A single-step co-treatment method for cobalt-containing organic wastewater based on titanate

Abstract

The application provides a single-step and synergistic treatment method for cobalt-containing organic wastewater based on titanate, wherein after adjusting the pH of the cobalt-containing organic wastewater, titanate is first added to adsorb and treat Co(II) and part of the organic matters, and then an oxidizing agent is added to perform advanced oxidation treatment; through in-situ functionalization modification of the titanate adsorbed with Co(II), three functionalization modes are formed via interface adsorption enhancement, advanced oxidation promotion and local micro-disturbance, so that the residual organic matters in the cobalt-containing organic wastewater can be significantly removed. The single-step and synergistic treatment method can combine the cobalt ion and organic pollutant removal processes based on the titanate, realize the coupled treatment of "adsorption-advanced oxidation", and greatly improve the treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of cobalt-containing organic wastewater technology, and specifically to a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates. Background Technology

[0002] With the development of metal refining, electroplating, pharmaceuticals, catalysis, and other fields, a series of cobalt-containing organic wastewaters have been discharged into the environment, causing great harm. Therefore, research on wastewater treatment for systems where cobalt and organic matter coexist is needed.

[0003] Currently, for wastewater containing both cobalt and organic matter, a stepwise removal method for cobalt ions and organic matter is generally adopted. For cobalt ions in cobalt-containing organic wastewater, the main treatment methods include chemical precipitation, adsorption, and membrane separation. Chemical precipitation is the most widely used method in industry. However, during the precipitation process, as the pH of the wastewater increases, the organic matter coexisting in the cobalt-containing organic wastewater system easily interacts with cobalt, changing the state of cobalt ions and thus inhibiting the chemical precipitation reaction. Furthermore, organic matter may also be adsorbed into the sludge containing cobalt precipitation, increasing the difficulty of sludge recovery. Therefore, when using traditional chemical precipitation to treat cobalt-containing organic wastewater, it is difficult to achieve the required cobalt ion concentration in the effluent. For adsorption methods, the interaction between organic pollutants and cobalt ions alters the adsorption characteristics of the process. Simultaneously, cobalt ions and organic pollutants are adsorbed on the adsorbent surface, leading to difficulties in pollutant separation and adsorbent regeneration. For membrane separation methods, on the one hand, organic pollutants may increase membrane fouling, reducing the operational stability of the treatment process; on the other hand, biological methods and advanced oxidation processes are generally more widely used for organic pollutants. However, the presence of cobalt ions in the biological process can be toxic to microorganisms, limiting its application in cobalt-containing multi-element wastewater systems. Furthermore, advanced oxidation processes cannot remove cobalt ions during the process.

[0004] For example, CN 116477805 A discloses a zero-discharge treatment process for cobalt sulfonate chemical plating cleaning wastewater, including sequential chemical oxidation, sodium ion exchange, and seawater desalination RO membrane treatment. First, sodium hypochlorite oxidizes ammonia nitrogen in the wastewater during chemical oxidation, destroying the cobalt sulfonate form. Then, ion exchange resin is used to exchange and adsorb cobalt ions. The regeneration eluent of the ion exchange resin is used to remove alkali and precipitate cobalt resources. Finally, freshwater is recovered through seawater desalination RO membrane treatment. CN 113003793 A discloses a cobalt recovery method for cobalt chloride wastewater based on two-stage resin separation. This method removes organic matter and metallic impurities from cobalt chloride wastewater through a two-stage resin adsorption process, achieving deep purification of the cobalt chloride solution. However, regardless of the technical effectiveness of stepwise removal methods, these methods often involve multiple steps and different processes to remove cobalt ions and organic pollutants separately, resulting in relatively low process efficiency.

[0005] Although existing technologies disclose the use of photocatalysis for the synergistic reduction of heavy metals and oxidation of organic pollutants, there are no reports on its application to cobalt-containing organic wastewater. Furthermore, cobalt ions are difficult to reduce, and single-step removal methods, especially single-step synergistic removal methods, need to be developed.

[0006] To improve treatment efficiency and achieve synergistic removal of multiple pollutants from cobalt-containing organic wastewater, given the excellent removal effect of adsorption on cobalt ions, it is urgent to organically combine adsorption with advanced oxidation. Essentially, this involves constructing a rational synergistic treatment system for cobalt-containing organic wastewater based on wastewater treatment materials that possess both high-efficiency adsorption and advanced oxidation capabilities. To achieve this goal, it is necessary to combine the removal processes of cobalt ions and organic pollutants. This essentially requires finding a material with both adsorption and advanced oxidation capabilities, and developing a synergistic treatment process for cobalt ions and organic matter based on this material.

[0007] As an important class of inorganic materials, titanates are widely used in ion exchange and advanced oxidation wastewater treatment processes. For ion exchange, thanks to their abundant surface groups, large theoretical cation exchange capacity, rapid cation intercalation ability, and surface electronegativity under acidic conditions, titanate materials can rapidly and efficiently remove cationic pollutants from wastewater, such as Ag(I), Tl(I), Cd(II), Co(II), Hg(II), Pb(II), Cr(III), and U(VI). Furthermore, the [TiO6] octahedral structure within the titanate unit cell possesses certain photocatalytic oxidation characteristics, exhibiting good degradation effects on a range of pollutants, including organic dyes, pharmaceuticals, and personal care products. Therefore, titanates can be used to construct cobalt-containing multi-element wastewater treatment systems to achieve the synergistic removal of cobalt ions and organic pollutants.

[0008] In summary, there is a need to develop a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates. Summary of the Invention

[0009] In view of the problems existing in the prior art, this invention provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates. After adjusting the pH of the cobalt-containing organic wastewater, titanates are first added to adsorb Co(II) and some organic matter, followed by the addition of an oxidant for advanced oxidation treatment. Utilizing the in-situ functionalization modification of the titanates adsorbed with Co(II), through three functionalization modes—enhanced interfacial adsorption, promoted advanced oxidation, and local micro-perturbation—the remaining organic matter in the cobalt-containing organic wastewater can be significantly removed. The single-step synergistic treatment method of this invention combines the removal processes of cobalt ions and organic pollutants based on titanates, achieving a coupled "adsorption-advanced oxidation" treatment, which greatly improves treatment efficiency.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] This invention provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates, the single-step synergistic treatment method comprising the following steps:

[0012] Prepare cobalt-containing organic wastewater, adjust the pH, first add titanate for adsorption treatment, then add oxidant for advanced oxidation treatment, and after solid-liquid separation, obtain adsorbed titanate and filtrate; the filtrate is then post-treated to meet discharge requirements.

[0013] This invention describes a single-step synergistic treatment method for cobalt-containing organic wastewater systems. It utilizes titanate materials to construct an "adsorption-advanced oxidation" coupled treatment technology, providing a unique solution for the efficient synergistic treatment of cobalt-containing organic wastewater. Based on the adsorption characteristics and performance of titanates, the method utilizes the embedding of cobalt ions from cobalt-containing multi-component wastewater into titanates to achieve in-situ functionalization modification. Through three functionalization modes—interfacial adsorption enhancement, advanced oxidation promotion, and local micro-disturbance formation—the titanate materials are endowed with highly efficient cobalt ion-organic matter treatment performance. This changes the fixed approach of preparing composite materials for the synergistic treatment of multi-component wastewater, achieving the goal of efficient, synergistic, and sustainable treatment of cobalt-containing multi-component wastewater, and providing a new approach for the treatment of multi-component wastewater containing both metals and organic matter.

[0014] It should be noted that interface adsorption enhancement refers to the fact that cobalt ions adsorbed into titanate promote the adsorption of organic pollutants; advanced oxidation promotion refers to the fact that cobalt ions adsorbed into titanate promote the generation of free radicals by oxidants (such as hydrogen peroxide), which degrade pollutants; local micro-perturbation mainly forms micro-nano motors, which target oxidants that react to generate gas. For example, cobalt ions adsorbed into titanate catalyze the degradation of hydrogen peroxide, and the generated oxygen drives the movement of titanate, which can enhance the mass transfer process.

[0015] It should be noted that in the single-step synergistic treatment method described in this invention, the post-treatment of the filtrate can be carried out using existing technologies such as RO reverse osmosis and nanofiltration. Since cobalt ions and organic pollutants are basically completely treated, those skilled in the art can reasonably choose specific post-treatment methods, which will not be elaborated here.

[0016] As a preferred technical solution of the present invention, the single-step synergistic processing method further includes: regenerating the adsorbed titanate to recover cobalt resources, and reusing the obtained regenerated titanate; wherein, the regeneration process includes: sequentially rinsing, eluting, soaking and drying the adsorbed titanate to obtain regenerated titanate, and the eluent obtained by elution is used to recover cobalt resources.

[0017] It should be noted that in the single-step synergistic treatment method described in this invention, the organic matter in the cobalt-containing organic wastewater is oxidized into small molecules, mainly CO2 and water. Nitrogen-containing organic matter may be oxidized into N2. Because the overall advanced oxidation treatment is strong, it can handle a wide range of organic matter concentrations. However, after solid-liquid separation, a small amount of unoxidized organic matter may sometimes adhere to the surface of the adsorbed titanate. This can be cleaned with ethanol, or even by adding ethanol elution before Co elution, without affecting the recovery of cobalt resources. The eluent obtained from Co elution is concentrated through reverse osmosis, electrodialysis, and other operations to obtain a Co concentrate. Cobalt hydroxide, cobalt oxalate, and other products can be obtained by precipitation. As a preferred technical solution of this invention, in the regeneration treatment, the rinsing is performed using ethanol.

[0018] Preferably, the elution uses an EDTA-2Na solution with a concentration of 0.08-0.12 mol / L, such as 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.11 mol / L, or 0.12 mol / L.

[0019] Preferably, the soaking uses a NaCl solution with a concentration of 0.8-1.2 mol / L, such as 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, or 1.2 mol / L, and the soaking time is 1-3 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0020] Preferably, the drying temperature is 50-80℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, and the drying time is 10-15h, such as 10h, 11h, 12h, 13h, 14h or 15h.

[0021] As a preferred embodiment of the present invention, the concentration of Co(II) in the cobalt-containing organic wastewater is 0.1-1.0 mmol / L, such as 0.1 mmol / L, 0.3 mmol / L, 0.5 mmol / L, 0.6 mmol / L, 0.8 mmol / L, or 1.0 mmol / L, and the organic matter content is 20-700 mg / L, such as 20 mg / L, 50 mg / L, 70 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, 500 mg / L, 600 mg / L, or 700 mg / L.

[0022] As a preferred technical solution of the present invention, the pH adjustment involves adjusting the pH value of the cobalt-containing organic wastewater to 5-9, such as 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9.

[0023] It should be noted that the inventors' research found that titanate materials are more conducive to the catalytic degradation of organic matter through advanced oxidation treatment under near-neutral pH conditions. However, common cobalt-containing organic wastewater has a weakly acidic pH; as long as the pH is within the range of 5-9, it can be directly treated by adsorption and advanced oxidation.

[0024] As a preferred embodiment of the present invention, the structure of the titanate is Na. x H 2-x Ti3O7·gH2O, that is, the titanate described in this invention is preferably tritiate.

[0025] As a preferred technical solution of the present invention, the titanate is prepared by liquid-phase hydrothermal method. The preparation method includes the following steps: dispersing anatase titanium dioxide in NaOH solution and stirring, subjecting the resulting suspension to hydrothermal reaction, and then sequentially cooling, washing, drying and grinding to obtain titanate.

[0026] Preferably, in the liquid-phase hydrothermal preparation method, the concentration of the NaOH solution is 9-11 mol / L, such as 9 mol / L, 9.5 mol / L, 10 mol / L, 10.5 mol / L, or 11 mol / L, etc., and the mass-to-volume ratio of anatase titanium dioxide to NaOH solution is 1 g:(50-70) mL, such as 1 g:50 mL, 1 g:55 mL, 1 g:60 mL, 1 g:65 mL, or 1 g:70 mL, etc.

[0027] Preferably, the temperature of the hydrothermal reaction is 130-180℃, such as 130℃, 140℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃ or 180℃, and the time of the hydrothermal reaction is 1-5 days, such as 2 days, 2.5 days, 3 days, 3.5 days, 4 days, 4.5 days or 5 days.

[0028] Preferably, the drying includes drying at 50-70℃ for 10-15 hours, wherein the drying temperature is 50-70℃, for example 50℃, 53℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃ or 70℃, and the drying time is 10-15 hours, for example 10 hours, 11 hours, 12 hours, 13 hours, 14 hours or 15 hours.

[0029] As a preferred embodiment of the present invention, in the adsorption treatment, the dosage of titanate is 0.5-2.0 g / L, such as 0.5 g / L, 0.8 g / L, 1.0 g / L, 1.2 g / L, 1.5 g / L, 1.8 g / L or 2.0 g / L.

[0030] Preferably, the adsorption treatment time is 1-4 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0031] As a preferred technical solution of the present invention, in the advanced oxidation treatment, the oxidant includes a hydrogen peroxide solution, and the oxygen generated by the degradation of hydrogen peroxide drives the titanate particles to achieve self-driven motion and enhance mass transfer.

[0032] Preferably, the concentration of the hydrogen peroxide solution is 15-30 wt%, such as 15 wt%, 18 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, or 30 wt%.

[0033] Preferably, by controlling the amount of hydrogen peroxide solution added, the initial H2O2 concentration of the reaction system is 90-210 mmol / L, such as 90 mmol / L, 100 mmol / L, 103 mmol / L, 105 mmol / L, 108 mmol / L, 110 mmol / L, 113 mmol / L, 115 mmol / L, 118 mmol / L, or 210 mmol / L.

[0034] As a preferred technical solution of the present invention, the advanced oxidation treatment time is 1-4 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0035] Preferably, the advanced oxidation treatment is enhanced by an applied physical field; the applied physical field includes an optical field and / or an ultrasonic field.

[0036] It should be noted that the inventors' research has found that if an external physical field is a light field, titanate and TiO2 have the same [TiO6] octahedral crystal structure and possess certain photocatalytic activity. Therefore, under both ultraviolet and visible light irradiation, the removal efficiency of advanced oxidation treatment can be significantly improved. Although pure titanate materials have a wide bandgap and low absorption efficiency in the visible light range, titanate can accept photons to generate photogenerated electrons (electrons). - ) and holes (h + In this process, photogenerated electrons can be captured by O2 to generate ·O2. - Following a free radical chain reaction, H2O2 and ·OH are further generated, realizing the recycling of reactive oxygen species in the reaction system. If an ultrasonic field is used as the external physical field, mass transfer can be promoted based on the ultrasonic effect, enhancing the degradation of organic pollutants by the oxidant. Furthermore, because some titanates have a certain piezoelectric effect, some titanates will generate polarization when subjected to ultrasound, thereby creating ultrasonic charges on the titanate surface and enhancing the degradation of organic pollutants by the oxidant.

[0037] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0038] (1) This invention provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. After adjusting the pH of the cobalt-containing organic wastewater, titanate is first added to adsorb Co(II) and some organic matter. Then, an oxidant is added for advanced oxidation treatment. By utilizing the in-situ functionalization modification of titanate adsorbed with Co(II), three functionalization modes are formed through interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance, which can significantly remove the remaining organic matter in cobalt-containing organic wastewater.

[0039] (2) The single-step synergistic treatment method described in this invention is based on the fact that titanates can combine the removal processes of cobalt ions and organic pollutants, realizing the "adsorption-advanced oxidation" coupled treatment, which greatly improves the treatment efficiency. Attached Figure Description

[0040] Figure 1 This is a schematic diagram illustrating the working principle of a single-step collaborative processing method according to a specific embodiment of the present invention.

[0041] Figure 2 This is a SEM image of titanate according to a specific embodiment of the present invention;

[0042] Figure 3 This is a titanate XRD pattern of a specific embodiment of the present invention;

[0043] Figure 4 This invention explores the trajectory of a titanate material at different times (a)-(d) during local micro-perturbation in a specific embodiment of the invention.

[0044] Figure 5 This is a graph showing the cyclic performance of the regenerated titanate obtained after drying in Example 1 of the present invention for adsorbing Co(II) in a cyclic experiment;

[0045] Figure 6 This is a graph showing the cyclic performance of the regenerated titanate obtained after drying in Example 1 of the present invention for removing TC in a cyclic experiment. Detailed Implementation

[0046] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0047] This invention provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates, the single-step synergistic treatment method comprising the following steps:

[0048] Prepare cobalt-containing organic wastewater, adjust the pH, first add titanate for adsorption treatment, then add an oxidant for advanced oxidation treatment, and after solid-liquid separation, obtain adsorbed titanate and filtrate; the filtrate is post-treated to meet discharge requirements; the adsorbed titanate is regenerated to recover cobalt resources, and the obtained regenerated titanate can be reused; wherein, the regeneration treatment includes: sequentially rinsing, eluting, soaking and drying the adsorbed titanate to obtain regenerated titanate, and the eluent obtained from elution is used to recover cobalt resources;

[0049] Figure 1 The diagram illustrates the working principle of the single-step synergistic treatment method described in this invention. It shows that, based on the adsorption characteristics and performance of titanates, cobalt ions in cobalt-containing multi-element wastewater are embedded in titanates to achieve in-situ functional modification. On one hand, cobalt ions adsorbed into titanates promote the adsorption of organic pollutants, forming a functional mode with enhanced interfacial adsorption. On the other hand, cobalt ions adsorbed into titanates promote the generation of free radicals by oxidants (e.g., hydrogen peroxide), promoting the generation of reactive oxygen species and degrading pollutants, forming a functional mode that promotes advanced oxidation. Furthermore, if the oxidant used is one that reacts to generate gas, such as cobalt ions adsorbed into titanates catalyzing the degradation of hydrogen peroxide, the generated oxygen drives the movement of titanates, enhancing the mass transfer process and forming a micro-nano motor, thus creating a functional mode with localized micro-perturbation. Through these three functional modes—enhanced interfacial adsorption, promoted advanced oxidation, and localized micro-perturbation—the oxidation of organic pollutants can be enhanced, resulting in the oxidation of small molecules. Moreover, the adsorbed titanates are regenerated to recover cobalt ions, achieving material recycling.

[0050] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0051] Titanate preparation: 1 g of anatase titanium dioxide was dispersed in 60 mL of a 10 mol / L NaOH solution and stirred continuously for 2 h. The suspension was then transferred to a 100 mL stainless steel autoclave lined with polystyrene (PPL) and heated at 155 °C for 3 days in a forced-air drying oven. After cooling to room temperature, the material in the autoclave was washed with deionized water until the pH of the supernatant was close to neutral. Then, it was dried in a vacuum drying oven at 60 °C for 12 h and ground into a loose powder using a mortar and pestle for later use.

[0052] Titanate characterization: (1) Scanning electron microscopy analysis, relevant SEM images are as follows Figure 2As shown, the prepared titanate is a uniform nanorod with a length of up to 7.35 μm and a width of about 0.38 μm; (2) The crystal structure and phase composition of the titanate material were analyzed using X-ray diffraction (XRD) in the scanning range of 5-70°, such as Figure 3 As shown, the diffraction peaks of the prepared titanate are mainly related to those of trititanate Na. x H 2-x The diffraction planes of Ti3O7·gH2O (JCPDS: 47-0561) correspond to the diffraction planes; (3) After fitting with the BJH method and BET model, the specific surface area of ​​the prepared titanate is 34.2 m². 2 / g, pore volume is 0.06cm 3 / g, with an average pore size of 21.8nm.

[0053] Example 1

[0054] This embodiment provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates. The single-step synergistic treatment method includes the following steps:

[0055] (1) Prepare 1L of cobalt-containing organic wastewater. The cobalt-containing organic wastewater is wastewater from a cattle farm in Tongliao City, Inner Mongolia. The Co(II) concentration is 0.5mmol / L, the organic matter content is 500mg / L, and the pH is 3.4. The pH value is adjusted to 6 using NaOH solution.

[0056] (2) Add titanate at a dosage of 1.0 g / L for 3 h of adsorption treatment, and then add hydrogen peroxide solution at a concentration of 20 wt% for advanced oxidation treatment. The oxygen generated by the degradation of hydrogen peroxide drives the titanate particles to achieve self-driven motion and enhance mass transfer. By controlling the dosage of the hydrogen peroxide solution, the initial H2O2 concentration of the reaction system is 150 mmol / L. An ultrasonic field is set as an external physical field to promote mass transfer. The advanced oxidation treatment time is controlled to be 3 h.

[0057] (3) After solid-liquid separation, adsorbed titanate and filtrate are obtained; the filtrate is post-treated to meet the discharge requirements; the adsorbed titanate is regenerated by first rinsing several times with ethanol, then eluting with 0.1 mol / L EDTA-2Na solution, and then soaking in 1.0 mol / L NaCl solution for 2 hours to embed Na. + The solution is dried at 60°C for 12 hours to obtain regenerated titanate. The eluent obtained from the elution is used to recover cobalt resources.

[0058] To investigate local micro-perturbations, the conditions of Example 1 were used, except that stirring and the ultrasonic field were removed, and the movement of the titanate material under no-stirring conditions was monitored. Figure 4The motion trajectory of the titanate material (circled in red) at four different times during the monitoring process is shown, indicating that H2O2 decomposes at the cobalt ion sites on the material surface to produce oxygen, enabling the material to overcome gravity and move on its own. This motion can achieve local micro-perturbation.

[0059] Example 2

[0060] This embodiment provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. The only difference from Embodiment 1 is that the adsorption treatment time is 4 hours.

[0061] Example 3

[0062] This embodiment provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. The only difference from Embodiment 1 is that the adsorption treatment time is 1 hour.

[0063] Example 4

[0064] This embodiment provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. The only difference from Embodiment 1 is that the adsorption treatment time is 0.5h.

[0065] Comparative Example 1

[0066] This comparative example provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. The only difference from Example 1 is that titanate and oxidant are added simultaneously, that is, adsorption treatment and advanced oxidation treatment are carried out at the same time.

[0067] Comparative Example 2

[0068] This comparative example provides a method for treating cobalt-containing organic wastewater. Compared with Example 1, the only difference is that titanate is completely omitted, and an oxidant is directly added to the cobalt-containing organic wastewater for advanced oxidation treatment.

[0069] Includes the following steps:

[0070] (1') Prepare 1L of cobalt-containing organic wastewater. The cobalt-containing organic wastewater is wastewater from a cattle farm in Tongliao City, Inner Mongolia. The Co(II) concentration is 0.5mmol / L, the organic matter content is 500mg / L, and the pH is 3.4. The pH value is adjusted to 6 using NaOH solution.

[0071] (2') Add a 20wt% hydrogen peroxide solution for oxidation treatment. By controlling the amount of hydrogen peroxide solution added, the initial H2O2 concentration of the reaction system is 150mmol / L. Set an ultrasonic field as an external physical field to promote mass transfer. Control the oxidation treatment time to 3h.

[0072] (3') After solid-liquid separation, filter residue and filtrate are obtained.

[0073] In the cobalt-containing organic wastewater treated in the above examples and comparative examples, the Co(II) concentration was 0.5 mmol / L and the organic matter content was 500 mg / L. The Co(II) ion and organic matter concentrations of the filtrate obtained after treatment were detected using the same detection method, and the Co(II) ion removal rate and organic matter removal rate were calculated. The specific results are summarized in Table 1.

[0074] Table 1

[0075]

[0076] As can be seen from Table 1;

[0077] (1) In Examples 1-3 of the present invention, titanate is first added for adsorption treatment, and the adsorption treatment time is controlled to be 1-4h. Then, an oxidant is added for advanced oxidation treatment, which provides sufficient time for cobalt ions to be inserted into titanate to achieve in-situ functionalization modification. This can effectively ensure that the Co(II) ion removal rate is ≥90% and the organic matter removal rate is ≥70%.

[0078] (2) Comparing Example 1 and Example 4, since Example 4 shortened the adsorption treatment time to 0.5h, the in-situ functionalization modification of cobalt ions into titanate was not sufficient. On the one hand, organic matter attached to the surface of titanate blocked some of the intercalation channels, resulting in some cobalt ions remaining in the filtrate, and the removal rate of Co(II) ions decreased to 70%. On the other hand, in titanate with insufficient cobalt ion intercalation, the three functionalization modes of enhanced interfacial adsorption, advanced oxidation promotion, and local micro-disturbance were weakened, and the removal rate of organic matter decreased to 68.0%.

[0079] (3) Comparing Example 1 with Comparative Example 1, if titanate and oxidant are added at the same time, that is, adsorption treatment and advanced oxidation treatment are carried out at the same time, some organic matter adheres to the surface of titanate, blocking the cobalt ion insertion channel. However, the in-situ functionalization modification of titanate by cobalt ion insertion is not sufficient, and the three functionalization modes of interface adsorption enhancement, advanced oxidation promotion and local micro-disturbance are greatly weakened.

[0080] (4) Comparing Example 1 with Comparative Example 2, if titanate is completely omitted and the operation of removing cobalt ions is not performed, the Co(II) ion removal rate is 0%. Without the cobalt ion embedding into titanate to achieve its in-situ functionalization modification, there are no three functionalization modes of interface adsorption enhancement, advanced oxidation promotion and local micro-disturbance. Under the same hydrogen peroxide concentration and oxidation time, the organic matter removal rate is only 34.0%, and the oxidation effect of organic matter is greatly reduced.

[0081] All of the regenerated titanate obtained after drying in Example 1 was used in the next cycle experiment, i.e., the operation of Example 1 was repeated 5 times to evaluate the stability of the titanate. In each repeated experiment, after the addition of titanate, the ratio of the real-time concentration of Co(II) to the initial concentration (C / C0) in the system was immediately monitored over time to determine the regeneration effect of the titanate and to explore the cycle performance of the regenerated titanate in adsorbing cobalt ions. In each repeated experiment, tetracycline (TC) was used as the detection target. After the addition of the oxidant, the ratio of the real-time concentration of TC to the initial concentration (C / C0) in the system was immediately monitored over time to explore the cycle performance of the regenerated titanate in removing organic matter. Figure 5 and Figure 6 The cyclic performance diagrams of regenerated titanate for adsorbing Co(II) and removing TC are shown respectively. It can be seen that the material still maintains high reactivity after five cycles and has a good synergistic effect on both TC and Co(II).

[0082] In summary, this invention provides a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates. After adjusting the pH of the cobalt-containing organic wastewater, titanates are first added to adsorb Co(II) and some organic matter, followed by the addition of an oxidant for advanced oxidation treatment. Utilizing the in-situ functionalization modification of titanates adsorbed with Co(II), through three functionalization modes—interfacial adsorption enhancement, advanced oxidation promotion, and local micro-disturbance formation—the remaining organic matter in the cobalt-containing organic wastewater can be significantly removed. The single-step synergistic treatment method of this invention combines the removal processes of cobalt ions and organic pollutants based on titanates, achieving "adsorption-advanced oxidation" coupled treatment, which greatly improves treatment efficiency.

[0083] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0084] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0086] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A single-step synergistic treatment method for cobalt-containing organic wastewater based on titanates, characterized in that, The single-step collaborative processing method includes the following steps: Prepare cobalt-containing organic wastewater, adjust the pH, first add titanate for adsorption treatment, then add an oxidant for advanced oxidation treatment, and after solid-liquid separation, obtain adsorbed titanate and filtrate; the filtrate is then post-treated to meet discharge requirements; The cobalt-containing organic wastewater has a Co(II) concentration of 0.1-1.0 mmol / L and an organic matter content of 20-700 mg / L. The pH adjustment method aims to adjust the pH value of the cobalt-containing organic wastewater to 5-9. The structural formula of the titanate is Na. x H 2-x Ti3O7·gH2O; The advanced oxidation treatment is enhanced by an applied physical field; the applied physical field includes an optical field and / or an ultrasonic field. In the advanced oxidation process, the oxidant includes a hydrogen peroxide solution. The oxygen generated from the degradation of hydrogen peroxide drives the titanate particles to achieve self-driven motion and enhance mass transfer.

2. The single-step collaborative processing method according to claim 1, characterized in that, The single-step collaborative processing method further includes: The adsorbed titanate is regenerated to recover cobalt resources, and the resulting regenerated titanate can be reused. The regeneration process includes: sequentially rinsing, eluting, soaking, and drying the adsorbed titanate to obtain regenerated titanate. The eluent obtained from the elution is used to recover cobalt resources.

3. The single-step collaborative processing method according to claim 2, characterized in that, In the regeneration process, the rinsing is performed using ethanol.

4. The single-step collaborative processing method according to claim 2, characterized in that, The elution was performed using an EDTA-2Na solution with a concentration of 0.08-0.12 mol / L.

5. The single-step collaborative processing method according to claim 2, characterized in that, The soaking is performed using a NaCl solution with a concentration of 0.8-1.2 mol / L, and the soaking time is 1-3 hours.

6. The single-step collaborative processing method according to claim 2, characterized in that, The drying temperature is 50-80℃, and the drying time is 10-15 hours.

7. The single-step collaborative processing method according to claim 1, characterized in that, The titanate is prepared by a liquid-phase hydrothermal method, which includes the following steps: anatase titanium dioxide is dispersed in NaOH solution and stirred, the resulting suspension is subjected to a hydrothermal reaction, and then cooled, washed, dried and ground to obtain the titanate.

8. The single-step collaborative processing method according to claim 7, characterized in that, In the liquid-phase hydrothermal preparation method, the concentration of NaOH solution is 9-11 mol / L, and the mass-to-volume ratio of anatase titanium dioxide to NaOH solution is 1 g:(50-70) mL.

9. The single-step collaborative processing method according to claim 7, characterized in that, The hydrothermal reaction temperature is 130-180℃, and the hydrothermal reaction time is 1-5 days.

10. The single-step collaborative processing method according to claim 7, characterized in that, The drying process includes drying at 50-70℃ for 10-15 hours.

11. The single-step collaborative processing method according to claim 1, characterized in that, In the adsorption treatment, the dosage of titanate is 0.5-2.0 g / L.

12. The single-step collaborative processing method according to claim 1, characterized in that, The adsorption treatment time is 1-4 hours.

13. The single-step collaborative processing method according to claim 1, characterized in that, The concentration of the hydrogen peroxide solution is 15-30 wt%.

14. The single-step collaborative processing method according to claim 1, characterized in that, By controlling the amount of hydrogen peroxide solution added, the initial H2O2 concentration of the reaction system is made to be 90-210 mmol / L.

15. The single-step collaborative processing method according to claim 1, characterized in that, The advanced oxidation treatment takes 1-4 hours.

Images