Device and method based on iron modified resin photo-Fenton complex breaking and heavy metal synchronous recovery

Abstract

The invention discloses a device and a method for synchronously recovering light Fenton complex breaking and heavy metals based on iron modified resin. The device comprises an acidity adjusting tank, an H2O2 pretreatment tank, a two-stage photo-Fenton reaction device, an iron recovery and iron modified resin regeneration device, a regeneration liquid storage tank, a heavy metal recovery concentrated solution storage tank, a resin recovery device and an iron agent storage tank. And then carrying out photo-Fenton complex breaking and heavy metal ion synchronous adsorption and recovery treatment on the wastewater by using iron modified resin under illumination, recovering iron ions from the treated effluent by using resin, discharging the treated effluent after reaching the standard, carrying out regeneration treatment on the iron modified resin adsorbing the heavy metal ions by using a regeneration solution, and recovering a heavy metal concentrated solution and desorption resin. The recycled desorption resin and the resin for recycling iron realize regeneration of the iron modified resin in the presence of an iron ion supplement, and are recycled for photo-Fenton complex breaking and synchronous recycling of heavy metals. According to the method, the purpose of synchronous complex breaking and adsorption recovery of the heavy metal wastewater can be achieved, iron recovery and regeneration and synthesis of the iron modified resin can be achieved, the resource utilization rate of the resin is high, and large-scale and batch production can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of heavy metal complex wastewater treatment technology, specifically relating to a device and method for simultaneous recovery of heavy metals based on photo-Fenton cleavage and heavy metal recovery using iron-modified resin. Background Technology

[0002] Complexed heavy metals are a class of pollutants that are difficult to treat in industrial wastewater. They are mainly formed by metal ions and various chelating ligands. The functional groups of these ligands (such as hydroxyl, carboxyl, amino, and thiol groups) form coordinate bonds with the metal ions through electron donor atoms (such as N, S, and O). For example, ethylenediaminetetraacetic acid (EDTA) is an organic chelating ligand with a strong ability to chelate heavy metals. Due to the strong coordination between heavy metals and organic ligands, traditional heavy metal wastewater treatment technologies (such as chemical precipitation, ion exchange, coprecipitation adsorption, electrolysis, redox, reverse osmosis, and membrane separation) are difficult to effectively remove them. Moreover, these methods have high investment costs, are cumbersome to operate and manage, cause secondary pollution, and are difficult to solve problems related to the reuse of metals and water resources.

[0003] Complex disruption is considered an important step in the effective removal of metal complexes. In recent years, many oxidation methods have been used to remove heavy metal complexes, including Fe(III) / ultraviolet irradiation (UV), photoelectrocatalysis, discharge plasma, Fenton reaction, and photocatalysis. However, these methods are difficult to apply in engineering for the following three reasons: (1) large consumption of oxidants and low utilization rate; (2) narrow pH range, easy generation of metal sludge, and difficulty in recovering heavy metals; (3) catalysts are not easy to form, lack immobilization processing capacity, and are difficult to meet the needs of large-scale application.

[0004] Photo-Fenton reaction can enhance the Fe(III) / Fe(II) cycle during the Fenton reaction and utilize photogenerated electrons and holes from the photocatalyst, as well as hydroxyl radicals (·OH) generated from the reaction of Fe(III) with hydrogen peroxide (H₂O₂), thereby improving the complex-breaking efficiency of complexed heavy metals. However, photo-Fenton catalysis has low efficiency and stability, making it difficult to achieve effective recovery of heavy metal ions. Therefore, there is an urgent need to develop a treatment technology that can simultaneously achieve complex-breaking and resource recovery of complexed heavy metals.

[0005] The emergence of fluidized bed Fenton or Fenton-like catalytic oxidation technology has provided a promising approach to solving problems such as high sludge content and difficulty in heavy metal recovery. However, currently, no reactor can simultaneously meet the requirements of breaking down complexed heavy metals and recovering them. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and method for simultaneous photo-Fenton complex lysis and heavy metal recovery based on iron-modified resin. This invention first acidifies the wastewater containing heavy metal complexes, then pretreats it by mixing it with H2O2. Next, under light irradiation, iron-modified resin is used to simultaneously adsorb and recover heavy metal ions from the wastewater through photo-Fenton complex lysis. The treated effluent, after iron ion recovery by the resin, meets discharge standards. The iron-modified resin adsorbing heavy metal ions is then regenerated using a regenerated solution, recovering the heavy metal concentrate and desorption resin. The recovered desorption resin and iron-recovered resin are then regenerated in the presence of an iron ion supplement, and recycled for simultaneous photo-Fenton complex lysis and heavy metal recovery.

[0007] The technical solution for achieving the objective of this invention is as follows:

[0008] An apparatus for simultaneous recovery of heavy metals and photo-Fenton complexation using iron-modified resin includes: an acidity adjustment tank, an H2O2 pretreatment tank, a two-stage photo-Fenton reaction device, an iron recovery and iron-modified resin regeneration device, a regenerated liquid storage tank, a heavy metal recovery concentrate storage tank, a resin recovery device, and an iron agent storage tank. The acidity adjustment tank is connected to the H2O2 pretreatment tank, which is connected to the two-stage photo-Fenton reaction device connected in series internally. The two-stage photo-Fenton reaction device is connected to the iron recovery and iron-modified resin regeneration device, the regenerated liquid storage tank, the heavy metal recovery concentrate storage tank, and the resin recovery device, respectively. The resin recovery device is connected to the iron recovery and iron-modified resin regeneration device, which is connected to the iron agent storage tank.

[0009] Furthermore, an acidic pH adjuster or an alkaline pH adjuster is introduced into the acidity adjustment tank. The acidic pH adjuster is preferably hydrochloric acid, sulfuric acid, or nitric acid, and the alkaline pH adjuster is preferably sodium hydroxide, potassium hydroxide, or ammonia.

[0010] Furthermore, an H2O2 solution is introduced into the H2O2 pretreatment tank, with a preferred concentration of 0.1–2 mmol / L.

[0011] Furthermore, an iron-modified resin, preferably an iron-modified macroporous cation exchange resin, is introduced into the two-stage photo-Fenton reaction device. The resin contains 4 to 10 wt% iron. In a specific embodiment of the present invention, iron-modified macroporous cation exchange resin D001 is used as an example.

[0012] Furthermore, resin is introduced into the iron recovery and iron-modified resin regeneration device.

[0013] Furthermore, a regenerated solution is introduced into the regenerated solution storage tank. The regenerated solution is a dilute nitric acid solution with a preferred concentration of 10–30 wt%.

[0014] Furthermore, an iron ion supplement and resin are introduced into the iron storage tank. The iron ion supplement is one or more of ferric chloride, ferric sulfate, and ferric nitrate, with a concentration of 1-3 mol / L. The resin is one or more of a strongly acidic macroporous cation exchange resin and an iron-modified resin obtained after desorption of heavy metal ions recovered in the resin recovery device.

[0015] Furthermore, the two-stage photo-Fenton reactor includes a primary photo-Fenton reactor, a secondary photo-Fenton reactor, a primary feed pump, a secondary feed pump, a primary regenerated liquid feed pump, a secondary regenerated liquid feed pump, a primary gas mixing device, a secondary gas mixing device, a primary gas pump, a secondary gas pump, a primary light source chamber, and a secondary light source chamber. The primary feed pump and the primary regenerated liquid feed pump are connected to the primary photo-Fenton reactor, and the secondary feed pump and the secondary regenerated liquid feed pump are connected to the secondary photo-Fenton reactor. The upper inlet of the primary photo-Fenton reactor is connected to an H2O2 preheater via the primary feed pump. The treatment tank has a primary photo-Fenton reactor whose lower outlet is connected to the upper inlet of a secondary photo-Fenton reactor via a secondary feed pump. The lower inlet of the primary photo-Fenton reactor is connected to a regenerated liquid storage tank via a primary regenerated liquid feed pump. The upper outlet of the primary photo-Fenton reactor is connected to the lower inlet of the secondary photo-Fenton reactor via a secondary regenerated liquid feed pump. The primary photo-Fenton reactor is equipped with a primary gas mixing module at the bottom, which is connected to a primary gas pump. The secondary photo-Fenton reactor is equipped with a secondary gas mixing module at the bottom, which is connected to a secondary gas pump.

[0016] Furthermore, the primary air-mixing module includes three air nozzles, and the secondary air-mixing module, like the primary air-mixing module, also includes three air nozzles.

[0017] Furthermore, the primary gas mixing module introduces air or nitrogen into the nozzle through a primary gas pump, with the nozzle having an angle of 15-45° with the bottom, and the three nozzles forming a spiral triangle; the secondary gas mixing module introduces air or nitrogen into the nozzle through a secondary gas pump, with the nozzle having an angle of 15-45° with the bottom, and the three nozzles forming a spiral triangle.

[0018] Furthermore, the primary and secondary light source chambers adopt an embedded structure, are cylindrical in shape, and are made of quartz.

[0019] A method for simultaneous recovery of heavy metals based on photo-Fenton complexation and heavy metals using iron-modified resin includes the following steps:

[0020] S1. Heavy metal complex wastewater is fed into an acidity adjustment tank, where its pH is adjusted to 3-5 using an acidic or alkaline pH adjuster.

[0021] S2. The acidified heavy metal complex wastewater is fed into the H2O2 pretreatment tank and mixed with the H2O2 solution for pretreatment.

[0022] The wastewater containing heavy metal complexes after pretreatment with S3 and H2O2 is pumped into a two-stage photo-Fenton reactor. Under light irradiation, iron-modified resin is used for photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions.

[0023] S4. The treated wastewater is pumped into the iron recovery and iron-modified resin regeneration unit, where the resin is used to purify and recover iron ions in the tailwater, and the treated effluent that meets the standards is discharged.

[0024] S5. The regenerated liquid in the regenerated liquid storage tank is pumped into the two-stage photo-Fenton reactor to regenerate the iron-modified resin that adsorbs heavy metal ions. The resulting heavy metal concentrate and desorption resin are then pumped into the heavy metal recovery concentrate storage tank and the resin recovery device, respectively.

[0025] S6. The desorbed resin recovered in the resin recovery device is fed into the iron recovery and iron-modified resin regeneration device, and iron ion supplements from the iron agent storage tank are introduced. The desorbed resin and the iron-recovered resin obtained in step S4 are regenerated in the presence of iron ion supplements to achieve iron-modified resin regeneration. The regenerated iron-modified resin is then recycled to the two-stage photo-Fenton reactor for photo-Fenton complex breaking and simultaneous recovery of heavy metals.

[0026] Furthermore, in step S1, the heavy metal complexes include, but are not limited to, heavy metal-ethylenediaminetetraacetic acid complexes, heavy metal-citric acid complexes, and heavy metal-tartaric acid complexes, and the heavy metals include, but are not limited to, copper, lead, cadmium, and nickel.

[0027] Furthermore, in step S3, the light source is an ultraviolet or visible light source.

[0028] Furthermore, in step S4 or S6, the pumping speed of the iron ion supplement is 0.5 L / min to 10 L / min.

[0029] Furthermore, step S3 specifically includes:

[0030] S31. The first-stage feed pump pumps the heavy metal complex wastewater pretreated by H2O2 into the first-stage photo-Fenton reactor. At the same time, the first-stage gas pump performs gas mixing treatment on the first-stage photo-Fenton reactor through the first-stage gas mixing module. Under gas mixing conditions and light irradiation, iron-modified resin is used to perform first-stage photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions.

[0031] S32. After primary treatment, the wastewater is pumped into the secondary photo-Fenton reactor through the lower outlet of the primary photo-Fenton reactor by the secondary feed pump. At the same time, the secondary air pump performs gas mixing treatment on the secondary photo-Fenton reactor through the secondary gas mixing module. Under gas mixing conditions and light, iron-modified resin is used to perform secondary photo-Fenton complex breaking and heavy metal ion simultaneous adsorption and recovery treatment to improve the treatment efficiency of wastewater with complexed heavy metals of different concentrations.

[0032] Furthermore, in steps S31 and S32, the gas source for the gas mixing process is air or nitrogen, and the gas flow rate is 0.1–1.0 m / s. 3 / min; the pumping speed of the primary feed pump is 0.5L / min to 10L / min, the pumping speed of the secondary feed pump is 0.25L / min to 5L / min, and the pumping speed ratio of the primary feed pump to the secondary feed pump is 5:1 to 1:1.

[0033] Furthermore, step S5 specifically includes:

[0034] The regenerated liquid in the regenerated liquid storage tank is pumped into the first-stage photo-Fenton reactor through the lower inlet of the first-stage photo-Fenton reactor by the first-stage regenerated liquid feed pump, and then into the second-stage photo-Fenton reactor through the upper outlet of the first-stage photo-Fenton reactor by the second-stage regenerated liquid feed pump, to regenerate the iron-modified resin that adsorbs heavy metal ions. At the same time, the first-stage and second-stage air pumps perform air mixing treatment on the first-stage and second-stage photo-Fenton reactors through the first-stage and second-stage air mixing modules, respectively, and pump the resulting heavy metal concentrate and desorption resin into the heavy metal recovery concentrate storage tank and the resin recovery device, respectively.

[0035] Furthermore, the pumping speed of the primary regenerated liquid feed pump is 0.1L / min to 1L / min, the pumping speed of the secondary regenerated liquid feed pump is 0.1L / min to 1L / min, and the pumping speed ratio of the primary regenerated liquid feed pump to the secondary regenerated liquid feed pump is 5:1 to 1:5.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) Using iron-modified resin for photo-Fenton reaction, on the one hand, the Fe(III) / Fe(II) cycle is realized, the transfer of photogenerated electrons is promoted, the utilization rate of hydrogen peroxide is improved, the generation of active species is enhanced, and the complex breaking efficiency of complexed heavy metals is improved, with a heavy metal complex breaking rate of 100%. At the same time, it avoids the problem of large consumption of Fe(III) resources and generation of heavy metal sludge in traditional Fenton reaction.

[0038] (2) The ion exchange capacity of the iron-modified resin itself can efficiently adsorb and recover the heavy metal ions generated by the complex breaking, and the Fe(III) released into the tail water can be enriched and recovered through the iron recovery and iron-modified resin regeneration device, which further improves the purification effect of wastewater, realizes the deep treatment of wastewater and near-zero discharge of heavy metals, with a resin regeneration rate of >90% and a heavy metal recovery rate of >90%.

[0039] (3) A two-stage photo-Fenton reactor is used, which can improve the treatment efficiency of complexed heavy metal wastewater of different concentrations under gas-mixing conditions. By using gas-mixing treatment, the superposition of circumferential tangential force and axial convection generates strong shear force and convection diffusion inside the liquid. The solute or particles in the liquid are rapidly dispersed and collided in the vortex, which improves the light conversion efficiency on the one hand and the adsorption mass transfer efficiency between the resin and heavy metal ions on the other. This mixing method avoids liquid pollution and the mixing efficiency is much higher than that of traditional mechanical stirring.

[0040] (4) The two-stage photo-Fenton reactor adopts a fluidized bed reactor design, which can be used for efficient wastewater treatment on the one hand, and is conducive to the regeneration of iron-modified resin and the concentration and recovery of heavy metals on the other hand, significantly improving the utilization of iron-modified resin and the ability to simultaneously recover heavy metal resources. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0042] Figure 1 This is a schematic diagram of the overall structure of the photo-Fenton complex breaking and heavy metal simultaneous recovery device;

[0043] Figure 2 This is a schematic diagram of a two-stage photo-Fenton reactor.

[0044] Figure 3 This is a structural diagram of the primary and secondary gas-liquid mixing modules;

[0045] In the diagram: 1. Acidity adjustment tank; 2. H2O2 pretreatment tank; 3. Two-stage photo-Fenton reactor; 4. Iron recovery and iron-modified resin regeneration unit; 5. Regenerated liquid storage tank; 6. Heavy metal recovery concentrate storage tank; 7. Resin recovery unit; 8. Iron agent storage tank; 31. Primary photo-Fenton reactor; 32. Secondary photo-Fenton reactor; 33. Primary feed pump; 34. Secondary feed pump; 35. Primary regenerated liquid feed pump; 36. Secondary regenerated liquid feed pump; 37. Primary gas mixing module; 38. Secondary gas mixing module; 39. Primary air pump; 40. Secondary air pump; 41. Primary light source chamber; 42. Secondary light source chamber; 371. Air nozzle; 381. Air nozzle. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The iron-modified resin described in this invention is an iron ion exchange resin, which is prepared by a strategy of iron ion exchange through macroporous cation exchange resin. The macroporous cation exchange resin is first completely soaked in an alkaline solution, washed with water until neutral, then completely soaked in an acidic solution, washed with water until neutral, then completely soaked in a neutral solution, dried, and finally the resin is stirred and mixed with an iron ion solution to exchange iron ions onto the resin. After separation, it is washed with water until neutral and dried to obtain the iron ion exchange resin. In a specific embodiment of the present invention, an iron-modified macroporous cation exchange resin with an iron content of 8 wt% is used as an example. It is prepared through the following steps: First, the macroporous cation exchange resin (trade code D001) is pretreated by soaking in a 4% sodium hydroxide solution for 12 hours, then rinsing with deionized water until neutral, then soaking in 4% hydrochloric acid for 12 hours, rinsing with deionized water until neutral, and finally soaking in a 4% sodium chloride solution for 12 hours, rinsing with deionized water until neutral, and then drying. Subsequently, the pretreated D001 is added to an aqueous solution containing ferric chloride and mechanically stirred at room temperature for 12 hours to allow iron ions to exchange onto the resin. After separating the resin from the mixture, it is rinsed with deionized water until nearly neutral, and then vacuum dried to obtain the iron-modified resin (Fe-D001).

[0048] like Figure 1 As shown, the present invention relates to an apparatus for simultaneous recovery of heavy metals and photo-Fenton complexation using iron-modified resin, comprising: an acidity adjustment tank 1, an H2O2 pretreatment tank 2, a two-stage photo-Fenton reaction device 3, an iron recovery and iron-modified resin regeneration device 4, a regenerated liquid storage tank 5, a heavy metal recovery concentrate storage tank 6, a resin recovery device 7, and an iron agent storage tank 8. The acidity adjustment tank 1 is connected to the H2O2 pretreatment tank 2, which is connected to the two-stage photo-Fenton reaction device 3 connected in series internally. The two-stage photo-Fenton reaction device 3 is connected to the iron recovery and iron-modified resin regeneration device 4, the regenerated liquid storage tank 5, the heavy metal recovery concentrate storage tank 6, and the resin recovery device 7, respectively. The resin recovery device 7 is connected to the iron recovery and iron-modified resin regeneration device 4, and the iron recovery and iron-modified resin regeneration device 4 is connected to the iron agent storage tank 8.

[0049] Furthermore, the acidity adjustment tank 1 of the present invention is circulated with an acidic pH adjuster or an alkaline pH adjuster. The acidic pH adjuster is preferably hydrochloric acid, sulfuric acid or nitric acid, and the alkaline pH adjuster is preferably sodium hydroxide, potassium hydroxide or ammonia.

[0050] Furthermore, the H2O2 pretreatment tank 2 of the present invention is filled with H2O2 solution, the concentration of which is preferably 0.1 to 2 mmol / L.

[0051] Furthermore, the two-stage photo-Fenton reaction device 3 of the present invention is introduced with iron-modified resin, preferably iron-modified macroporous cation exchange resin, and the iron content of the resin is 4-10 wt%.

[0052] Furthermore, resin is introduced into the iron recovery and iron-modified resin regeneration device 4 described in this invention.

[0053] Furthermore, the regenerated liquid storage tank 5 of the present invention is filled with regenerated liquid, which is a dilute nitric acid solution with a preferred concentration of 10-30 wt%.

[0054] Furthermore, the iron storage tank 8 of the present invention is filled with an iron ion supplement and a resin, wherein the iron ion supplement is one or more of ferric chloride, ferric sulfate and ferric nitrate, with a concentration of 1 to 3 mol / L, and the resin is one or more of a strong acid macroporous cation exchange resin and an iron-modified resin recovered from the desorption of heavy metal ions in the resin recovery device 7.

[0055] like Figure 1 As shown, utilizing the above-mentioned apparatus, the present invention provides a method for simultaneous recovery of heavy metals based on iron-modified resin photo-Fenton complex disruption and heavy metal recovery, comprising the following steps:

[0056] S1. Heavy metal complex wastewater is introduced into acidity adjustment tank 1, and its pH is adjusted to 3-5 using acidic or alkaline pH adjusters. The pH of subsequent reactions can be controlled through acidity adjustment tank 1, thereby improving the utilization rate of H2O2 in the reaction system and achieving effective breakdown of heavy metal complexes in the wastewater.

[0057] S2. The acidified heavy metal complex wastewater is fed into H2O2 pretreatment tank 2 and mixed with H2O2 solution for pretreatment.

[0058] The wastewater containing heavy metal complexes after pretreatment with S3 and H2O2 is pumped into a two-stage photo-Fenton reactor 3. Under light irradiation, the wastewater undergoes photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions using iron-modified resin.

[0059] S4. The treated wastewater is pumped into the iron recovery and iron modification resin regeneration device 4, where the resin is used to purify and recover iron ions in the tailwater, and the treated effluent that meets the standards is discharged.

[0060] S5. The regenerated liquid in the regenerated liquid storage tank 5 is pumped into the two-stage photo-Fenton reaction device 3 to regenerate the iron-modified resin that adsorbs heavy metal ions. The resulting heavy metal concentrate and desorption resin are then pumped into the heavy metal recovery concentrate storage tank 6 and the resin recovery device 7, respectively.

[0061] S6. The desorbed resin recovered in the resin recovery device 7 is fed into the iron recovery and iron-modified resin regeneration device 4, and iron ion supplements in the iron agent storage tank 8 are fed in. The desorbed resin and the iron-recovered resin obtained in step S4 are regenerated in the presence of iron ion supplements to achieve iron-modified resin regeneration. The regenerated iron-modified resin is then recycled to the two-stage photo-Fenton reaction device 3 for photo-Fenton complex breaking and simultaneous recovery of heavy metals.

[0062] Furthermore, in step S3, the light source is an ultraviolet or visible light source.

[0063] Furthermore, in step S4 or S6, the pumping speed of the iron ion supplement is 0.5 L / min to 10 L / min.

[0064] like Figure 2 As shown, the two-stage photo-Fenton reactor 3 includes a primary photo-Fenton reactor 31, a secondary photo-Fenton reactor 32, a primary feed pump 33, a secondary feed pump 34, a primary regenerated liquid feed pump 35, a secondary regenerated liquid feed pump 36, a primary gas mixing device 37, a secondary gas mixing device 38, a primary gas pump 39, a secondary gas pump 40, a primary light source chamber 41, and a secondary light source chamber 42. The primary feed pump 33 and the primary regenerated liquid feed pump 35 are connected to the primary photo-Fenton reactor 31, and the secondary feed pump 34 and the secondary regenerated liquid feed pump 36 are connected to the secondary photo-Fenton reactor 32. The upper inlet of the primary photo-Fenton reactor 31 is connected to H2 through the primary feed pump 33. The O2 pretreatment tank 2 and the lower outlet of the primary photo-Fenton reactor 31 are connected to the upper inlet of the secondary photo-Fenton reactor 32 via a secondary feed pump 34. The lower inlet of the primary photo-Fenton reactor 31 is connected to the regenerated liquid storage tank 5 via a primary regenerated liquid feed pump 35. The upper outlet of the primary photo-Fenton reactor 31 is connected to the lower inlet of the secondary photo-Fenton reactor 32 via a secondary regenerated liquid feed pump 36. The bottom of the primary photo-Fenton reactor 31 is equipped with a primary gas mixing module 37, which is connected to a primary air pump 39. The bottom of the secondary photo-Fenton reactor 32 is equipped with a secondary gas mixing module 38, which is connected to a secondary air pump 40.

[0065] like Figure 3 As shown, the primary air-mixing module 37 includes three air nozzles 371, and the secondary air-mixing module 38 is the same as the primary air-mixing module 37, also including three air nozzles.

[0066] Furthermore, the primary gas mixing module 37 introduces air or nitrogen gas into the nozzle 371 through the primary gas pump 39. The nozzle 371 has an angle of 15-45° with the bottom, and the three nozzles form a spiral triangle. The secondary gas mixing module 38 introduces air or nitrogen gas into the nozzle 381 through the secondary gas pump 40. The nozzle 381 has an angle of 15-45° with the bottom, and the three nozzles form a spiral triangle.

[0067] Furthermore, the primary light source chamber 41 and the secondary light source chamber 42 adopt an embedded structure, are cylindrical in shape, and are made of quartz.

[0068] In the method for simultaneous recovery of heavy metals based on photo-Fenton complexation and heavy metals using iron-modified resin described in this invention, step S3 specifically comprises:

[0069] S31, the first-stage feed pump 33 pumps the heavy metal complex wastewater pretreated by H2O2 into the first-stage photo-Fenton reactor 31. At the same time, the first-stage air pump 39 performs gas mixing treatment on the first-stage photo-Fenton reactor 31 through the first-stage gas mixing module 37, which promotes the rapid dispersion and collision of solutes or particles in the liquid in the vortex. Under gas mixing conditions and light irradiation, iron-modified resin is used to perform first-stage photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions.

[0070] S32. After primary treatment, the wastewater is pumped into the secondary photo-Fenton reactor 32 through the lower outlet of the primary photo-Fenton reactor 31 by the secondary feed pump 34. At the same time, the secondary air pump 40 performs gas mixing treatment on the secondary photo-Fenton reactor 32 through the secondary gas mixing module 38, which promotes the rapid dispersion and collision of solutes or particles in the liquid in the vortex. Under gas mixing conditions and light, iron-modified resin is used to perform secondary photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions, so as to improve the treatment efficiency of wastewater with complexed heavy metals of different concentrations.

[0071] This invention further employs gas-liquid mixing to treat wastewater. By utilizing the superposition of circumferential tangential force and axial convection, strong shear forces and convective diffusion are generated within the liquid. Solutes or particles in the liquid are rapidly dispersed and collided within the vortex, improving both light conversion efficiency and the adsorption mass transfer efficiency between the resin and heavy metal ions. This mixing method avoids liquid contamination and has a mixing efficiency far exceeding that of traditional mechanical stirring.

[0072] Furthermore, in steps S31 and S32, the gas source for the gas mixing process is air or nitrogen, and the gas flow rate is 0.1–1.0 m / s. 3 / min; the pumping speed of the primary feed pump 33 is 0.5L / min to 10L / min, the pumping speed of the secondary feed pump 34 is 0.25L / min to 5L / min, and the pumping speed ratio of the primary feed pump 33 to the secondary feed pump 34 is 5:1 to 1:1.

[0073] In the method for simultaneous recovery of heavy metals based on photo-Fenton complexation and heavy metals using iron-modified resin described in this invention, step S5 specifically comprises:

[0074] The regenerated liquid in the regenerated liquid storage tank 5 is pumped into the first-stage photo-Fenton reactor 31 through the lower inlet of the first-stage photo-Fenton reactor 31 via the first-stage regenerated liquid feed pump 34, and then into the second-stage photo-Fenton reactor 32 through the upper outlet of the first-stage photo-Fenton reactor 31 via the second-stage regenerated liquid feed pump 36, to regenerate the iron-modified resin that adsorbs heavy metal ions. At the same time, the first-stage air pump 39 and the second-stage air pump 40 respectively perform air mixing treatment on the first-stage photo-Fenton reactor 31 and the second-stage photo-Fenton reactor 32 through the first-stage air mixing module 37 and the second-stage air mixing module 38, to promote the rapid dispersion and collision of solutes or particles in the liquid in the vortex. The resulting heavy metal concentrate and desorption resin are then pumped into the heavy metal recovery concentrate storage tank 6 and the resin recovery device 7, respectively.

[0075] Furthermore, the pumping speed of the primary regenerated liquid feed pump is 0.1L / min to 1L / min, the pumping speed of the secondary regenerated liquid feed pump is 0.1L / min to 1L / min, and the pumping speed ratio of the primary regenerated liquid feed pump to the secondary regenerated liquid feed pump is 5:1 to 1:5.

[0076] Example 1

[0077] This embodiment illustrates a method for simultaneous recovery of heavy metals based on photo-Fenton complex cleavage and heavy metal recovery using iron-modified resin. The heavy metal complexes in the wastewater are complexes containing ethylenediaminetetraacetic acid ligands, with an initial concentration of 10 mg / L. The heavy metals are copper, lead, cadmium, and nickel. The specific steps include:

[0078] S1. The wastewater containing heavy metal complexes is fed into an acidity adjustment tank containing 0.5 wt% dilute sulfuric acid. The pH is adjusted to 3 through acid treatment.

[0079] S2. The acidified heavy metal complex wastewater is passed into an H2O2 pretreatment tank containing 0.1 mmol / L H2O2 solution for mixing and pretreatment.

[0080] S3. The heavy metal complex wastewater pretreated with H2O2 is pumped into a two-stage photo-Fenton reactor. Iron-modified macroporous cation exchange resin D001 (styrene-divinylbenzene copolymer with sulfonic acid groups) with an iron content of 8wt% is selected as the iron-modified resin, and its dosage is fixed at 1g / L. Under air-gas mixing conditions and simulated sunlight, 3.5L of heavy metal complex wastewater is continuously treated by photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions within 2 hours.

[0081] S4. The treated wastewater is pumped into the iron recovery and iron-modified resin regeneration device. The iron ions in the tailwater are purified and recovered using macroporous cation exchange resin D001. The loading amount of macroporous cation exchange resin D001 is 1g / L. The treated effluent that meets the standards is discharged.

[0082] S5. Pump 5wt% dilute nitric acid from the regenerated liquid storage tank into the two-stage photo-Fenton reactor. The iron-modified resin that adsorbs heavy metal ions is backwashed with 5wt% dilute nitric acid to obtain a heavy metal concentrate and a desorption resin. Pump the obtained heavy metal concentrate into the heavy metal recovery concentrate storage tank and pump the desorption resin into the resin recovery device.

[0083] S6. The desorbed resin recovered in the resin recovery device is passed into the iron recovery and iron-modified resin regeneration device, and a 5 mg / L ferric nitrate solution from the iron agent storage tank is passed in. The desorbed resin and the iron-recovered resin obtained in step S4 are regenerated in the presence of iron ion supplement. The regenerated iron-modified resin is then recycled to the two-stage photo-Fenton reactor for photo-Fenton complex breaking and simultaneous recovery of heavy metals.

[0084] The concentrations of heavy metals (C1, mg / L) and total volume (V1, L) in the effluent from the two-stage photo-Fenton reactor were measured, as were the concentrations of heavy metals (C2, mg / L) and total volume (V2, L) in the effluent from the heavy metal recovery and concentration unit. The iron content (η1, %) in the iron-modified resin before reaction and the iron content (η2, %) in the regenerated iron-modified resin were also measured. The initial concentration of the heavy metal complex wastewater was C0 (mg / L), and the treatment volume was V0 (L). The heavy metal removal rate, heavy metal recovery efficiency, and resin regeneration efficiency were calculated using the following formulas, and the results are shown in Table 1.

[0085]

[0086] Table 1

[0087]

[0088] Comparative Example 1

[0089] This comparative example is roughly the same as Example 1, except that in S3: the heavy metal complex wastewater pretreated with H2O2 is pumped into a two-stage photo-Fenton reactor and 8 mg / L of ferric nitrate is added. Macroporous cation exchange resin D001 is selected to replace the iron-modified resin and its dosage is fixed at 1 g / L. Under air-gas mixing conditions and simulated sunlight, 3.5 L of heavy metal complex wastewater is continuously treated by photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions within 2 hours.

[0090] The calculation methods for heavy metal removal rate, heavy metal recovery efficiency and resin regeneration efficiency are the same as in Example 1, and the results are shown in Table 2.

[0091] Table 2

[0092]

[0093] As shown in Tables 1 and 2, in Example 1, iron-modified macroporous cation exchange resin D001 with an iron content of 8 wt% was selected as the reaction material. Photo-Fenton complex lysis and simultaneous adsorption and recovery of heavy metal ions were carried out under simulated sunlight conditions. Since Fe exists in different spin states in the iron-modified resin, it can generate ·OH through the free radical pathway and non-free radical pathways. 1 O2 oxidizes organic ligands, thereby breaking down heavy metal complexes. In the iron-modified resin, Fe(III) is reduced to Fe(II), which further activates H2O2 to generate ·OH and... 1 O2 is used to generate Fe(III), which, under light irradiation, can be reduced to Fe(II) and continue to participate in the generation of ROS, achieving an efficient Fe(III) / Fe(II) cycle and improving the utilization rate of iron ions. The free heavy metal ions released after complex disruption are then captured by the resin carrier through ion exchange, achieving efficient removal of heavy metal complexes while recovering heavy metal resources. The method of this invention achieves a heavy metal removal rate >95% for four types of heavy metal complex wastewater, and a heavy metal recovery rate >90% after desorption with dilute nitric acid. Furthermore, the desorbed resin can regain an iron content of 8 wt% after ion exchange adsorption treatment in the presence of ferric nitrate supplement, with a regeneration efficiency >90%. Comparative Example 1 used 8 mg / L of ferric nitrate and macroporous cation exchange resin D001 instead of iron-modified resin for photo-Fenton complex cleavage and simultaneous adsorption and recovery of heavy metal ions. Compared with Example 1, the synergistic effect of free iron ions and resin resulted in a heavy metal removal rate of <50% for the four heavy metal complex wastewaters, but the heavy metal recovery rate and resin regeneration efficiency were both >90%. This is because the high concentration of Fe(II) in the homogeneous system catalyzes the rapid generation of fast ·OH and OH- from H2O2. - This leads to an increase in the solution pH, causing Fe(II) and Fe(III) to form hydroxide precipitates, affecting catalytic activity and complex-breaking performance, and generating a large amount of heavy metal sludge. Therefore, the method of this invention not only satisfies the need for complex breaking in heavy metal wastewater, but also simultaneously achieves the recovery of heavy metals from the wastewater and the regeneration of the resin.

[0094] Comparative Example 2

[0095] This comparative example is largely the same as Example 1, except for S3: the heavy metal complex wastewater pretreated with H2O2 is pumped into a two-stage photo-Fenton reactor. Iron-modified macroporous cation exchange resin D001 with an iron content of 8wt% is selected as the iron-modified resin, and its dosage is fixed at 1g / L. Under simulated sunlight, 3.5L of heavy metal complex wastewater is continuously treated by photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions under simulated sunlight for 2 hours without the use of an air mixing device.

[0096] The calculation methods for heavy metal removal rate, heavy metal recovery efficiency and resin regeneration efficiency are the same as in Example 1, and the results are shown in Table 3.

[0097] Table 3

[0098]

[0099] The results in Tables 1 and 3 show that, compared to Example 1, without the use of an air mixing device, using iron-modified macroporous cation exchange resin with an iron content of 8 wt% as the reaction material, and conducting simultaneous adsorption and recovery of heavy metal ions under simulated sunlight conditions, the heavy metal removal rate of the four heavy metal complex wastewaters was all <55%, and the heavy metal recovery rate and resin regeneration efficiency were both <65%. This is because the lack of air mixing operation led to severe accumulation of the iron-modified resin in the photo-Fenton reactor, preventing effective dispersion in the solution. This problem directly resulted in a decrease in the light utilization rate of the iron-modified resin and affected the sufficient contact between the iron-modified resin and the wastewater, making it difficult to effectively adsorb and decomplex the heavy metal ions, ultimately leading to a low heavy metal removal rate. Furthermore, when the regenerated liquid was pumped into the two-stage photo-Fenton reactor, the lack of an air mixing device prevented sufficient contact between the regenerated liquid and the iron-modified resin, making it difficult to effectively desorb the heavy metal ions adsorbed by the resin and further affecting the effective regeneration of the iron-modified resin.

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for simultaneous recovery of heavy metals based on photo-Fenton complex disruption and heavy metal recovery using iron-modified resin, characterized in that, include: The system comprises an acidity adjustment tank, an H2O2 pretreatment tank, a two-stage photo-Fenton reactor, an iron recovery and iron-modified resin regeneration device, a regenerated liquid storage tank, a heavy metal recovery concentrate storage tank, a resin recovery device, and an iron agent storage tank. The acidity adjustment tank is connected to the H2O2 pretreatment tank, which is connected to the two-stage photo-Fenton reactor connected in series internally. The two-stage photo-Fenton reactor is connected to the iron recovery and iron-modified resin regeneration device, the regenerated liquid storage tank, the heavy metal recovery concentrate storage tank, and the resin recovery device, respectively. The resin recovery device is connected to the iron recovery and iron-modified resin regeneration device, which is connected to the iron agent storage tank.

2. The apparatus according to claim 1, characterized in that, An acidic pH adjuster or an alkaline pH adjuster is introduced into the acidity adjustment tank. The acidic pH adjuster is hydrochloric acid, sulfuric acid, or nitric acid, and the alkaline pH adjuster is sodium hydroxide, potassium hydroxide, or ammonia. An H2O2 solution is introduced into the H2O2 pretreatment tank. Iron-modified resin is introduced into the two-stage photo-Fenton reaction device. Resin is introduced into the iron recovery and iron-modified resin regeneration device. Regeneration solution is introduced into the regeneration liquid storage tank. The regeneration liquid is a dilute nitric acid solution. An iron agent storage tank is introduced into the iron ion supplement and resin. The iron ion supplement is one or more of ferric chloride, ferric sulfate, and ferric nitrate. The resin is one or more of a strongly acidic macroporous cation exchange resin and iron-modified resin after desorption of heavy metal ions recovered in the resin recovery device.

3. The apparatus according to claim 2, characterized in that, The concentration of the H2O2 solution is 0.1~2 mmol / L; the iron-modified resin is an iron-modified macroporous cation exchange resin with an iron content of 4~10 wt%; the concentration of the dilute nitric acid solution is 10~30 wt%; and the concentration of the iron ion supplement is 1~3 mol / L.

4. The apparatus according to claim 1, characterized in that, The two-stage photo-Fenton reactor includes a primary photo-Fenton reactor, a secondary photo-Fenton reactor, a primary feed pump, a secondary feed pump, a primary regenerated liquid feed pump, a secondary regenerated liquid feed pump, a primary gas mixing device, a secondary gas mixing device, a primary gas pump, a secondary gas pump, a primary light source chamber, and a secondary light source chamber. The primary feed pump and the primary regenerated liquid feed pump are connected to the primary photo-Fenton reactor, and the secondary feed pump and the secondary regenerated liquid feed pump are connected to the secondary photo-Fenton reactor. The upper inlet of the primary photo-Fenton reactor is connected to an H2O2 pretreatment system via the primary feed pump. The tank has a primary light-emitting Fenton reactor. The lower outlet of the primary light-emitting Fenton reactor is connected to the upper inlet of the secondary light-emitting Fenton reactor via a secondary feed pump. The lower inlet of the primary light-emitting Fenton reactor is connected to a regenerated liquid storage tank via a primary regenerated liquid feed pump. The upper outlet of the primary light-emitting Fenton reactor is connected to the lower inlet of the secondary light-emitting Fenton reactor via a secondary regenerated liquid feed pump. The bottom of the primary light-emitting Fenton reactor is equipped with a primary gas mixing module, which is connected to a primary gas pump. The bottom of the secondary light-emitting Fenton reactor is equipped with a secondary gas mixing module, which is connected to a secondary gas pump. The primary or secondary gas-mixing module includes three air nozzles that form a spiral triangle with an angle of 15-45° between the nozzles and the bottom. The primary and secondary light source chambers are embedded in a cylindrical shape and made of quartz.

5. A method for simultaneous recovery of heavy metals based on photo-Fenton complex disruption and heavy metal recovery using iron-modified resin, characterized in that... Includes the following steps: S1. Heavy metal complex wastewater is fed into an acidity adjustment tank, where its pH is adjusted to 3-5 using an acidic or alkaline pH adjuster. S2. The acidified heavy metal complex wastewater is fed into the H2O2 pretreatment tank and mixed with the H2O2 solution for pretreatment. The wastewater containing heavy metal complexes after pretreatment with S3 and H2O2 is pumped into a two-stage photo-Fenton reactor. Under light irradiation, iron-modified resin is used for photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions. S4. The treated wastewater is pumped into the iron recovery and iron-modified resin regeneration unit, where the resin is used to purify and recover iron ions in the tailwater, and the treated effluent that meets the standards is discharged. S5. The regenerated liquid in the regenerated liquid storage tank is pumped into the two-stage photo-Fenton reactor to regenerate the iron-modified resin that adsorbs heavy metal ions. The resulting heavy metal concentrate and desorption resin are then pumped into the heavy metal recovery concentrate storage tank and the resin recovery device, respectively. S6. The desorbed resin recovered in the resin recovery device is fed into the iron recovery and iron-modified resin regeneration device, and iron ion supplements from the iron agent storage tank are introduced. The desorbed resin and the iron-recovered resin obtained in step S4 are regenerated in the presence of iron ion supplements to achieve iron-modified resin regeneration. The regenerated iron-modified resin is then recycled to the two-stage photo-Fenton reactor for photo-Fenton complex breaking and simultaneous recovery of heavy metals.

6. The method according to claim 5, characterized in that, In step S1, the heavy metal complex is one or more of heavy metal-ethylenediaminetetraacetic acid complex, heavy metal-citric acid complex, and heavy metal-tartaric acid complex, and the heavy metal is one or more of copper, lead, cadmium, and nickel; in step S3, the light source is an ultraviolet or visible light source; in step S4 or S6, the pumping speed of the iron ion supplement is 0.5 L / min to 10 L / min.

7. The method according to claim 5, characterized in that, Step S3 is as follows: S31. The first-stage feed pump pumps the heavy metal complex wastewater pretreated by H2O2 into the first-stage photo-Fenton reactor. At the same time, the first-stage gas pump performs gas mixing treatment on the first-stage photo-Fenton reactor through the first-stage gas mixing module. Under gas mixing conditions and light irradiation, iron-modified resin is used to perform first-stage photo-Fenton complex breaking and simultaneous adsorption and recovery of heavy metal ions. S32. After primary treatment, the wastewater is pumped into the secondary photo-Fenton reactor through the lower outlet of the primary photo-Fenton reactor by the secondary feed pump. At the same time, the secondary air pump performs gas mixing treatment on the secondary photo-Fenton reactor through the secondary gas mixing module. Under gas mixing conditions and light, iron-modified resin is used to perform secondary photo-Fenton complex breaking and heavy metal ion simultaneous adsorption and recovery treatment to improve the treatment efficiency of wastewater with complexed heavy metals of different concentrations.

8. The method according to claim 7, characterized in that, In steps S31 and S32, the gas source for the gas mixing process is air or nitrogen, and the gas flow rate is 0.1~1.0 m. 3 / min; the pumping speed of the primary feed pump is 0.5 L / min to 10 L / min, the pumping speed of the secondary feed pump is 0.25 L / min to 5 L / min, and the pumping speed ratio of the primary feed pump to the secondary feed pump is 5:1 to 1:

1.

9. The method according to claim 7, characterized in that, Step S5 is as follows: The regenerated liquid in the regenerated liquid storage tank is pumped into the first-stage photo-Fenton reactor through the lower inlet of the first-stage photo-Fenton reactor by the first-stage regenerated liquid feed pump, and then into the second-stage photo-Fenton reactor through the upper outlet of the first-stage photo-Fenton reactor by the second-stage regenerated liquid feed pump, to regenerate the iron-modified resin that adsorbs heavy metal ions. At the same time, the first-stage and second-stage air pumps perform air mixing treatment on the first-stage and second-stage photo-Fenton reactors through the first-stage and second-stage air mixing modules, respectively, and pump the resulting heavy metal concentrate and desorption resin into the heavy metal recovery concentrate storage tank and the resin recovery device, respectively.

10. The method according to claim 9, characterized in that, The pumping speed of the primary regenerated liquid feed pump is 0.1 L / min to 1 L / min, and the pumping speed of the secondary regenerated liquid feed pump is 0.1 L / min to 1 L / min. The pumping speed ratio between the primary and secondary regenerated liquid feed pumps is 5:1 to 1:5.

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