JP5164511B2 - Microbial fuel cell, diaphragm cassette for microbial fuel cell and waste water treatment apparatus - Google Patents
Microbial fuel cell, diaphragm cassette for microbial fuel cell and waste water treatment apparatus Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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本発明は微生物燃料電池及び微生物燃料電池用の隔膜カセット並びに排水処理装置に関し、とくに嫌気性微生物の代謝反応を利用して有機性基質から電気を取り出す微生物燃料電池、及びその微生物燃料電池に用いる隔膜カセット、並びに排水から電気を取り出しつつ排水中の有機物を分解する排水処理装置に関する。 TECHNICAL FIELD The present invention relates to a microbial fuel cell, a diaphragm cassette for a microbial fuel cell, and a wastewater treatment apparatus , and more particularly, a microbial fuel cell that extracts electricity from an organic substrate by utilizing metabolic reaction of anaerobic microorganisms, and a diaphragm used for the microbial fuel cell. The present invention relates to a cassette and a wastewater treatment apparatus that decomposes organic matter in the wastewater while taking out electricity from the wastewater .
従来から、特許文献１及び２が開示するように、嫌気性微生物を用いたメタン発酵その他の嫌気発酵処理により有機性基質からメタンガスや水素ガス等のバイオガスを回収し、そのバイオガスをタービン、燃料電池等に供給することでエネルギーを取り出すシステムが開発されている。例えば特許文献１は、生ごみスラリー・有機排液等の廃棄物系有機性基質をメタン生成菌等の嫌気性微生物の担体が保持されたバイオリアクターに投入してバイオガスに変換（分解）し、そのバイオガスを燃料電池に導入して電気エネルギーを生産する生ごみのエネルギー回収システムを開示している。しかし、このように有機性基質を一旦バイオガス等に変換したうえでエネルギーを回収するシステムは、変換ステップにおけるエネルギーロスが大きく、有機性基質からのエネルギー回収効率が低い（通常は40％程度又はそれ以下）という問題点がある。 Conventionally, as disclosed in Patent Documents 1 and 2, biogas such as methane gas or hydrogen gas is recovered from an organic substrate by methane fermentation or other anaerobic fermentation using anaerobic microorganisms, and the biogas is converted into a turbine, Systems that extract energy by supplying fuel cells and the like have been developed. For example, in Patent Document 1, waste organic substrates such as garbage slurry and organic effluent are introduced into a bioreactor in which a carrier for anaerobic microorganisms such as methanogens is held and converted (decomposed) into biogas. , An energy recovery system for garbage that introduces the biogas into a fuel cell to produce electric energy is disclosed. However, a system that recovers energy after converting an organic substrate into biogas or the like in this way has a large energy loss in the conversion step and low energy recovery efficiency from the organic substrate (usually about 40% or There is a problem of less than that).
これに対し、例えば特許文献３及び４が開示するように、バイオガス等への変換ステップを経ることなく、嫌気性微生物により有機性基質から直接的に電気エネルギーを回収する微生物燃料電池（Microbial Fuel Cell；以下、ＭＦＣということがある）の開発が進められている。図１２（Ａ）及び（Ｂ）は、特許文献３及び４の開示する微生物燃料電池をそれぞれ示す。以下、同図を参照して微生物燃料電池の原理を、本発明の理解に必要な程度において簡単に説明する。 In contrast, as disclosed in Patent Documents 3 and 4, for example, a microbial fuel cell (Microbial Fuel cell) that directly recovers electrical energy from an organic substrate by anaerobic microorganisms without undergoing a conversion step to biogas or the like. Cell; hereinafter referred to as MFC) is being developed. 12A and 12B show microbial fuel cells disclosed in Patent Documents 3 and 4, respectively. Hereinafter, the principle of the microbial fuel cell will be briefly described with reference to the figure to the extent necessary for understanding the present invention.
図１２（Ａ）の微生物燃料電池50は、微生物を担持する導電性で多孔質（例えば炭素繊維製）の作用極（負電極）51と、酸化性物質に接触させる導電性の対極（正電極）52と、両電極の間に挟持させたイオン透過性隔膜53とを有し、作用極51に有機性物質含有水等の被電解物質含有液（又はガス）57を供給すると共に、対極52に空気（又は酸素）58を供給する。作用極51及び対極52に仕切板54、54を介して電気的に接続された集電シート55、55は、外部回路（図示せず）を介して相互に接続することにより閉回路を形成する。作用極51では微生物の触媒作用により被電解物質含有液57から水素イオン（Ｈ＋）及び電子（ｅ−）が生成され、水素イオンはイオン透過性隔膜53を透過して対極52側へ移動し、電子は集電シート55及び外部回路を介して対極52側へ移動する。作用極51から移動した水素イオン及び電子は対極52において酸素（Ｏ２）と結合し、水（Ｈ２Ｏ）となって消費される。その際に、閉回路に流れる電気エネルギーを回収する。 The microbial fuel cell 50 of FIG. 12A includes a conductive porous (for example, carbon fiber) working electrode (negative electrode) 51 that supports microorganisms, and a conductive counter electrode (positive electrode) that contacts an oxidizing substance. ) 52 and an ion-permeable separation membrane 53 sandwiched between both electrodes, supplying an electrolyzed substance-containing liquid (or gas) 57 such as organic substance-containing water to the working electrode 51, and a counter electrode 52 Is supplied with air (or oxygen) 58. The current collecting sheets 55 and 55 electrically connected to the working electrode 51 and the counter electrode 52 via the partition plates 54 and 54 are connected to each other via an external circuit (not shown) to form a closed circuit. . In the working electrode 51, hydrogen ions (H + ) and electrons (e − ) are generated from the electrolyzed substance-containing liquid 57 by the catalytic action of microorganisms, and the hydrogen ions pass through the ion-permeable diaphragm 53 and move to the counter electrode 52 side. The electrons move to the counter electrode 52 side via the current collector sheet 55 and the external circuit. Hydrogen ions and electrons moved from the working electrode 51 are combined with oxygen (O 2 ) at the counter electrode 52 and consumed as water (H 2 O). At that time, the electric energy flowing in the closed circuit is recovered.
図１２（Ｂ）の微生物燃料電池60は、内側の円筒形アノード61（負電極）と外側の円筒形カソード（正電極）63との間に円筒形のイオン透過性膜62を挟持させて３重筒状体とし、円筒形アノード61の内側空隙に嫌気性下で生育可能な微生物及び有機性物質を含む溶液又は懸濁液64を流し、円筒形カソード63の外側周面を空気65と接触させる。同図（Ａ）の場合と同様に、アノード61では微生物により有機性物質64から水素イオン（Ｈ＋）及び電子（ｅ−）が生成され、水素イオンはイオン透過性隔膜62を透過してカソード63側へ移動するので、アノード61とカソード63との間に電位差が生じる。この状態で、アノード61とカソード63とを導線66によって接続すると電位差電流が流れるので閉回路が形成され、導線66に流れる電気エネルギーを回収する。 The microbial fuel cell 60 of FIG. 12B has a cylindrical ion permeable membrane 62 sandwiched between an inner cylindrical anode 61 (negative electrode) and an outer cylindrical cathode (positive electrode) 63. A heavy cylindrical body is passed, and a solution or suspension 64 containing microorganisms and organic substances that can grow under anaerobic conditions is passed through the inner space of the cylindrical anode 61, and the outer peripheral surface of the cylindrical cathode 63 is brought into contact with the air 65. Let As in the case of FIG. 6A, in the anode 61, hydrogen ions (H + ) and electrons (e − ) are generated from the organic material 64 by microorganisms, and the hydrogen ions permeate the ion permeable diaphragm 62 to form the cathode. Since it moves to the 63 side, a potential difference is generated between the anode 61 and the cathode 63. In this state, when the anode 61 and the cathode 63 are connected by the conducting wire 66, a potential difference current flows, so that a closed circuit is formed and the electrical energy flowing through the conducting wire 66 is recovered.
図１２に示す微生物燃料電池50、60は何れも、微生物の触媒作用（代謝反応、生物化学的変換）によって有機性基質等から直接的に電気エネルギーを生産し、バイオガス等に変換するステップが存在しないので、従来の変換ステップを用いるエネルギー回収システムに比して回収効率の向上が期待できる。また、発電のみならず、排水処理、有機性廃棄物処理、有機性廃棄物処理の付帯設備等としても利用できる。なお、作用極51又はアノード61において生成された有機性基質由来の電子は微生物の電子伝達系等を介して最終的に作用極51又はアノード61に受け渡されるが、微生物からの電子の受け渡しを促進するため、メディエータ（電子伝達体）を微生物に加える場合もある。 Each of the microbial fuel cells 50 and 60 shown in FIG. 12 has a step of directly producing electric energy from an organic substrate or the like by a catalytic action (metabolic reaction, biochemical conversion) of the microorganism and converting it into biogas or the like. Since it does not exist, an improvement in recovery efficiency can be expected as compared with an energy recovery system using a conventional conversion step. Moreover, it can be used not only for power generation but also as ancillary equipment for wastewater treatment, organic waste treatment, organic waste treatment, and the like. The electrons derived from the organic substrate generated at the working electrode 51 or the anode 61 are finally delivered to the working electrode 51 or the anode 61 through the electron transfer system of the microorganism, but the electrons from the microorganism are delivered. In order to promote, a mediator (electron carrier) may be added to the microorganism.
図１２の微生物燃料電池において、燃料たる有機性基質を分解して電気を生産する微生物（発電を担う微生物）は負電極51、61又はその近傍で生息・活動しているが、運転状況によって隔膜53、62又は正電極52、63においても或る種の微生物（好気性微生物等）が付着・増殖し、隔膜53、62又は正電極52、63の発電に関する性能が低下（劣化）する場合がある。また、一般に燃料電池においては、長期間使用すると発電時に生じるラジカル等によって隔膜又は正電極に劣化が発生することも報告されている。従って、微生物燃料電池の高いエネルギー回収効率を長期間維持するためには、劣化した隔膜及び／又は正電極を定期的に又は必要に応じて交換する必要がある。 In the microbial fuel cell of FIG. 12, microorganisms that produce electricity by decomposing an organic substrate as fuel (microorganisms responsible for power generation) live and operate at or near the negative electrodes 51 and 61, but depending on the operating conditions Some types of microorganisms (aerobic microorganisms, etc.) may also adhere to and proliferate on 53, 62 or positive electrodes 52, 63, and the power generation performance of diaphragms 53, 62 or positive electrodes 52, 63 may decrease (deteriorate). is there. In general, it has also been reported that in a fuel cell, when used for a long period of time, the diaphragm or the positive electrode deteriorates due to radicals generated during power generation. Therefore, in order to maintain the high energy recovery efficiency of the microbial fuel cell for a long period of time, it is necessary to replace the deteriorated diaphragm and / or positive electrode periodically or as necessary.
しかし、図１２（Ａ）及び（Ｂ）の微生物燃料電池は、何れも隔膜53、62及び正電極52、63が負電極51、61の密閉を維持するための構造部材となっており、隔膜53、62又は正電極52、63を交換する際に電池を分解して負電極51、61の密閉を解除しなければならない問題点がある。微生物燃料電池の負電極に生息する微生物（発電を担う微生物）は嫌気性微生物が主体であり、一般に酸素に弱く、空気への暴露により生物活性（発電活性）が著しい損傷を受けることが分かっている。従って、劣化した隔膜53、62又は正電極52、63を交換するために負電極51、61の密閉を解除すると、負電極51、61に生息する微生物が空気に暴露されて損傷を受け、交換後に負電極51、61の微生物を再度馴養しなければ所定の出力を回復することができず、数日から数週間にわたりエネルギー回収効率が低下してしまう（後述の実験例２参照）。 However, in the microbial fuel cell of FIGS. 12A and 12B, the diaphragms 53 and 62 and the positive electrodes 52 and 63 are structural members for maintaining the sealing of the negative electrodes 51 and 61, respectively. When replacing 53, 62 or the positive electrodes 52, 63, there is a problem that the negative electrode 51, 61 must be unsealed by disassembling the battery. Microorganisms that inhabit the negative electrode of microbial fuel cells (microorganisms responsible for power generation) are mainly anaerobic microorganisms, and are generally vulnerable to oxygen, and it is known that biological activity (power generation activity) is significantly damaged by exposure to air. Yes. Therefore, if the negative electrode 51, 61 is unsealed in order to replace the deteriorated diaphragm 53, 62 or the positive electrode 52, 63, the microorganisms inhabiting the negative electrode 51, 61 are exposed to air and damaged and replaced. If the microorganisms of the negative electrodes 51 and 61 are not acclimated later, the predetermined output cannot be recovered, and the energy recovery efficiency decreases for several days to several weeks (see Experimental Example 2 described later).
このような微生物の損傷（死滅や活性低下等）を避けるため、研究室等では微生物燃料電池を嫌気インキュベータ内に持ち込み、酸素のない雰囲気下で電池の解体と劣化した部品の交換とを行なっている。しかし、電池の形状・大きさ・設置場所等の理由によって嫌気インキュベータ内に持ち込めない場合、或いは利用できる嫌気インキュベータがない場合があり、そのような場合は微生物活性の著しい損傷を覚悟の上で部品の交換作業を空気中で行わざるを得ないのが実情である。また、現時点で商品化等されている微生物燃料電池は存在しないが、今後実用化が望まれる長期運転可能な大型の微生物燃料電池では、劣化した部品の交換のために嫌気インキュベータを利用することは困難である。微生物燃料電池の実用化を図るため、エネルギー回収効率を低下させずに劣化した部品を交換できる技術の開発が求められている。 In order to avoid such microbial damage (death, decreased activity, etc.), laboratories bring microbial fuel cells into an anaerobic incubator, disassemble the cells and replace deteriorated parts in an oxygen-free atmosphere. Yes. However, there may be cases where the battery cannot be brought into the anaerobic incubator due to the shape, size, installation location, etc., or there is no anaerobic incubator that can be used. Actually, it is necessary to perform the replacement work in the air. In addition, there is no microbial fuel cell that has been commercialized at the present time, but it is not possible to use an anaerobic incubator for replacement of deteriorated parts in large-scale microbial fuel cells that can be operated for a long period of time. Have difficulty. In order to put the microbial fuel cell into practical use, there is a need for the development of a technology that can replace deteriorated parts without reducing energy recovery efficiency.
そこで本発明の目的は、エネルギー回収効率を低下させずに部品を交換できる微生物燃料電池及び微生物燃料電池用の隔膜カセットを提供することにある。 Accordingly, an object of the present invention is to provide a microbial fuel cell and a diaphragm cassette for the microbial fuel cell that can replace components without reducing energy recovery efficiency.
図１の実施例及び図２のブロック図を参照するに、本発明による微生物燃料電池１は、有機性基質Ｓに浸漬して嫌気性微生物11を担持させる負電極10、及び少なくとも一部分がイオン透過性隔膜21で形成された外殻25（図３（Ｂ）及び図４（Ｇ）参照）と入出孔22、23とを有する密閉型中空カセット20内に電解液Ｄと共に封入して（図５参照）又はカセット20のイオン透過性隔膜21の内側に結合して（図３（Ｂ）参照）有機性基質Ｓ中に差し込む正電極15を備え、入出孔22、23経由でカセット20内に酸素Ｏを供給しつつ負電極10及び正電極15を電気的に接続する回路18（図２参照）経由で電気を取り出すものである。有機性基質Ｓを有機排水とした実施例では、微生物燃料電池１を、回路18経由で電気を取り出しつつ排水中の有機物を分解する排水処理装置とすることができる。 Referring to the embodiment of FIG. 1 and the block diagram of FIG. 2, a microbial fuel cell 1 according to the present invention includes a negative electrode 10 immersed in an organic substrate S to carry anaerobic microorganisms 11, and at least a portion of which is ion permeable. A sealed hollow cassette 20 having an outer shell 25 (see FIGS. 3 (B) and 4 (G)) formed by a conductive diaphragm 21 and inlet / outlet holes 22 and 23 is sealed together with the electrolyte D (FIG. 5). Or a positive electrode 15 that is bonded to the inside of the ion-permeable membrane 21 of the cassette 20 (see FIG. 3B) and is inserted into the organic substrate S, and oxygen is introduced into the cassette 20 through the inlet / outlet ports 22 and 23. Electricity is taken out via a circuit 18 (see FIG. 2) for electrically connecting the negative electrode 10 and the positive electrode 15 while supplying O. In the embodiment in which the organic substrate S is used as the organic wastewater, the microbial fuel cell 1 can be a wastewater treatment apparatus that decomposes organic substances in the wastewater while taking out electricity via the circuit 18.
好ましくは、図３（Ｂ）の実施例に示すように、密閉型中空カセット20に、イオン透過性隔膜21を張設することで密閉される開口26と入出孔22、23とを有する中空外殻フレーム25を含め、イオン透過性隔膜21を正電極15と一体成形された膜・電極接合体（Membrane Electrode Assembly；以下、ＭＥＡということがある）とする。或いは、図４（Ｇ）の実施例に示すように、正電極15を通気加工された電極15aとし、密閉型中空カセット20を、その通気性正電極15aの全表面にコーティングされたイオン透過性隔膜21とその通気性正電極15aに接続された微細孔22a、23a付き通気管22、23とにより形成してもよい。 Preferably, as shown in the embodiment of FIG. 3 (B), the hollow outer cassette 20 has an opening 26 and an inlet / outlet hole 22, 23 that are hermetically sealed by stretching an ion-permeable diaphragm 21. The ion permeable diaphragm 21 including the shell frame 25 is a membrane electrode assembly (hereinafter, also referred to as MEA) integrally formed with the positive electrode 15. Alternatively, as shown in the embodiment of FIG. 4G, the positive electrode 15 is an air-permeable electrode 15a, and the airtight positive electrode 15a is coated on the entire surface of the air-permeable positive electrode 15a. It may be formed by the diaphragm 21 and the vent pipes 22 and 23 with the fine holes 22a and 23a connected to the breathable positive electrode 15a.
更に好ましくは、図１及び図２に示すように、負電極10を保持しつつ有機性基質Ｓを滞留させて負電極10を浸漬させる内部空間３と、内部空間３の有機性基質Ｓに密閉型中空カセット20を差し込む開閉可能な差込口６と、差込口６の開放時に内部空間３へ不活性ガスＧを注入するガス注入口７とを有する嫌気性電解槽２を設ける。この場合は、図３（Ａ）に示すように、密閉型中空カセット20に嫌気性電解槽２の差込口６を閉鎖する蓋部材29を含めることができる。 More preferably, as shown in FIGS. 1 and 2, the organic substrate S is retained while holding the negative electrode 10 and the negative electrode 10 is immersed, and the organic substrate S in the internal space 3 is sealed. An anaerobic electrolytic cell 2 having an openable / closable insertion port 6 for inserting the mold hollow cassette 20 and a gas injection port 7 for injecting an inert gas G into the internal space 3 when the insertion port 6 is opened is provided. In this case, as shown in FIG. 3A, a lid member 29 for closing the insertion port 6 of the anaerobic electrolytic cell 2 can be included in the sealed hollow cassette 20.
また、図３の実施例を参照するに、本発明による微生物燃料電池用の隔膜カセット19は、有機性基質Ｓに浸漬して嫌気性微生物11を担持させる負電極10と酸素Ｏに接触させる正電極15とを有する微生物燃料電池１の両電極10、15の間に設ける隔膜において、少なくとも一部分がイオン透過性隔膜21で形成された外殻25（図３（Ｂ）参照）と入出孔22、23とを有する密閉型中空カセット20を備えてなるものである。好ましくは、密閉型中空カセット20に、イオン透過性隔膜21を張設することで密閉される開口26と入出孔22、23とを有する中空外殻フレーム25を含め、イオン透過性隔膜21を正電極15と一体成形された膜・電極接合体（ＭＥＡ）とする。 Referring to the embodiment of FIG. 3, the diaphragm cassette 19 for a microbial fuel cell according to the present invention is a positive electrode that is immersed in an organic substrate S and is brought into contact with oxygen O and the negative electrode 10 that carries the anaerobic microorganism 11. In the diaphragm provided between the electrodes 10 and 15 of the microbial fuel cell 1 having the electrode 15, an outer shell 25 (see FIG. 3 (B)) and an inlet / outlet hole 22, at least partially formed of an ion permeable diaphragm 21, And a closed type hollow cassette 20 having the structure 23. Preferably, the ion-permeable diaphragm 21 is placed in the sealed hollow cassette 20 including the hollow outer shell frame 25 having the opening 26 and the inlet / outlet holes 22 and 23 that are sealed by stretching the ion-permeable diaphragm 21. A membrane / electrode assembly (MEA) integrally formed with the electrode 15 is used.
本発明による微生物燃料電池は、嫌気性微生物11を担持させる負電極10を有機性基質Ｓに浸漬すると共に、少なくとも一部分がイオン透過性隔膜21で形成された外殻25と入出孔22、23とを有する密閉型中空カセット20内に電解液Ｄと共に封入した又はカセット20のイオン透過性隔膜21の内側に結合した正電極15を有機性基質Ｓに差し込み、入出孔22、23経由でカセット20内に酸素Ｏを供給しつつ負電極10及び正電極15を電気的に接続する回路18経由で電気を取り出すので、次の顕著な効果を奏する。 In the microbial fuel cell according to the present invention, a negative electrode 10 supporting anaerobic microorganisms 11 is immersed in an organic substrate S, and an outer shell 25 formed of an ion-permeable diaphragm 21 and inlet / outlet holes 22 and 23 are formed at least partially. A positive electrode 15 encapsulated with an electrolytic solution D in a sealed hollow cassette 20 having an inner diameter or bonded to the inside of the ion-permeable membrane 21 of the cassette 20 is inserted into the organic substrate S, and the cassette 20 is inserted into the cassette 20 via the inlet / outlet holes 22 and 23. Since electricity is taken out via the circuit 18 that electrically connects the negative electrode 10 and the positive electrode 15 while supplying oxygen O to the cathode, the following remarkable effects are obtained.
（Ａ）イオン透過性隔膜21を正電極15が内側に封入又は結合された密閉型中空カセット20としているので、負電極10を有機性基質Ｓに浸漬させたまま、カセット20だけを有機性基質Ｓに差し込み又は抜き出して隔膜21及び／又は正電極15を簡単に交換することができる。
（Ｂ）また、密閉型中空カセット20を交換する際に負電極10を有機性基質Ｓに浸漬させたままとすることができ、空気への暴露による負電極10の嫌気性微生物11の損傷（死滅や活性低下等）を小さく抑えることができる。
（Ｃ）有機性基質Ｓを滞留して負電極10を浸漬させる内部空間３と、密閉型中空カセット20を有機性基質Ｓに差し込む開閉可能な差込口６と、不活性ガスＧの注入口７とを有する嫌気性電解槽２を設け、差込口６の開放時に不活性ガスＧを注入しながらカセット20を交換すれば、カセット20の交換に伴う負電極10の嫌気性微生物11の損傷を更に小さく抑えることができる。
（Ｄ）従って、従来の微生物燃料電池のように隔膜21及び／又は正電極15の交換の際に微生物を再馴養することが不要となり、交換後直ちに微生物燃料電池の所定発電能力を発揮させ、エネルギー回収効率の低下を避けることができる。
（Ｅ）嫌気インキュベータの利用が困難な大型の微生物燃料電池にも適用可能であり、微生物燃料電池の実用化への寄与が期待できる。
(A) Since the ion-permeable diaphragm 21 is a sealed hollow cassette 20 in which the positive electrode 15 is enclosed or bonded inside, the cassette 20 alone is the organic substrate while the negative electrode 10 is immersed in the organic substrate S. The diaphragm 21 and / or the positive electrode 15 can be easily exchanged by inserting or extracting from S.
(B) Further, when the sealed hollow cassette 20 is replaced, the negative electrode 10 can be kept immersed in the organic substrate S, and the anaerobic microorganisms 11 of the negative electrode 10 are damaged by exposure to air ( Such as death or reduced activity).
(C) Internal space 3 in which the organic substrate S stays and the negative electrode 10 is immersed, an openable / closable inlet 6 for inserting the sealed hollow cassette 20 into the organic substrate S, and an inlet for the inert gas G If the cassette 20 is replaced while injecting the inert gas G when the inlet 6 is opened, the anaerobic microorganism 11 of the negative electrode 10 is damaged due to the replacement of the cassette 20. Can be further reduced.
(D) Therefore, it becomes unnecessary to re-accommodate microorganisms when replacing the diaphragm 21 and / or the positive electrode 15 as in the conventional microbial fuel cell, and the predetermined power generation capacity of the microbial fuel cell is exhibited immediately after the replacement, A reduction in energy recovery efficiency can be avoided.
(E) It can also be applied to large microbial fuel cells where it is difficult to use anaerobic incubators, and can be expected to contribute to the practical use of microbial fuel cells.
図１は、カセット差込口６を有する嫌気性電解槽２を用いた本発明の微生物燃料電池１の一実施例を示し、図２はそのブロック図を示す。図示例の嫌気性電解槽２は蓋体８により密閉された内部空間３を有し、その内部空間３の内側に負電極10を保持すると共に燃料たる有機性基質Ｓを滞留させて負電極10を浸漬する。内部空間３に保持された負電極10は、嫌気性微生物11が付着して生息する固定床としての機能も果たす。例えば生ごみスラリー・有機排液等の廃棄物系有機性基質Ｓを流入口４から電解槽２の内部空間３へ流入させ、内部空間３に一定時間滞留させて基質Ｓ中の有機物を負電極10と接触させて分解したのち、流出口５から電解槽２外へ排出する。 FIG. 1 shows an embodiment of a microbial fuel cell 1 of the present invention using an anaerobic electrolytic cell 2 having a cassette insertion slot 6, and FIG. 2 shows a block diagram thereof. The anaerobic electrolytic cell 2 of the illustrated example has an internal space 3 sealed by a lid 8, holds a negative electrode 10 inside the internal space 3 and retains an organic substrate S as a fuel to hold the negative electrode 10. Soak. The negative electrode 10 held in the internal space 3 also functions as a fixed bed where anaerobic microorganisms 11 adhere and inhabit. For example, a waste organic substrate S such as garbage slurry / organic waste liquid is allowed to flow into the internal space 3 of the electrolytic cell 2 from the inlet 4 and stays in the internal space 3 for a certain period of time, so that the organic matter in the substrate S is a negative electrode. After being brought into contact with 10 and decomposed, it is discharged out of the electrolytic cell 2 from the outlet 5.
また図示例の電解槽２（図示例では蓋体８）は開閉可能な差込口６を有し、その差込口６から内部空間３の有機性基質Ｓ中に、外殻25の少なくとも一部分がイオン透過性隔膜21で形成され且つ内側に正電極15が封入又は結合された隔膜カセット19（密閉型中空カセット20）を差し込む。好ましくは、負電極10と近接対向するが接触しないようにカセット19を差し込み、負電極10と対向するカセット19の外殻面をイオン透過性隔膜21で形成する。負電極10に接続されて電解槽２外に引き出した負極導線（リード線）12と、カセット19内の正電極15に接続されて電解槽２外に引き出した正極導線（リード線）16とを、図２に示すような外部回路18を介して電気的に接続することにより微生物燃料電池１のセルを構成する。 The illustrated electrolytic cell 2 (the lid body 8 in the illustrated example) has an opening 6 that can be opened and closed, and at least a part of the outer shell 25 from the insertion port 6 into the organic substrate S in the internal space 3. Is formed of an ion-permeable diaphragm 21 and a diaphragm cassette 19 (sealed hollow cassette 20) in which a positive electrode 15 is enclosed or bonded is inserted. Preferably, the cassette 19 is inserted so as to be close to and opposed to the negative electrode 10, but the outer shell surface of the cassette 19 facing the negative electrode 10 is formed by the ion permeable diaphragm 21. A negative electrode lead (lead wire) 12 connected to the negative electrode 10 and drawn out of the electrolytic cell 2 and a positive electrode lead (lead wire) 16 connected to the positive electrode 15 in the cassette 19 and drawn out of the electrolytic cell 2 The cells of the microbial fuel cell 1 are configured by electrical connection via an external circuit 18 as shown in FIG.
ただし、本発明の微生物燃料電池１は、嫌気性微生物11を担持する負電極10と正電極15が内側に封入又は結合された隔膜カセット19を備えていれば足り、電解槽２を必須の構成とするものではない。例えば、特許文献１及び２が開示するような既存の嫌気性処理槽（バイオリアクター）に、その微生物固定床に代えて負電極10を浸漬し又は炭素繊維製等の導電性のある微生物固定床を負電極10として用い、且つ、隔膜カセット19を差し込むことで、本発明の微生物燃料電池１を適用することができる。 However, the microbial fuel cell 1 according to the present invention only needs to include the diaphragm cassette 19 in which the negative electrode 10 carrying the anaerobic microorganism 11 and the positive electrode 15 are enclosed or bonded inside, and the electrolytic cell 2 is an essential component. It is not something to do. For example, a negative electrode 10 is immersed in an existing anaerobic treatment tank (bioreactor) as disclosed in Patent Documents 1 and 2 instead of the microorganism fixed bed, or a conductive microorganism fixed bed made of carbon fiber or the like. Can be used as the negative electrode 10, and the microbial fuel cell 1 of the present invention can be applied by inserting the diaphragm cassette 19.
図３（Ｃ）は、嫌気性微生物11を担持できる導電性材料、例えば炭素繊維の織布又は不織布製の電極材料に負極導線12を接続した負電極10の一例を示す。炭素繊維製の負電極10は多くの細孔を有しており、その細孔に微生物が付着して生息するので、短時間のうちに微生物を効率的に担持させることができ、しかも担持させた微生物が剥離しにくい利点を有している。負電極10に担持させる嫌気性微生物11はとくに培養して用意する必要はなく、負電極10を有機性基質Ｓ中に浸漬しておけば、嫌気条件下で有機性基質Ｓ中に自然状態で存在する発電を担う微生物（通常は嫌気性の混合微生物群）を負電極10上で馴養することができる。ただし、必要に応じて有機性基質Ｓ中へ浸漬する前に、別途培養した発電を担う嫌気性微生物11を負電極10に付着させてもよい。また、必要に応じて嫌気性微生物11にメディエータ（電子伝達体）を加えてもよい。なお、図示例は板状の負電極10を示しているが、炭素繊維の織布又は不織布は様々な形状に加工することが可能であり、例えば図１２（Ｂ）に示すように負電極10を円筒形状とすることもできる。 FIG. 3C shows an example of the negative electrode 10 in which the negative electrode conductor 12 is connected to an electrode material made of a conductive material capable of supporting the anaerobic microorganisms 11, for example, a carbon fiber woven or non-woven fabric. The negative electrode 10 made of carbon fiber has many pores, and microorganisms adhere to the pores and inhabit them, so that the microorganisms can be efficiently supported in a short time and also supported. It has the advantage that the microorganisms are difficult to peel off. The anaerobic microorganism 11 to be supported on the negative electrode 10 does not need to be cultured and prepared. If the negative electrode 10 is immersed in the organic substrate S, the anaerobic microorganism 11 is naturally in the organic substrate S under anaerobic conditions. Microorganisms (usually anaerobic mixed microorganisms) that are responsible for power generation can be acclimatized on the negative electrode 10. However, an anaerobic microorganism 11 responsible for power generation separately cultured may be attached to the negative electrode 10 before being immersed in the organic substrate S as necessary. Further, a mediator (electron carrier) may be added to the anaerobic microorganism 11 as necessary. Although the illustrated example shows a plate-like negative electrode 10, a carbon fiber woven or non-woven fabric can be processed into various shapes. For example, as shown in FIG. Can also be cylindrical.
図３（Ａ）及び同図（Ｂ）は、内側に正電極15を封入又は結合すべき隔膜カセット19の一例を示す。同図（Ｂ）の分解図に示すように、図示例の隔膜カセット19は、入出孔22、23及び開口26を有する中空外殻フレーム25（同図（Ｄ）及び同図（Ｆ）も参照）と、そのフレーム25の開口26に張設する一対のイオン透過性隔膜21と、各隔膜21をフレーム25の開口26に固定する一対の開口26付き固定部材28とで構成された密閉型中空カセット20を有している。図示例では、フレーム25を貫通する開口26の両端にそれぞれ隔膜21を張設し、その隔膜21を固定部材28で開口26の周縁に固定又は接着することにより、密閉された中空部27を有するカセット20が形成される（同図（Ｅ）も参照）。ただし、開口26は必ずしもフレーム25を貫通している必要はなく、中空部27に連通する少なくとも１つの開口26を設け、その開口26を隔膜21で密閉すれば足りる。また、隔膜21の固定に接着剤等を用いることができれば固定部材28を省略してもよい。 FIG. 3A and FIG. 3B show an example of a diaphragm cassette 19 in which the positive electrode 15 is enclosed or bonded inside. As shown in the exploded view of FIG. 5B, the diaphragm cassette 19 in the illustrated example has a hollow outer shell frame 25 having inlet / outlet holes 22 and 23 and an opening 26 (see also FIG. 4D and FIG. 5F). ), A pair of ion-permeable diaphragms 21 stretched around the openings 26 of the frame 25, and a pair of fixing members 28 with the openings 26 that fix the respective diaphragms 21 to the openings 26 of the frame 25. It has a cassette 20. In the illustrated example, the diaphragm 21 is stretched at both ends of the opening 26 penetrating the frame 25, and the diaphragm 21 is fixed or adhered to the periphery of the opening 26 by a fixing member 28, thereby having a sealed hollow portion 27. A cassette 20 is formed (see also FIG. 5E). However, the opening 26 does not necessarily pass through the frame 25, and it is sufficient to provide at least one opening 26 communicating with the hollow portion 27 and seal the opening 26 with the diaphragm 21. Further, the fixing member 28 may be omitted if an adhesive or the like can be used for fixing the diaphragm 21.
密閉型中空カセット20のフレーム25及び固定部材28は、例えば塩化ビニール、アクリル、ボリカーボネート、フッ素樹脂等のプラスチック材料製とすることができる。フレーム25及び固定部材28を鉄、ステンレス等の金属材料製としてもよいが、有機性基質Ｓに浸漬して長期間使用するためには腐食防止塗装等を施すことが望ましい。図示例の固定部材28はイオン透過性隔膜21の外側に配置され、隔膜21と負電極10との接触を避ける機能を果たし得るが、後述するように隔膜21を膜・電極接合体（ＭＥＡ）とする場合は、隔膜21と負電極10との電気的接触（導通）を避けるために固定部材28を絶縁材料製とすることも有効である。 The frame 25 and the fixing member 28 of the sealed hollow cassette 20 can be made of a plastic material such as vinyl chloride, acrylic, polycarbonate, or fluororesin. The frame 25 and the fixing member 28 may be made of a metal material such as iron or stainless steel. However, in order to use the frame 25 and the fixing member 28 for a long period of time by being immersed in the organic substrate S, it is desirable to apply a corrosion prevention coating or the like. The fixing member 28 in the illustrated example is disposed outside the ion permeable diaphragm 21 and can function to avoid contact between the diaphragm 21 and the negative electrode 10, but the diaphragm 21 is a membrane-electrode assembly (MEA) as described later. In this case, it is also effective to make the fixing member 28 made of an insulating material in order to avoid electrical contact (conduction) between the diaphragm 21 and the negative electrode 10.
カセット20に張設するイオン透過性隔膜21は、イオン交換膜、又は膜状の基体にイオン交換樹脂を塗布したもの等とすることができ、例えばアメリカデュポン社製のナフィオン、株式会社トクヤマ製のネオセプタ等のイオン交換樹膜又は樹脂を用いることができる。ただし、隔膜21は必ずしもイオン選択透過性がなくてもよく、最低限、止水性能（水漏れしない能力）があれば足りる。酸素透過性は低い方が好ましいが、イオン透過性能は高い方がよく、この性質は一般に相反する。また、隔膜21としてセラミック等を利用することも考えられる。 The ion permeable diaphragm 21 stretched on the cassette 20 can be an ion exchange membrane or a membrane-like substrate coated with an ion exchange resin, for example, Nafion manufactured by DuPont USA, manufactured by Tokuyama Corporation. An ion exchange resin membrane such as Neoceptor or a resin can be used. However, the diaphragm 21 does not necessarily have ion selective permeability, and at least it is sufficient if it has a water stopping performance (capability of preventing water leakage). A lower oxygen permeability is preferable, but a higher ion permeability is better, and this property is generally contradictory. It is also conceivable to use ceramic or the like as the diaphragm 21.
カセット20には、図５に示すように中空部27に正電極15を電解液Ｄ（例えばNaCl溶液、KCl溶液等）と共に封入するか、又は図３（Ｂ）に示すようにイオン透過性隔膜21の内側に正電極15を結合する。正電極15は金属又は炭素繊維等の導電性材料製とすることができるが、従来の燃料電池分野の研究からとくに白金（Pt）が優れていることが知られている。ただし、白金は非常に高価な貴金属材料であることから、有効表面積を最大化するために白金パウダー又はカーボンパウダーに担持させた白金をカーボン電極材料等に塗布して正電極15とする。図３の実施例では、イオン透過性隔膜21を正電極15が一体成形されたＭＥＡ（15＋21）としている。従来から固体高分子型燃料電池の分野においてフッ素系ＭＥＡ、炭化水素系ＭＥＡ等が開発されており、そのようなＭＥＡ（15＋21）をカセット20の開口26に張設して利用することができる。イオン透過性隔膜21をＭＥＡ（15＋21）とすることにより、カセット20内の中空部27に電解液Ｄを封入する必要がなくなり、カセット20を構成が簡単な空気正極（エアカソード）とすることができる。 In the cassette 20, as shown in FIG. 5, the positive electrode 15 is enclosed in the hollow portion 27 together with the electrolyte D (for example, NaCl solution, KCl solution, etc.), or as shown in FIG. A positive electrode 15 is coupled inside 21. Although the positive electrode 15 can be made of a conductive material such as metal or carbon fiber, it is known that platinum (Pt) is particularly excellent from conventional research in the field of fuel cells. However, since platinum is a very expensive noble metal material, in order to maximize the effective surface area, platinum powder or platinum supported on carbon powder is applied to the carbon electrode material or the like to form the positive electrode 15. In the embodiment of FIG. 3, the ion permeable diaphragm 21 is MEA (15 + 21) in which the positive electrode 15 is integrally formed. Conventionally, fluorine-based MEA, hydrocarbon-based MEA, and the like have been developed in the field of polymer electrolyte fuel cells, and such MEA (15 + 21) can be stretched and used in the opening 26 of the cassette 20. By using MEA (15 + 21) as the ion permeable membrane 21, it is not necessary to enclose the electrolyte D in the hollow portion 27 in the cassette 20, and the cassette 20 can be an air positive electrode (air cathode) with a simple configuration. it can.
密閉型中空カセット20に設けた一対の入出孔22、23は、密閉されたカセット20の中空部27に正電極15と接触させる酸素（又は空気）Ｏを供給するためのものである。例えば、ＭＥＡ（15＋21）を用いてカセット20を空気正極とした場合は、入出孔22、23をガス送入孔22及びガス送出孔23とし、図２に示すようにガス送入装置31から酸素（又は空気）Ｏをカセット20の中空部27に供給する。図３（Ｄ）に示すように、送入孔22には中空部27の下端部にまで延びる延長管（例えばホース等）24を接続し、中空部27の下端部に酸素Ｏを供給して上端部の送出孔23から排出することにより中空部27の全体に酸素Ｏを均等に供給し、正電極15と酸素Ｏとの接触の効率化を図ることができる。図５のように正電極15を電解液Ｄと共に封入したカセット20においても図３（Ｄ）と同様に酸素を供給することができるが、正電極15の邪魔とならないように、カセット20の中空部27の周縁に沿わせて比較的小径の（細い）延長管24を用いることが望ましい。また加工がやや難しくなるが、同図（Ｇ）に示すように、送入孔22（又は送出孔23）を外殻フレーム25の内部に上端部から下端部まで穿った貫通孔とすることも有効である。 The pair of inlet / outlet holes 22 and 23 provided in the sealed hollow cassette 20 are for supplying oxygen (or air) O to be brought into contact with the positive electrode 15 into the hollow portion 27 of the sealed cassette 20. For example, when the cassette 20 is an air positive electrode using MEA (15 + 21), the inlet / outlet holes 22 and 23 are used as the gas inlet hole 22 and the gas outlet hole 23, and oxygen is supplied from the gas inlet device 31 as shown in FIG. (Or air) O is supplied to the hollow portion 27 of the cassette 20. As shown in FIG. 3D, an extension pipe (for example, a hose) 24 extending to the lower end of the hollow portion 27 is connected to the inlet hole 22, and oxygen O is supplied to the lower end of the hollow portion 27. By discharging from the delivery hole 23 at the upper end, oxygen O is uniformly supplied to the entire hollow portion 27, and the efficiency of contact between the positive electrode 15 and oxygen O can be improved. As shown in FIG. 5, even in the cassette 20 in which the positive electrode 15 is enclosed with the electrolyte D, oxygen can be supplied in the same manner as in FIG. 3D, but the cassette 20 is hollow so as not to obstruct the positive electrode 15. It is desirable to use a relatively small (thin) extension tube 24 along the periphery of the portion 27. Although processing is somewhat difficult, as shown in FIG. 4G, the feed hole 22 (or the feed hole 23) may be a through hole bored from the upper end to the lower end inside the outer shell frame 25. It is valid.
なお、図示例では、カセット20内の正電極15に接続された正極導線16を入出孔22、23の一方（図示例では送出孔23）を介してカセット20の外部に引き出している。ただし、正極導線16の引き出し方法は図示例に限定されない。また、図示例では断面矩形の中空外殻フレーム25を用いてカセット20を矩形箱型としているが、フレーム25及びカセット20の形状は電解槽２及び負電極10の形状等に応じて任意に選択可能である。例えば、カセット20を外周面の全体又は少なくとも一部分がイオン透過性隔膜21で形成された円筒形とし、そのようなカセット20を図１２（Ｂ）に示すように円筒形状の負電極10の中空部に差し込んで多重筒状（入れ子状）構造の微生物燃料電池１とすることができる。 In the illustrated example, the positive electrode conductor 16 connected to the positive electrode 15 in the cassette 20 is drawn out of the cassette 20 through one of the inlet / outlet holes 22 and 23 (the delivery hole 23 in the illustrated example). However, the method of drawing out the positive electrode lead wire 16 is not limited to the illustrated example. In the illustrated example, the cassette 20 is formed into a rectangular box shape using a hollow outer shell frame 25 having a rectangular cross section. However, the shapes of the frame 25 and the cassette 20 are arbitrarily selected according to the shape of the electrolytic cell 2 and the negative electrode 10. Is possible. For example, the cassette 20 has a cylindrical shape in which the whole or at least a part of the outer peripheral surface is formed of the ion permeable diaphragm 21, and the cassette 20 has a hollow portion of the cylindrical negative electrode 10 as shown in FIG. It is possible to obtain a microbial fuel cell 1 having a multi-tubular (nested) structure by being inserted into the structure.
図４（Ｇ）は、図３のような外殻フレーム25を用いない密閉型中空カセット20の他の一例を示す。図示例では、通気加工された正電極15aを用い、その通気性正電極15aの全表面にコーティングされたイオン透過性隔膜21と、その通気性正電極15aに接続された一対の微細孔22a、23a付き通気管22、23とによりカセット20を形成している。通気加工された正電極15aの一例は、例えば通気加工された正電極材料15aに正極導線16を接続し（同図（Ｂ）参照）、更に正電極材料15aの一端縁に沿って微細孔22a付き通気管22を密着させて接続すると共に他端縁に沿って微細孔23a付き通気管23を密着させて接続したのち（同図（Ｃ）参照）、電極材料15aの表面全体に白金パウダー等を塗布したものである（同図（Ｄ）参照）。例えば、そのように形成された正電極15aをイオン透過性樹脂溶液30中に浸漬することで正電極15aの全表面にイオン透過性隔膜21を塗布し（同図（Ｅ）参照）、塗布したイオン透過性隔膜21を固化・重合・乾燥させることでカセット20の外殻25を形成する（同図（Ｆ）参照）。同図（Ｄ）の白金塗布工程を省略し、例えば白金パウダー等が懸濁したイオン透過性樹脂溶液30を正電極材料15aの全表面に塗布することにより、イオン透過性隔膜21でコーティングされた正電極15（カセット20）を形成してもよい。なお、図４に示すカセット20も、正電極15の形状に応じて板状、棒状、筒状等の任意の形状とすることが可能である。 FIG. 4G shows another example of the sealed hollow cassette 20 that does not use the outer shell frame 25 as shown in FIG. In the illustrated example, an air permeable positive electrode 15a is used, an ion permeable diaphragm 21 coated on the entire surface of the air permeable positive electrode 15a, and a pair of fine holes 22a connected to the air permeable positive electrode 15a, A cassette 20 is formed by the vent pipes 22 and 23 with 23a. An example of the vented positive electrode 15a is, for example, that the positive electrode wire 16 is connected to the vented positive electrode material 15a (see FIG. 5B), and further, the fine holes 22a are formed along one edge of the positive electrode material 15a. Attached and connected with the attached vent tube 22 and connected with the attached vent tube 23 with the fine hole 23a along the other end edge (see FIG. 5C), platinum powder or the like on the entire surface of the electrode material 15a Is applied (see FIG. 4D). For example, the positive electrode 15a thus formed is immersed in the ion permeable resin solution 30 so that the ion permeable diaphragm 21 is applied to the entire surface of the positive electrode 15a (see FIG. 5E) and applied. The outer shell 25 of the cassette 20 is formed by solidifying, polymerizing and drying the ion permeable diaphragm 21 (see FIG. 8F). The platinum coating step of FIG. 4D is omitted, and, for example, the ion permeable resin solution 30 in which platinum powder or the like is suspended is applied to the entire surface of the positive electrode material 15a to be coated with the ion permeable diaphragm 21. The positive electrode 15 (cassette 20) may be formed. Note that the cassette 20 shown in FIG. 4 can also have an arbitrary shape such as a plate shape, a rod shape, or a cylindrical shape according to the shape of the positive electrode 15.
図１及び図２の微生物燃料電池１を駆動する場合は、嫌気性電解槽２の差込口６を開放して負電極10が浸漬する有機性基質Ｓ中に正電極15が封入又は保持された隔膜カセット19（密閉型中空カセット20）を差し込み、差込口６を蓋部材29で閉鎖したうえでカセット20内に入出孔22、23経由で酸素Ｏを供給する。図示例では、差込口６の蓋部材29をカセット20に一体的に取り付け、その蓋部材29をカセット20が電解槽２内の所定位置に位置決めされるように設計している。図１２を参照して上述したように、有機性基質Ｓに浸漬した負電極10では、担持させた嫌気性微生物11により水素イオン（Ｈ＋）及び電子（ｅ−）が生成される。生成された水素イオンはイオン透過性隔膜21を透過してカセット20の内側へ移動し、電子は負極導線12、外部回路18、正極導線16を介してカセット20の内側の正電極15へ移動し、両者は正電極15において供給された酸素Ｏと結合して水（Ｈ２Ｏ）となる。その際に、外部回路18に流れる電気を取り出すことでエネルギーを回収する。 When driving the microbial fuel cell 1 of FIGS. 1 and 2, the positive electrode 15 is enclosed or held in the organic substrate S in which the insertion port 6 of the anaerobic electrolytic cell 2 is opened and the negative electrode 10 is immersed. The membrane cassette 19 (sealed hollow cassette 20) is inserted, and the insertion port 6 is closed by the lid member 29, and then oxygen O is supplied into the cassette 20 through the inlet / outlet ports 22 and 23. In the illustrated example, the lid member 29 of the insertion port 6 is integrally attached to the cassette 20, and the lid member 29 is designed so that the cassette 20 is positioned at a predetermined position in the electrolytic cell 2. As described above with reference to FIG. 12, in the negative electrode 10 immersed in the organic substrate S, hydrogen ions (H + ) and electrons (e − ) are generated by the supported anaerobic microorganisms 11. The generated hydrogen ions permeate the ion permeable membrane 21 and move to the inside of the cassette 20, and the electrons move to the positive electrode 15 inside the cassette 20 through the negative electrode lead 12, the external circuit 18, and the positive electrode lead 16. Both combine with oxygen O supplied at the positive electrode 15 to form water (H 2 O). At that time, energy is recovered by taking out electricity flowing in the external circuit 18.
負電極10で生成した水素イオンがイオン透過性隔膜21を透過して密閉型中空カセット20の内側へ移動するためには、カセット20のイオン透過性隔膜21と負電極10とをできるだけ接近させることが望ましく、両者の間隔が大きくなるとエネルギー回収効率（発電効率）の低下の原因となる。図示例では、説明容易化のため負電極10とカセット20との間に比較的広い間隔を設けて表しているが、望ましくはイオン透過性隔膜21と負電極10とを水素イオンが移動容易な微小間隔、例えば１cm以下、好ましくは５mm以下の間隙で対向するように、カセット20を位置決めする。更に望ましくは、負電極10と対向するカセット20の外殻面の全体又はできるだけ広範囲をイオン透過性隔膜21で形成し、負電極10とイオン透過性隔膜21との対向面積を大きくする。 In order for the hydrogen ions generated at the negative electrode 10 to pass through the ion permeable diaphragm 21 and move to the inside of the sealed hollow cassette 20, the ion permeable diaphragm 21 of the cassette 20 and the negative electrode 10 should be as close as possible. Desirably, an increase in the distance between the two causes a reduction in energy recovery efficiency (power generation efficiency). In the illustrated example, a relatively wide space is provided between the negative electrode 10 and the cassette 20 for ease of explanation. Preferably, hydrogen ions can easily move between the ion permeable diaphragm 21 and the negative electrode 10. The cassette 20 is positioned so as to face each other with a small interval, for example, a gap of 1 cm or less, preferably 5 mm or less. More desirably, the entire outer shell surface of the cassette 20 facing the negative electrode 10 or the widest possible area is formed by the ion permeable diaphragm 21, and the facing area between the negative electrode 10 and the ion permeable diaphragm 21 is increased.
図５のように密閉型中空カセット20内に正電極15が電解液Ｄと共に封入されてイオン透過性隔膜21と正電極15との間に電解液Ｄが介在する場合、又は図３（Ｂ）のようなＭＥＡ（15＋21）においてイオン透過性隔膜21の内側に結合された正電極15が外側（負電極10に面した側）へ滲出しない場合は、イオン透過性隔膜21の外側面と負電極10とが接触してもとくに問題はない。しかし、ＭＥＡ（15＋21）のイオン透過性隔膜21の内側に結合された正電極15が外側へ滲出しうる場合、又は上述した図４において白金パウダー等が懸濁したイオン透過性樹脂溶液30を正電極材料15aの表面に塗布することで正電極15（カセット20）を形成した場合は、イオン透過性隔膜21の外側面と負電極10とが電気的に接触（導通）すると負電極10で生成された電子が外部回路18ではなく正電極15に流れ、外部回路18を介して電気エネルギーを効率的に回収できなくなるので、イオン透過性隔膜21と負電極10とをできるだけ接近させつつ接触させないことが有効である。そのような場合は、例えばカセット20の隔膜21の外側に配置する固定部材28（図３（Ｂ）参照）を絶縁材料製とし、その固定部材28によってイオン透過性隔膜21と負電極10との間に導通しない微小間隙を確保してもよい。 When the positive electrode 15 is enclosed with the electrolyte D in the sealed hollow cassette 20 as shown in FIG. 5 and the electrolyte D is interposed between the ion-permeable diaphragm 21 and the positive electrode 15, or FIG. When the positive electrode 15 coupled to the inside of the ion permeable membrane 21 in the MEA (15 + 21) does not exude to the outside (side facing the negative electrode 10), the outer surface of the ion permeable membrane 21 and the negative electrode There is no particular problem even if 10 contacts. However, when the positive electrode 15 coupled to the inside of the ion permeable membrane 21 of MEA (15 + 21) can exude to the outside, the ion permeable resin solution 30 in which platinum powder or the like is suspended in FIG. When the positive electrode 15 (cassette 20) is formed by applying to the surface of the electrode material 15a, the negative electrode 10 generates when the outer surface of the ion-permeable membrane 21 and the negative electrode 10 are in electrical contact (conduction) The collected electrons flow not to the external circuit 18 but to the positive electrode 15, and electric energy cannot be efficiently recovered via the external circuit 18. Therefore, the ion-permeable diaphragm 21 and the negative electrode 10 should not be brought into contact with each other as close as possible. Is effective. In such a case, for example, the fixing member 28 (see FIG. 3B) disposed outside the diaphragm 21 of the cassette 20 is made of an insulating material, and the ion permeable diaphragm 21 and the negative electrode 10 are separated by the fixing member 28. A minute gap that does not conduct between them may be secured.
なお、図示例では微生物燃料電池１の複数のセルを外部回路18により並列に接続しているが、図５に示すように、外部回路18により微生物燃料電池１の複数のセルを直列接続としてもよい。また、図６に示すように、微生物燃料電池１の複数のセルをそれぞれ隔壁32で分離し、各セルを電気的に隔離することができる。燃料たる有機性基質Ｓの導電性がそれほど高くない場合は、燃料を介して生じる各セル間の干渉による電圧低下は小さいので各セルを隔壁32で分離する必要性はあまり大きくないが、導電性の高い有機性基質Ｓを使用する場合は、各セルを隔壁32により電気的に隔離しなければ電子が燃料を導通して異なるセル間でリーク電流が生じ得るので、直列接続の利点を生かすために各セルを隔壁32で隔離することが有効である。理想的には、図６に示すように各セル毎に有機性基質Ｓの流入口４及び流出口５を設け、各セルの有機性基質Ｓを完全に絶縁する。ただし、各セルの有機性基質Ｓが完全に絶縁されていなくても、適切な隔壁32により各セル間の干渉を十分に低く抑える設計は可能であり、その場合は流入口４及び流出口５を各セル毎に設ける必要はない。なお、カセット20と負電極10とは図１、２、５のように平行に対向させる必要はなく、例えば図８に示すように断面円形の電解槽２を用いる場合は、カセット20と負電極10とを同一中心の周りに放射状に並べて相互に対向させてもよい。 In the illustrated example, the plurality of cells of the microbial fuel cell 1 are connected in parallel by the external circuit 18, but as shown in FIG. 5, the plurality of cells of the microbial fuel cell 1 may be connected in series by the external circuit 18. Good. In addition, as shown in FIG. 6, a plurality of cells of the microbial fuel cell 1 can be separated by partition walls 32 to electrically isolate each cell. When the conductivity of the organic substrate S as the fuel is not so high, the voltage drop due to the interference between the cells generated through the fuel is small, so the necessity of separating each cell with the partition wall 32 is not so great. In order to take advantage of the series connection, when an organic substrate S having a high thickness is used, if each cell is not electrically isolated by the partition wall 32, electrons can conduct fuel and leak current can be generated between different cells. It is effective to isolate each cell by a partition wall 32. Ideally, as shown in FIG. 6, the inlet 4 and the outlet 5 of the organic substrate S are provided for each cell, and the organic substrate S of each cell is completely insulated. However, even if the organic substrate S of each cell is not completely insulated, it is possible to design the interference between the cells sufficiently low by an appropriate partition wall 32. In that case, the inlet 4 and the outlet 5 Need not be provided for each cell. The cassette 20 and the negative electrode 10 do not need to face each other in parallel as shown in FIGS. 1, 2, and 5. For example, when the electrolytic cell 2 having a circular cross section is used as shown in FIG. 10 may be arranged radially around the same center and face each other.
嫌気性電解槽２の有機性基質Ｓ中に差し込んだ密閉型中空カセット20は、隔膜21又は正電極15の劣化等に応じて差込口６を開放して抜き出すことにより、新たなカセット20に容易に交換することができる。その際に、負電極10は有機性基質Ｓに浸漬させたままとし、負電極10を空気に晒さないようにすることができるので、負電極10に付着した嫌気性微生物11の損傷（死滅や活性低下等）を抑えることができる。好ましくは、図１及び２に示すように電解槽２の気相部に不活性ガスＧを注入するガス注入口７を設け、差込口６の開放時に電解槽２の内部空間３（この場合は気相部）に酸素を含まない不活性ガス（窒素ガス等）を注入し、差込口６から電解槽２内への空気の進入を防止する。差込口６からの空気の混入を防止しながら緩やかに素早くカセット20の交換を行なえば、負電極10の嫌気性微生物11の損傷を更に小さく抑えることができる。 The sealed hollow cassette 20 inserted into the organic substrate S of the anaerobic electrolytic cell 2 is opened to the new cassette 20 by opening the outlet 6 according to the deterioration of the diaphragm 21 or the positive electrode 15. Can be easily replaced. At that time, the negative electrode 10 can be kept immersed in the organic substrate S so that the negative electrode 10 is not exposed to the air, so that the anaerobic microorganisms 11 attached to the negative electrode 10 can be damaged (dead or dead). Activity reduction). Preferably, as shown in FIGS. 1 and 2, a gas injection port 7 for injecting an inert gas G is provided in the gas phase portion of the electrolytic cell 2, and the internal space 3 (in this case) of the electrolytic cell 2 when the insertion port 6 is opened. Injects an inert gas (nitrogen gas or the like) that does not contain oxygen into the gas phase part) to prevent air from entering the electrolytic cell 2 from the inlet 6. If the cassette 20 is replaced slowly and quickly while preventing air from entering the insertion port 6, damage to the anaerobic microorganisms 11 on the negative electrode 10 can be further reduced.
なお、嫌気性電解槽２から抜き出した密閉型中空カセット20、すなわち微生物の付着や汚れ・析出物により劣化した密閉型中空カセット20は、例えば活性汚泥法で実用化されている浸漬膜と同様に、イオン透過性隔膜21又はＭＥＡ（15＋21）を洗浄したのち再利用することが可能である。図５のようにイオン透過性隔膜21と正電極15とを分離している場合は、劣化したカセット20から抜き出した正電極15を新たなカセット20に封入して再利用することが可能であり、高価な貴金属を利用する正電極15を比較的寿命の短い隔膜21から分離して隔膜21のみを交換すれば足りるので、図３に示すようなＭＥＡ（15＋21）を用いたカセット20（エアカソード）に比してカセット20の交換に伴う費用を低く抑えることも可能である The sealed hollow cassette 20 extracted from the anaerobic electrolytic cell 2, that is, the sealed hollow cassette 20 deteriorated due to the adhesion of microorganisms or dirt / precipitates, for example, is the same as the immersion membrane put to practical use by the activated sludge method. The ion-permeable diaphragm 21 or MEA (15 + 21) can be washed and reused. When the ion-permeable diaphragm 21 and the positive electrode 15 are separated as shown in FIG. 5, the positive electrode 15 extracted from the deteriorated cassette 20 can be enclosed in a new cassette 20 and reused. Since it is sufficient to replace the positive electrode 15 using an expensive noble metal from the diaphragm 21 having a relatively short life and replace only the diaphragm 21, a cassette 20 (air cathode) using an MEA (15 + 21) as shown in FIG. It is also possible to keep costs associated with the replacement of the cassette 20 low compared to
［実験例１］
本発明による微生物燃料電池１及び密閉型中空カセット20の有効性を確認するため、容積３リットルの嫌気性電解槽２を用いて微生物燃料電池１を試作し、先ず長期連続運転時のエネルギー回収効率の変化を確認する実験を行なった。本実験では、図３（Ｂ）のような中空外殻フレーム25（約50×200mm）を貫通する開口26（断面約40×180mm）の両端にＭＥＡ（15＋21）を張設した密閉型中空カセット20を空気正極（エアカソードユニット）として用い、図８に示す断面円形の電解槽２内に５枚のカーボンフェルト製負電極10（約50×200mm、アノード）を浸漬し、その間に５枚のカセット20を負電極10に対向するように差し込むことにより微生物燃料電池１を構成した。また、電解槽２内にスターチ等の有機性高分子を含む人工廃水（有機性基質）Ｓを所定COD負荷（１〜３kg/m3/日）で連続的に流入させつつ160日間にわたり微生物燃料電池１を連続運転し、外部回路18の抵抗器（負荷２Ω）で電圧を継続的に測定した。人工廃水（有機性基質）Ｓ中には、発電を担う嫌気性微生物11として土壌微生物を植種した。本実験による150日間の電圧の測定結果を図９のグラフに示す。
[Experimental Example 1]
In order to confirm the effectiveness of the microbial fuel cell 1 and the sealed hollow cassette 20 according to the present invention, the microbial fuel cell 1 was prototyped using an anaerobic electrolytic cell 2 having a volume of 3 liters. An experiment was conducted to confirm the change of. In this experiment, a sealed hollow cassette with MEA (15 + 21) stretched at both ends of an opening 26 (cross section about 40 x 180 mm) passing through the hollow shell frame 25 (about 50 x 200 mm) as shown in FIG. 20 is used as an air cathode (air cathode unit), and five carbon felt negative electrodes 10 (about 50 × 200 mm, anode) are immersed in an electrolytic cell 2 having a circular cross section shown in FIG. The microbial fuel cell 1 was constructed by inserting the cassette 20 so as to face the negative electrode 10. In addition, microbial fuel for 160 days while continuously flowing artificial wastewater (organic substrate) S containing organic polymers such as starch into the electrolytic cell 2 at a predetermined COD load (1 to 3 kg / m 3 / day) The battery 1 was continuously operated, and the voltage was continuously measured with the resistor (load 2Ω) of the external circuit 18. In the artificial wastewater (organic substrate) S, soil microorganisms were planted as anaerobic microorganisms 11 responsible for power generation. The measurement results of the voltage for 150 days in this experiment are shown in the graph of FIG.
図９のグラフは、負電極10の発電を担う嫌気性微生物11の初期馴養に30日程度の期間が必要であり、その間に外部回路18で得られる電圧が徐々に上昇することを示す。また同グラフから、約30日後に安定期に入り、外部回路18の電圧がほぼ350mVで一定に維持され、エネルギー回収効率が安定的に維持されることが分かる。しかし、運転開始から100日程度を経過すると電圧が徐々に下降し、エネルギー回収効率が低下した。この効率の低下は、カセット20のＭＥＡ（15＋21）の表面に形成された好気性微生物を主とするバイオフィルム等が原因であると考えられる。すなわち、実験に用いた微生物燃料電池１では、100日程度の連続運転によりイオン透過性隔膜21が劣化し、エネルギー回収効率を維持するために劣化した隔膜21を交換する必要が生じた。 The graph of FIG. 9 shows that the initial acclimatization of the anaerobic microorganism 11 responsible for power generation of the negative electrode 10 requires a period of about 30 days, during which the voltage obtained in the external circuit 18 gradually increases. Also, from the graph, it can be seen that the stable period starts after about 30 days, the voltage of the external circuit 18 is kept constant at approximately 350 mV, and the energy recovery efficiency is stably maintained. However, after about 100 days from the start of operation, the voltage gradually decreased and the energy recovery efficiency decreased. This decrease in efficiency is considered to be caused by a biofilm mainly composed of aerobic microorganisms formed on the surface of the MEA (15 + 21) of the cassette 20. That is, in the microbial fuel cell 1 used in the experiment, the ion permeable diaphragm 21 deteriorates due to continuous operation for about 100 days, and it is necessary to replace the deteriorated diaphragm 21 in order to maintain energy recovery efficiency.
［実験例２］
続いて、実験例１と同じ微生物燃料電池１及び有機性基質Ｓを用いて長期連続運転を行い、運転開始から101日目に微生物燃料電池１を分解し、負電極10が空気に晒される状態で密閉型中空カセット20を交換する実験を行なった。本実験では、カセット20の交換時にボルト９（図１及び図２参照）を解除して嫌気性電解槽２から蓋体８を外し、電解槽２の内部空間３を空気中に開放しながら劣化した５つのカセット20を基質Ｓから抜き出し、新たな５つのカセット20を差し込んだのち再度蓋体８で電解槽２を密閉して実験を再開した。本実験による電圧の測定結果を図１０のグラフに示す。図１０のグラフから、負電極10が空気に晒される状態で隔膜21を交換すると負電極10に生息する微生物が損傷を受け、外部回路18で得られる電圧が著しく低下することが分かる。また、交換前の電圧に復帰するために初期馴養（再立ち上げ）に近い約25日の期間が必要であることが分かる。
[Experiment 2]
Subsequently, long-term continuous operation is performed using the same microbial fuel cell 1 and organic substrate S as in Experimental Example 1, and the microbial fuel cell 1 is disassembled on the 101st day from the start of operation, and the negative electrode 10 is exposed to air. An experiment was conducted to replace the hermetic hollow cassette 20. In this experiment, when the cassette 20 was replaced, the bolt 9 (see FIGS. 1 and 2) was released, the lid 8 was removed from the anaerobic electrolytic cell 2, and the internal space 3 of the electrolytic cell 2 was deteriorated while being opened to the air. The five cassettes 20 were extracted from the substrate S, and after inserting five new cassettes 20, the electrolytic cell 2 was sealed again with the lid 8 and the experiment was resumed. The measurement result of the voltage by this experiment is shown in the graph of FIG. From the graph of FIG. 10, it can be seen that if the diaphragm 21 is exchanged while the negative electrode 10 is exposed to air, microorganisms living in the negative electrode 10 are damaged, and the voltage obtained in the external circuit 18 is significantly reduced. It can also be seen that a period of about 25 days close to initial acclimatization (re-startup) is required to return to the voltage before replacement.
［実験例３］
更に、実験例１と同じ微生物燃料電池１及び有機性基質Ｓを用いて長期連続運転を行い、運転開始から101日目に嫌気性電解槽２の差込口６を一時的に開放して密閉型中空カセット20を交換する実験を行なった。電解槽２には各カセット20に対応する５つの差込口６を設け、各差込口６を順次に開放してカセット20を１枚ずつ抜き出したのち、迅速に新たなカセット20を差し込んで差込口６を閉鎖するサイクルを繰り返した。負電極10は有機性基体Ｓ中に保持し、できるだけ空気に晒されないようにした。本実験による電圧の測定結果を図１１のグラフに示す。
[Experiment 3]
Furthermore, long-term continuous operation is performed using the same microbial fuel cell 1 and organic substrate S as in Experimental Example 1, and the inlet 6 of the anaerobic electrolytic cell 2 is temporarily opened and sealed on the 101st day from the start of operation. An experiment was conducted to replace the mold hollow cassette 20. The electrolytic cell 2 is provided with five insertion ports 6 corresponding to the respective cassettes 20, and the respective insertion ports 6 are sequentially opened to extract the cassettes 20 one by one, and then a new cassette 20 is quickly inserted. The cycle of closing the outlet 6 was repeated. The negative electrode 10 was held in the organic substrate S so as not to be exposed to air as much as possible. The measurement result of the voltage by this experiment is shown in the graph of FIG.
図１１のグラフから、開閉可能な差込口６を介してカセット20を交換した場合は、差込口６の開放時に嫌気性電解槽２内に僅かに混入した空気の影響と思われる若干の電圧低下が発生したが、カセット20を交換したのち数日以内に交換前の電圧に復帰することが分かる。すなわち、本発明の微生物燃料電池１及び密閉型中空カセット20は、隔膜21及び／又は正電極15を交換時におけるエネルギー回収効率の低下を抑えることに有効であることが確認できた。また、差込口６の開放時にガス注入口７から電解槽２の気相部に不活性ガスＧを注入しながらカセット20を交換する更なる実験を行なった結果、図１１に示す電圧低下を更に小さくできることを確認できた。すなわち、本発明の微生物燃料電池１及び密閉型中空カセット20を用いれば、実質的にエネルギー回収効率を安定的に維持しながら微生物燃料電池１の隔膜21及び／又は正電極15を交換可能であることを確認することができた。 From the graph of FIG. 11, when the cassette 20 is exchanged through the opening 6 that can be opened and closed, there is a slight effect that is considered to be due to air slightly mixed in the anaerobic electrolytic cell 2 when the insertion opening 6 is opened. Although a voltage drop occurs, it can be seen that the voltage returns to the voltage before replacement within a few days after the cassette 20 is replaced. That is, it was confirmed that the microbial fuel cell 1 and the sealed hollow cassette 20 of the present invention are effective in suppressing a decrease in energy recovery efficiency when replacing the diaphragm 21 and / or the positive electrode 15. Further, as a result of a further experiment in which the cassette 20 was replaced while injecting the inert gas G from the gas injection port 7 into the gas phase portion of the electrolytic cell 2 when the insertion port 6 was opened, the voltage drop shown in FIG. It was confirmed that it could be further reduced. That is, if the microbial fuel cell 1 and the sealed hollow cassette 20 of the present invention are used, the diaphragm 21 and / or the positive electrode 15 of the microbial fuel cell 1 can be exchanged while substantially maintaining energy recovery efficiency. I was able to confirm that.
こうして本発明の目的である「エネルギー回収効率を低下させずに部品を交換できる微生物燃料電池及び微生物燃料電池用の隔膜カセット」の提供を達成できる。 Thus, the provision of “a microbial fuel cell and a diaphragm cassette for a microbial fuel cell in which parts can be replaced without reducing energy recovery efficiency”, which is an object of the present invention, can be achieved.
以上、正電極15が内側に封入又は結合された隔膜カセット19（密閉型中空カセット20）を負電極10が浸漬する有機性基質Ｓ中に差し込み、入出孔22、23を介してカセット19内に酸素Ｏを供給しながら外部回路18を介して電気エネルギーを回収する微生物燃料電池について説明したが、本発明による密閉型中空カセット20を備えた隔膜カセット19は、図７のように負電極10が浸漬する負極槽（嫌気性電解槽）２と正電極15が浸漬する正極槽42とを分離した２槽式の微生物燃料電池１においても有効に利用できる。 As described above, the diaphragm cassette 19 (sealed hollow cassette 20) in which the positive electrode 15 is sealed or bonded is inserted into the organic substrate S in which the negative electrode 10 is immersed, and the cassette 19 is inserted into the cassette 19 through the inlet / outlet holes 22 and 23. Although the microbial fuel cell that recovers electric energy through the external circuit 18 while supplying oxygen O has been described, the diaphragm cassette 19 having the sealed hollow cassette 20 according to the present invention has a negative electrode 10 as shown in FIG. The present invention can also be effectively used in a two-tank type microbial fuel cell 1 in which a negative electrode tank (anaerobic electrolytic cell) 2 to be immersed and a positive electrode tank 42 to which the positive electrode 15 is immersed are separated.
図７の２槽式の微生物燃料電池１は、有機性基質Ｓを滞留させて負電極10を浸漬させる内部空間３を有する負極槽（嫌気性電解槽）２と、電解液Ｄを滞留させて正電極15及び密閉型中空カセット20を浸漬させる内部空間43を有する正極槽42と、負極槽２の有機性基質Ｓを正極槽42のカセット20に循環させるポンプ等の基質循環装置41とを有する。負極槽２の負電極10に接続されて負極槽２外に引き出した負極導線12と、正電槽42の正電極15に接続されて正極槽42外に引き出した正極導線16とを、外部回路18を介して電気的に接続することにより微生物燃料電池１を構成する。正極槽42の電解液Ｄ内には、例えば電解液Ｄの正電極15の下端付近に差し込んだ散気管（図示せず）を介して、正電極15と接触させる酸素（又は空気）を供給する。或いは、予め十分に酸素（空気）を飽和させた電解液Ｄを正極槽42の流入口44から供給し、流出口43から排出された電解液Ｄに再び酸素（空気）を飽和させて流入口44へ戻して循環させる方法も考えられる。 7 has a negative electrode tank (anaerobic electrolytic cell) 2 having an internal space 3 in which the organic substrate S is retained and the negative electrode 10 is immersed, and an electrolytic solution D is retained. A positive electrode tank 42 having an internal space 43 into which the positive electrode 15 and the sealed hollow cassette 20 are immersed, and a substrate circulation device 41 such as a pump for circulating the organic substrate S in the negative electrode tank 2 to the cassette 20 in the positive electrode tank 42. . A negative electrode conductor 12 connected to the negative electrode 10 of the negative electrode tank 2 and drawn out of the negative electrode tank 2 and a positive electrode conductor 16 connected to the positive electrode 15 of the positive electrode tank 42 and drawn out of the positive electrode tank 42 are connected to an external circuit. The microbial fuel cell 1 is configured by being electrically connected via 18. For example, oxygen (or air) to be brought into contact with the positive electrode 15 is supplied into the electrolytic solution D of the positive electrode tank 42 through an air diffuser (not shown) inserted near the lower end of the positive electrode 15 of the electrolytic solution D. . Alternatively, the electrolyte D in which oxygen (air) is sufficiently saturated in advance is supplied from the inlet 44 of the positive electrode tank 42, and oxygen (air) is again saturated in the electrolyte D discharged from the outlet 43 to the inlet. A method of returning to 44 and circulating is also conceivable.
図７の微生物燃料電池１では、正極槽42に浸漬させた密閉型中空カセット20の入出孔22、23を基質送入孔22及び基質送出孔23とし、負極槽２の負電極10で生成された水素イオン（Ｈ＋）を有機性基質Ｓと共にカセット20の内側に循環させ、その水素イオンを正極槽42内のカセット20外に配置された正電極15へカセット20のイオン透過性隔膜21と電解液Ｄとを介して移動させる。また、負極槽２の負電極10で生成された電子は負極導線12、外部回路18、正極導線16を介して正極槽42の正電極15へ移動させ、その外部回路18に流れる電気を取り出すことでエネルギーを回収する。なお、図示例ではカセット20と正電極15とを分離しているが、カセット20の隔膜21を外側に正電極15が一体成形されたＭＥＡとし、その隔膜21の外側を酸素（又は空気）と接触させてもよく、その場合は電解液Ｄがなくてもよい。 In the microbial fuel cell 1 of FIG. 7, the inlet and outlet holes 22 and 23 of the sealed hollow cassette 20 immersed in the positive electrode tank 42 are used as the substrate inlet hole 22 and the substrate outlet hole 23, and are generated by the negative electrode 10 of the negative electrode tank 2. The hydrogen ions (H + ) are circulated inside the cassette 20 together with the organic substrate S, and the hydrogen ions are transferred to the positive electrode 15 arranged outside the cassette 20 in the positive electrode tank 42 and the ion permeable membrane 21 of the cassette 20. It moves through the electrolyte D. Further, electrons generated at the negative electrode 10 of the negative electrode tank 2 are moved to the positive electrode 15 of the positive electrode tank 42 via the negative electrode lead 12, the external circuit 18, and the positive electrode lead 16, and the electricity flowing through the external circuit 18 is taken out. To recover energy. In the illustrated example, the cassette 20 and the positive electrode 15 are separated, but the diaphragm 21 of the cassette 20 is an MEA in which the positive electrode 15 is integrally formed on the outside, and the outside of the diaphragm 21 is oxygen (or air). In this case, the electrolyte solution D may not be present.
図７のように微生物燃料電池１を２槽式とすれば、負電極10と正電極15との間の距離が長くなって電池の内部抵抗が高くなる可能性はあるものの、イオン透過性隔膜21又は正電極15の劣化時に正極槽42において密閉型中空カセット20を交換すれば足り、負極槽２を何ら開放する必要がなくなる。従って、隔膜21及び／又は正電極15を交換時に負電極10の嫌気性微生物11が空気に晒されて損傷を受けるおそれがなく、交換後直ちに微生物燃料電池１の所定発電能力を発揮させることが可能となる。また、高価な貴金属を利用する正電極15と寿命の短いイオン透過性隔膜21とを分離することができ、カセット20の交換に伴う費用を低く抑えることができる。なお、図７のように負極槽２と正極槽42とを分離した２槽式において、図１及び図２のようにカセット20を負極槽２に差し込み、正極槽42の電解液Ｄをカセット21の入出孔22、23に循環させて微生物燃料電池１を構成することも可能である。 If the microbial fuel cell 1 is of a two-tank type as shown in FIG. 7, the distance between the negative electrode 10 and the positive electrode 15 may become longer and the internal resistance of the cell may increase, but the ion permeable diaphragm It is sufficient to replace the sealed hollow cassette 20 in the positive electrode tank 42 when the 21 or the positive electrode 15 deteriorates, and it is not necessary to open the negative electrode tank 2 at all. Therefore, there is no possibility that the anaerobic microorganisms 11 of the negative electrode 10 are exposed to air and damaged when the diaphragm 21 and / or the positive electrode 15 are replaced, and the predetermined power generation capacity of the microbial fuel cell 1 can be exhibited immediately after the replacement. It becomes possible. Further, the positive electrode 15 using an expensive noble metal and the ion permeable diaphragm 21 having a short lifetime can be separated, and the cost associated with the replacement of the cassette 20 can be kept low. In the two tank type in which the negative electrode tank 2 and the positive electrode tank 42 are separated as shown in FIG. 7, the cassette 20 is inserted into the negative electrode tank 2 as shown in FIGS. It is also possible to constitute the microbial fuel cell 1 by circulating it through the inlet / outlet holes 22 and 23.
１…微生物燃料電池 ２…嫌気性電解槽（負極槽）
2a…フランジ ３…内部空間
４…基質流入口 4a…基質流入管
５…基質流出口 5a…基質流出管
６…カセット差込口 ７…不活性ガス注入口
８…蓋体 ９…ボルト
10…負電極 11…嫌気性微生物
12…負極導線（リード線） 15…正電極
15a…通気性正電極（材料） 16…正極導線（リード線）
18…外部回路 19…隔膜カセット
20…密閉型中空カセット 21…イオン透過性隔膜
22…送入孔又は通気管 22a…通気管の微細孔
23…送出孔又は通気管 23a…通気管の微細孔
24…延長管 25…中空外殻フレーム（外殻）
26…開口（窓） 27…中空部
28…固定部材（窓枠部材） 29…差込口蓋部材
30…イオン透過性樹脂溶液 30a…容器
31…ガス送入装置 32…隔壁
41…基質循環装置 42…正極槽
43…内部空間 44…電解液流入口
45…電解液流出口
50…微生物燃料電池 51…作用極（負電極）
52…対極（正電極） 53…イオン透過性隔膜
54…仕切板 55…集電シート
56…押さえ板 57…被電解物質含有液（又はガス）
58…空気（又は酸素） 59…加湿用水溶液
60…微生物燃料電池 61…アノード（負電極）
62…イオン透過性隔膜 63…カソード（正電極）
64…有機性溶液又は懸濁液 65…空気
66…導線
Ｄ…電解液 Ｇ…不活性ガス
Ｏ…酸素（又は空気） Ｓ…有機性基質
1 ... Microbial fuel cell 2 ... Anaerobic electrolytic cell (negative electrode cell)
2a ... Flange 3 ... Internal space 4 ... Substrate inlet 4a ... Substrate inlet 5 ... Substrate outlet 5a ... Substrate outlet 6 ... Cassette inlet 7 ... Inert gas inlet 8 ... Lid 9 ... Bolt
10 ... Negative electrode 11 ... Anaerobic microorganism
12 ... Negative electrode lead (lead wire) 15 ... Positive electrode
15a ... Breathable positive electrode (material) 16 ... Positive electrode lead (lead wire)
18 ... external circuit 19 ... diaphragm cassette
20 ... Sealed hollow cassette 21 ... Ion-permeable membrane
22 ... Inlet hole or vent tube 22a ... Vent tube fine hole
23 ... Delivery hole or vent pipe 23a ... Fine hole in vent pipe
24 ... Extension pipe 25 ... Hollow outer shell frame (outer shell)
26 ... Opening (window) 27 ... Hollow part
28… Fixing member (window frame member) 29… Inlet port lid member
30… Ion permeable resin solution 30a… Container
31… Gas feeding device 32… Partition wall
41 ... Substrate circulation device 42 ... Cathode
43… Internal space 44… Electrolyte inlet
45 ... Electrolyte outlet
50… Microbial fuel cell 51… Working electrode (negative electrode)
52… Counter electrode (positive electrode) 53… Ion permeable membrane
54 ... Partition plate 55 ... Current collector sheet
56 ... Presser plate 57 ... Electrolyte-containing liquid (or gas)
58… Air (or oxygen) 59… Aqueous solution for humidification
60 ... Microbial fuel cell 61 ... Anode (negative electrode)
62 ... Ion permeable membrane 63 ... Cathode (positive electrode)
64… Organic solution or suspension 65… Air
66 ... Conductor D ... Electrolyte G ... Inert gas O ... Oxygen (or air) S ... Organic substrate
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB0720203D0 (en) * | 2007-10-16 | 2007-11-28 | Goryanin Irina | Microbial fuel cell cathode assembly |
| JP5526505B2 (en) * | 2008-07-28 | 2014-06-18 | 栗田工業株式会社 | Microbial power generator |
| JP2010102953A (en) * | 2008-10-23 | 2010-05-06 | Kurita Water Ind Ltd | Microbiological power generation device and positive electrode for the microbiological power generation device |
| WO2011025021A1 (en) * | 2009-08-31 | 2011-03-03 | 独立行政法人科学技術振興機構 | Electrode for microbial fuel cell, and microbial fuel cell using same |
| EP2524411A4 (en) * | 2010-01-14 | 2013-10-09 | Craig Venter Inst J | Modular energy recovering water treatment devices |
| JP5709125B2 (en) * | 2010-08-03 | 2015-04-30 | 鹿島建設株式会社 | Nitrous oxide decomposition equipment |
| WO2012066806A1 (en) * | 2010-11-18 | 2012-05-24 | 独立行政法人科学技術振興機構 | Electrode for microbial fuel cells and microbial fuel cell using same |
| KR101210841B1 (en) * | 2011-04-12 | 2012-12-11 | 부산대학교 산학협력단 | Non-aeration organic matter removing apparatus |
| JP5812874B2 (en) * | 2012-01-13 | 2015-11-17 | 積水化学工業株式会社 | Microbial fuel cell system |
| JP6065321B2 (en) | 2013-04-22 | 2017-01-25 | パナソニックＩｐマネジメント株式会社 | Liquid processing equipment |
| AU2014352728A1 (en) * | 2013-11-22 | 2016-06-16 | Cambrian Innovation Inc. | Electrodes for cost-effective bio-electrochemical systems |
| JP6254884B2 (en) | 2014-03-27 | 2017-12-27 | パナソニック株式会社 | Microbial fuel cell |
| WO2016114139A1 (en) * | 2015-01-15 | 2016-07-21 | パナソニック株式会社 | Microbial fuel cell system |
| US20180294501A1 (en) * | 2015-06-05 | 2018-10-11 | Panasonic Corporation | Electrode assembly, and microbial fuel cell and water treatment device using same |
| CN105552416B (en) * | 2016-01-13 | 2018-06-19 | 山东星火科学技术研究院 | A kind of microbiological fuel cell |
| JP2017183011A (en) * | 2016-03-29 | 2017-10-05 | シャープ株式会社 | Microbial fuel cell, and microbial fuel cell system |
| WO2017199475A1 (en) * | 2016-05-17 | 2017-11-23 | パナソニックＩｐマネジメント株式会社 | Liquid processing unit and liquid processing device |
| WO2017208495A1 (en) * | 2016-06-01 | 2017-12-07 | パナソニックＩｐマネジメント株式会社 | Purification unit and purification device |
| WO2019069851A1 (en) * | 2017-10-03 | 2019-04-11 | パナソニックＩｐマネジメント株式会社 | Electrode assembly, and microbial fuel cell and water treatment device using same |
| CN108461770A (en) * | 2018-06-06 | 2018-08-28 | 广西师范大学 | A kind of multi-stage series connection MFC- aerobe slot coupling devices of processing industrial wastewater containing toxicant |
| JP6960886B2 (en) * | 2018-06-21 | 2021-11-05 | 本田技研工業株式会社 | Fuel cell module and fuel cell system |
| KR102157094B1 (en) * | 2018-12-10 | 2020-09-17 | 대한민국(농촌진흥청장) | Microbial Fuel Cell system integrated substrate cycle and electricity interface structure |
| CN116425298B (en) * | 2023-03-09 | 2023-09-19 | 福建省厦门环境监测中心站(九龙江流域生态环境监测中心) | Microbial fuel cell sewage treatment equipment |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH03147269A (en) * | 1989-11-02 | 1991-06-24 | Honda Motor Co Ltd | Reserve type microorganism battery |
| KR100224381B1 (en) * | 1996-08-29 | 1999-10-15 | 박호군 | Biofuel cell using metal salt-reducing bacteria |
| JP2000133327A (en) * | 1998-10-29 | 2000-05-12 | Canon Inc | Power generating method and device using micro-organism |
| JP5114612B2 (en) * | 2004-10-15 | 2013-01-09 | 株式会社三重ティーエルオー | Microbial battery for sludge treatment and sludge purification apparatus using the same |
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