmosphere and sufficient residence time, it can ensure that PFAS molecules are effectively removed and the organic matter removal rate can reach more than 99.9%.

[0018] (3) The abundant alkali metals / alkaline earth metals (such as CaO) in the raw materials are used to generate and fix fluorine, thereby inhibiting the generation and emission of harmful gases such as HF at the source. The fixed fluoride (CaF2) is chemically extremely stable, is encapsulated in solid products, has low leaching toxicity, and can be safely utilized or landfilled without the risk of secondary pollution. The trace amounts of HF gas generated can also be removed by subsequent desulfurization equipment.

[0019] (4) This invention proposes a platform-based technological paradigm. Its success does not depend on a specific process, but rather on three common conditions prevalent in many basic industries: high temperature, alkali / alkaline earth metals, and accessibility to liquids. This allows the solution to be rapidly replicated and promoted in multiple industries such as steel and ferroalloys, with huge market potential.

[0020] (5) It shifts the solution to environmental problems from end-of-pipe treatment to process absorption, perfectly interpreting the concepts of circular economy and industrial symbiosis. It transforms the disposal of pollutants into a value-added link in industrial production (such as the recycling of water resources), achieving a deep integration of environmental benefits and industrial development. Attached Figure Description

[0021] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 This is a block diagram illustrating the overall process coupling principle of the method of the present invention.

[0022] Figure 2 This is a schematic diagram of the system configuration of the present invention using the steel sintering process as an example.

[0023] Figure 3 This is a schematic diagram of the system configuration of the present invention using the chain grate machine-rotary kiln pelletizing process as an example.

[0024] Figure 4 This is an evaluation chart of the overall processing effect of Embodiment 1 of the present invention.

[0025] Figure 5 This is an evaluation chart of the overall processing effect in Embodiment 2 of the present invention.

[0026] Figure 6 This is an evaluation chart of the overall processing effect in Embodiment 3 of the present invention. Detailed Implementation

[0027] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0028] High-temperature incineration is currently the most reliable technological approach for the complete destruction of PFAS concentrates or high-concentration wastewater. Efficient PFAS removal requires temperatures exceeding 1000°C and sufficient residence time. However, constructing and operating dedicated high-temperature hazardous waste incinerators involves huge investments, extremely high energy consumption, expensive operating costs, and the need for strict control of potential secondary pollution from fluorinated acid gases (such as HF), which significantly limits the large-scale application of this technology.

[0029] On the other hand, my country has a large number of continuously operating high-temperature industrial kilns in industries such as steel, metallurgy, and ferroalloys, including sintering machines, chain grate rotary kilns, and vertical shaft furnaces. These production processes typically handle large quantities of mineral raw materials containing calcium, silicon, aluminum, magnesium, etc., with core temperatures inside the furnace generally between 1000℃ and 1600℃, far exceeding the temperature required for PFAS decomposition. Simultaneously, these processes often require the addition of water for raw material granulation, dust control, or as a process medium. Currently, there is no systematic method to use high-concentration, highly toxic PFAS-contaminated water as a specific "reaction feed" or "process regulator" to deeply couple with the main production process, achieving "waste treatment and capacity sharing."

[0030] Therefore, developing a synergistic technology that can utilize existing industrial capacity to achieve efficient, economical, and safe treatment of PFAS wastewater is an urgent practical need and has broad application prospects.

[0031] This invention provides a method for the synergistic treatment of perfluorinated / polyfluorinated alkyl compounds contaminated water based on an industrial high-temperature process, comprising the following steps: (1) Polluted water containing perfluorinated and / or polyfluorinated alkyl compounds is used as a complete or partial replacement water source for the original process water in the industrial high-temperature production process. It is introduced into the raw material system of the industrial high-temperature production process through the liquid addition process node in the industrial high-temperature production process, so that the polluted water is mixed with the raw materials. (2) The raw materials mixed with polluted water are sent to the high-temperature treatment section of the industrial high-temperature production process to pyrolyze the perfluorinated and / or polyfluoroalkyl compounds. The temperature of the high-temperature treatment process section is ≥900℃, and the time of the high-temperature treatment process section is ≥3min; The raw materials used in the industrial high-temperature production process include alkali metal compounds and / or alkaline earth metal compounds.

[0032] This invention uses contaminated water containing perfluorinated and polyfluoroalkyl substances (PFAS) as a process medium, adding it to an existing high-temperature industrial production process that meets specific conditions. Under high temperature, PFAS are efficiently removed by pyrolysis, and the fluorine produced by its decomposition reacts with alkali metals and / or alkaline earth metals in the raw materials to form stable fluorides, which are then fixed in situ. This invention replaces end-of-pipe treatment with the disposal of contaminated water in existing high-temperature industrial production processes (such as steel and ferroalloy industries). Utilizing existing high-temperature production capacity, it simultaneously achieves efficient destruction of PFAS and safe fixation of fluorine at extremely low cost, overcoming the core bottlenecks of traditional treatment technologies, such as high cost, difficulty in engineering, and the risk of secondary pollution.

[0033] In this invention, the conditions that must be met in existing industrial high-temperature production processes include: a) High-temperature field conditions: The industrial high-temperature production process has a high-temperature treatment process section (high-temperature area). The temperature of the high-temperature treatment process section is not lower than 900℃, and the residence time of the material or airflow in the high-temperature treatment process section is not less than 3 minutes. That is, the temperature of the high-temperature treatment process section in the industrial high-temperature production process is ≥900℃ and the time is ≥3 minutes.

[0034] b) Material Chemical Conditions: The main raw materials or necessary auxiliary materials used in this process naturally contain or are formulated with a certain amount of oxides, carbonates, or silicates of alkali metals / alkaline earth metals such as calcium (Ca), magnesium (Mg), aluminum (Al), and sodium (Na). These alkali metal / alkaline earth metal components can effectively capture fluoride ions (F ions) generated by the decomposition of PFAS at high temperatures. - This process forms thermodynamically stable fluorides (such as CaF2 and MgF2), achieving in-situ fixation of fluorine. The trace amounts of HF gas generated can also be removed by subsequent desulfurization equipment. The mass ratio of alkali metals / alkaline earth metals in the raw materials should preferably be greater than 1%, and more preferably greater than 4%.

[0035] c) Process accessibility conditions: The process has a process node that allows, requires, or accepts the addition of liquid for wetting materials, pelletizing, dust suppression, or reaction regulation. This node must be located before the high-temperature treatment process section and have good mixing properties.

[0036] Any industrial high-temperature production process that meets the above conditions can be applied by those skilled in the art to achieve the synergistic treatment of water contaminated with perfluorinated and / or polyfluoroalkyl compounds with minimal creative effort.

[0037] In this invention, the perfluorinated and / or polyfluoroalkyl compounds (PFAS) include, but are not limited to, perfluorocarboxylic acids, perfluorosulfonic acids and other fluorinated organic compounds, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and their structural analogs.

[0038] In some embodiments, the concentration of contaminated water containing perfluorinated and polyfluorinated alkyl compounds is 1 × 10⁻⁶. 3 ng / L ~ 1×10 7 ng / L. In this invention, the concentration of contaminated water containing perfluorinated and / or polyfluoroalkyl compounds in the entire system is very small, and therefore will not affect the original industrial high-temperature production process.

[0039] In some embodiments, water quality analysis is performed on polluted water containing perfluorinated and polyfluoroalkyl compounds to identify the main perfluorinated / polyfluoroalkyl compounds (PFAS), such as PFOA and PFOS, and their concentrations. After water sample collection, non-fluoroplastic containers, such as high-density polyethylene (HDPE), are used to protect the water from light and to ensure prompt use.

[0040] In this invention, PFAS-contaminated water is continuously or intermittently injected into a designated node of a selected high-temperature industrial production process via a quantitative dispensing system consisting of a corrosion-resistant pump and a flow meter. The injection flow rate is determined by the main material flow rate of the high-temperature industrial production process and a preset moisture content target value, and closed-loop regulation is achieved through an automatic control system. The water required for the high-temperature industrial production process is replaced with contaminated water containing perfluorinated and / or polyfluoroalkyl compounds, and the overall moisture content of the mixed material is based on the original high-temperature industrial production process.

[0041] In this invention, a mixture containing PFAS-contaminated water enters the high-temperature treatment section of an industrial high-temperature production process. Here, the following key reactions occur: (1) Pyrolysis and removal: Under high temperature (>1000℃) and the presence of a normally present oxidizing atmosphere, the extremely strong CF and CC bonds in the PFAS molecule undergo homolytic cleavage and oxidation reactions, and are rapidly destroyed. The organic skeleton is decomposed and eventually mineralized into carbon dioxide (CO2), water (H2O) and trace amounts of hydrogen fluoride (HF) gas.

[0042] (2) In-situ fixation of fluorine: The gaseous HF produced by decomposition rapidly reacts with the alkali metals / alkaline earth metals (taking Ca as an example) present in large quantities in the material in a gas-solid reaction: Ca-containing substance (s) + HF (g) → CaF2 (s) + H2O (g). The generated calcium fluoride (CaF2) is an extremely stable compound, which is encapsulated in the matrix of the formed sinter, pellets or slag, thereby achieving the inertization and stabilization fixation of fluorine.

[0043] (3) Treatment of small amount of exhaust gas: The small amount of HF gas generated can be removed by the subsequent exhaust gas purification unit.

[0044] In this invention, a complete sampling and analysis procedure is established to verify the treatment effect and environmental impact. Sampling is performed simultaneously at at least the following three points: Node A (Inlet): Before the injection of PFAS contaminated water.

[0045] Node B (feed): The mixed material after it has been thoroughly mixed and before it enters the high-temperature processing section.

[0046] Node C (Product): Solid products after high-temperature processing (such as sinter, pellets, clinker, metal or waste residue).

[0047] Node D (exhaust gas): Exhaust gas after treatment in the high-temperature treatment process section.

[0048] Sample analysis: Characteristic PFAS (such as PFOA) concentrations were determined using liquid chromatography-tandem mass spectrometry (LC-MS / MS); water-soluble fluoride ions (F ions) were determined using ion chromatography or fluoride ion-selective electrode method. - The total fluorine content can be determined by measuring the PFAS content or by X-ray fluorescence spectroscopy (XRF). The removal rate (degradation rate) of PFAS is calculated by comparing data from nodes B and C. The environmental risk of the process is analyzed using the PFAS (e.g., PFOA) concentration at node D.

[0049] In some embodiments, the industrial high-temperature production process includes at least one of sintering, chain grate-rotary kiln pellet roasting, and vertical shaft furnace.

[0050] In some embodiments, the alkali metal compound includes at least one of an alkali metal oxide, an alkali metal carbonate, or an alkali metal hydroxide.

[0051] In some embodiments, the alkaline earth metal compound includes at least one of an oxide of an alkaline earth metal, a carbonate of an alkaline earth metal, or a hydroxide of an alkaline earth metal.

[0052] In some embodiments, the total mass content of alkali metal elements and alkaline earth metal elements in the metal compounds of raw materials during industrial high-temperature production is ≥1%, preferably ≥4wt%.

[0053] In some embodiments, the amount of contaminated water containing perfluorinated and / or polyfluorinated alkyl compounds introduced accounts for 1 wt% to 100 wt% of the water used in industrial high-temperature production processes.

[0054] In some embodiments, the temperature of the high-temperature treatment process is 1000~1600℃, and the time of the high-temperature treatment process is 10min~2h.

[0055] In some embodiments, the method further includes: monitoring and treating the exhaust gas generated during the pyrolysis process.

[0056] A second aspect of the present invention also provides an industrial co-processing system for the above-described method, comprising: A contaminated water supply unit for storing and transporting the contaminated water containing perfluorinated and / or polyfluorinated alkyl compounds; The high-temperature processing unit is an inherent production equipment in the industrial high-temperature production process, used to pyrolyze raw materials mixed with polluted water.

[0057] In some embodiments, a high-temperature processing unit, which is a core production equipment inherent in industrial high-temperature production processes, such as a belt sintering machine, a chain grate-rotary kiln system, etc., is utilized in this invention as a reactor for PFAS pyrolysis treatment.

[0058] In some embodiments, it also includes a metering unit, a main control system, and an exhaust gas purification unit; The quantitative dispensing unit is connected to the polluted water supply unit and is used to add the polluted water containing perfluorinated and / or polyfluoroalkyl compounds to the raw material stream of the industrial high-temperature production process in a preset ratio. The quantitative dispensing unit is connected to the main control system of the industrial high-temperature production process and can dynamically adjust the amount of polluted water added according to the raw material feed amount. The exhaust gas purification unit is connected to the flue gas outlet of the high-temperature treatment unit and is used to purify the exhaust gas generated during the treatment process.

[0059] In some embodiments, the exhaust gas purification unit includes a dust collector and a desulfurization tower for purifying the exhaust gas generated during the treatment process.

[0060] In some embodiments, the metering unit typically consists of a high-precision metering pump, a flow meter, and a regulating valve. This unit is communicatively connected to the main control system and can adjust the injection flow rate of PFAS contaminated water in real time and accurately according to the water consumption of the original high-temperature industrial production process based on the main material flow signal of the host process, ensuring a constant mixing ratio.

[0061] In some embodiments, a safety monitoring unit is further included, comprising: sampling interfaces disposed at the polluted water addition point, the feed point of the high-temperature treatment unit, and the discharge point of the high-temperature treatment unit, and instruments for online monitoring of the temperature of the high-temperature treatment process section and the components of the exhaust gas at the outlet of the exhaust gas purification unit.

[0062] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] Example 1 A method for co-processing PFOA concentrate based on steel / ferroalloy sintering process, with a system configuration diagram as shown below. Figure 2 As shown, it includes the following steps: The concentrated solution of polluted water in a certain area after reverse osmosis treatment has PFOA as the main pollutant, with an initial concentration of about 76,000 ng / L and pH=7.9. ​​The water sample is stored in a high-density polyethylene (HDPE) ton container. The belt sintering process of a certain ferroalloy plant was selected. This process mixes iron ore powder, flux (limestone powder, providing Ca element), and fuel (coke powder), and ignites it on the sintering machine. The combustion occurs from top to bottom, and the highest temperature of the material layer can reach 1200-1400℃. The high temperature holding time exceeds 20-30 minutes. The Ca content in the raw material is 5wt%. A mixer is set at the front end of the process, and water needs to be added to wet the mixture to facilitate granulation. The moisture content of the mixture is usually controlled at 5%. PFOA concentrate is injected into the primary mixer via a metering pump, replacing conventional process water. The amount of concentrate added is controlled according to the original water consumption on the sintering machine trolley. The concentrate is thoroughly mixed with mineral powder, flux, and fuel, with the total mixture having a moisture content of 5wt%~10wt%. The mixture is fed onto the sintering machine trolley. After ignition, the combustion zone moves downward under the action of ventilation. PFOA is rapidly decomposed and removed under the high temperature (>1100℃) and strong oxidizing atmosphere of the combustion zone. The generated HF gas immediately reacts with Ca in the mixture to form CaF2, which is fixed in the sinter and sinter ash. A comparative analysis was conducted on the mixed minerals (node ​​B, before the kiln) and the sintered finished product (node ​​C, after the kiln). The results showed that ( Figure 4 (As shown in Table 1), PFOA in the minerals was completely removed, the finished pellets met the product requirements, and fluorine existed in the finished product in a stable form.

[0064] Table 1. Concentration changes and removal rates of PFOA before and after pyrolysis treatment in Example 1.

[0065] Example 2 A method for co-processing PFOA concentrate based on the first-chain grate machine-rotary kiln pelletizing process is illustrated in the following schematic diagram: Figure 3 As shown, it includes the following steps: The concentrated solution from a contaminated water body in a certain area, after reverse osmosis treatment, has PFOA as the main pollutant, with an initial concentration of approximately 45,000 ng / L and a pH of 8.3. The water sample is stored in HDPE tonnes. The chain grate-rotary kiln system of a pelletizing plant was selected. This process involves mixing minerals and binders (bentonite), adding water to form pellets, and then treating the green pellets at high temperatures in the chain grate before they enter the rotary kiln for oxidative roasting and solidification at 1250-1350℃. The material's residence time at high temperature is approximately 20-30 minutes. The calcium and aluminum components (total content 4 wt%) contained in the raw materials and bentonite can fix fluorine. PFOA wastewater is added to the disc pelletizer as part of the pelletizing process water, and the total water addition rate is controlled to keep the green pellets at a stable moisture content (about 10~12%). After being treated at high temperature on a chain grate machine, the green pellets re-enter a high-temperature rotary kiln. Under a high-temperature oxidizing atmosphere, PFOA is decomposed, and the fluorine produced by decomposition reacts with alkali metals / alkaline earth metals in the material to solidify. To quantitatively evaluate the PFOA removal efficiency of the method of this invention, four batches of pre-pyrolysis mixed mineral raw materials (node ​​B) and corresponding post-pyrolysis mineral slag samples (node ​​C) were continuously collected during the stable operation of the sintering process. All samples were pretreated and then analyzed for PFOA content using liquid chromatography-tandem mass spectrometry (LC-MS / MS). LC-MS / MS analysis showed (Table 2 and...) Figure 5 The removal rate of PFOA from the minerals was 100%. The machine operated stably and the products passed the inspection, indicating that the addition of PFOA concentrate did not have a negative impact on the quality of the main product.

[0066] Table 2. Concentration changes and removal rates of PFOA before and after pyrolysis treatment in Example 2.

[0067] Example 3 A method for co-processing PFOA concentrate based on a second-chain grate machine-rotary kiln pelletizing process is illustrated in the following schematic diagram: Figure 3 As shown, this embodiment demonstrates the application of the present invention to the chain grate-rotary kiln process of another ferroalloy company (hereinafter referred to as Company B) to treat high-concentration PFOA wastewater from another water treatment plant after reverse osmosis treatment, in order to demonstrate the universality of the technology and its ability to treat high-load wastewater. Specifically, it includes the following steps: The concentrate after reverse osmosis treatment has PFOA as the main contaminant, with an initial concentration of approximately 130,000 ng / L and a pH of 7.4. The water sample is stored in HDPE I / O tanks. Company B's chain grate-rotary kiln process is used to process mineral raw materials. Its key features include a high temperature in the chain grate-rotary kiln, reaching approximately 1250-1350℃, with the material remaining at this high temperature for about 20-30 minutes. Furthermore, the raw material contains added calcium (Ca), with a Ca content of 4 wt%. High-concentration PFAS waste liquid is transported to the plant's water pool via a dedicated tank truck, added to the raw material mixer through a quantitative system, and then processed by a chain grate machine and a rotary kiln to produce pellets; This embodiment includes a more comprehensive environmental safety assessment (Table 3 and...). Figure 6 In addition to detecting PFOA in the finished pellet product (not detected), the focus was on sampling and analyzing the activated carbon adsorption of the tail gas from the desulfurization tower after the rotary kiln process. The results showed that the PFOA concentration decreased to below the detection limit, and the PFOA concentration detected by activated carbon in the 24-hour tail gas adsorption was also very low. This fully demonstrates the environmental safety of this method in treating high-concentration PFOA wastewater.

[0068] Table 3. Concentration changes and removal rates of PFOA before and after pyrolysis treatment in Example 3.

[0069] As can be seen from the above embodiments, the present invention introduces polluted water containing perfluorinated and / or polyfluoroalkyl compounds as a process medium into the high-temperature industrial production process. Without affecting the quality of the main product and the stability of production, it achieves efficient removal of PFAS pollutants and in-situ fixation of fluorine, reduces the risk of secondary pollution, and has good industrial applicability and promotion value.

[0070] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A method for the co-treatment of PFAS-contaminated water based on industrial high-temperature processes, characterized in that, The method comprises the following steps: (1) introducing the contaminated water containing perfluoro and / or polyfluoro alkyl compounds into the raw material system of the industrial high-temperature production process through the liquid addition process node in the industrial high-temperature production process as all or part of the original process water in the industrial high-temperature production process, so that the contaminated water is mixed with the raw material; (2) sending the raw material mixed with the contaminated water into the high-temperature treatment process section of the industrial high-temperature production process to pyrolyze the perfluoro and / or polyfluoro alkyl compounds; The temperature of the high-temperature treatment process section is ≥900℃, and the time of the high-temperature treatment process section is ≥3min. The raw material of the industrial high-temperature production process comprises at least one of an alkali metal compound and / or an alkaline earth metal compound.

2. The method for co-treatment of PFAPFC-contaminated water based on industrial high-temperature processes according to claim 1, characterized in that, The industrial high-temperature production process comprises at least one of a sintering process, a grate-kiln pelletizing process, and a shaft furnace process.

3. The method for co-treatment of PFAPFC-contaminated water based on industrial high-temperature processes according to claim 1, characterized in that, The alkali metal compound comprises at least one of an oxide of an alkali metal, a carbonate of an alkali metal, and a hydroxide of an alkali metal. The alkaline earth metal compound comprises at least one of an oxide of an alkaline earth metal, a carbonate of an alkaline earth metal, and a hydroxide of an alkaline earth metal.

4. The method for co-treatment of PFAPFC-contaminated water based on industrial high-temperature processes according to claim 1, characterized in that, The total mass content of alkali metal elements and alkaline earth metal elements in the raw material of the industrial high-temperature production process is ≥1%.

5. The method for co-treatment of PF / PFAA contaminated water based on industrial high temperature processes according to claim 1, characterized in that, The amount of the contaminated water containing perfluoro and / or polyfluoro alkyl compounds introduced accounts for 1wt%-100wt% of the amount of water used in the industrial high-temperature production process.

6. The method for co-treatment of PFAPFC-contaminated water based on industrial high-temperature processes according to claim 1, characterized in that, The temperature of the high-temperature treatment process section is 1000-1600℃, and the time of the high-temperature treatment process section is 10min-2h.

7. The method for co-treatment of PFAPFC-contaminated water based on industrial high-temperature processes according to claim 1, characterized in that, Further comprising: Monitoring and treating the tail gas generated in the pyrolysis process.

8. An industrial symbiotic treatment system for use in the method of any one of claims 1 to 7, characterized in that, Comprising: A contaminated water supply unit for storing and delivering the contaminated water containing perfluoro and / or polyfluoro alkyl compounds; A high-temperature treatment unit, which is the production equipment inherent to the industrial high-temperature production process, for pyrolyzing the raw material mixed with the contaminated water.

9. The industrial symbiotic treatment system according to claim 8, characterized by, Further comprising a quantitative dosing unit, a main control system, and a tail gas purification unit; The quantitative dosing unit is connected with the contaminated water supply unit and is used for adding the contaminated water containing perfluoro and / or polyfluoro alkyl compounds to the raw material system of the industrial high-temperature production process according to a preset proportion; The quantitative dosing unit is communicatively connected with the main control system of the industrial high-temperature production process and can dynamically adjust the amount of the contaminated water added according to the amount of raw material fed; The tail gas purification unit is connected with the flue gas outlet of the high-temperature treatment unit and is used for purifying the tail gas generated in the treatment process.

10. The industrial symbiotic treatment system according to claim 9, characterized by, Further comprising a safety monitoring unit, which comprises sampling interfaces arranged at the contaminated water addition point, the high-temperature treatment unit feeding point, and the high-temperature treatment unit discharging point, and instruments for online monitoring the temperature of the high-temperature treatment process section and the composition of the outlet tail gas of the tail gas purification unit.

Images