Titanate-based cobalt-containing organic wastewater single-step cooperative treatment method

Abstract

The invention provides a titanate-based cobalt-containing organic wastewater single-step cooperative treatment method, which comprises the following steps: after adjusting the pH value of cobalt-containing organic wastewater, firstly adding titanate to adsorb Co (II) and part of organic matters, then adding an oxidant to carry out advanced oxidation treatment, and carrying out in-situ functional modification by using the titanate adsorbed with Co (II), thereby obtaining the cobalt-containing organic wastewater. Three functional modes are formed through interface adsorption enhancement, advanced oxidation promotion and local perturbation, and residual organic matters in the cobalt-containing organic wastewater can be remarkably removed. According to the single-step cooperative treatment method, cobalt ions and the organic pollutant removal process can be combined based on titanate, adsorption-advanced oxidation coupling treatment is achieved, and the treatment efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of cobalt-containing organic wastewater, and in particular to a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate. Background Art

[0002] With the development of metal refining, electroplating, medicine, catalysis and other fields, a series of cobalt-containing organic wastewaters have been discharged into the environment, causing great harm. Therefore, it is necessary to carry out corresponding wastewater treatment research for the system where cobalt-organic matter coexists.

[0003] At present, for wastewater containing cobalt and organic matter, the method of removing cobalt ions and organic matter in steps is generally adopted. For cobalt ions in cobalt-containing organic wastewater, the main treatment methods include chemical precipitation, adsorption, membrane separation, etc. 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 is easy to interact with cobalt, changing the state of cobalt ions, thereby inhibiting the chemical precipitation reaction. In addition, organic matter may also be adsorbed in the sludge of cobalt precipitation, increasing the difficulty of sludge recovery. Therefore, when the traditional chemical precipitation method is used to treat cobalt-containing organic wastewater, the cobalt ion concentration in the effluent is difficult to meet the standard. For the adsorption method, the interaction between organic pollutants and cobalt ions will change the adsorption characteristics of the process. At the same time, cobalt ions and organic pollutants are adsorbed on the surface of the adsorbent at the same time, resulting in difficulties in pollutant separation and adsorbent regeneration. For the membrane separation method, on the one hand, organic pollutants may increase membrane pollution and reduce the operating stability of the treatment process. On the other hand, for organic pollutants, general biological methods and advanced oxidation methods are more widely used. For biological methods, however, the coexisting cobalt ions in the system may poison microorganisms, limiting the application of biological methods in cobalt-containing multi-component wastewater systems; for advanced oxidation methods, it is impossible to remove cobalt ions during the process.

[0004] For example, CN 116477805 A discloses a zero-discharge treatment process for sulfamic acid cobalt chemical plating cleaning wastewater, including chemical oxidation, sodium ion exchange and seawater RO membrane treatment performed in sequence, firstly oxidizing ammonia nitrogen in wastewater with sodium hypochlorite in chemical oxidation to destroy the form of sulfamic acid cobalt, then exchanging and adsorbing cobalt ions with ion exchange resin, and the regenerated eluent of ion exchange resin is de-alkali precipitated to recycle cobalt resources, and finally fresh water is reclaimed by seawater RO membrane treatment. CN 113003793 A discloses a cobalt recovery method for cobalt chloride wastewater based on two-stage resin separation, and organic matter and metal impurities in cobalt chloride wastewater are removed by two-stage resin adsorption process to achieve the purpose of deep purification of cobalt chloride solution. However, leaving aside the technical effect of step-by-step removal method, step-by-step removal method is often multi-step and adopts different processes to remove cobalt ions and organic pollutants respectively, and the process efficiency is relatively low.

[0005] Although the prior art discloses the use of photocatalysis to synergistically reduce heavy metal-oxidized organic pollutants, there are no related reports on cobalt-containing organic wastewater. In addition, cobalt ions are difficult to reduce, and the single-step removal of this system, especially the single-step synergistic removal method, needs to be developed.

[0006] In this regard, in order to improve the treatment efficiency and achieve the synergistic removal of multiple pollutants in cobalt-containing organic wastewater, considering the good removal effect of adsorption on cobalt ions, it is urgent to organically combine adsorption with advanced oxidation. Its essence is to build a reasonable synergistic treatment system for cobalt-containing organic wastewater around wastewater treatment materials with both efficient adsorption characteristics and advanced oxidation performance. To achieve this goal, it is necessary to combine the removal process of cobalt ions and organic pollutants. In essence, it is to find a material with both adsorption and advanced oxidation capabilities, and develop a synergistic treatment process of cobalt ions and organic matter based on this.

[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 rich surface groups, large theoretical cation exchange capacity, rapid cation embedding ability and surface electronegativity under acidic conditions, titanate materials can quickly and efficiently remove cationic pollutants in wastewater, such as Ag(I), Tl(I), Cd(II), Co(II), Hg(II), Pb(II), Cr(III), U(VI), etc. In addition, there is [TiO 6 ] octahedral structure, with certain photocatalytic oxidation properties, has a good degradation effect on a series of pollutants such as organic dyes, drugs and personal care products. Therefore, titanate can be used to construct a cobalt-containing multi-element wastewater treatment system to achieve the synergistic removal of cobalt ions and organic pollutants.

[0008] In summary, it is necessary to develop a single-step synergistic treatment method for cobalt-containing organic wastewater based on titanate. Summary of the invention

[0009] In view of the problems existing in the prior art, the present 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, and then an oxidant is added for advanced oxidation treatment. The in-situ functional modification of titanate adsorbed with Co(II) is used to form three functionalization modes through interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance, which can significantly remove the remaining organic matter in the cobalt-containing organic wastewater. The single-step synergistic treatment method of the present invention can combine the removal process of cobalt ions and organic pollutants based on titanate, realize the "adsorption-advanced oxidation" coupling treatment, and greatly improve the treatment efficiency.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] The present invention provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate, and the single-step coordinated treatment method comprises 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 obtain adsorbed titanate and filtrate through solid-liquid separation; post-treat the filtrate to meet emission requirements.

[0013] The single-step synergistic treatment method described in the present invention is aimed at the cobalt-containing organic wastewater system, and uses titanate materials to construct an "adsorption-advanced oxidation" coupling treatment technology, which provides a unique solution for the efficient synergistic treatment of cobalt-containing organic wastewater. Based on the adsorption characteristics and adsorption performance of titanates, the cobalt ions in the cobalt-containing multi-component wastewater are embedded in titanates to achieve its in-situ functional modification, and three functionalization modes are formed through interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance, giving the titanate material efficient cobalt ion-organic treatment performance, changing the fixed idea of ​​preparing composite materials for synergistic treatment of multi-component wastewater, and achieving the purpose of efficient synergistic and sustainable treatment of cobalt-containing multi-component wastewater, providing new ideas for the treatment of metal- and organic-containing multi-component wastewater.

[0014] It should be noted that enhanced interfacial adsorption means that after cobalt ions are adsorbed into titanate, they will promote the adsorption of organic pollutants; advanced oxidation promotion means that after cobalt ions are adsorbed into titanate, they will promote oxidants (such as hydrogen peroxide) to produce free radicals and degrade pollutants; local micro-disturbance mainly forms micro-nanomotors, which are aimed at oxidants that react to generate gases. For example, after cobalt ions are adsorbed into titanate, they catalyze the degradation of hydrogen peroxide. The generated oxygen will drive the movement of titanate, which can enhance the mass transfer process.

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

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

[0017] It should be noted that in the single-step coordinated treatment method of the present invention, the organic matter in the cobalt-containing organic wastewater will be oxidized into small molecules, mainly CO2 , water, nitrogen-containing organic matter may be oxidized to N 2 , because the overall advanced oxidation treatment has a strong effect, the concentration range of organic matter that can be treated is relatively large; however, on the surface of the adsorbed titanate obtained after solid-liquid separation, a small amount of organic matter is sometimes attached and not completely oxidized, which can be rinsed with ethanol, and even ethanol elution can be added before Co elution, which will not affect the elution and recovery of cobalt resources. The eluate obtained by Co elution is concentrated by reverse osmosis, electrodialysis and other operations to obtain Co concentrated solution, and cobalt hydroxide, cobalt oxalate and other products can be obtained by precipitation method. As a preferred technical solution of the present invention, in the regeneration process, the rinsing is performed by ethanol.

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

[0019] Preferably, the immersion 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 immersion time is 1-3 h, such as 1 h, 1.5 h, 2 h, 2.5 h or 3 h.

[0020] Preferably, the drying temperature is 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, and the drying time is 10-15h, for example, 10h, 11h, 12h, 13h, 14h or 15h, etc.

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

[0022] As a preferred technical solution of the present invention, the pH is adjusted to adjust 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 have found that under conditions of neutral pH, titanate materials are more conducive to the catalytic degradation of organic matter by advanced oxidation treatment. However, the pH value of common cobalt-containing organic wastewater is weakly acidic. As long as the pH value is within the range of 5-9, adsorption treatment and advanced oxidation treatment can be directly carried out.

[0024] As a preferred technical solution of the present invention, the structural formula of the titanate is Na x H 2-x Ti 3 O 7 ·gH 2 O, that is, the titanate described in the present invention is preferably trititanate.

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

[0026] Preferably, in the liquid phase hydrothermal preparation method, the concentration of the NaOH solution is 9-11 mol / L, for example, 9 mol / L, 9.5 mol / L, 10 mol / L, 10.5 mol / L or 11 mol / L, and the mass volume ratio of anatase titanium dioxide to the NaOH solution is 1 g:(50-70) mL, for example, 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°C, for example, 130°C, 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C or 180°C, etc., and the time of the hydrothermal reaction is 1-5 days, for example, 2 days, 2.5 days, 3 days, 3.5 days, 4 days, 4.5 days or 5 days, etc.

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

[0029] As a preferred technical solution of the present invention, in the adsorption treatment, the dosage of titanate is 0.5-2.0 g / L, for example, 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 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h.

[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 the hydrogen peroxide drives the titanate particles to achieve self-driven movement to enhance mass transfer.

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

[0033] Preferably, by controlling the dosage of the hydrogen peroxide solution, the initial H 2 O 2 The concentration is 90-210mmol / L, for example, 90mmol / L, 100mmol / L, 103mmol / L, 105mmol / L, 108mmol / L, 110mmol / L, 113mmol / L, 115mmol / L, 118mmol / L or 210mmol / L, etc.

[0034] As a preferred technical solution of the present invention, the time of the advanced oxidation treatment is 1-4 hours, for example, 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 with an external physical field; the external physical field includes a light field and / or an ultrasonic field.

[0036] It should be noted that the inventors have found that if the external physical field is a light field, titanate and TiO 2 With the same [TiO 6 ] octahedral crystal structure, has a certain photocatalytic activity, so under the irradiation of ultraviolet light and visible light, it can significantly improve the removal efficiency of advanced oxidation treatment. Although pure titanate materials have a wide energy band and low absorption efficiency in the visible light range, titanates can accept photons to generate photogenerated electrons (e - ) and holes (h + ), where the photogenerated electrons can be 2 Captured, generated 2 - , and then through the free radical chain reaction, further generate H 2 O 2If the external physical field is an ultrasonic field, it can not only promote mass transfer based on ultrasonic action and strengthen the degradation of organic pollutants by oxidants, but also because some titanates have a certain piezoelectric effect, some titanates will produce electric polarization when subjected to ultrasound, thereby ultrasonically charging the surface of titanates and strengthening the degradation of organic pollutants by oxidants.

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

[0038] (1) The present 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 part of the organic matter, and then an oxidant is added for advanced oxidation treatment. By utilizing the in-situ functional 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 the cobalt-containing organic wastewater.

[0039] (2) The single-step synergistic treatment method described in the present invention can combine the removal process of cobalt ions and organic pollutants based on titanate, realize the "adsorption-advanced oxidation" coupling treatment, and greatly improve the treatment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0043] Figure 4 It is a specific embodiment of the present invention to explore the motion trajectory of a titanate material at different times (a)-(d) in a local micro-perturbation;

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

[0045] Figure 6 This is a cycle performance diagram of the regenerated titanate obtained after drying in Example 1 of the present invention for removing TC in a cycle experiment. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0047] The present invention provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate, and the single-step coordinated treatment method comprises the following steps:

[0048] Prepare cobalt-containing organic wastewater, adjust the pH, first add titanate for adsorption treatment, then add oxidant for advanced oxidation treatment, and obtain adsorbed titanate and filtrate through solid-liquid separation; post-treat the filtrate to meet the emission requirements; regenerate the adsorbed titanate to recover cobalt resources, and reuse the obtained regenerated titanate; wherein the regeneration treatment includes: washing, eluting, soaking and drying the adsorbed titanate in sequence to obtain regenerated titanate, and the eluate obtained by elution is used to recover cobalt resources;

[0049] Figure 1 The working principle diagram of the single-step synergistic treatment method of the present invention is shown, and it can be seen that: based on the adsorption characteristics and adsorption performance of titanate, the cobalt ions in the cobalt-containing multi-element wastewater are embedded in titanate to realize its in-situ functional modification. On the one hand, after the cobalt ions are adsorbed into the titanate, they will promote the adsorption of organic pollutants to form a functional mode of enhanced interface adsorption. On the other hand, after the cobalt ions are adsorbed into the titanate, they will promote the oxidant (such as hydrogen peroxide) to produce free radicals, promote the generation of active oxygen, degrade pollutants, and form a functional mode of advanced oxidation promotion. In addition, if the oxidant used is an oxidant that can react to generate gas, for example, after the cobalt ions are adsorbed into the titanate, they catalyze the degradation of hydrogen peroxide, and the generated oxygen will drive the movement of the titanate, which can enhance the mass transfer process, form a micro-nano motor, and form a functional mode of local micro-disturbance. The three functional modes are formed through interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance, which can realize the synergistic oxidation of organic pollutants and oxidize them into small molecules; moreover, the adsorbed titanate is regenerated to recycle the cobalt ion resources, and the regenerated titanate obtained can realize material recycling.

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

[0051] Preparation of titanate: Disperse 1g of anatase titanium dioxide in 60mL of 10mol / L NaOH solution, stir continuously for 2h, then transfer the suspension to a 100mL stainless steel autoclave lined with polystyrene (PPL), and heat at 155°C in a forced air drying oven for 3 days. After cooling to room temperature, wash the material in the autoclave with deionized water until the pH value of the supernatant is close to neutral, then dry it in a vacuum drying oven at 60°C for 12h, grind it into loose powder using a mortar and pestle, and store it for later use.

[0052] Titanate characterization: (1) After scanning electron microscopy analysis, the relevant SEM images are as follows Figure 2As shown in FIG. 1 , the prepared titanate is a nanorod with uniform morphology, and the length of the nanorod can reach 7.35 μm and the width is about 0.38 μm; (2) the crystal structure and phase composition of the titanate material are analyzed by X-ray diffractometer (XRD) in the scanning range of 5-70°, as shown in FIG. Figure 3 As shown, the diffraction peaks of the prepared titanate are mainly related to the trititanate Na x H 2-x Ti 3 O 7 ·gH 2 O (JCPDS: 47-0561); (3) After the BJH method and BET model fitting, the specific surface area of ​​the prepared titanate is 34.2 m 2 / g, pore volume is 0.06cm 3 / g, and the average pore size is 21.8nm.

[0053] Example 1

[0054] This embodiment provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate, and the single-step coordinated treatment method comprises the following steps:

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

[0056] (2) According to the dosage of 1.0 g / L, titanate was first added for 3 h of adsorption treatment, and then a 20 wt% hydrogen peroxide solution was added for advanced oxidation treatment. The oxygen generated by the degradation of hydrogen peroxide drove the titanate particles to achieve self-driven motion and enhance mass transfer. By controlling the dosage of the hydrogen peroxide solution, the initial H 2 O 2 The concentration was 150mmol / L, and the ultrasonic field was set as an external physical field to promote mass transfer, and the time of advanced oxidation treatment was controlled to be 3h;

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

[0058] In order to explore the local micro-disturbance, the conditions of Example 1 were adopted, except that stirring and ultrasonic field were removed, and the movement of titanate material was monitored without stirring. Figure 4 The motion trajectory of the titanate material (circled in red) at four different moments during the monitoring process is shown, indicating that H 2 O 2 The cobalt ion sites on the surface of the material will decompose to produce oxygen, allowing the material to overcome gravity and move in a self-driven manner. This form of movement can achieve local micro-disturbance.

[0059] Example 2

[0060] This embodiment provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate. Compared with Example 1, the only difference is that the adsorption treatment time is 4 hours.

[0061] Example 3

[0062] This embodiment provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate. Compared with Example 1, the only difference is that the adsorption treatment time is 1 hour.

[0063] Example 4

[0064] This embodiment provides a single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate. Compared with Example 1, the only difference is that the adsorption treatment time is 0.5h.

[0065] Comparative Example 1

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

[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] The steps include:

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

[0071] (2') adding a 20 wt% hydrogen peroxide solution for oxidation treatment, and controlling the amount of the hydrogen peroxide solution added so that the initial H 2 O 2 The concentration was 150mmol / L, and the ultrasonic field was set as an external physical field to promote mass transfer, and the oxidation treatment time was controlled to be 3h;

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

[0073] In the cobalt-containing organic wastewater treated in the above embodiments and comparative examples, the Co(II) concentration was 0.5 mmol / L and the organic matter content was 500 mg / L. The same detection method was used to detect the Co(II) ion and organic matter concentrations of the filtrate obtained after treatment, and the Co(II) ion removal rate and the 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 1-4 hours, and then an oxidant is added for advanced oxidation treatment, which provides sufficient time for cobalt ions to be embedded in titanate to achieve in-situ functional modification, and 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 with Example 4, since Example 4 shortens the adsorption treatment time to 0.5 h, the cobalt ion embedding into titanate to achieve its in-situ functionalization modification is not sufficient. On the one hand, organic matter attached to the surface of titanate blocks part of the embedding channel, resulting in some cobalt ions remaining in the filtrate, and the Co(II) ion removal rate is reduced to 70%. On the other hand, some cobalt ions are not fully embedded in titanate, and the three functionalization modes of interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance are weakened, and the organic matter removal rate is reduced 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 embedding channel, and the cobalt ion embedding into titanate to achieve its in-situ functionalization modification 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, there is no operation to remove cobalt ions, and the Co(II) ion removal rate is 0%. Without the cobalt ions embedded in titanate to achieve its in-situ functional modification, the three functionalization modes of interface adsorption enhancement, advanced oxidation promotion, and local micro-disturbance are lost. At 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] The regenerated titanate obtained after drying in Example 1 was used in the next cycle experiment, that is, the operation of Example 1 was repeated for a total of 5 times to evaluate the stability of the titanate. In each repeated experiment, after adding the titanate, the ratio of the real-time concentration of Co(II) in the system to the initial concentration, C / C 0 The curve of change over time is used to determine the regeneration effect of titanate and explore the cyclic performance of regenerated titanate adsorbing cobalt ions. In each repeated experiment, tetracycline (TC) is used as the detection object. After adding the oxidant, the ratio of the real-time concentration of TC in the system to the initial concentration C / C is immediately monitored. 0 The time-varying curves are used to investigate the cyclic performance of regenerated titanate for removing organic matter. Figure 5 and Figure 6 The cyclic performance diagrams of the regenerated titanate for the adsorption of Co(II) and the removal of TC are shown respectively. It can be seen that the material still maintains a high reaction activity after five cycles and has a good synergistic treatment effect on both TC and Co(II).

[0082] In summary, the present 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, and then an oxidant is added for advanced oxidation treatment. By utilizing the in-situ functional 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 the cobalt-containing organic wastewater. The single-step synergistic treatment method of the present invention can combine the removal process of cobalt ions and organic pollutants based on titanate, realize the "adsorption-advanced oxidation" coupling treatment, and greatly improve the treatment efficiency.

[0083] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but 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 improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, 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 are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to 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 further describe various possible combinations.

[0086] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A single-step coordinated treatment method for cobalt-containing organic wastewater based on titanate, characterized in that: The single-step collaborative processing method comprises the following steps: Prepare cobalt-containing organic wastewater, adjust the pH, first add titanate for adsorption treatment, then add oxidant for advanced oxidation treatment, and obtain adsorbed titanate and filtrate through solid-liquid separation; post-treat the filtrate to meet emission requirements.

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 obtained regenerated titanate is reused; wherein, the regeneration treatment comprises: washing, eluting, soaking and drying the adsorbed titanate in sequence to obtain regenerated titanate, and the eluate obtained by 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 flushing is performed using ethanol; Preferably, the elution uses an EDTA-2Na solution with a concentration of 0.08-0.12 mol / L; Preferably, the immersion is carried out in a NaCl solution with a concentration of 0.8-1.2 mol / L, and the immersion time is 1-3 h; Preferably, the drying temperature is 50-80° C., and the drying time is 10-15 hours.

4. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: In the cobalt-containing organic wastewater, the Co(II) concentration is 0.1-1.0 mmol / L, and the organic matter content is 20-700 mg / L.

5. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: The pH adjustment is to adjust the pH value of the cobalt-containing organic wastewater to 5-9.

6. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: The structural formula of the titanate is Na x H 2-x Ti3O7·gH2O.

7. The single-step collaborative processing method according to claim 6, characterized in that: The titanate is prepared by a liquid phase hydrothermal method, and the preparation method comprises the following steps: dispersing anatase titanium dioxide into a NaOH solution and stirring, subjecting the obtained suspension to a hydrothermal reaction, and sequentially cooling, washing, drying, and grinding to obtain the titanate; Preferably, in the liquid phase hydrothermal preparation method, the concentration of the NaOH solution is 9-11 mol / L, and the mass volume ratio of anatase titanium dioxide to the NaOH solution is 1 g: (50-70) mL; Preferably, the temperature of the hydrothermal reaction is 130-180° C., and the time of the hydrothermal reaction is 1-5 days; Preferably, the drying comprises drying at 50-70° C. for 10-15 hours.

8. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: In the adsorption treatment, the dosage of titanate is 0.5-2.0 g / L; Preferably, the adsorption treatment time is 1-4 hours.

9. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: In the advanced oxidation treatment, the oxidant includes a hydrogen peroxide solution, and the oxygen generated by the degradation of the hydrogen peroxide drives the titanate particles to achieve self-driven movement to enhance mass transfer; Preferably, the concentration of the hydrogen peroxide solution is 15-30wt%; Preferably, the dosage of the hydrogen peroxide solution is controlled so that the initial H2O2 concentration of the reaction system is 90-210 mmol / L.

10. The single-step collaborative processing method according to any one of claims 1 to 3, characterized in that: The advanced oxidation treatment time is 1-4h; Preferably, the advanced oxidation treatment is enhanced with an external physical field; the external physical field includes a light field and / or an ultrasonic field.

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