CN107245580A - It is a kind of to clean the effective method that copper, tin and iron are separated and recovered from from spent acidic etching solution - Google Patents

Abstract

The invention discloses a clean and effective method for separating and recovering copper, tin and iron from acidic waste etching solution, belonging to the field of heavy metal treatment and separation and recovery. Multilevel MFCs are composed of three MFCs units. The anode electrode of multilevel MFCs is attached with an electrochemically active biofilm; the anode feedwater is a mixed solution containing organic carbon source and microbial nutrient solution. The acidic spent etching solution containing Sn(II), Fe(II) and Cu(II) is recovered by forming stannous hydroxide and/or tin hydroxide, and iron hydroxide precipitation at the bottom of the tin and iron removal MFCs unit and separation, while Cu(II) was reduced and recovered on the copper-removing MFCs cathode. The present invention proposes a new method for simultaneously treating acidic waste etching solutions containing Sn(II), Fe(II) and Cu(II) and municipal organic sewage and separating and recovering heavy metals and energy therein, expanding the capabilities of multi-stage MFCs Application fields and scope of use; at the same time, the process produces electric energy, which is clean and environmentally friendly.

Description

A clean and efficient separation and recovery of copper, tin and iron from acidic waste etching solutions Methods

technical field

The invention belongs to the field of heavy metal treatment, separation and recovery, and in particular relates to the stepwise separation and recovery of tin, iron and copper by a multi-stage microbial fuel cell from an acidic waste printed circuit board etching solution.

Background technique

With the improvement of people's living standards and the production, use and replacement of a large number of electronic products, a large amount of acidic etching waste containing Sn(II), Fe(II) and Cu(II) is produced. The discharge of these waste liquids into the environment not only caused serious environmental pollution, but also resulted in a great waste of metal resources. Therefore, the treatment and recycling of this kind of waste liquid not only solves the problem of environmental pollution, but also realizes the resource utilization of valuable products, which has environmental, economic and social benefits (Hydrometallurgy 70(2003) 23-29; Green Chem 17(2015) 3979-3991; Green Chem 17(2015) 4418-4431; Environmental Engineering 22(2004) 75-77). At present, the treatment of acidic waste etching solution and metal recovery methods are mainly chemical, physical or electrochemical methods, such as metal replacement method (CN91100122.0; CN201010189919.1; Electroplating and Environmental Protection 9 (1989) 44-46), solvent萃取法(CN201310174581.6；CN201510335589.5；CN201410016262.7)、电解法(CN201310554271.7；CN201610639169.0；CN201510293669.9；CN201410530489.3)、内晶法(CN201510815459.1)、热解法(CN201310554271 .7) and precipitation method (CN201020658781.0; CN200910030842.0; New Technology and New Process 1 (1993) 41-42), etc. These methods not only have the disadvantages of high reagent consumption, high energy consumption, and secondary pollution, but also only recover a single metal copper in the waste etching solution, and do not consider other metals such as tin and iron. Although Swain et al. (Green Chem 17 (2015) 3979-3991; Green Chem 17 (2015) 4418-4431) utilized liquid-liquid extraction to recover metal indium, molybdenum, tin and copper in the waste etching solution step by step, Scott et al. (Resour Conserv Recy 20 (1997) 43-55) based on chemical-electrochemical principles, through hydrated tin oxide precipitation, electrochemical step-by-step separation and recovery of tin, copper and lead, but these processes need to consume a large amount of organic solvents, or consume a large amount of strong alkali, resulting in secondary Secondary pollution; at the same time, the process consumes high energy and is cumbersome and complicated to operate. Therefore, seeking a clean, effective, and low-energy-consumption technology for separating and recovering tin, iron, and copper from acidic waste etching solutions has become a hot spot of concern.

Microbial Fuel Cells ( M icrobial Fuel Cells, MFCs ) is a new technology emerging in recent years, which uses microorganisms to convert chemical energy in organic sewage into electrical energy and/or generate reducing products at the same time. It is clean, environmentally friendly, simple, and Efficient and stable features. MFCs are mainly composed of anode chamber, anode electrode, cathode chamber, cathode electrode, proton exchange membrane and external resistance (Fig. 2). At present, studies on single MFCs, single microbial electrolytic cells with external pressure, multi-stage MFCs, and combination of MFCs and microbial electrolytic cells have been extensively carried out. The metals used for recovery include Cu(II), Ag(I), Zn(II ), Hg(II), Cd(II), Cr(VI) and Cd(II) and other single metals (CN201310345579, Environ Sci Technol 44(2010)4376-4381; Appl Energy 112(2013)1337-1341; Bioresour Technol 102(2011)6304-6307; J PowerSources 273(2015)1103-1113); Inter J Hydrogen Energy 41(2016)13368-13379), and mixed metal Cu(II) and Ni(II)(FrontEnvironSciEng 9(2015) 522-527), Cu(II) and Cd(II) (CN201410669734.9; Bioresour Technol 200(2016)565-571), Cu(II), Co(II) and Li(I)(SepPurifTechnol 147(2015) 114-124), Cr(VI), Cu(II) and Cd(II) (EnvironSci Technol 49(2015):9914-9924), Pb(II), Zn(II), Cu(II) and Ni(II ) (J Hazard Mater 235-236(2012) 291-297) et al. However, these bioelectrochemical processes for recovering metals all use the difference in oxidation-reduction potential of different metals to deposit metals on electrodes, and the electrodes need to be scraped to recover metals, thus increasing the cost of subsequent treatment. In addition, when the mixed metal materials enter the multi-stage reactor unit sequentially, with the change of the solution chemistry of the reactor unit, such as pH and conductivity, the deposition rates of different metal components in the same unit are different, so that different reactor units have different The separation efficiency of the same metal is different. Accordingly, optimizing and regulating the deposition conditions (pH, time, etc.) of different metal components in the same unit can achieve efficient deposition and separation of mixed metals. According to this idea, combined with the current status of acid etching wastewater treatment and recovery technology, and overcoming the technical bottleneck of the above-mentioned multi-stage bioelectrochemical reactor separation and recovery of metals, it is expected to develop a high-efficiency treatment and cascade separation recovery of tin, Multilevel MFCs technology for iron and copper.

The technical principle of the present invention is as follows: the air cathode MFCs with oxygen as the electron acceptor reacts under acidic conditions (Formula 1), so that the pH of the catholyte is continuously increased; while the dissolved Sn(OH) ₂ and Sn(OH) ₄ The specific products are 1.4×10 ^-28 and 1.0×10 ^-56 , respectively, and the pH required for the formation of Sn(OH) ₂ and Sn(OH) ₄ precipitation under the condition of acidic etching wastewater is 0.79-2.45, which is lower than that of Fe(II) in the air The pH 3.10 required for the reaction (Equation 5) and the formation of Fe(OH) ₃ precipitation (Equation 6) in the cathode MFCs is lower than the pH 5.68 required for Cu(II) to form Cu(OH) ₂ precipitation. Therefore, Sn(II) and Fe(II) in acidic etching wastewater can control the increasing pH of catholyte through different reaction time/residence time in MFCs cathode compartment with oxygen as electron acceptor, and finally Sn(OH) ₂ or Sn(OH) ₄ (Formula 2-4), and Fe(OH) ₃ (Formula 5-6) are recovered at the bottom of different reactor units by way of precipitation. For Cu(II), since the pH of the solution for removing Sn(II) and Fe(II) is up to 5.14, it is still lower than the pH 5.68 required for the formation of Cu(OH) ₂ precipitation, but in the form of formula (7) It is recovered at the cathode reduction. A cascade separation of the three metals is achieved due to the recovery of the different metals in the different reactor units.

O ₂ +4H ⁺ +4e ^- ＝2H ₂ OE ^θ ＝+1.229V _SHE (1)

Sn ²⁺ +2H ₂ O＝Sn(OH) ₂ ↓+2H ⁺ K _sp ＝1.4×10 ^－28 (2)

2Sn ²⁺ +O ₂ +4H ⁺ ＝2Sn ⁴⁺ +2H ₂ O (3)

Sn ⁴⁺ +4H ₂ O＝Sn(OH) ₄ ↓+4H ⁺ K _sp ＝1.0×10 ^-56 (4)

4Fe ²⁺ +4H ⁺ +O ₂ ＝4Fe ³⁺ +2H ₂ O (5)

Fe ³⁺ +3OH ^- ＝Fe(OH) ₃ ↓ K _sp ＝2.8×10 ^-39 (6)

Cu ²⁺ +2e ^- ＝Cu(s) E ^θ ＝+0.340V _SHE (7)

Contents of the invention

The invention provides a method for cascade separation and recovery of tin, iron and copper from acidic waste etching solution by using multi-stage MFCs. That is, by utilizing the chemical conversion of Sn(II) and Fe(II) in air cathode MFCs and different pH response degrees, the precipitation of Sn(OH) ₂ and/or Sn(OH) ₄ , Fe (OH) ₃ was precipitated to separate and recover tin and iron; while Cu(II) was reduced and recovered at the cathode of anaerobic MFCs, so as to achieve the purpose of gradually separating and recovering tin, iron and copper from acidic waste etching solution.

Technical scheme of the present invention:

The acidic waste etching solution containing Sn(II), Fe(II) and Cu(II) first enters the first-stage MFCs cathode chamber, and the first-stage MFCs removes copper or tin; the first-stage reactor effluent is pumped into the second-stage MFCs cathode chamber, and the second The first-stage MFCs remove tin, iron or copper; the effluent from the second-stage reactor is pumped into the third-stage MFCs cathode chamber, and the third-stage MFCs removes iron or copper. Based on this, there are three combinations of multi-level MFCs: copper removal-tin removal-iron removal, tin removal-iron removal-copper removal, and tin removal-copper removal-iron removal (Figure 1). Each MFCs unit includes an anode chamber, an anode electrode, a cathode chamber, a cathode electrode, an ion exchange membrane and an external resistance, and each MFCs unit is connected to a data collection system through an external resistance; the ion exchange membrane is an anion exchange membrane. The anode electrode of each MFCs unit is made of carbon materials such as carbon rods, carbon cloth, carbon particles or carbon felt, and the cathode of MFCs for tin removal and iron removal is carbon cloth material, and the side facing the air is coated with polytetrafluoroethylene Allow a certain amount of air to enter while preventing water leakage, the side facing the solution is coated with carbon powder, and the cathode electrode is exported through a titanium wire; the cathode electrode used for copper removal MFCs is carbon rod, carbon cloth, carbon particles, carbon felt Carbon materials such as stainless steel mesh, titanium sheets and other metal materials. All MFCs units are connected to the data collection system through external resistance. The catholyte feed water composition of multi-stage MFCs is an acidic waste etching solution containing Sn(II), Fe(II) and Cu(II), the content of each metal is 1-50000mg/L; the initial pH value is 0.0-2.0; the cathode The conductivity of the liquid is 0.8-20.0mS/cm; the cathode potential is -0.10-0.60V. Inject the organic carbon source and microbial nutrient solution into all the anode chambers of multi-stage MFCs. The initial pH of the anode chamber is 7.0-8.0, the conductivity is 1.0-2.0mS/cm, and the chemical oxygen demand is 100-1000mg/L; the anode potential -0.30~0.00V.

The external resistance is 1-1000Ω.

The composition of MFCs anolyte is: 12.0mM sodium acetate; 2.9mM (NH ₄ ) ₂ SO ₄ ; 0.1mM KH ₂ PO ₄ ; mineral elements: 12.5mL/L, the composition is MgSO ₄ : 3.0g/L, MnSO ₄ · H ₂ O: 0.5g/L, NaCl: 1.0g/L, FeSO ₄ 7H ₂ O: 0.1g/L, CaCl ₂ 2H ₂ O: 0.1g/L, CoCl ₂ 6H ₂ O: 0.1g/L L, ZnCl ₂ : 0.13g/L, CuSO ₄ 5H ₂ O: 0.01g/L, KAl(SO ₄ ) ₂ 12H ₂ O: 0.01g/L, H ₃ BO ₃ : 0.01g/L, NiCl ₂ 6H ₂ O: 0.024g/L and Na ₂ WO ₄ 2H ₂ O: 0.024g/L; Vitamins: 12.5mL/L The composition is vitamin B ₁ : 5.0g/L, vitamin B ₂ : 5.0g/L , vitamin B ₃ : 5.0g/L, vitamin B ₅ : 5.0g/L, vitamin B ₆ : 10.0g/L, vitamin B ₁₁ : 2.0g/L, vitamin H: 2.0g/L, p-aminobenzoic acid: 5.0g/L, lipoic acid: 5.0g/L and aminotriacetic acid: 1.5g/L.

The anode chamber is inoculated with sludge from a clarification tank of a sewage treatment plant as a bacterial source for acclimating electrochemically active microorganisms. The pH of the clarifier sludge is 7.0-8.0; the electrical conductivity is 1.0-2.0 mS/cm; the suspended solids are 10-20 g/L; the chemical oxygen demand is 100-1000 mg/L.

The anode chamber of all MFCs units of the present invention and the cathode chamber of copper-removing MFCs need keep anaerobic environment during operation, can feed nitrogen to realize anaerobic condition; And in removing tin MFCs and deironing MFCs cathode chamber, air Air is supplied naturally through the PTFE layer and is also actively aerated.

The system operation process of the present invention is: the organic matter in the anolyte is oxidized by microorganisms in the anode chamber, and the electrons transferred to the anode electrode are introduced into the cathode electrode through an external circuit. And the electronic reaction generates water (formula 1), the pH of the solution continues to rise, and Sn(II) and oxidized Sn(IV) (formula 3) generate stannous hydroxide and tin hydroxide precipitation (formula 2 and 4) and deposit at the bottom of the reactor. The cathode effluent of the tin removal reactor enters the cathode chamber of the iron removal reactor, Fe(II) is oxidized to Fe(III) (formula 5), and as the pH value increases, iron hydroxide precipitates (formula 6) are formed and deposited on bottom of the reactor. The cathode effluent of the iron removal reactor enters the cathode chamber of the anaerobic copper removal reactor, and Cu(II) is reduced and recovered on the electrode surface (Formula 7). A cascade separation of the three metals is achieved due to the recovery of the different metals in the different reactor units. At the same time, the cathode chamber for tin and iron deposition at the bottom also acts as a sedimentation tank, reducing subsequent separation operations. This process achieves the effects of resource recovery and cascade separation of tin, iron and copper while by-producing electric energy, and has multiple benefits of environment and ecology, society and economy.

Description of drawings

Fig. 1 is the multi-stage MFCs process flow diagram of reclaiming and separating tin, iron and copper in the acidic etching solution of the present invention.

Fig. 2 is a schematic structural diagram of multi-stage MFCs for recovering and separating tin, iron and copper in the acidic etching solution under the method of tin removal-iron removal-copper removal in the present invention.

FIG. 3 is the tin, iron and copper removal rates of the multistage MFCs of Example 1. FIG.

FIG. 4 is the tin, iron and copper separation coefficients of the multistage MFCs of Example 1. FIG.

FIG. 5 is the cathode influent and effluent pH of the multistage MFCs of Example 1. FIG.

FIG. 6 is the conductivity of the multistage MFCs cathode water inflow and outflow water in Example 1. FIG.

FIG. 7 is the average current of the multistage MFCs of Example 1. FIG.

FIG. 8 is the anode potential and cathode potential of the multi-stage MFCs of Example 1. FIG.

In the figure: 1 anode chamber; 2 reference electrode; 3 anode carbon rod electrode; 4 anion exchange membrane;

5 external resistance; 6 acidic etching solution containing tin, iron and copper; 7 peristaltic pump; 8 cathode carbon cloth electrode;

9 anode carbon felt electrode; 10 cathode chamber; 11 sampling point; 12 nitrogen; 13 cathode carbon rod electrode;

14 out of water.

detailed description

The specific implementation manners of the present invention will be further described below in conjunction with the accompanying drawings and technical solutions.

Example 1

Step 1: Build three MFCs reactor units, as shown in Figure 2: the MFCs anode chamber and cathode chamber are made of plexiglass, the effective volume of the anode chamber is 13mL, and the effective volume of the cathode chamber is 25mL. Anion exchange membrane ( AEM-7000) separated.

Step 2: carbon felt 9 is placed in each reactor anode chamber; carbon rods 3 and 13 are placed in each reactor anode chamber and copper-removing MFCs cathode chamber, respectively as respective anode electrodes and cathode electrodes; carbon cloth The side of 8 facing the air is coated with four layers of polytetrafluoroethylene, and the other side of the carbon cloth 8 is coated with carbon powder, which are respectively used as cathodes of MFCs for tin removal and iron removal, with an effective area of 7.1 cm ² , and titanium wires as wires. The anode carbon felt is a small piece of 1.0cm×1.0cm×1.0cm; the size of the carbon rod is 0.8cm×L: 7cm. The reference electrode 2 is connected to the anode chamber of each reactor, and the voltage of the external resistance 5 of each MFCs unit is collected through the computer and the data acquisition system and the current is calculated; the anode and cathode potentials of each MFCs unit are collected according to the reference electrode.

Step 3: Add deionized water to the cathode chamber.

Step 4: Prepare the anode solution, the composition of which is as described in the previous technical scheme. Expose the anolyte to nitrogen for 15 to 20 minutes, then connect it to the anode chamber of each reactor, at the same time inoculate 10g of sludge from the clarification tank of the sewage treatment plant, and then seal it.

Step 5: Put the device at room temperature (20-25° C.) for acclimatization and operation. When the current drops below 0.01mA, one cycle is completed, and the above-mentioned medium components are added. When the output voltage stabilized at a similar value for three consecutive cycles, it indicated that the anode electrochemically active bacteria had been domesticated and started successfully.

Step 6: configure the solution with cupric chloride, tin protochloride and ferrous chloride, so that the concentrations of Sn(II), Fe(II) and Cu(II) are 80mg/L, 40mg/L and 60mg/L respectively ; Adjust the conductivity of the solution to 4.0mS/cm and the pH to 2.0.

Step 7: Expose the solution in step 6 to nitrogen gas for 15-20 minutes, then pump it into the copper removal MFCs cathode chamber, and run it in the copper removal MFCs for 12 hours; pump the effluent from the copper removal MFCs cathode chamber into the tin removal MFCs cathode chamber, Run for 4 hours; pump the effluent from the cathode chamber of the MFCs for iron removal into the cathode chamber of the MFCs for iron removal, and run for 8 hours in the iron removal MFCs.

Step 8: Pump the solution of step 6 into the cathode chamber of the MFCs for removing tin, and run it for 4 hours in the MFCs for removing tin; The water out of the MFCs cathode chamber is exposed to nitrogen for 15-20 minutes, and then pumped into the copper removal MFCs cathode chamber, and operated in the copper removal MFCs for 12 hours.

Step 9: Pump the solution in step 6 into the cathode chamber of the MFCs for removing tin, and run it in the MFCs for removing tin for 4 hours; after exposing the water from the cathode chamber of the MFCs for removing tin to nitrogen for 15-20 minutes, pump it into the cathode chamber of MFCs for removing copper, and run it in the MFCs for removing tin Run for 12 hours; pump the effluent from the copper removal MFCs cathode chamber into the iron removal MFCs cathode chamber, and run in the iron removal MFCs for 8 hours.

Step 10: Measure the total copper, tin and iron concentrations of the catholyte effluent of the step 6 solution and the MFCs units at all levels in steps 7, 8 and 9 respectively, and calculate the tin removal in the tin removal MFCs, iron removal MFCs and copper removal MFCs respectively rate (α _Sn,Sn , α _Fe,Sn , α _Cu,Sn , %), iron removal rate (α _Sn,Fe , α _Fe,Fe , α _Cu,Fe , %), copper removal rate (α _Sn,Cu , α _{Fe, Cu} , α _{Cu, Cu} , %), and the separation coefficient (ε _Cu , ε _Sn , ε _Fe ) of removing the target metal relative to other metals by each reactor unit.

In this case, multi-stage MFCs are implemented to recover and separate tin, iron and copper in the acidic waste etching solution. Since the pH, conductivity, metal ion concentration and reaction time of each reactor unit catholyte are different, the recovery and separation effects on tin, iron and copper are all different. α _Sn,Cu , α _Sn,Sn , α _Sn,Fe , α _Fe,Cu , α _Fe,Sn , α _Fe,Fe , α _Cu,Cu , α _Cu,Sn , α _Cu,Fe and ε _Cu , ε _Sn , ε _Fe are calculated as shown in formulas (8)-(19).

In the formula: C _{Sn, Cu, 0} and C _{Sn, Cu, f} , C _{Sn, Sn, 0} and C _{Sn, Sn, f} , and C _{Sn, Fe, 0} and C _{Sn, Fe, f} : respectively Concentrations of total copper, total tin and total iron in the influent and effluent of MFCs unit (g/L); C _Fe,Cu,0 and C _Fe,Cu,f , C _Fe,Sn,0 and C _Fe,Sn,f , and C _{Fe, Fe, 0} and C _{Fe, Fe, f} : the concentration of total copper, total tin and total iron in the influent and effluent water of the MFCs unit for iron removal, respectively (g/L); C _{Cu, Cu, 0} and C _{Cu, Cu ,f} , C _Cu,Sn,0 and C _Cu,Sn,f , and C _Cu,Fe,0 and C _Cu,Fe,f : the total copper, total tin and total iron in the influent and effluent water of the copper removal MFCs unit, respectively Concentration (g/L).

Results: In the three combinations of multistage MFCs, copper can be completely removed and recovered. The removal rates of tin and iron were 90.2±0.1% and 78.9±0.4% respectively under the (first) copper removal-tin removal-iron removal sequence (Fig. 3); in the (second type) tin removal-iron removal- Under the order of copper removal, they were 87.4±0.1% and 76.1±0.2% (Figure 3); under the (third) order of tin removal-copper removal-iron removal, they were 90.1±0.1% and 77.1±1.3% ( image 3). Correspondingly, the separation coefficients of tin under the above three combined conditions are 0.87±0.05, 47.02±4.74 and 48.18±5.42; while those of iron and copper are 0.84±0.02, 3.76±0.18 and 0.70±0.06, respectively, and 7.38±0.29, +∞ (complete separation of copper) and 3.92±0.21 (Fig. 4). The initial pH of the influent water under the three combinations is 2.00±0.03. Under the first method above, the pH of the effluent water increases to 2.33±0.02, 4.05±0.03 and 5.82±0.01 in turn (Figure 5), and the conductivity drops to 3.08 in turn. ±0.02, 1.76±0.04, and 1.08±0.01mS/cm (Figure 6); in the second method above, the pH of the effluent rises to 2.83±0.02, 4.94±0.01, and 5.40±0.01 (Figure 5), and the conductivity decreases in turn are 2.93±0.05, 2.01±0.04 and 1.13±0.06mS/cm (Fig. 6); in the above third mode, the pH of the effluent rises to 2.83±0.02, 3.14±0.01 and 5.60±0.01 (Fig. 5), and the conductivity Decrease to 2.92±0.02, 1.56±0.04 and 1.09±0.06mS/cm in turn (Figure 6). The anode potentials of each reactor unit under the three combinations are all stable at -0.20±0.02V (Fig. 8). In the first way, the current density of each unit is 0.25±0.01A/m ² , 0.38±0.02A/m ² and 0.25±0.02A/m ² (Figure 7), and the cathode potential is -0.03±0.02V ^{. _ 2} (Figure 7), the cathode potentials are 0.18±0.04V, 0.09±0.05V and -0.11±0.00V (Figure 8); in the third mode, the current density of each unit is 0.53±0.00A/m ² , 0.20±0.00A/m ² and 0.28±0.03A/m ² (Fig. 7), and the cathode potentials are 0.18±0.05V, -0.09±0.00V and 0.07±0.01V respectively (Fig. 8).

The experimental results show that: 1) The combination of multi-stage MFCs unit combination of tin removal-iron removal-copper removal is more conducive to the stepwise separation and recovery of the three metals (Figure 4); 2) as the reaction progresses, due to oxygen, electrons and hydrogen The ion reaction (formula 1) causes the pH of the solution to rise continuously (Figure 5), and the sharp rise in pH provides favorable conditions for the hydrolysis and precipitation of tin and iron, making Sn(II) and Fe(II) form stannous hydroxide, Precipitation in the form of tin hydroxide and iron hydroxide (Equations 2, 4, and 6), resulting in a continuous decrease in solution conductivity (Figure 6); 3) The current density and cathodic potential of the MFCs unit for tin removal and iron removal were significantly higher than those for copper removal MFCs unit (Fig. 7 and 8), it shows that the aerobic condition of the former is more favorable to the power output of the corresponding reactor unit than the anaerobic condition of the latter; 4) As the reaction proceeds, the current density and the cathode potential show a downward trend ( Figures 7 and 8), the main reason is that as the reaction proceeds, the solution conductivity decreases (Figure 6), and the internal resistance of the system increases, causing the current density and cathode potential to decrease.

In summary, the multi-stage MFCs system can effectively separate and recover tin, iron and copper in the acidic waste etching solution step by step under the condition of by-product electricity, which not only provides an effective method for the treatment and resource utilization of the acidic waste etching solution, but also expands The application field and usage range of multistage MFCs are discussed. The whole process is clean and pollution-free, and has both environmental and ecological benefits, social benefits and economic benefits.

Claims (10)

1. a kind of clean the effective method that copper, tin and iron are separated and recovered from from spent acidic etching solution, it is characterised in that step It is rapid as follows：

Described method uses multistage MFCs combinations, and specially three MFCs units are completed jointly, and each MFCs units are equal Including anode chamber, anode electrode, cathode chamber, cathode electrode, amberplex and extrernal resistance, each MFCs units through external resistance with Data gathering system is connected；Described amberplex is anion-exchange membrane；

The spent acidic etching solution that Sn (II), Fe (II) and Cu (II) will be contained passes through the moon that intake pump injects one-level MFCs units Pole room, one-level MFCs units copper removal or tin；First-stage reactor water outlet enters two grades of MFCs cathode chambers, two grades of MFCs units except tin, Iron or copper；Second reactor water outlet enters three-level MFCs cathode chambers, and three-level MFCs units remove iron or copper；The multistage built accordingly MFCs combinations have three kinds：Copper removal-except tin-- removes iron-copper removal and except tin-copper removal-except iron, except tin and removes iron, gone according to above-mentioned Except MFCs units at different levels of sequentially arranging；The anode electrode of all MFCs units is carbon material；Except tin and except the MFCs negative electrodes of iron Electrode is carbon cloth material, and polytetrafluoroethylene (PTFE) is scribbled towards the side of air, and carbon dust is scribbled towards the side of solution, and cathode electrode leads to Cross titanium wire export；The MFCs cathode electrodes of copper removal are carbon material or metal material；

The described spent acidic etching solution containing Sn (II), Fe (II) and Cu (II), Sn (II), Fe (II) and Cu (II) are in acid Property useless etching solution in concentration be 1~50000mg/L；Initial pH value is 0~2.0；Catholyte electrical conductivity be 0.8~ 20.0mS/cm；Cathode electrode potential is -0.10~0.60V；Anode electrode potential is -0.30~0.00V；

Organic carbon source and microbial nutrient solution are injected to the anode chamber of multistage MFCs units, the initial pH for controlling anode chamber is 7.0 ~8.0, electrical conductivity is 1.0~2.0mS/cm, and COD is 100~1000mg/L；Anode potential is -0.30~0.00V.

2. the effective side that copper, tin and iron are separated and recovered from from spent acidic etching solution of cleaning according to claim 1 Method, it is characterised in that multistage MFCs all anode chambers and the cathode chamber of copper removal MFCs units keep anaerobic in the process of running Environment, is passed through nitrogen to realize anaerobic condition；In the cathode chamber except tin and except iron MFCs units, air passes through polytetrafluoroethylene (PTFE) Layer enters naturally or actively aeration supplies air.

3. cleaning according to claim 1 or 2 is effectively separated and recovered from copper, tin and iron from spent acidic etching solution Method, it is characterised in that described carbon material is carbon-point, carbon cloth, carbon granules or carbon felt；Described metal material be stainless (steel) wire or Titanium sheet.

4. cleaning according to claim 1 or 2 is effectively separated and recovered from copper, tin and iron from spent acidic etching solution Method, it is characterised in that the resistance of described external resistance is 1~1000 Ω.

5. the effective side that copper, tin and iron are separated and recovered from from spent acidic etching solution of cleaning according to claim 3 Method, it is characterised in that the resistance of described external resistance is 1~1000 Ω.

6. the cleaning according to claim 1,2 or 5 is effectively separated and recovered from copper, tin and iron from spent acidic etching solution Method, it is characterised in that the composition of microbial nutrient solution is in described anode chamber：12.0mM sodium acetates；2.9mM(NH₄)₂SO₄；0.1mM KH₂PO₄；Mineral element：12.5mL/L composition is MgSO₄:3.0g/L、MnSO₄·H₂O:0.5g/L、NaCl: 1.0g/L、FeSO₄·7H₂O:0.1g/L、CaCl₂·2H₂O:0.1g/L、CoCl₂·6H₂O:0.1g/L、ZnCl₂:0.13g/L、 CuSO₄·5H₂O:0.01g/L、KAl(SO₄)₂·12H₂O:0.01g/L、H₃BO₃:0.01g/L、NiCl₂·6H₂O:0.024g/L And Na₂WO₄·2H₂O:0.024g/L；Vitamin:12.5mL/L composition is vitamin B₁:5.0g/L, vitamin B₂:5.0g/L、 Vitamin B₃:5.0g/L, vitamin B₅:5.0g/L, vitamin B₆:10.0g/L, vitamin B₁₁:2.0g/L, biotin:2.0g/ L, p-aminobenzoic acid:5.0g/L, lipoic acid:5.0g/L and aminotriacetic acid:1.5g/L.

7. the effective side that copper, tin and iron are separated and recovered from from spent acidic etching solution of cleaning according to claim 3 Method, it is characterised in that the composition of microbial nutrient solution is in described anode chamber：12.0mM sodium acetates；2.9mM(NH₄)₂SO₄； 0.1mM KH₂PO₄；Mineral element：12.5mL/L composition is MgSO₄:3.0g/L、MnSO₄·H₂O:0.5g/L、NaCl:1.0g/ L、FeSO₄·7H₂O:0.1g/L、CaCl₂·2H₂O:0.1g/L、CoCl₂·6H₂O:0.1g/L、ZnCl₂:0.13g/L、CuSO₄· 5H₂O:0.01g/L、KAl(SO₄)₂·12H₂O:0.01g/L、H₃BO₃:0.01g/L、NiCl₂·6H₂O:0.024g/L and Na₂WO₄·2H₂O:0.024g/L；Vitamin:12.5mL/L composition is vitamin B₁:5.0g/L, vitamin B₂:5.0g/L, dimension Raw element B₃:5.0g/L, vitamin B₅:5.0g/L, vitamin B₆:10.0g/L, vitamin B₁₁:2.0g/L, biotin:2.0g/L、 P-aminobenzoic acid:5.0g/L, lipoic acid:5.0g/L and aminotriacetic acid:1.5g/L.

8. the effective side that copper, tin and iron are separated and recovered from from spent acidic etching solution of cleaning according to claim 4 Method, it is characterised in that the composition of microbial nutrient solution is in described anode chamber：12.0mM sodium acetates；2.9mM(NH₄)₂SO₄； 0.1mM KH₂PO₄；Mineral element：12.5mL/L composition is MgSO₄:3.0g/L、MnSO₄·H₂O:0.5g/L、NaCl:1.0g/ L、FeSO₄·7H₂O:0.1g/L、CaCl₂·2H₂O:0.1g/L、CoCl₂·6H₂O:0.1g/L、ZnCl₂:0.13g/L、CuSO₄· 5H₂O:0.01g/L、KAl(SO₄)₂·12H₂O:0.01g/L、H₃BO₃:0.01g/L、NiCl₂·6H₂O:0.024g/L and Na₂WO₄·2H₂O:0.024g/L；Vitamin:12.5mL/L composition is vitamin B₁:5.0g/L, vitamin B₂:5.0g/L, dimension Raw element B₃:5.0g/L, vitamin B₅:5.0g/L, vitamin B₆:10.0g/L, vitamin B₁₁:2.0g/L, biotin:2.0g/L、 P-aminobenzoic acid:5.0g/L, lipoic acid:5.0g/L and aminotriacetic acid:1.5g/L.

9. the cleaning according to claim 1,2,5,7 or 8 is effectively separated and recovered from copper, tin from spent acidic etching solution With the method for iron, it is characterised in that described anode chamber's inoculation sewage treatment plant's depositing reservoir sludge is used as domestication electro-chemical activity The bacterium source of microorganism；The pH of described depositing reservoir sludge is 7.0~8.0；Electrical conductivity is 1.0~2.0mS/cm；Suspension solid Thing:10~20g/L；COD is 100~1000mg/L.

10. the effective side that copper, tin and iron are separated and recovered from from spent acidic etching solution of cleaning according to claim 6 Method, it is characterised in that described anode chamber's inoculation sewage treatment plant's depositing reservoir sludge is used as domestication electro-chemical activity microorganism Bacterium source；The pH of described depositing reservoir sludge is 7.0~8.0；Electrical conductivity is 1.0~2.0mS/cm；Suspension solid content:10~ 20g/L；COD is 100~1000mg/L.