CN103266331A - Method for recovery of elemental cobalt from lithium cobaltate by microbial fuel cell (MFC) self-driven microbial electrolysis cell (MEC) coupled system - Google Patents

Abstract

The invention discloses a method for recovery of elemental cobalt from lithium cobaltate by a microbial fuel cell (MFC) self-driven microbial electrolysis cell (MEC) coupled system. The method is characterized in that an MFC anode is directly connected to an MEC cathode; an MFC cathode is connected to an MEC anode by a resistance; an MFC cathode chamber is filled with a cathode liquid and lithium cobaltate particles; an MFC anode chamber is inoculated with sludge as an electrochemical activity microbe source in a clarification pool of a sewage treatment plant, an MEC cathode chamber is filled with a Co(II)-containing aqueous solution; an MEC anode chamber is inoculated with the sludge as an electrochemical activity microbe source in a clarification pool of a sewage treatment plant; and anode and cathode materials are graphite materials. The method provides an effective approach for in-situ utilization of MFC output electric energy and provides a wide space for extra electric energy input-free and cathode liquid acidity limit-free MEC application.

Description

The self-driven microorganism electrolysis cell coupled system of a kind of microbiological fuel cell reclaims the method for simple substance cobalt from cobalt acid lithium

Technical field

The invention belongs to the microorganism electrochemical technical field, specifically utilize microbiological fuel cell MFCs and microorganism electrolysis cell MECs characteristics separately, in conjunction with the Co (III) of cobalt acid lithium particle leach into liquid phase Co (II), the partial potential that is reduced to simple substance cobalt by liquid phase Co (II) changes, realize leaching that MFCs for Co (II) drives and coupling Co (II) is reduced to the MECs process of simple substance cobalt by Co (III).

Background technology

(Microbial Fuel Cells, MFCs) (Microbial Electrolysis Cells MECs) includes anolyte compartment, anode electrode, cathode compartment, cathode electrode, proton exchange membrane to microbiological fuel cell with microorganism electrolysis cell.Different is that the Gibbs free energy that the negative electrode of MFCs and anode react is reacted spontaneous the carrying out of energy less than zero, system's output electric energy; On the contrary, the Gibbs free energy that the negative electrode of MECs and anode react is greater than zero, and reaction can not spontaneously be carried out, extraneous need the reaction of input energy drives carrying out.Utilize the MFCs driving of output electric energy and the MECs that coupling needs the input electric energy, when can directly utilize the MFCs electric energy in position, at MFCs and the valuable chemical of MECs cathodic synthesis, also can utilize MFCs and MECs anode to remove organic pollutant simultaneously, the process cleaning is the inevitable requirement of sustainability social development.

Cobalt is the important rare metal of producing lithium ion battery, and content reaches 15 – 20% in battery.Along with the mass production of lithium ion battery be extensive use of, its environmental problem of bringing is also serious day by day.Simultaneously, China is again largest production, consumption and the export State of lithium ion battery, accounts for global share more than 1/3, and is also urgent to the demand of cobalt.Clean, reclaim rare metal cobalt in the waste and old lithium ion battery efficiently, not only effectively solve battery pollution, and the recycling waste, tangible environmental benefit, economic benefit and social benefit had.

Cobalt in lithium ion battery with cobalt acid lithium (LiCoO ₂) exist, traditional recovery method mainly comprises physics method, chemical method, biological process, mainly is with LiCoO ₂Middle Co (III) goes out to be reduced to liquid phase Co (II) through acidleach, and subsequently reclaim cobalt by liquid phase Co (II) through advanced treatment (electroless plating, solvent extraction, galvanic deposit), shortcoming such as have energy consumption and cost height, secondary pollution, by product is many, the cycle is long, usefulness is low, technology is loaded down with trivial details.As emerging technology, though MFCs can be with LiCoO ₂Co in the particle (III) is reduced to solubilised state Co (II), but also needs advanced treatment to reclaim cobalt from liquid phase; And the output electric energy of MFCs is effectively collected and is utilized.Though MECs can leach LiCoO ₂And obtain simple substance cobalt, but system need import big energy; And catholyte need be defined as stronger sour environment.Material preparation that seek more to clean, short distance and the cobalt acid lithium resource utilization technology that combines is still the focus that people pay close attention to.

Be example with pH2.0, LiCoO ₂In Co (III) the theoretical redox potential that is reduced to Co (II) be 1.845V, with organism (be example with the sodium acetate) exhaustive oxidation be CO ₂Redox-potential (– 0.30V) can be configured to MFCs; And Co (II) reduction is irrelevant with pH, arbitrarily the theoretical redox potential Jin that Co (II) (calculating with 50mg/L) is reduced to simple substance cobalt under the pH is – 0.373V, owing to be lower than the redox-potential (– 0.30V of organism (be example with the sodium acetate)), need to make up MECs, take place by the reaction of input energy drives.Therefore, if be the MECs that the self-driven and coupling Co (II) of the MFCs of Co (II) is reduced to simple substance cobalt with Co (III) leaching, can be in realizing waste and old lithium ion battery in the cleaning recovery of simple substance cobalt, utilize the output electric energy of MFCs for original position effective way is provided; Simultaneously also for no additional electrical energy is imported, the application of the MECs of no catholyte acidity restriction provides the broad space.

Summary of the invention

The invention provides a kind of cleaning, that no outside energy consumes, as from cobalt acid lithium, the to reclaim simple substance cobalt self-driven microorganism electrolysis cell technology of microbiological fuel cell.

The present invention utilizes the self-driven MECs of MFCs to reclaim the method for simple substance cobalt from cobalt acid lithium, be the inorganic acid solutions such as cathode compartment adding hydrochloric acid at MFCs, cathode electrode is electro-conductive materials such as carbon-point and carbon felt, cobalt acid lithium add-on≤100g/L (w/v), cobalt acid lithium granularity 8～9 μ m, cobalt acid lithium particle is attached to cathode electrode surface.

Cathode compartment at MECs adds CoCl ₂Solution, cathode electrode are electro-conductive materials such as carbon-point.

Electrochemical activity microorganism and anolyte all are housed in the anolyte compartment of MFCs and MECs, and anode electrode is electro-conductive materials such as carbon-point and carbon felt.

The negative electrode of MFCs links to each other by the series resistance coupling with the MECs anode, by electric current in this resistance collection and the counting circuit.

Described anolyte compartment inoculation sewage work settling pond mud is as the electrochemical activity microorganism.

The pH:6.8 – 7.0 of described settling pond mud; Specific conductivity: 0.80 – 0.93mS/cm; Suspension solid substance: 30 – 35g/L; Chemical oxygen demand (COD) (COD): 150 – 300mg/L.

The anolyte composition is: the 12.0mM sodium acetate; 5.8mM NH ₄Cl; 1.7mM KCl; 17.8mMNaH ₂PO ₄H ₂O; 32.3mM Na ₂HPO ₄Mineral element: 12.5mL/L (consists of MgSO ₄: 3.0g/L; MnSO ₄H ₂O:0.5g/L; NaCl:1.0g/L; FeSO ₄7H ₂O:0.1g/L; CaCl ₂2H ₂O:0.1g/L; CoCl ₂6H ₂O:0.1g/L; ZnCl ₂: 0.13g/L; CuSO ₄5H ₂O:0.01g/L; KAl (SO ₄) ₂12H ₂O:0.01g/L; H ₃BO ₃: 0.01g/L; Na ₂MoO ₄: 0.025g/L; NiCl ₂6H ₂O:0.024g/L; Na ₂WO ₄2H ₂O:0.024g/L); VITAMIN: 12.5mL/L (consists of vitamins B ₁: 5.0g/L; Vitamins B ₂: 5.0g/L; Vitamins B ₃: 5.0g/L; Vitamins B ₅: 5.0g/L; Vitamins B ₆: 10.0g/L; Vitamins B ₁₁: 2.0g/L; Vitamin H: 2.0g/L; Para-amino benzoic acid: 5.0g/L; Thioctic Acid: 5.0g/L; Nitrilotriacetic acid: 1.5g/L).

MFCs of the present invention and MECs anolyte compartment need to keep oxygen-free environment in operational process, can be by feeding nitrogen to realize anaerobic condition.

MFCs operation phase flow process of the present invention is: by microbiological oxidation, the proton that process produces passes proton and enters cathode compartment through film the organism in the anolyte in the anolyte compartment, and electronics imports negative electrode by external circuit.On the negative electrode surface, the electronics that the Co (III) that adheres to cobalt acid lithium particle and negative electrode provide and the proton H-H reaction in the solution are reduced to solubilised state Co (II).MECs operation phase flow process of the present invention is: by microbiological oxidation, the electronics that MFCs produces imports the MECs negative electrode to the organism in the anolyte in the anolyte compartment.On the negative electrode surface, solubilised state Co (II) obtains the electronics that negative electrode provides, and is reduced to simple substance cobalt, thereby realizes reclaiming from cobalt acid lithium the self-driven MECs coupling process of MFCs of simple substance cobalt.Organic municipal wastewater is contained in MFCs and MECs anolyte compartment, and MFCs and MECs cathode compartment to take place respectively with cobalt acid lithium be that the set out Co (III) of substrate is reduced to the reaction that Co (II), Co (II) are reduced to simple substance cobalt, system's original position is utilized the MFCs electric energy, need not MECs is additionally imported energy, need not the sour environment that keeps the MECs catholyte stronger.In reclaiming waste and old lithium ion battery, also can handle organic sewages such as municipal administration in the valuable metal cobalt, reach environmental pollution improvement and resource utilization effect preferably.The process cleaning has environment and ecological benefits, social benefit and economic benefit concurrently.

Accompanying drawing and subordinate list explanation

Fig. 1 is the self-driven MECs coupled system of MFCs of the present invention reclaims simple substance cobalt from cobalt acid lithium particle structural representation.

Fig. 2 is the time variation diagram that the Co (II) of cobalt acid lithium among the MFCs of embodiment 1 leaches.

Fig. 3 is the time variation diagram of Co (II) reduction among the MECs of embodiment 1.

Fig. 4 is the polarization curve of the MFCs of embodiment 1.

Fig. 5 is the cyclic voltammetry curve of the MECs of embodiment 1.

Among the figure: 1 carbon-point; The 2MFCs anolyte compartment; 3 carbon felts; 4 ion-exchange membranees; The 5MFCs cathode compartment; 6 carbon felts; 7 cobalts acid lithium particle; 8 carbon-points; 9 reference electrodes; 10 data acquisition board; 11 external resistances; 12 reference electrodes; 13 carbon-points; The 14MECs anolyte compartment; 15 carbon felts; 16 ion-exchange membranees; The 17MECs cathode compartment; 18 simple substance cobalts; 19 carbon-points.

Embodiment

Embodiment 1

Step 1: make up MFCs and MECs, as shown in Figure 1: MFCs anolyte compartment 2 and cathode compartment 5, MECs anolyte compartment 14 and cathode compartment 17 are the synthetic glass material, anolyte compartment's liquor capacity of MFCs and MECs is 15mL, the cathode chamber solution volume of MFCs and MECs is 25mL, separate with ion-exchange membrane (CMI-7000) 4 or 16, series connection 10 Ω small resistors 11 between MFCs and MECs are so that electric current in collection and the counting circuit.

Step 2: respectively MFCs anode electrode (carbon-point and carbon felt) and cathode electrode (carbon-point and carbon felt) are placed MFCs anolyte compartment 2 and cathode compartment 5, MECs anode electrode (carbon-point and carbon felt) and cathode electrode (carbon-point) are placed MECs anolyte compartment 14 and cathode compartment 17.Carbon-point (Beijing three industry carbon material companies) apparent size is

0.8cm * 3.5cm, carbon felt (Beijing three industry carbon material companies) apparent size is 3.0cm * 2.0cm * 1.0cm).Insert reference electrode 9 and 12 in MFCs anolyte compartment and MECs cathode compartment respectively, collect small resistor 11 both end voltage and calculate electric current by computer and data collecting system 10; Collect MFCs anode and MECs cathode potential according to reference electrode.

Step 3: 0.25g cobalt acid lithium powder (granularity 8～9 μ m), MFCs cathode electrode 8 are placed the 100mL deionized water, 100rpm magnetic agitation 20min, cobalt acid lithium particle is adsorbed on the carbon felt fully, thereby makes the cathode electrode of Co (III) in MFCs leaching and the reduction cobalt acid lithium.

Step 4: at the 0.01M HCl solution of MFCs cathode compartment adding 25mL, nitrogen 20min exposes to the sun.

Step 5: at the 25mL of MECs cathode compartment borate buffer (0.1M, pH6.0) the middle CoCl that adds ₂, making its concentration is 50mg/L.

Step 6: add the 15mL nutrient solution respectively in MFCs and MECs anolyte compartment, it consists of the 12.0mM sodium acetate; 5.8mM NH ₄Cl; 1.7mM KCl; 17.8mM NaH ₂PO ₄H ₂O; 32.3mMNa ₂HPO ₄Mineral element: 12.5mL/L (MgSO ₄: 3.0g/L; MnSO ₄H ₂O:0.5g/L; NaCl:1.0g/L; FeSO ₄7H ₂O:0.1g/L; CaCl ₂2H ₂O:0.1g/L; CoCl ₂6H ₂O:0.1g/L; ZnCl ₂: 0.13g/L; CuSO ₄5H ₂O:0.01g/L; KAl (SO ₄) ₂12H ₂O:0.01g/L; H ₃BO ₃: 0.01g/L; Na ₂MoO ₄: 0.025g/L; NiCl ₂6H ₂O:0.024g/L; Na ₂WO ₄2H ₂O:0.024g/L); VITAMIN: 12.5mL/L (vitamins B ₁: 5.0g/L; Vitamins B ₂: 5.0g/L; Vitamins B ₃: 5.0g/L; Vitamins B ₅: 5.0g/L; Vitamins B ₆: 10.0g/L; Vitamins B ₁₁: 2.0g/L; Vitamin H: 2.0g/L; Para-amino benzoic acid: 5.0g/L; Thioctic Acid: 5.0g/L; Nitrilotriacetic acid: 1.5g/L).Anolyte compartment's inoculation settling pond mud 10g of sewage work (Dalian Ling Shuihe sewage work).Anolyte exposes to the sun and seals behind the nitrogen 20min.

Step 7: the MFCs negative electrode of step 3 and MFCs cathode compartment and the catholyte of step 4 are assembled.Device is placed domestication and operation under the room temperature (25 ° of C of 20 –).When electric current drops to 0.02mA when following, namely finish one-period, and add above-mentioned medium component.Treat continuous three cycle output voltage stabilizations when similar value, show the active bacterium domestication of anode electrochemical and start successfully.

Step 8: the MECs carbon-point negative electrode of step 2 is combined with the MECs of step 5 cathode compartment and catholyte.Device is placed domestication and operation under the room temperature (25 ° of C of 20 –).When the electric current under the certain voltage drops to 0.02mA when following, namely finish one-period, and add above-mentioned medium component.

Step 9: with the MECs of MFCs actuation step eight in the step 7.

Step 10: sampling regularly, analyze Co (II) content in the liquid phase; Characterize MFCs polarization curve and MECs cyclic voltammetry curve; Calculate the ratio leaching yield of cobalt acid lithium, the ratio yield of simple substance cobalt, negative electrode coulombic efficiency, system capacity efficient and sour effective rate of utilization, MECs negative electrode coulombic efficiency and system capacity efficient and the MFCs – MECs system total efficiency of MFCs.

Following table 1 is that the cobalt acid lithium of embodiment 1 is than the total efficiency of sour effective rate of utilization, MECs negative electrode coulombic efficiency, MECs system capacity efficient and the MFCs – MECs coupled system of the ratio yield that leaches yield, simple substance cobalt, MFCs negative electrode coulombic efficiency, MFCs system capacity efficient, MFCs.

The self-driven MECs coupled system of the MFCs of this enforcement example reclaims simple substance cobalt from cobalt acid lithium.The reaction that takes place at the MFCs negative electrode is formula (1), and the reaction of carrying out at the MECs negative electrode is formula (2), and the net reaction of cobalt experience is shown in (3).The ratio leaching yield (Y of cobalt acid lithium _LiCoO2), the ratio yield (Y of simple substance cobalt _Co), MFCs negative electrode coulombic efficiency (CE _MFC), MECs negative electrode coulombic efficiency (CE _MEC), MFCs system capacity efficient (η _MFC), MECs system capacity efficient (η _MEC), MFCs – MECs coupled system total efficiency (η _Sys) and the calculating of the sour effective rate of utilization (AUE) of MFCs suc as formula (shown in the 4) – (11).

LiCoO ₂(s)+4H ⁺+e ^-→Co ²⁺+Li ⁺+2H ₂O (1)

Co ²⁺+2e ^-→Co (2)

LiCoO ₂(s)+4H ⁺+3e ^-→Co+Li ⁺+2H ₂O (3)

$Y_{{\mathrm{<figure-callout\; id="2"\; label="LiCoO"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">LiCoO</figure-callout>}}_2}=\frac{{\mathrm{\&Delta;<figure-callout\; id="2"\; label="n\; Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">n</figure-callout>}}_{{\mathrm{Co}}^{}}\&times;V_{\mathrm{ca}}\&times;a_1\&times;M_{{\mathrm{LiCoO}}_2}}{1000\&times;M_{\mathrm{Co}}\&times;V_{\mathrm{an}}\&times;{\mathrm{\&Delta;COD}}_{\mathrm{MFC}}}---\left(4\right)$

$Y_{\mathrm{Co}}=\frac{{\mathrm{\&Delta;n}}_{{\mathrm{<figure-callout\; id="2"\; label="Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">Co</figure-callout>}}^{2+}}\&times;V_{\mathrm{ca}}\&times;a_2}{1000\&times;V_{\mathrm{an}}{\mathrm{\&Delta;COD}}_{\mathrm{MEC}}}---\left(5\right)$

${\mathrm{CE}}_{\mathrm{MFC}}=\frac{\&Integral;\mathrm{Idt}}{96485\&times;\frac{4\&times;{\mathrm{\&Delta;COD}}_{\mathrm{MFC}}\&times;V_{\mathrm{an}}}{{\mathrm{<figure-callout\; id="2"\; label="M\; O"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">M</figure-callout>}}_{O_{}}}}\&times;100\%---\left(6\right)$

${\mathrm{CE}}_{\mathrm{MEC}}=\frac{\&Integral;\mathrm{Idt}}{96485\&times;\frac{4\&times;{\mathrm{\&Delta;COD}}_{\mathrm{MEC}}\&times;V_{\mathrm{an}}}{{\mathrm{<figure-callout\; id="2"\; label="M\; O"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">M</figure-callout>}}_{O_{}}}}\&times;100\%---\left(7\right)$

${\mathrm{\&eta;}}_{\mathrm{MFC}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="HDA00003097648900012.png"\; state="\{\{state\}\}">b</figure-callout>}}_1\&times;V_{\mathrm{ca}}\&times;\mathrm{\&Delta;}\left[{\mathrm{<figure-callout\; id="2"\; label="Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">Co</figure-callout>}}^{2+}\right]\&times;96485}{1000\&times;M_{\mathrm{Co}}\&times;\&Integral;\mathrm{Idt}}\&times;100\%---\left(8\right)$

${\mathrm{\&eta;}}_{\mathrm{MEC}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\&times;V_{\mathrm{ca}}\&times;\mathrm{\&Delta;}\left[{\mathrm{<figure-callout\; id="2"\; label="Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">Co</figure-callout>}}^{2+}\right]\&times;96485}{1000\&times;M_{\mathrm{Co}}\&times;\&Integral;\mathrm{Idt}}\&times;100\%---\left(9\right)$

${\mathrm{\&eta;}}_{\mathrm{sys}}=\frac{{\mathrm{\&Delta;n}}_{{\mathrm{<figure-callout\; id="2"\; label="Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">Co</figure-callout>}}^{2+}}\&times;V_{\mathrm{ca}}\&times;\frac{{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="HDA00003097648900012.png"\; state="\{\{state\}\}">b</figure-callout>}}_1}{1000\&times;M_{\mathrm{Co}}}+{\mathrm{\&Delta;<figure-callout\; id="2"\; label="n\; Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">n</figure-callout>}}_{{\mathrm{Co}}^{}}\&times;V_{\mathrm{ca}}\&times;\frac{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">b</figure-callout>}}_2}{1000\&times;M_{\mathrm{Co}}}}{(V_{\mathrm{an}}{\mathrm{\&Delta;COD}}_{\mathrm{MFC}}+V_{\mathrm{an}}{\mathrm{\&Delta;COD}}_{\mathrm{MEC}})\&times;\frac{4}{{\mathrm{<figure-callout\; id="2"\; label="M\; O"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">M</figure-callout>}}_{O_{}}}}\&times;100\%---\left(10\right)$

$\mathrm{AUE}=\frac{4\&times;{\mathrm{\&Delta;n}}_{{\mathrm{<figure-callout\; id="2"\; label="Co"\; filenames="HDA00003097648900011.png,HDA00003097648900012.png"\; state="\{\{state\}\}">Co</figure-callout>}}^{2+}}\&times;V_{\mathrm{ca}}}{1000\&times;M_{\mathrm{Co}}\&times;V_{\mathrm{ca}}\&times;\mathrm{\&Delta;}\left[H^{+}\right]}\&times;100\%---\left(11\right)$

Δ n _Co2+Be the changing value (mg/L) that reacts the concentration of cobalt ions of initial and final state among MFC or the MEC, the 1st, the stoichiometric number ratio of cobalt acid lithium and Co (II); a ₁And a ₂It is respectively cobalt acid lithium and Co (II), Co (II) and the stoichiometric number ratio of simple substance cobalt; b ₁And b ₂Be respectively that unit cobalt acid lithium leaching and the Co of unit (II) reduce needed electronic number (mol/mol); M _LiCoO2And M _CoBe the relative molecular mass (g/mol) of cobalt acid lithium and cobalt, V _AnBe the anolyte volume (L) of MFC or MEC, V _CaBe the catholyte volume (L) of MFC or MEC, Δ COD _MFCWith Δ COD _MECBe respectively the changing value (g/L) of chemical oxygen demand (COD) among MFC and the MEC, I is electric current in the loop (A), and t is reactor working time (s), and Δ [H+] is the hydrogen ion concentration changing value (mol/L) of the initial and final state of MFC cathode compartment, M _LiCoO2, M _CoAnd M _O2Be respectively average molecular or the nucleidic mass (g/mol) of cobalt acid lithium, simple substance cobalt and oxygen, 96485 is Faraday's number, (C/mol e ^-); The 4th, the electronic number (mol/mol) that the oxygen of unit amount of substance obtains, the 1000th, dimension conversion unit (mg/g).

The result: in reaction times 0-6h, Co among the MFCs (II) concentration is increased to 12.7 ± 0.2mg/L (Fig. 2) gradually.And drive at MFCs, starting point concentration is among the MECs of 50mg/L, Co (II) concentration is reduced to 35.1 ± 0.2mg/L (Fig. 3) gradually, when showing this MFCs leaching cobalt acid lithium, utilizes the output electric energy to drive MECs Co (II) is reduced.The open circuit voltage of MFCs system is 0.80V, and maximum output electric energy is 1.0W/m ³(4.4A/m ³) (Fig. 4).The cyclic voltammetric analysis revealed, the redox peak Chu Xian Zai – 0.30V of MECs negative electrode and+0.20V, and maximum current window Wei – 1.35mA (– 0.3V) (Fig. 5), coincide with the reduction potential of Co (II), show that Co (II) is reduced at the MECs electrode surface.

During the operation 6h of system, the cobalt acid lithium of MFCs is 0.65 ± 0.01g Co/g COD than the leaching yield, and the negative electrode coulombic efficiency is 26 ± 2%, and system capacity efficient is 22 ± 1%, and the effective rate of utilization of acid is 9 ± 0% (tables 1); The simple substance cobalt of MECs is 0.83 ± 0.14g Co/g COD than yield, and the negative electrode coulombic efficiency is 44 ± 7%, and system capacity efficient is 52 ± 1% (tables 1); MFCs – MECs coupled system total efficiency is 11 ± 2%.These results show, the self-driven MECs coupled system of MFCs can be from cobalt acid lithium the efficient recovery simple substance cobalt, system need not to import energy.Utilize the MFCs electric energy in position, can handle municipal wastewater when reclaiming in the waste and old lithium ion battery valuable metal cobalt; Also the MECs application for no additional electrical energy input, the restriction of no catholyte acidity provides the broad space.The process cleanliness without any pollution has environment and ecological benefits, social benefit and economic benefit concurrently.

Claims (8)

1. method of utilizing the self-driven microorganism electrolysis cell MECs of microbiological fuel cell MFCs coupled system from cobalt acid lithium, to reclaim simple substance cobalt, it is characterized in that, the anode of MFCs links to each other with the cathode coupling of MECs, and the negative electrode of MFCs links to each other by the series resistance coupling with the MECs anode; The catholyte of MECs is for containing the aqueous solution of Co (II); The catholyte of MFCs is inorganic acid solution.

2. method according to claim 1 is characterized in that, described series resistance is 1 Ω～1000 Ω.

3. method according to claim 1 and 2 is characterized in that, cobalt acid lithium particle add-on≤100g/L (w/v).

4. method according to claim 1 and 2 is characterized in that, described graphite material is carbon-point and carbon felt.

5. method according to claim 1 and 2 is characterized in that, described settling pond sludge pH: 6.8 – 7.0; Specific conductivity: 0.80 – 0.93mS/cm; Suspension solid substance: 30 – 35g/L; Chemical oxygen demand (COD): 150 – 300mg/L.

6. method according to claim 3 is characterized in that, described MFCs and MECs anolyte composition are: the 12.0mM sodium acetate; 5.8mM NH ₄Cl; 1.7mM KCl; 17.8mM NaH ₂PO ₄H ₂O; 32.3mM Na ₂HPO ₄Mineral element: 12.5mL/L (consists of MgSO ₄: 3.0g/L; MnSO ₄H ₂O:0.5g/L; NaCl:1.0g/L; FeSO ₄7H ₂O:0.1g/L; CaCl ₂2H ₂O:0.1g/L; CoCl ₂6H ₂O:0.1g/L; ZnCl ₂: 0.13g/L; CuSO ₄5H ₂O:0.01g/L; KAl (SO ₄) ₂12H ₂O:0.01g/L; H ₃BO ₃: 0.01g/L; Na ₂MoO ₄: 0.025g/L; NiCl ₂6H ₂O:0.024g/L; Na ₂WO ₄2H ₂O:0.024g/L); VITAMIN: 12.5mL/L (consists of vitamins B ₁: 5.0g/L; Vitamins B ₂: 5.0g/L; Vitamins B ₃: 5.0g/L; Vitamins B ₅: 5.0g/L; Vitamins B ₆: 10.0g/L; Vitamins B ₁₁: 2.0g/L; Vitamin H: 2.0g/L; Para-amino benzoic acid: 5.0g/L; Thioctic Acid: 5.0g/L; Nitrilotriacetic acid: 1.5g/L).

7. method according to claim 4 is characterized in that, described MFCs and MECs anolyte composition are: the 12.0mM sodium acetate; 5.8mM NH ₄Cl; 1.7mM KCl; 17.8mM NaH ₂PO ₄H ₂O; 32.3mM Na ₂HPO ₄Mineral element: 12.5mL/L (consists of MgSO ₄: 3.0g/L; MnSO ₄H ₂O:0.5g/L; NaCl:1.0g/L; FeSO ₄7H ₂O:0.1g/L; CaCl ₂2H ₂O:0.1g/L; CoCl ₂6H ₂O:0.1g/L; ZnCl ₂: 0.13g/L; CuSO ₄5H ₂O:0.01g/L; KAl (SO ₄) ₂12H ₂O:0.01g/L; H ₃BO ₃: 0.01g/L; Na ₂MoO ₄: 0.025g/L; NiCl ₂6H ₂O:0.024g/L; Na ₂WO ₄2H ₂O:0.024g/L); VITAMIN: 12.5mL/L (consists of vitamins B ₁: 5.0g/L; Vitamins B ₂: 5.0g/L; Vitamins B ₃: 5.0g/L; Vitamins B ₅: 5.0g/L; Vitamins B ₆: 10.0g/L; Vitamins B ₁₁: 2.0g/L; Vitamin H: 2.0g/L; Para-amino benzoic acid: 5.0g/L; Thioctic Acid: 5.0g/L; Nitrilotriacetic acid: 1.5g/L).

8. method according to claim 5 is characterized in that, described MFCs and MECs anolyte composition are: the 12.0mM sodium acetate; 5.8mM NH ₄Cl; 1.7mM KCl; 17.8mM NaH ₂PO ₄H ₂O; 32.3mM Na ₂HPO ₄Mineral element: 12.5mL/L (consists of MgSO ₄: 3.0g/L; MnSO ₄H ₂O:0.5g/L; NaCl:1.0g/L; FeSO ₄7H ₂O:0.1g/L; CaCl ₂2H ₂O:0.1g/L; CoCl ₂6H ₂O:0.1g/L; ZnCl ₂: 0.13g/L; CuSO ₄5H ₂O:0.01g/L; KAl (SO ₄) ₂12H ₂O:0.01g/L; H ₃BO ₃: 0.01g/L; Na ₂MoO ₄: 0.025g/L; NiCl ₂6H ₂O:0.024g/L; Na ₂WO ₄2H ₂O:0.024g/L); VITAMIN: 12.5mL/L (consists of vitamins B ₁: 5.0g/L; Vitamins B ₂: 5.0g/L; Vitamins B ₃: 5.0g/L; Vitamins B ₅: 5.0g/L; Vitamins B ₆: 10.0g/L; Vitamins B ₁₁: 2.0g/L; Vitamin H: 2.0g/L; Para-amino benzoic acid: 5.0g/L; Thioctic Acid: 5.0g/L; Nitrilotriacetic acid: 1.5g/L).

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