Method for recovering valuable metal copper in water and simultaneously removing organic phosphorus

Abstract

The invention belongs to the technical field of wastewater resourceful treatment and disposal, and provides a method for recovering valuable metal copper in water and removing organic phosphorus at the same time. The copper-containing wastewater is mixed with acid, so that metal copper in a complexing state in the wastewater is converted into a salt ion state; adjusting the pH value to enable the residual copper element to be in an ionic state and most of phosphate to exist in an anion form, and adding an iron-carbon adsorbent to remove phosphate substances in water; then, the iron-carbon adsorbent is separated through magnetic separation, and a mixture of iron oxide and copper oxide is obtained through calcination; and finally, the iron oxide is removed through magnetic separation, and then the copper oxide is obtained. The result of the embodiment shows that after the wastewater with the copper ion content of 21.02 mg / L and the total phosphorus content of 1.107 mg / L is treated by adopting the method provided by the invention, the concentration of the copper ions in the filtrate is measured to be 0.6103 mg / L, and the concentration of the total phosphorus is measured to be 0.59 mg / L.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater resource treatment and disposal, and in particular to a method for recovering valuable metal copper in water and removing organic phosphorus at the same time. Background Art

[0002] The printing and dyeing industry requires a large amount of water in its production process. According to statistics, its wastewater discharge and total pollutant volume rank second and fourth in the national industrial sector respectively, making it one of the key polluting industries in my country. Textile printing and dyeing wastewater has the characteristics of high pollutant content, high alkalinity, and large changes in water quality. It is one of the difficult-to-treat industrial wastewaters. Pollutants include dyes, slurries, auxiliaries, oils, acids and alkalis, fiber impurities, sand substances, inorganic salts, etc. Although there are many types of pollutants in printing and dyeing wastewater, different printing and dyeing factories have their own characteristics. For example, taking the wastewater generated by a copper-containing dye factory as an example, the main pollutants involve heavy metal copper chelates and alkaline inorganic salts.

[0003] For wastewater generated by copper-containing dye factories, although the metallic copper in the water is precipitated in the flocculation sedimentation tank after aeration treatment, the heavy metal copper in the wastewater is not recycled and most of it is precipitated in the sludge and treated as hazardous waste, resulting in a waste of resources; at the same time, the phosphate substances in the wastewater after secondary treatment also need to be further treated. Therefore, a method that can recover valuable metallic copper in water and remove organic phosphorus at the same time is urgently needed to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a method for recovering valuable metallic copper in water and removing organic phosphorus at the same time. The method provided by the present invention can recover valuable metallic copper in wastewater and remove organic phosphorus therein at the same time.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for recovering valuable metal copper in water and removing organic phosphorus at the same time, comprising the following steps:

[0007] (1) mixing copper-containing wastewater and acid to obtain acidified copper-containing wastewater;

[0008] (2) mixing the acidified copper-containing wastewater obtained in step (1) with an iron-carbon adsorbent and adjusting the pH value, and then sequentially adsorbing and filtering to obtain a low-phosphorus filtrate and a filter residue;

[0009] (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, and then calcining the filter residue to obtain a mixture of iron oxide and copper oxide;

[0010] (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide.

[0011] Preferably, the content of metallic copper in the copper-containing wastewater in step (1) is 20-25 mg / L, and the total phosphorus content is 1.0-1.5 mg / L.

[0012] Preferably, the acid in step (1) comprises sulfuric acid and / or nitric acid.

[0013] Preferably, the amount of acid used in step (1) is 80-100 mL / L.

[0014] Preferably, the iron-carbon adsorbent in step (2) comprises paper-based biochar loaded with iron or a biochar modified material with similar paper-like properties and easy to burn.

[0015] Preferably, the amount of the iron-carbon adsorbent used in step (2) is 50-80 g / L.

[0016] Preferably, the pH value in step (2) is 5 to 6.5.

[0017] Preferably, the reagent for adjusting the pH value in step (2) is sodium hydroxide solution.

[0018] Preferably, the mass concentration of the sodium hydroxide solution is 5-10%.

[0019] Preferably, the calcination in step (3) is carried out under aerobic conditions.

[0020] The present invention provides a method for recovering valuable metallic copper in water and removing organic phosphorus at the same time, comprising the following steps: (1) mixing copper-containing wastewater with acid to obtain acidified copper-containing wastewater; (2) mixing the acidified copper-containing wastewater obtained in step (1) with an iron-carbon adsorbent and adjusting the pH value, and then sequentially adsorbing and filtering to obtain a low-phosphorus filtrate and a filter residue; (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, and then calcining to obtain a mixture of iron oxide and copper oxide; (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide. The present invention first converts the metallic copper in the complex state of the wastewater into a salt ion state by mixing the copper-containing wastewater with an acid; then adjusting the pH value to make the remaining copper element also in the copper ion state, while most of the phosphate exists in the form of anions, and simultaneously adding an iron-carbon adsorbent to remove phosphate substances in the water; then separating the iron-carbon adsorbent by magnetic separation, and obtaining a mixture of iron oxide and copper oxide by calcining; finally, continuing to remove the iron oxide by magnetic separation to obtain copper oxide. The results of the embodiment show that after using the method provided by the present invention to treat wastewater with a copper ion content of 21.02 mg / L and a total phosphorus content of 1.107 mg / L, the concentration of copper ions in the filtrate was measured to be 0.6103 mg / L, and the concentration of total phosphorus was 0.59 mg / L.

[0021] The method for recovering valuable copper metal in water and removing organic phosphorus provided by the present invention can simultaneously realize the recovery of heavy metal copper and the treatment of phosphate. Compared with the method of using iron salt and calcium salt flocculants to treat phosphate in water, the method provided by the present invention can reduce the phosphate content in the water body while the copper in the flocculation precipitation can be directly recovered and treated, avoiding the heavy metal copper from becoming sludge hazardous waste, which is difficult to separate and forms a waste of resources. In addition, compared with the method of using activated carbon to treat water bodies to adsorb heavy metal copper, the method provided by the present invention makes up for the disadvantage that activated carbon does not act on phosphate in water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for recovering valuable metal copper in water and removing organic phosphorus simultaneously provided by the present invention;

[0023] Figure 2 This is the apparent morphology of the iron oxide obtained in Example 1 of the present invention;

[0024] Figure 3 This is the apparent morphology of the copper oxide obtained in Example 1 of the present invention;

[0025] Figure 4 is the XRD pattern of the iron oxide obtained in Example 1 of the present invention;

[0026] Figure 5This is the XRD pattern of the copper oxide obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides a method for recovering valuable metal copper in water and removing organic phosphorus at the same time, comprising the following steps:

[0028] (1) mixing copper-containing wastewater and acid to obtain acidified copper-containing wastewater;

[0029] (2) mixing the acidified copper-containing wastewater obtained in step (1) with an iron-carbon adsorbent and adjusting the pH value, and then sequentially adsorbing and filtering to obtain a low-phosphorus filtrate and a filter residue;

[0030] (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, and then calcining the filter residue to obtain a mixture of iron oxide and copper oxide;

[0031] (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide.

[0032] The invention mixes copper-containing wastewater with acid to obtain acidified copper-containing wastewater. The invention converts the metal copper in the complex state in the wastewater into a salt ion state by mixing the copper-containing wastewater with acid.

[0033] The method provided by the present invention is applicable to treating various copper-containing wastewaters. In the present invention, the copper-containing wastewater is preferably copper-containing printing and dyeing wastewater.

[0034] In the present invention, the content of metallic copper in the copper-containing wastewater is preferably 20 to 25 mg / L; the content of total phosphorus in the copper-containing wastewater is preferably 1.0 to 1.5 mg / L.

[0035] In the present invention, the acid preferably includes sulfuric acid and / or nitric acid. In the present invention, the sulfuric acid is preferably concentrated sulfuric acid; the nitric acid is preferably concentrated nitric acid. The present invention has no particular limitation on the concentrations of the concentrated sulfuric acid and concentrated nitric acid, and the concentrations commonly used in the art can be used.

[0036] In the present invention, the dosage of the acid is preferably 80-100 mL / L, more preferably 90-100 mL / L. The present invention preferably controls the dosage of the acid within the above range, which is conducive to fully converting the metallic copper in the complex state in the wastewater into the salt ion state.

[0037] In the present invention, the mixing of the copper-containing wastewater and the acid is preferably carried out under stirring conditions. In the present invention, the stirring speed is preferably 800 to 1000 rpm / min; and the stirring time is preferably 20 to 30 min.

[0038] In the present invention, the temperature at which the copper-containing wastewater and the acid are mixed is preferably 40°C.

[0039] After obtaining the acidified copper-containing wastewater, the present invention mixes the acidified copper-containing wastewater with an iron-carbon adsorbent and adjusts the pH value, and then sequentially performs adsorption and filtration to obtain a low-phosphorus filtrate and a filter residue. The present invention adjusts the pH value so that the remaining copper element is also in the copper ion state, and most of the phosphate exists in the form of anions, and at the same time, the iron-carbon adsorbent is added to remove phosphate substances in the water.

[0040] The present invention has no special limitation on the operation of mixing the acidified copper-containing wastewater and the iron-carbon adsorbent, and a mixing technical solution well known to those skilled in the art can be adopted.

[0041] In the present invention, the iron-carbon adsorbent preferably includes paper-based biomass charcoal loaded with iron elements or biomass charcoal modified materials with similar paper properties and easy to burn, and more preferably paper-based biomass charcoal loaded with iron elements. The present invention adopts the above-mentioned iron-carbon adsorbent to make up for the disadvantage that activated carbon does not work on phosphates in water bodies, and is a measure to treat waste with waste, with low raw material cost.

[0042] In the present invention, the amount of the iron-carbon adsorbent is preferably 50-80 g / L, more preferably 50 g / L. In the present invention, the amount of the iron-carbon adsorbent is preferably controlled within the above range, which ensures the adsorption effect and does not waste raw materials.

[0043] In the present invention, the pH value is preferably 5 to 6.5, more preferably 6 to 6.2. The present invention preferably controls the pH value within the above range to ensure that the remaining copper element is in the state of copper ions, while most of the phosphate exists in the form of anions.

[0044] In the present invention, the pH adjusting agent is preferably a sodium hydroxide solution. In the present invention, the mass concentration of the sodium hydroxide solution is preferably 5-10%.

[0045] In the present invention, the adsorption is preferably carried out under stirring conditions; the stirring speed is preferably 150 to 800 rpm / min; and the stirring time is preferably 1 to 1.5 hours. In the present invention, a certain stirring speed is preferably ensured during the adsorption process to ensure sufficient contact between the adsorbent and the solution. As time increases, the stirring speed decreases, and a high stirring speed is no longer maintained to prevent a reverse reaction in the adsorption process.

[0046] The present invention has no special limitation on the filtering operation, and any filtering technical solution well known to those skilled in the art may be used.

[0047] After obtaining the filter residue, the present invention performs a first magnetic separation on the filter residue, and then calcines it to obtain a mixture of iron oxide and copper oxide. The present invention uses magnetic separation to separate the iron-carbon adsorbent, and obtains a mixture of iron oxide and copper oxide by calcining.

[0048] The present invention has no special limitation on the operation of the first magnetic separation, and the magnetic separation technical solution well known to those skilled in the art may be adopted.

[0049] After the first magnetic separation, the present invention preferably dries the product of the first magnetic separation. The present invention has no special limitation on the drying operation, and a drying technical solution well known to those skilled in the art can be used. In the present invention, the drying temperature is preferably 105°C. The present invention has no special limitation on the drying time, and the purpose of removing moisture can be achieved.

[0050] The present invention has no special limitation on the calcination operation, and the calcination technical schemes well known to those skilled in the art can be adopted. The present invention oxidizes, burns and volatilizes the carbon-based material in the iron-carbon adsorbent by calcination to obtain iron oxide and copper oxide.

[0051] In the present invention, the calcination is preferably carried out under aerobic conditions; the aerobic conditions are preferably air conditions.

[0052] After obtaining the mixture of iron oxide and copper oxide, the present invention performs a second magnetic separation on the mixture of iron oxide and copper oxide to obtain copper oxide. The present invention removes iron oxide by magnetic separation to obtain copper oxide.

[0053] The present invention has no special limitation on the operation of the second magnetic separation, and the magnetic separation technical solution well known to those skilled in the art may be adopted.

[0054] The flow chart of the method for recovering valuable metal copper in water and removing organic phosphorus provided by the present invention is as follows: Figure 1 As shown, the wastewater is first acidified to obtain acidified wastewater; then an iron-carbon adsorbent is added for adsorption and flocculation and then filtered to obtain a filter residue and a low-phosphorus filtrate; the filter residue is then separated from the iron-carbon adsorbent by magnetic separation, and then calcined to obtain iron oxide and copper oxide; finally, the iron oxide is removed by magnetic separation to obtain copper oxide.

[0055] The present invention firstly mixes copper-containing wastewater with acid to convert metallic copper in a complex state in the wastewater into a salt ion state; then adjusts the pH value so that the remaining copper element is also in a copper ion state, while most of the phosphate exists in the form of anions, and simultaneously adds an iron-carbon adsorbent to remove phosphate substances in the water; then uses magnetic separation to separate the iron-carbon adsorbent, and obtains a mixture of iron oxide and copper oxide by calcination; finally, continues to remove the iron oxide by magnetic separation to obtain copper oxide.

[0056] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Example 1

[0058] Wastewater from the neutralization tank sedimentation of a printing and dyeing factory in Hebei Province was collected. Testing showed that the copper ion content in the wastewater was 21.02 mg / L and the total phosphorus content was 1.107 mg / L.

[0059] (1) Weigh 100 mL of the wastewater collected by the plant into a 250 mL beaker, measure 10 mL of concentrated nitric acid, place it at 40°C and stir at a speed of 800 rpm / min for 30 min to obtain acidified copper-containing wastewater.

[0060] (2) Add 5.0000 g of iron-loaded paper-based biochar in an amount of 50 g / L, add it to the acidified copper-containing wastewater in step (1) at a rotation speed of 800 rpm / min, and adsorb for 30 minutes; reduce the stirring speed to 250 rpm / min, continue to use 5% sodium hydroxide to add to the solution to adjust the pH to 6.2, and continue the adsorption reaction for 60 minutes; then filter to obtain a filter residue and a low-phosphorus filtrate; determine the concentration of copper ions in the filtrate by inductively coupled plasma to be 0.8355 mg / L, and determine the concentration of total phosphorus by spectrophotometry to be 0.41 mg / L.

[0061] (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, then drying at 105° C., and then calcining in air to obtain a mixture of iron oxide and copper oxide.

[0062] (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide.

[0063] Figure 2 This is the apparent morphology of the iron oxide obtained in this example.

[0064] Figure 3 This is the apparent morphology of the copper oxide obtained in this example.

[0065] Figure 4 is the XRD pattern of the iron oxide obtained in this example.

[0066] Figure 5 is the XRD pattern of the copper oxide obtained in this example.

[0067] Example 2

[0068] Wastewater from the neutralization tank sedimentation of a printing and dyeing factory in Hebei Province was collected. Testing showed that the copper ion content in the wastewater was 21.02 mg / L and the total phosphorus content was 1.107 mg / L.

[0069] (1) Weigh 100 mL of the wastewater collected from the plant into a 250 mL beaker, measure 10 mL of concentrated sulfuric acid, place it at 40°C and stir it at a speed of 800 rpm / min for 20 min to obtain acidified copper-containing wastewater.

[0070] (2) 8.0000 g of paper-based biochar loaded with iron element was added at a ratio of 50 g / L, and added to the acidified copper-containing wastewater in step (1) at a rotation speed of 800 rpm / min, and adsorbed for 25 minutes. 5% sodium hydroxide was added to the solution to adjust the pH to 6.0, and the adsorption reaction was continued for 60 minutes; then, the solution was filtered to obtain a filter residue and a low-phosphorus filtrate; the concentration of copper ions in the filtrate was determined by inductively coupled plasma to be 0.6103 mg / L, and the concentration of total phosphorus was determined by spectrophotometry to be 0.59 mg / L.

[0071] (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, then drying at 105° C., and then calcining in air to obtain a mixture of iron oxide and copper oxide.

[0072] (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide.

[0073] It can be seen from the above embodiments that the method provided by the present invention can recover valuable metal copper in wastewater and remove organic phosphorus therein at the same time; and, after using the method provided by the present invention to treat wastewater with a copper ion content of 21.02 mg / L and a total phosphorus content of 1.107 mg / L, the concentration of copper ions in the filtrate was measured to be 0.6103 mg / L, and the concentration of total phosphorus was 0.59 mg / L.

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recovering valuable metal copper in water and removing organic phosphorus simultaneously, comprising the following steps: (1) mixing copper-containing wastewater and acid to obtain acidified copper-containing wastewater; (2) mixing the acidified copper-containing wastewater obtained in step (1) with an iron-carbon adsorbent and adjusting the pH value, and then sequentially adsorbing and filtering to obtain a low-phosphorus filtrate and a filter residue; (3) subjecting the filter residue obtained in step (2) to a first magnetic separation, and then calcining the filter residue to obtain a mixture of iron oxide and copper oxide; (4) subjecting the mixture of iron oxide and copper oxide obtained in step (3) to a second magnetic separation to obtain copper oxide.

2. The method according to claim 1, characterized in that The copper-containing wastewater in step (1) has a content of metallic copper of 20 to 25 mg / L and a total phosphorus content of 1.0 to 1.5 mg / L.

3. The method according to claim 1, characterized in that: The acid in step (1) includes sulfuric acid and / or nitric acid.

4. The method according to claim 1, characterized in that: The amount of acid used in step (1) is 80-100 mL / L.

5. The method according to claim 1, characterized in that The iron-carbon adsorbent in step (2) includes paper-based biochar loaded with iron elements or a biochar modified material with similar paper properties and easy to burn.

6. The method according to claim 1 or 5, characterized in that: The amount of the iron-carbon adsorbent used in step (2) is 50-80 g / L.

7. The method according to claim 1, characterized in that The pH value in the step (2) is 5 to 6.

5.

8. The method according to claim 1, characterized in that The reagent for adjusting the pH value in step (2) is sodium hydroxide solution.

9. The method according to claim 8, characterized in that The mass concentration of the sodium hydroxide solution is 5-10%.

10. The method according to claim 1, characterized in that The calcination in step (3) is carried out under aerobic conditions.

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