A micro-electrolysis-photocatalysis synergistic high-efficiency removal of recalcitrant organic matter and new pollutants in constructed wetland system
Patent Information
- Application Number
- CN202522420245.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-09-25
- Estimated Expiration
- 2035-11-14
AI Technical Summary
[0004]目前，电化学技术、光催化氧化和芬顿技术等高级氧化工艺虽可以有效降解上述难降解有机物，但在实际应用中仍面临运行成本高、反应条件控制严格等技术经济性挑战
先由上行式潜流人工湿地有效分解微污染水中大分子有机物，并对常规污染物（如：COD、氮磷）和悬浮物（SS）进行初步去除，从而让后续流入多级跌水平台内的出水较为清澈，多级跌水平台利用水位差，使水流在跌落过程中自然复氧，形成良好的好氧环境，可进一步削减COD、氨氮及总磷，其内所分布的铁碳微电解填料和光催化填料在光照与水力作用的协同下构成“微电解-光催化-芬顿”协同氧化核心，可以高效降解前段未被去除的难降解有机物（如：农药、染料组分）及部分难生物降解的抗生素（如：磺胺类、喹诺酮类等），铁碳微电解填料提供基础的还原、絮凝和持续的铁离子来源，光催化填料在太阳光照下激发下产生强氧化性的自由基，二者之间的协同铁循环与光催化的相互促进，使得人工湿地系统能够持续、高效、稳定地去除污染物，从而成为一种非常有前景的难降解有毒有害污水深度处理技术，最后，多级跌水平台中经光电协同处理的出水进入表流湿地，在表流湿地中，对剩余的常规污染物以及被光电技术分解后生成的小分子有机物进行最终的生态化深度净化与稳定，确保出水水质达标后排入受纳水体，通过多级单元的有序组合，以及引入微电解与光催化的协同作用，提升人工湿地对难降解有机物与新污染物的整体去除能力，实现污染物的梯级深度净化，同时具备运行稳定、能耗低、适应性强等优势，为人工湿地技术的功能强化与推广应用提供新的解决方案。
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Figure CN224798671U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of water treatment technology, specifically to an artificial wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants through micro-electrolysis and photocatalysis. Background Technology
[0002] In reclaimed water recycling systems, constructed wetlands, as a key component, are often used for the advanced treatment of wastewater effluent from sewage treatment plants and non-point source pollution, resulting in the treated water entering surface water recycling systems such as rivers and lakes. Constructed wetlands can effectively remove conventional pollutants from slightly polluted water, but their effectiveness in removing some recalcitrant organic compounds and emerging pollutants is limited. Examples include persistent organic compounds (POCs) in pesticides and dyeing wastewater, as well as antibiotics with poor biodegradability such as sulfonamides, quinolones, and tetracyclines. Some POCs (such as certain pesticide and dye intermediates) have been proven or are suspected of having carcinogenic, teratogenic, and mutagenic effects, and may interfere with the endocrine systems of humans and wild animals, affecting reproduction and development. Even at low concentrations, antibiotics entering the environment can inhibit the structure, function, and diversity of microbial communities in aquatic ecosystems, impairing the self-purification capacity of water bodies and producing chronic toxic effects on the growth and development of aquatic animals (such as fish and algae).
[0003] Therefore, these pollutants are considered typical "emerging pollutants" or "priority control pollutants." They cause a typical "low concentration, high hazard" environmental problem, and their efficient and in-depth purification is an urgent and severe challenge in the field of water environment safety.
[0004] Currently, although advanced oxidation processes such as electrochemical technology, photocatalytic oxidation, and Fenton technology can effectively degrade the aforementioned recalcitrant organic compounds, they still face technical and economic challenges in practical applications, such as high operating costs and strict control of reaction conditions. Utility Model Content
[0005] The technical problem to be solved by this invention is to provide an artificial wetland system that uses micro-electrolysis-photocatalysis to efficiently remove recalcitrant organic matter and new pollutants, thereby overcoming the shortcomings of the prior art.
[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An artificial wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis includes: an upward subsurface flow artificial wetland, in which the effluent from the upper part of the upward subsurface flow artificial wetland flows into a multi-stage cascade platform, and iron-carbon micro-electrolysis packing material and photocatalytic packing material are distributed in each stage of the multi-stage cascade platform, and the effluent from the lower part of the multi-stage cascade platform flows into a surface flow wetland.
[0007] The beneficial effects of this utility model are as follows: First, the upward-flowing subsurface constructed wetland effectively decomposes large-molecule organic matter in slightly polluted water and initially removes conventional pollutants (such as COD, nitrogen, and phosphorus) and suspended solids (SS), resulting in clearer effluent flowing into the multi-tiered cascade platform. The multi-tiered cascade platform utilizes water level differences to naturally reoxygenate the water during its cascading flow, creating a favorable aerobic environment that further reduces COD, ammonia nitrogen, and total phosphorus. The iron-carbon micro-electrolysis and photocatalytic packing materials distributed within the platform, under the synergistic effect of light and hydraulic action, form a "micro-electrolysis-photocatalysis-Fenton" synergistic oxidation core. This core efficiently degrades recalcitrant organic matter (such as pesticides and dye components) and some recalcitrant antibiotics (such as sulfonamides and quinolones) that were not removed in the initial stage. The iron-carbon micro-electrolysis packing material provides basic reduction, flocculation, and a continuous source of iron ions, while the photocatalytic packing material generates strong oxidation under sunlight. The interaction between free radicals and the synergistic effects of iron cycling and photocatalysis enables constructed wetland systems to continuously, efficiently, and stably remove pollutants, making it a promising technology for the deep treatment of recalcitrant toxic and hazardous wastewater. Finally, the effluent from the multi-stage cascade platform, treated by photoelectric synergy, enters the surface flow wetland. In the surface flow wetland, the remaining conventional pollutants and small-molecule organic matter generated after photoelectric decomposition undergo final ecological deep purification and stabilization, ensuring that the effluent meets quality standards before being discharged into the receiving water body. Through the orderly combination of multi-stage units and the synergistic effect of micro-electrolysis and photocatalysis, the overall removal capacity of constructed wetlands for recalcitrant organic matter and new pollutants is enhanced, achieving tiered deep purification of pollutants. It also possesses advantages such as stable operation, low energy consumption, and strong adaptability, providing a new solution for the functional enhancement and widespread application of constructed wetland technology.
[0008] 1) Iron-carbon micro-electrolysis removes recalcitrant toxic and harmful pollutants. Galvanic cell effect and strong redox ability: When iron (anode) and carbon (cathode, such as activated carbon, coke, etc.) come into contact in wastewater, countless tiny galvanic cells are formed, and the newly generated nascent Fe... 2+ The hydrogen atom (H) has strong reducing properties and can directly break the chemical bonds of some reducing pollutants (such as nitro compounds and azo dyes); Flocculation and precipitation: Fe generated during the reaction 2+ Further oxidized to Fe 3+ Fe 3+ Hydrolysis generates Fe(OH)3 colloids with highly efficient flocculation, which can adsorb and trap colloidal particles, tiny suspended solids and some hydrophobic organic matter in water, forming flocs and settling down; 2) Photocatalytic removal of recalcitrant toxic and harmful pollutants When exposed to sunlight, the valence band electrons in the photocatalytic filler are excited and transition to the conduction band, leaving a hole (h) in the valence band.+ ), forming highly active "electron-hole pairs", holes (h + It possesses strong oxidizing power, capable of directly oxidizing organic matter adsorbed on the surface of photocatalytic fillers, or reacting with water to generate hydroxyl radicals (˙OH) and electrons (e). - It has a strong reducing ability and can react with oxygen to generate superoxide radicals: e - +O2→•O2 - It can also react further to generate ˙OH. Hydroxyl radicals (˙OH) are highly reactive species with extremely strong oxidizing power (redox potential as high as +2.8V). They can non-selectively attack and degrade most organic matter, eventually mineralizing it into CO2 and H2O.
[0009] 3) Iron-carbon micro-electrolysis provides both energy and clearance for photocatalysis. Iron-carbon micro-electrolysis continuously produces Fe 2+ Fe 2+ It can react with H2O2 (produced by •O2) generated in the photocatalytic reaction. - (Generation pathway) undergoes a Fenton-like reaction: Fe 2+ +H₂O₂→Fe 3+ +˙OH+OH - This greatly promotes the generation of ˙OH, forming a coupled reaction chain of micro-electrolysis-photocatalysis-Fenton, resulting in an exponential increase in oxidation capacity; Iron can act as a source of photogenerated electrons (e.g., electrons). - It is a good acceptor for Fe, which can quickly capture electrons (Fe) on the conduction band of the photocatalytic filler. 3+ +e - →Fe 2+ This effectively suppresses the recombination of electron-hole pairs, allowing holes (h) to recombine. + It has more opportunities to oxidize pollutants or generate ˙OH, thereby significantly improving photocatalytic efficiency.
[0010] 4) Photocatalysis "regenerates" and "enhances" iron-carbon microelectrolysis: Photocatalytic reaction and ultraviolet light themselves can convert the Fe generated in the reaction 3+ Reduced to Fe 2+ (Fe) 3+ +e - →Fe 2+ ), construct Fe 2+ / Fe 3+ The circulation process enables in-situ regeneration of the iron catalyst, reducing iron loss and the generation of iron sludge, and maintaining the system's continuous and efficient reaction capacity.
[0011] 5) Low-carbon, green, and pollution-free The photocatalytic process of iron-carbon microelectrolysis and photocatalytic filler does not require the addition of additional chemical reagents, and the reaction products are non-toxic and harmless, which is in line with the concept of green chemistry.
[0012] Based on the above technical solution, the present invention can be further improved as follows. Further, the depth of each stage of the multi-stage drop platform is 0.1m to 0.3m.
[0013] Furthermore, the length of each stage of the multi-stage cascade platform along the water flow direction is 30cm to 80cm.
[0014] Furthermore, the hydraulic retention time of the effluent from the top of the upward-flowing subsurface constructed wetland after flowing into the multi-stage cascade platform is 3 to 5 hours.
[0015] Furthermore, the multi-level cascading platform has 2-5 levels.
[0016] Furthermore, in the multi-stage drop platform, the mass ratio of iron-carbon micro-electrolysis filler to photocatalytic filler in each stage of the drop platform is 3–6. Furthermore, the photocatalytic filler is wolframite.
[0017] The further beneficial effects of the above-mentioned method are as follows: Wolframite is a natural semiconductor mineral with a band gap of only 1.5 eV, which can absorb visible light and thus exhibit good photocatalytic activity under visible light. Wolframite has the ability to degrade various organic pollutants under visible light. For example, some scholars have shown that in the degradation experiment of methylene blue (MB), the degradation rate of wolframite is 3 times that of the control group without light or H2O2. In the experiment of degrading oxytetracycline, its removal efficiency can reach 94.3% under specific conditions. Moreover, the main component of wolframite is FeWO4, which is a natural mineral with abundant reserves and relatively low price, and has a significant cost advantage as a photocatalyst.
[0018] Furthermore, trace elements are added to the iron-carbon micro-electrolysis filler.
[0019] Furthermore, the trace element is copper.
[0020] The additional beneficial effects of the above are: the added copper can form more micro-galvanic cells, improve reaction efficiency, resist water flow impact, and is not easily pulverized. Attached Figure Description
[0021] Figure 1 This is a structural diagram of the artificial wetland system for the efficient removal of recalcitrant organic matter and new pollutants through a synergistic effect of micro-electrolysis and photocatalysis.
[0022] The attached diagram lists the components represented by each number as follows: 1. Upward-flowing subsurface constructed wetland; 2. Multi-stage cascading platform; 3. Iron-carbon micro-electrolysis packing material; 4. Photocatalytic packing material; 5. Surface flow wetland. Detailed Implementation
[0023] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0024] Example 1 like Figure 1 As shown, an artificial wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis includes: an upward-flowing subsurface artificial wetland 1, a multi-stage cascading platform 2, iron-carbon micro-electrolysis packing material 3, photocatalytic packing material 4, and a surface flow wetland 5. The upward-flowing subsurface artificial wetland 1 adopts a water distribution method of bottom inlet and top outlet, which is existing technology, so its structure will not be described in detail here. The water effluent from the upper part of the upward-flowing subsurface artificial wetland 1 flows into the multi-stage cascading platform 2, and the multi-stage cascading platform 2 has iron-carbon micro-electrolysis packing material 3 and photocatalytic packing material 4 distributed in each stage of the cascading platform. The water effluent from the lower part of the multi-stage cascading platform 2 flows into the surface flow wetland 5.
[0025] The operation process is as follows: The slightly polluted water first enters the upflow subsurface flow constructed wetland 1, where the water level is effectively raised, creating favorable hydraulic conditions for subsequent treatment. Within the upflow subsurface flow constructed wetland 1, the wastewater undergoes a sufficient anaerobic-anoxic environment, effectively decomposing large molecular organic matter and initially removing conventional pollutants (such as COD, nitrogen and phosphorus) and suspended solids (SS). The slightly polluted water treated by the upflow subsurface flow constructed wetland 1 is relatively clear, creating conditions for the smooth progress of the subsequent micro-electrolysis-photocatalysis-Fenton reaction, thereby improving the reaction efficiency. After being treated by the upward-flowing subsurface constructed wetland 1, the effluent enters the multi-stage cascading platform 2. The multi-stage cascading platform 2 utilizes the water level difference to allow the water to naturally reoxygenate during the cascading process, forming a good aerobic environment, which can further reduce COD, ammonia nitrogen and total phosphorus. The iron-carbon micro-electrolysis packing 3 and photocatalytic packing 4 distributed within the multi-stage cascading platform 2 form a "micro-electrolysis-photocatalysis-Fenton" synergistic oxidation core under the combined action of light and hydraulics. This core can efficiently degrade recalcitrant organic matter (such as pesticides and dye components) and some recalcitrant antibiotics (such as sulfonamides and quinolones) that were not removed in the previous stage. The iron-carbon micro-electrolysis packing 3 provides basic reduction, flocculation, and a continuous source of iron ions. The photocatalytic packing 4 generates highly oxidizing free radicals under the excitation of sunlight. The synergistic iron cycle and photocatalysis between the two enable the constructed wetland system to continuously, efficiently, and stably remove pollutants, thus becoming a very promising technology for the deep treatment of recalcitrant toxic and harmful wastewater. Finally, the effluent from the multi-stage cascading platform 2, after photoelectric co-treatment, enters the surface flow wetland 5. In the surface flow wetland 5, the remaining conventional pollutants and the small molecule organic matter generated after decomposition by photoelectric technology undergo final ecological deep purification and stabilization, ensuring that the effluent meets the standards before being discharged into the receiving water body. Through the orderly combination of multi-stage units and the synergistic effect of micro-electrolysis and photocatalysis, the aim is to enhance the overall removal capacity of constructed wetlands for recalcitrant organic matter and new pollutants, achieving tiered deep purification of pollutants. It also has advantages such as stable operation, low energy consumption, and strong adaptability, providing a new solution for the functional enhancement and promotion of constructed wetland technology.
[0026] 1) Iron-carbon micro-electrolysis removes recalcitrant toxic and harmful pollutants. Galvanic cell effect and strong redox ability: When iron (anode) and carbon (cathode, such as activated carbon, coke, etc.) come into contact in wastewater, countless tiny galvanic cells are formed, and the newly generated nascent Fe... 2+ The hydrogen atom (H) has strong reducing properties and can directly break the chemical bonds of some reducing pollutants (such as nitro compounds and azo dyes); Flocculation and precipitation: Fe generated during the reaction 2+ Further oxidized to Fe 3+ Fe 3+ Hydrolysis generates Fe(OH)3 colloids with highly efficient flocculation, which can adsorb and trap colloidal particles, tiny suspended solids and some hydrophobic organic matter in water, forming flocs and settling down; 2) Photocatalytic removal of recalcitrant toxic and harmful pollutants When exposed to sunlight, the valence band electrons in the photocatalytic filler are excited and transition to the conduction band, leaving a hole (h) in the valence band. + ), forming highly active "electron-hole pairs", holes (h + It possesses strong oxidizing power, capable of directly oxidizing organic matter adsorbed on the surface of photocatalytic fillers, or reacting with water to generate hydroxyl radicals (˙OH) and electrons (e). - It has a strong reducing ability and can react with oxygen to generate superoxide radicals: e - +O2→•O2 - It can also react further to generate ˙OH. Hydroxyl radicals (˙OH) are highly reactive species with extremely strong oxidizing power (redox potential as high as +2.8V). They can non-selectively attack and degrade most organic matter, eventually mineralizing it into CO2 and H2O.
[0027] 3) Iron-carbon micro-electrolysis provides both energy and clearance for photocatalysis. Iron-carbon micro-electrolysis continuously produces Fe 2+ Fe 2+It can react with H2O2 (produced by •O2) generated in the photocatalytic reaction. - (Generation pathway) undergoes a Fenton-like reaction: Fe 2+ +H₂O₂→Fe 3+ +˙OH+OH - This greatly promotes the generation of ˙OH, forming a coupled reaction chain of micro-electrolysis-photocatalysis-Fenton, resulting in an exponential increase in oxidation capacity; Iron can act as a source of photogenerated electrons (e.g., electrons). - It is a good acceptor for Fe, which can quickly capture electrons (Fe) on the conduction band of the photocatalytic filler. 3+ +e - →Fe 2+ This effectively suppresses the recombination of electron-hole pairs, allowing holes (h) to recombine. + It has more opportunities to oxidize pollutants or generate ˙OH, thereby significantly improving photocatalytic efficiency.
[0028] 4) Photocatalysis "regenerates" and "enhances" iron-carbon microelectrolysis: Photocatalytic reaction and ultraviolet light themselves can convert the Fe generated in the reaction 3+ Reduced to Fe 2+ (Fe) 3+ +e - →Fe 2+ ), construct Fe 2+ / Fe 3+ The circulation process enables in-situ regeneration of the iron catalyst, reducing iron loss and the generation of iron sludge, and maintaining the system's continuous and efficient reaction capacity.
[0029] 5) Low-carbon, green, and pollution-free The photocatalytic process of iron-carbon microelectrolysis and photocatalytic filler does not require the addition of additional chemical reagents, and the reaction products are non-toxic and harmless, which is in line with the concept of green chemistry.
[0030] Example 2 like Figure 1 As shown, this embodiment is a further improvement on embodiment 1, specifically as follows: the depth of each stage of the multi-stage cascading platform 2 is 0.1m to 0.3m, the length of each stage of the multi-stage cascading platform 2 along the water flow direction is 30cm to 80cm, the height difference between each stage of the multi-stage cascading platform 2 is determined according to the site elevation, and the cascading water can meet the gravity flow requirement. The hydraulic retention time of the water flowing from the top of the upward subsurface flow artificial wetland 1 into the multi-stage cascading platform 2 is 3h to 5h.
[0031] Furthermore, the multi-level cascading platform 2 has 2 to 5 levels.
[0032] Example 3 like Figure 1As shown, this embodiment is a further improvement on embodiment 1 or 2, as detailed below: In the multi-stage drop platform 2, the mass ratio of iron-carbon micro-electrolysis filler 3 and photocatalytic filler 4 in each stage of the drop platform is 3 to 6.
[0033] Example 4 like Figure 1 As shown, this embodiment is a further improvement on embodiment 1, 2, or 3, specifically as follows: the photocatalytic filler 4 is preferably wolframite. Wolframite is a natural semiconductor mineral with a band gap of only 1.5 eV, which can absorb visible light and thus exhibit good photocatalytic activity under visible light. Wolframite has the ability to degrade various organic pollutants under visible light. For example, some scholars have shown that in the degradation experiment of methylene blue (MB), the degradation rate of wolframite is 3 times that of the control group without light or without H2O2. In the experiment of degrading oxytetracycline, its removal efficiency can reach 94.3% under specific conditions. Moreover, the main component of wolframite is FeWO4, which is a natural mineral with abundant reserves and relatively low price, and has a significant cost advantage as a photocatalyst.
[0034] Example 5 like Figure 1 As shown, this embodiment is a further improvement on any one of embodiments 1 to 4, as detailed below: Trace elements are added to the iron-carbon micro-electrolysis filler 3, with copper being the preferred trace element.
[0035] The iron-carbon micro-electrolysis filler 3 uses high-temperature sintering technology to melt and solidify iron powder and carbon powder, while adding other trace elements. It has abundant micropores and mesopores, a large specific surface area, and provides a large number of reaction interfaces. Iron and carbon form a stable and interconnected skeleton structure in three-dimensional space, avoiding the compaction and caking problems that occur with traditional fillers over time. The added copper can form more micro-galvanic cells, improve reaction efficiency, resist water flow impact, and is not easy to pulverize.
[0036] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. An artificial wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants through micro-electrolysis and photocatalysis, characterized in that, include: An upward-flowing subsurface constructed wetland (1) has its effluent flowing into a multi-stage cascading platform (2). Each stage of the multi-stage cascading platform (2) contains iron-carbon micro-electrolysis filler (3) and photocatalytic filler (4). The effluent flowing below the multi-stage cascading platform (2) flows into a surface flow wetland (5).
2. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, The depth of each stage of the multi-stage drop platform (2) is 0.1m to 0.3m.
3. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, The length of each stage of the multi-stage drop platform (2) along the water flow direction is 30cm to 80cm.
4. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, The hydraulic retention time of the outflow from the above-ground subsurface flow constructed wetland (1) into the multi-stage drop platform (2) is 3h to 5h.
5. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to any one of claims 1 to 4, characterized in that, The multi-level drop platform (2) has 2 to 5 levels.
6. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, The mass ratio of iron-carbon micro-electrolysis filler (3) and photocatalytic filler (4) in each stage of the multi-stage drop platform (2) is 3 to 6.
7. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, The photocatalytic filler (4) is wolframite.
8. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 1, characterized in that, Trace elements are added to the iron-carbon micro-electrolysis filler (3).
9. The constructed wetland system for the synergistic and efficient removal of recalcitrant organic matter and new pollutants by micro-electrolysis and photocatalysis according to claim 8, characterized in that, The trace element is copper.