JP2016029199A - Method and apparatus for producing chemical by electrochemical process - Google Patents
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- 238000000034 method Methods 0.000 title claims abstract description 42
- 239000000126 substance Substances 0.000 title claims abstract description 33
- 239000007864 aqueous solution Substances 0.000 claims abstract description 48
- 239000012528 membrane Substances 0.000 claims abstract description 47
- 238000005341 cation exchange Methods 0.000 claims abstract description 46
- 239000000243 solution Substances 0.000 claims abstract description 32
- 238000006243 chemical reaction Methods 0.000 claims abstract description 30
- 150000003839 salts Chemical class 0.000 claims abstract description 29
- 238000013032 photocatalytic reaction Methods 0.000 claims abstract description 24
- 230000002378 acidificating effect Effects 0.000 claims abstract description 21
- 239000002184 metal Substances 0.000 claims abstract description 18
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 150000001768 cations Chemical class 0.000 claims abstract description 17
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 12
- 230000002829 reductive effect Effects 0.000 claims abstract description 11
- 239000002994 raw material Substances 0.000 claims abstract description 9
- 239000003011 anion exchange membrane Substances 0.000 claims description 29
- 238000005868 electrolysis reaction Methods 0.000 claims description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 25
- 239000011941 photocatalyst Substances 0.000 claims description 21
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 16
- 239000001301 oxygen Substances 0.000 claims description 16
- 229910052760 oxygen Inorganic materials 0.000 claims description 16
- 238000012824 chemical production Methods 0.000 claims description 13
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- 238000006722 reduction reaction Methods 0.000 claims description 7
- 150000001450 anions Chemical class 0.000 claims description 6
- -1 iron ion Chemical class 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 2
- 238000003487 electrochemical reaction Methods 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910017604 nitric acid Inorganic materials 0.000 claims description 2
- 150000007524 organic acids Chemical class 0.000 claims description 2
- 239000003014 ion exchange membrane Substances 0.000 abstract description 11
- 238000003786 synthesis reaction Methods 0.000 abstract description 6
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 230000033116 oxidation-reduction process Effects 0.000 abstract 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 48
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 16
- 235000011121 sodium hydroxide Nutrition 0.000 description 16
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 14
- 239000001257 hydrogen Substances 0.000 description 14
- 229910052739 hydrogen Inorganic materials 0.000 description 14
- 238000004448 titration Methods 0.000 description 13
- 238000002474 experimental method Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 8
- 239000011780 sodium chloride Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000000460 chlorine Substances 0.000 description 7
- 238000006479 redox reaction Methods 0.000 description 7
- 239000002253 acid Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000011259 mixed solution Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- 229910020366 ClO 4 Inorganic materials 0.000 description 3
- 239000013064 chemical raw material Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 3
- 239000012466 permeate Substances 0.000 description 3
- 239000006228 supernatant Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 229910001413 alkali metal ion Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Chemical compound [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 description 2
- 230000001443 photoexcitation Effects 0.000 description 2
- 239000003115 supporting electrolyte Substances 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 229910003071 TaON Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 238000004577 artificial photosynthesis Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 150000007514 bases Chemical class 0.000 description 1
- 229940063013 borate ion Drugs 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000011033 desalting Methods 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229940006477 nitrate ion Drugs 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 229940085991 phosphate ion Drugs 0.000 description 1
- 230000001699 photocatalysis Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- LLTOPKQGFAAMKH-UHFFFAOYSA-N siderin Chemical compound COC1=CC(=O)OC2=CC(OC)=CC(C)=C21 LLTOPKQGFAAMKH-UHFFFAOYSA-N 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
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Abstract
Description
本発明は、イオン交換膜を用いた電気化学プロセスによる酸性および塩基性の化学品合成に関し、特に、酸化還元媒体(レドックス媒体)の光触媒反応を用いた低電圧化の方法、並びに当該方法を用いた装置に関する。 The present invention relates to acidic and basic chemical synthesis by an electrochemical process using an ion exchange membrane, and in particular, a method for lowering voltage using a photocatalytic reaction of a redox medium (redox medium), and the method is used. Related to the device.
人類社会は経済活動(物質・人・金・情報)の流動の中で様々な価値を創造しているが、その流動は膨大なエネルギー消費によって生み出されている。持続可能社会の構築のためには省エネルギーおよび再生可能エネルギーの両方の推進が不可欠である。再生可能エネルギーの中で最も膨大な太陽エネルギーを積極的に利用する方法として、太陽光発電による一次エネルギーとしての利用だけでは無く、その光エネルギーを様々な化学反応プロセスに組み込むことができれば、創エネと省エネを同時に達成できるためにまさに理想的である。 The human society creates various values in the flow of economic activities (materials, people, money, information), but the flow is generated by enormous energy consumption. In order to build a sustainable society, it is essential to promote both energy conservation and renewable energy. As a method of positively utilizing the vast amount of solar energy among renewable energies, if it can be incorporated into various chemical reaction processes as well as being used as primary energy by photovoltaic power generation, It is ideal for achieving energy savings at the same time.
太陽エネルギーを化学物質に変換する技術として、半導体光触媒や光電極を利用した人工光合成技術がある。水を水素と酸素に分解するソーラー水素製造や炭酸ガスを有機物に変換するソーラー燃料技術などが世界中で研究されている。しかし、このような反応だけで無く、この技術形態や反応の種類には植物のようにもっと多様性が有って良い。早期の実用化を目指すためには、多くの新規反応と新規技術を開発する必要がある。 As a technique for converting solar energy into a chemical substance, there is an artificial photosynthesis technique using a semiconductor photocatalyst or a photoelectrode. Solar hydrogen production that decomposes water into hydrogen and oxygen and solar fuel technology that converts carbon dioxide into organic matter are being studied around the world. However, not only such reactions, but also the technology forms and types of reactions may be more diverse like plants. In order to achieve early commercialization, it is necessary to develop many new reactions and new technologies.
発明者らは以前、レドックス反応を進行する光触媒と水分解水素製造を組み合わせた光触媒−電解ハイブリッドシステムを考案している(特許文献１−３、非特許文献１)。例えば、Ｆｅ3+水溶液からＦｅ2+を生成しながら水を酸化して酸素を発生させる。このレドックス反応は光エネルギーを蓄積するアップヒル反応である。Ｆｅ2+イオンのままではエネルギーを利用しにくいので、カチオン交換膜で仕切った２室型の水電解装置のアノード電極でＦｅ2+をＦｅ3+に酸化しながらカソード電極で水素を製造する。カチオン交換膜ではプロトン(Ｈ+)が移動する。トータルでは水を水素と酸素に分解するソーラー水素製造が進行できる。必要な理論電圧はレドックス反応と水素発生の酸化還元準位の差になる。 The inventors have previously devised a photocatalyst-electrolytic hybrid system combining a photocatalyst that proceeds with a redox reaction and water-splitting hydrogen production (Patent Documents 1-3 and Non-Patent Document 1). For example, oxygen is generated by oxidizing water while producing Fe 2+ from an Fe 3+ aqueous solution. This redox reaction is an uphill reaction that accumulates light energy. Since it is difficult to use energy as it is with Fe 2+ ions, hydrogen is produced at the cathode electrode while oxidizing Fe 2+ to Fe 3+ at the anode electrode of a two-chamber water electrolysis apparatus partitioned by a cation exchange membrane. In the cation exchange membrane, protons (H + ) move. In total, solar hydrogen production that decomposes water into hydrogen and oxygen can proceed. The required theoretical voltage is the difference between the redox reaction and the redox level of hydrogen evolution.
しかし、現状では大規模な水素製造の需要は少なく、このような新エネルギーの未来技術の実用化は進んでいない。光触媒のレドックス反応で蓄えられたエネルギーを現実の社会に役立てるためには、その蓄えられたエネルギーの活用技術を新規に開発する必要がある。発明者らは、光触媒のレドックス反応で蓄えられたエネルギーを応用できる技術を模索した結果、本発明を考案した。 However, at present, there is little demand for large-scale hydrogen production, and the practical application of such new energy future technology is not progressing. In order to use the energy stored by the redox reaction of the photocatalyst for the real society, it is necessary to develop a technology for utilizing the stored energy. The inventors devised the present invention as a result of searching for a technique that can apply the energy stored in the redox reaction of the photocatalyst.
実用化されている電気化学プロセスにはいくつかの種類かある。例えば、苛性ソーダ(ＮａＯＨ)電解合成(日本で年産４００万トン)に適応し、レドックス媒体を用いた半導体光触媒を組み込めれば省エネ化に貢献できる可能性がある。日本の電解ソーダ工業の年間電力消費量は約１１０億ｋＷｈで、化学工業全体の約１７％を占めるほど膨大である。従来技術では海水を電解してカソード側でＮａＯＨと水素を製造するとともにアノード側で塩素(Ｃｌ-／Ｃｌ2＝＋１.３６Ｖ)が生成する。理論電解電圧は２.１９Ｖであるが、実際は過電圧により約３Ｖで稼働している。この電解電圧を少しでも低下できれば非常に大きな省エネにつながる。例えば、単純計算でＮａＯＨ製造の２割に適応するだけで４億ｋＷｈ分に相当する省エネ効果がある。また、電解を利用して様々なイオンを含む溶液から酸や塩基を製造するプロセスも工業的に稼働しているが、その電圧を低下できれば大きな省エネになる。 There are several types of electrochemical processes in practical use. For example, adapting to caustic soda (NaOH) electrolytic synthesis (annual production of 4 million tons in Japan) and incorporating a semiconductor photocatalyst using a redox medium may contribute to energy saving. The annual power consumption of the Japanese electrolytic soda industry is about 11 billion kWh, which is so large that it accounts for about 17% of the entire chemical industry. In the prior art, seawater is electrolyzed to produce NaOH and hydrogen on the cathode side, and chlorine (Cl − / Cl 2 = + 1.36 V) is generated on the anode side. The theoretical electrolysis voltage is 2.19V, but it is actually operating at about 3V due to overvoltage. If this electrolysis voltage can be reduced as much as possible, it will lead to significant energy savings. For example, there is an energy saving effect equivalent to 400 million kWh just by adapting to 20% of NaOH production by simple calculation. In addition, a process for producing acids and bases from a solution containing various ions using electrolysis is also industrially operated. However, if the voltage can be lowered, a great energy saving can be achieved.
光エネルギーによって電解電圧を低下させる技術としては光電極反応があるが、通常はレドックス媒体を用いない。半導体膜を導電性基板に成膜し、対極とともに用いる技術である(非特許文献２)。しかし、大面積化においては、導電性基板や配線を用いる光電極よりも光触媒の方が優れている。レドックス媒体を介在することで、昼間だけでなく、安い夜間電力を使えるメリットおよび変動の激しい再生可能エネルギー由来の電力変動を吸収するメリットがある。 As a technique for reducing the electrolysis voltage by light energy, there is a photoelectrode reaction, but usually a redox medium is not used. This is a technique of forming a semiconductor film on a conductive substrate and using it together with a counter electrode (Non-patent Document 2). However, in increasing the area, the photocatalyst is superior to the photoelectrode using a conductive substrate or wiring. By using a redox medium, there are advantages that not only daytime but also cheap nighttime electric power can be used and that electric power fluctuations derived from renewable energy that is fluctuating rapidly can be absorbed.
以上のような背景から、本発明は、原料塩水溶液から酸性または塩基性の化学品合成を行うイオン交換膜を用いた電気化学プロセスにおいて、光触媒のレドックス反応で蓄えられたエネルギーを適応して電解電圧を低下できる技術を提供することを課題としている。 From the background as described above, the present invention adapts the energy stored in the redox reaction of the photocatalyst in an electrochemical process using an ion exchange membrane that synthesizes an acidic or basic chemical product from a raw salt aqueous solution. An object is to provide a technology capable of reducing the voltage.
本発明者らは、原料塩水溶液から酸性または塩基性の化学品合成を行うイオン交換膜を用いた電気化学プロセスに、光触媒のレドックス反応で蓄えられたエネルギーを適応して電解電圧を低下できる技術を鋭意検討し、本発明を完成するに至った。 The present inventors have been able to reduce the electrolysis voltage by adapting the energy stored in the redox reaction of the photocatalyst to an electrochemical process using an ion exchange membrane that performs acidic or basic chemical synthesis from a raw salt aqueous solution. As a result, the present invention has been completed.
すなわち、この本発明は以下のことを特徴としている。
［１］金属塩の水溶液を原料とし、カチオン交換膜で原料金属のカチオンをカソード電極側に移動させて、カソード電極側で塩基性の水溶液を製造し、アノード電極側で酸性の水溶液を製造する電気化学プロセスにおいて、
光触媒反応で生じたレドックス媒体の還元体を、アノード電極に接触させることにより電解電圧を低下させることを特徴とする光エネルギーを利用した化学品製造方法。
［２］前記レドックス媒体は、その標準酸化還元準位が、酸素発生準位(Ｏ2／Ｈ2Ｏ＝＋１.２３Ｖ、ＮＨＥ、ｐＨ＝０)よりも負側にあることを特徴とする請求項１に記載の光エネルギーを利用した化学品製造方法。
［３］前記レドックス媒体が、鉄イオンであることを特徴とする[１]又は[２]に記載の光エネルギーを利用した化学品製造方法。
［４］前記カチオン交換膜に接触する反応溶液において、金属カチオン濃度がプロトン濃度より高い条件で反応を行うことを特徴とする[１]〜[３]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［５］前記カチオン交換膜に、アノード電極側にアニオンを移動させるアニオン交換膜を組み合わせて用いることを特徴とする[１]〜[４]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［６］前記アノード電極と前記カソード電極の間に、プロトン選択性カチオン交換膜およびアニオン交換膜、カチオン交換膜をこの順に設置することを特徴とする[１]〜[５]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［７］前記塩基性の水溶液が、アルカリ金属の水酸化物水溶液であることを特徴とする[１]〜[６]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［８］前記アノード電極側で生成する酸性の水溶液が、塩酸、硫酸、硝酸、過塩素酸又は有機酸の水溶液であることを特徴とする[１]〜[７]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［９］前記カソード電極での反応が、酸素還元反応であることを特徴とする[１]〜[８]のいずれかに記載の光エネルギーを利用した化学品製造方法。
［１０］金属塩の水溶液を原料とし、電気化学反応により塩基性の水溶液及び酸性の水溶液を製造する化学品製造装置であって、
内部にアノード電極及びカソード電極並びに両電極間に配置されたカチオン交換膜を備えた電解槽と、光触媒を備えた光触媒反応槽とを有し、
該光触媒反応槽で生成されたレドックス媒体の還元体を含む溶液を、前記アノード電極側の電解槽に導入する手段を設けたことを特徴とする化学品製造装置。
［１１］[１０]に記載の化学品製造装において、前記電解槽内の前記アノード電極と前記カチオン交換膜の間にさらにアニオン交換膜を備え、
前記光触媒反応槽で生成されたレドックス媒体の還元体を含む溶液を、前記アノード電極側の電解槽に導入する手段と、
前記金属塩の水溶液を、前記アニオン交換膜とカチオン交換膜の間の電解槽に導入する手段とを設けたことを特徴とする化学品製造装置。
［１２］[１１]に記載の化学品製造装置において、前記電解槽内の前記アノード電極と前記アニオン交換膜の間にさらにＨ＋選択性カチオン交換膜を備えたことを特徴とする化学品製造装置。
That is, the present invention is characterized by the following.
[1] Using an aqueous solution of a metal salt as a raw material, a cation of a raw material metal is moved to the cathode electrode side by a cation exchange membrane, a basic aqueous solution is produced on the cathode electrode side, and an acidic aqueous solution is produced on the anode electrode side In electrochemical processes,
A chemical production method using light energy, characterized in that an electrolysis voltage is lowered by bringing a reduced form of a redox medium generated by a photocatalytic reaction into contact with an anode electrode.
[2] The redox medium has a standard redox level on the negative side of an oxygen generation level (O 2 / H 2 O = + 1.23 V, NHE, pH = 0). Item 10. A chemical production method using light energy according to Item 1.
[3] The chemical production method using light energy according to [1] or [2], wherein the redox medium is an iron ion.
[4] The light energy as described in any one of [1] to [3], wherein the reaction solution in contact with the cation exchange membrane is reacted under a condition in which a metal cation concentration is higher than a proton concentration. Chemical manufacturing method.
[5] The chemical production using light energy according to any one of [1] to [4], wherein the cation exchange membrane is used in combination with an anion exchange membrane that moves anions to the anode electrode side Method.
[6] The proton selective cation exchange membrane, the anion exchange membrane, and the cation exchange membrane are disposed in this order between the anode electrode and the cathode electrode, according to any one of [1] to [5] Chemical manufacturing method using light energy of
[7] The chemical production method using light energy according to any one of [1] to [6], wherein the basic aqueous solution is an alkali metal hydroxide aqueous solution.
[8] The light according to any one of [1] to [7], wherein the acidic aqueous solution generated on the anode electrode side is an aqueous solution of hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, or an organic acid. A chemical manufacturing method using energy.
[9] The chemical production method using light energy according to any one of [1] to [8], wherein the reaction at the cathode electrode is an oxygen reduction reaction.
[10] A chemical production apparatus for producing a basic aqueous solution and an acidic aqueous solution by an electrochemical reaction using an aqueous solution of a metal salt as a raw material,
It has an electrolytic cell provided with a cation exchange membrane disposed between an anode and a cathode and both electrodes inside, and a photocatalytic reaction vessel equipped with a photocatalyst,
An apparatus for producing a chemical product, comprising means for introducing a solution containing a reductant of a redox medium produced in the photocatalytic reaction tank into the electrolytic cell on the anode electrode side.
[11] In the chemical manufacturing equipment according to [10], further comprising an anion exchange membrane between the anode electrode and the cation exchange membrane in the electrolytic cell,
Means for introducing a solution containing a reductant of the redox medium generated in the photocatalytic reaction tank into the electrolytic cell on the anode electrode side;
An apparatus for producing a chemical product, comprising means for introducing an aqueous solution of the metal salt into an electrolytic cell between the anion exchange membrane and the cation exchange membrane.
[12] The chemical production apparatus according to [11], further comprising an H + selective cation exchange membrane between the anode electrode and the anion exchange membrane in the electrolytic cell. apparatus.
本発明によれば、原料塩水溶液から酸性または塩基性の化学品合成を行うイオン交換膜を用いた電気化学プロセスに、光触媒のレドックス反応で蓄えられたエネルギーを適応することにより、電解電圧を低下させることができる。 According to the present invention, the electrolysis voltage is reduced by adapting the energy stored in the redox reaction of the photocatalyst to an electrochemical process using an ion exchange membrane that performs acidic or basic chemical synthesis from a raw salt aqueous solution. Can be made.
本発明の光エネルギーを利用した化学品製造方法は、金属塩の水溶液を原料とし、カチオン交換膜で原料金属のカチオンをカソード電極側に移動させて、カソード電極側で塩基性の水溶液を製造し、アノード電極側で酸性の水溶液を製造する電気化学プロセスにおいて、光触媒反応で生じたレドックス媒体の還元体を、アノード電極に接触させることにより電解電圧を低下させることを特徴とする。
以下、本発明について、図面を用いて説明する。
The method for producing a chemical product using light energy of the present invention uses a metal salt aqueous solution as a raw material, moves a cation of the raw metal to the cathode electrode side by a cation exchange membrane, and produces a basic aqueous solution on the cathode electrode side. In the electrochemical process for producing an acidic aqueous solution on the anode electrode side, the electrolysis voltage is lowered by bringing the reduced form of the redox medium generated by the photocatalytic reaction into contact with the anode electrode.
Hereinafter, the present invention will be described with reference to the drawings.
図１は、本発明の１実施形態を模式的に示す図であり、化学品の原料の塩(ＭＸ)の溶解した水溶液から塩基性化学品(ＭＯＨ)高濃度溶液及び酸性化学品(ＨＸ)高濃度溶液を製造する電気化学プロセスを模式的に示している。
図１に示すとおり、本発明の該実施形態における電気化学プロセスは、２室型の電解槽内にそれぞれアノード電極及びカソード電極が配置されており、両室間に設けられたカチオン交換膜により、カチオンをアノード電極側からカソード電極側に移動させて、アノード電極側及びカソード電極側のそれぞれに、酸性の水溶液及び塩基性の水溶液を製造するものである。すなわち、カソード電極側の電解槽は塩基性化学品の濃度が高くなることで強い塩基性水溶液となり、アノード電極側の電解槽は酸性化学品の濃度が高くなることで強い酸性水溶液となる。
FIG. 1 is a diagram schematically showing an embodiment of the present invention, in which a basic chemical (MOH) high-concentration solution and an acidic chemical (HX) are dissolved from an aqueous solution in which a chemical raw material salt (MX) is dissolved. 1 schematically shows an electrochemical process for producing a high concentration solution.
As shown in FIG. 1, the electrochemical process in this embodiment of the present invention has an anode electrode and a cathode electrode arranged in a two-chamber electrolytic cell, respectively, and a cation exchange membrane provided between both chambers. The cation is moved from the anode electrode side to the cathode electrode side to produce an acidic aqueous solution and a basic aqueous solution on each of the anode electrode side and the cathode electrode side. That is, the electrolytic cell on the cathode electrode side becomes a strong basic aqueous solution by increasing the concentration of the basic chemical product, and the electrolytic cell on the anode electrode side becomes a strong acidic aqueous solution by increasing the concentration of the acidic chemical product.
本発明においては、前記のカチオン交換膜で金属カチオンを移動させる点に加え、光触媒反応で生じたレドックス媒体を含む水溶液を、上記のアノード電極側の電解槽に流入させることにより、還元体(Ａ−Ｒｅｄ)をアノード電極側に接触させる点に特徴を有するものである。
すなわち、図１に図示する「光触媒反応槽」では、光触媒及びレドックス媒体の酸化体(Ａ−Ｏｘ)が存在する水溶液に光照射することにより、レドックス媒体の酸化体(Ａ−Ｏｘ)をレドックス媒体の還元体(Ａ−Ｒｅｄ)に変化させる還元反応が進行する。該Ａ−Ｏｘ／Ａ−Ｒｅｄの対としては、標準酸化還元準位として、酸素発生準位(Ｏ2／Ｈ2Ｏ＝＋１.２３Ｖ、ＮＨＥ、ｐＨ＝０)よりも負側の酸化還元準位の反応種が利用できる。特に好ましくはＦｅ3+／Ｆｅ2+(＋０.７７Ｖ)である。
本発明においては、この還元体(Ａ−Ｒｅｄ)を含んだ水溶液を、電気化学プロセスのアノード電極側の電解槽に流入させることにより、還元体(Ａ−Ｒｅｄ)をアノード電極側に接触させて電解電圧を低下させるものである。
In the present invention, in addition to the point of moving metal cations by the cation exchange membrane, an aqueous solution containing a redox medium generated by the photocatalytic reaction is allowed to flow into the electrolytic cell on the anode electrode side, thereby reducing the reductant (A -Red) is characterized in that it contacts the anode electrode side.
That is, in the “photocatalyst reaction tank” illustrated in FIG. 1, the redox medium oxide (A-Ox) is applied to the redox medium by irradiating an aqueous solution containing the photocatalyst and the redox medium oxide (A-Ox). The reductive reaction for changing to the reduced form (A-Red) of the compound proceeds. The A-Ox / A-Red pair includes, as a standard redox level, a redox level that is more negative than the oxygen generation level (O 2 / H 2 O = + 1.23 V, NHE, pH = 0). Reactive species can be used. Particularly preferred is Fe 3+ / Fe 2+ (+0.77 V).
In the present invention, the reducing agent (A-Red) is brought into contact with the anode electrode side by flowing the aqueous solution containing the reducing agent (A-Red) into an electrolytic cell on the anode electrode side of the electrochemical process. The electrolytic voltage is lowered.
化学品の原料の塩(ＭＸ)(カチオン(Ｍ+)とアニオン(Ｘ-)からなる塩)における「カチオン」としては、様々なプラス電荷のイオンが用いられるが、アルカリ金属イオン、アルカリ土類金属イオン、有機金属イオンなどであるが、好ましくはアルカリ金属イオンである。特にＮａ+イオンが好ましい。金属イオンだけで無くアンモニウムイオンなどのカチオンも利用できる。
また、化学品の原料の塩(ＭＸ)における「アニオン」としては、塩化物イオン、硫酸イオン、硝酸イオン、リン酸イオン、ホウ酸イオン、過塩素酸イオン、有機酸イオンなどであ。特に塩化物イオンと硫酸イオン、過塩素酸イオンが好ましい。
本発明の電気化学プロセスにおける生成物は、カチオン(Ｍ+)の水酸化物(ＭＯＨ)(塩基性化学品)の高濃度溶液及びアニオン(Ｘ-)の酸(ＨＸ)(酸性化学品)の高濃度溶液である。
Various positively charged ions are used as the “cation” in the chemical raw material salt (MX) (a salt comprising a cation (M + ) and an anion (X − )), and alkali metal ions and alkaline earths are used. Although it is a metal ion, an organic metal ion, etc., Preferably it is an alkali metal ion. Na + ions are particularly preferable. Not only metal ions but also cations such as ammonium ions can be used.
The “anion” in the chemical raw material salt (MX) includes chloride ion, sulfate ion, nitrate ion, phosphate ion, borate ion, perchlorate ion, organic acid ion, and the like. Particularly preferred are chloride ion, sulfate ion and perchlorate ion.
The products in the electrochemical process of the present invention include a high concentration solution of hydroxide (MOH) (basic chemical) of cation (M + ) and acid (HX) (acidic chemical) of anion (X − ). High concentration solution.
アノード電極上では、レドックス媒体の還元体(Ａ−Ｒｅｄ)が酸化体(Ａ−Ｏｘ)になる酸化反応が進行する。この時の反応はそのＡ−Ｏｘ／Ａ−Ｒｅｄの標準酸化還元準位付近で進行する。つまり、酸素発生や塩素発生よりも進行しやすい。
カソード電極上では、ある酸化体(Ｃ−Ｏｘ)が還元体(Ｃ−Ｒｅｄ)になる還元反応が進行する。主な反応としては、水からの水素製造や酸素の還元反応がある。電圧低下の観点からは、好ましくは酸素の還元反応である。
On the anode electrode, an oxidation reaction in which the reduced form (A-Red) of the redox medium becomes an oxidant (A-Ox) proceeds. The reaction at this time proceeds in the vicinity of the standard redox level of A-Ox / A-Red. That is, it proceeds more easily than oxygen generation or chlorine generation.
On the cathode electrode, a reduction reaction in which an oxidant (C-Ox) becomes a reductant (C-Red) proceeds. The main reactions include hydrogen production from water and oxygen reduction reaction. From the viewpoint of voltage reduction, oxygen reduction reaction is preferable.
カチオン交換膜では、塩(ＭＸ)のカチオン(Ｍ+)がプロトンよりも優先して透過する条件で反応を行うことが好ましい。その膜の両側を弱酸性や特に、中性付近から塩基性で反応を行うと、塩(ＭＸ)のカチオン(Ｍ+)がカソード電極側に移動するので、その水酸化物(ＭＯＨ)の高濃度溶液が得られる。その高濃度溶液はカソード電極槽から流出し、その後脱水することで塩基性の化学品(ＭＯＨ)が得られる。特に、金属カチオン濃度がプロトン濃度より高い条件での反応が良い。カチオン交換膜付近を強い酸性にするとプロトンが優先的にカソード側に透過して好ましくないので、その場合は酸を別途回収(透析、蒸留、イオン交換など)することが好ましい。 In the cation exchange membrane, the reaction is preferably carried out under the condition that the cation (M + ) of the salt (MX) permeates preferentially over the proton. When the reaction is carried out on the both sides of the membrane with weak acidity, in particular, from near neutral to basic, the cation (M + ) of the salt (MX) moves to the cathode electrode side, so that the hydroxide (MOH) A concentrated solution is obtained. The high-concentration solution flows out from the cathode electrode tank and is then dehydrated to obtain a basic chemical (MOH). In particular, the reaction is good under conditions where the metal cation concentration is higher than the proton concentration. If the vicinity of the cation exchange membrane is made strongly acidic, protons preferentially permeate to the cathode side, which is not preferable. In this case, it is preferable to collect the acid separately (dialysis, distillation, ion exchange, etc.).
カソード電極槽に流入する溶液は、初期は純水でも良いが、好ましくは水酸化物(ＭＯＨ)の低濃度溶液または支持電解質を初期に入れることが良い。 The solution flowing into the cathode electrode tank may be initially pure water, but preferably a low concentration solution of hydroxide (MOH) or a supporting electrolyte is initially added.
本発明においては、上記の電気化学プロセスに、アニオン交換膜とカチオン交換膜をそれぞれ1枚以上組み合わせると塩(ＭＸ)や生成する酸(ＨＸ)を分離することができる。 In the present invention, when one or more anion exchange membranes and cation exchange membranes are combined in the above electrochemical process, the salt (MX) and the acid (HX) produced can be separated.
図２は、その１つの実施形態を模式的に示す図であり、アニオン交換膜とカチオン交換膜をそれぞれ１枚組み合わせた、３室型電解槽を用いた場合を示している。
図２に示すように、アニオン交換膜をアノード電極とカチオン交換膜の間に配置した３室型とすることにより、塩(ＭＸ)のカチオンはアノード電極槽に移動しない。また、レドックス媒体がカチオンまたはアニオンの場合、それぞれアニオン交換膜とカチオン交換膜を透過できないので、生成物の分離が容易になる。水溶液の移動に妨げにならない範囲で、イオン交換膜同士の間隔は狭いほど過電圧は小さくなるので好ましい。電解質が十分に高濃度であれば導電性は確保できる。
FIG. 2 is a diagram schematically showing one embodiment, and shows a case where a three-chamber electrolytic cell in which one anion exchange membrane and one cation exchange membrane are combined is used.
As shown in FIG. 2, by using a three-chamber type anion exchange membrane disposed between the anode electrode and the cation exchange membrane, salt (MX) cations do not move to the anode electrode tank. In addition, when the redox medium is a cation or an anion, the product can be easily separated because it cannot permeate the anion exchange membrane and the cation exchange membrane, respectively. As the distance between the ion exchange membranes is narrow, the overvoltage becomes smaller as long as the movement of the aqueous solution is not hindered. If the electrolyte has a sufficiently high concentration, conductivity can be ensured.
図３は、もう１つの実施形態を模式的に示す図であり、Ｈ+選択性カチオン交換膜と、アニオン交換膜と、カチオン交換膜とを、それぞれ１枚組み合わせた、４室型電解槽を用いた場合を示している。
図に示すように、Ｈ+選択性アニオン交換膜をアノード電極とアニオン交換膜の間に配置した４室型とすることにより、塩(ＭＸ)自体はアノード電極槽に移動しない。また、生成した酸(ＨＸ)もアノード電極槽に移動しないので、光触媒用のＡ−Ｏｘ／Ａ−Ｒｅｄを含んだ水溶液を分離することができる。特にＭＸに塩化物(Ｘ＝Ｃｌ-)を用いた場合は、塩素として回収するよりも塩酸として回収する方が、そのＸの回収は容易であるが、特に、図３に示す実施形態では、分離も容易になる。
Ｈ+選択性カチオン交換膜とアニオン交換膜に挟まれた部分に流入する溶液は、初期は純水でも良いが、好ましくは酸(ＨＸ)の低濃度溶液であるか、または、支持電解質を初期に入れることが良い。
FIG. 3 is a diagram schematically showing another embodiment. A four-chamber electrolytic cell in which one H + selective cation exchange membrane, one anion exchange membrane, and one cation exchange membrane are combined is shown. The case where it is used is shown.
As shown in the figure, the salt (MX) itself does not move to the anode electrode tank by adopting a four-chamber type in which the H + selective anion exchange membrane is disposed between the anode electrode and the anion exchange membrane. Further, since the generated acid (HX) does not move to the anode electrode tank, an aqueous solution containing A-Ox / A-Red for photocatalyst can be separated. In particular, when chloride (X = Cl − ) is used for MX, it is easier to recover X as hydrochloric acid than to recover it as chlorine. In particular, in the embodiment shown in FIG. Separation is also facilitated.
The solution flowing into the portion sandwiched between the H + selective cation exchange membrane and the anion exchange membrane may be initially pure water, but is preferably a low-concentration solution of acid (HX), or the supporting electrolyte is initially Good to put in.
電解に必要な理論上の電圧は、ｐＨ補正した後のＡ−Ｏｘ／Ａ−ＲｅｄとＣ−Ｏｘ／Ｃ−Ｒｅｄの酸化還元準位の差である。Ａ−Ｏｘ／Ａ−Ｒｅｄとして、酸素発生(＋１.２３Ｖ)や塩素発生(＋１.３６Ｖ)よりも負のＡ−Ｏｘ／Ａ−Ｒｅｄ準位の還元体がアノード電極槽に流入すれば、電解電圧は低下できる。 The theoretical voltage required for electrolysis is the difference between the redox levels of A-Ox / A-Red and C-Ox / C-Red after pH correction. As A-Ox / A-Red, if a reductant having a negative A-Ox / A-Red level than oxygen generation (+1.23 V) or chlorine generation (+1.36 V) flows into the anode electrode tank, electrolysis will occur. The voltage can be lowered.
光触媒反応槽では、酸化体(Ａ−Ｏｘ)が還元体(Ａ−Ｒｅｄ)になる還元反応が進行させるが、特に、酸素発生反応に優れた光触媒が利用できる。光触媒の半導体としては、その伝導帯準位がＡ−Ｏｘ／Ａ−Ｒｅｄの準位よりも負であり、その価電子帯準位が酸素発生準位よりも正である材料が利用できる。具体的には、ＴｉＯ2、ＷＯ3、ＢｉＶＯ4、Ｆｅ2Ｏ3、ＴａＯＮ、Ｔａ3Ｎ5などがある。
光励起により生成した電子はＡ−Ｒｅｄを生成する。光励起により生成した正孔は水を酸化して酸素を生成しても良いし、また有機物などの還元し易い物質を添加してそれを酸化分解しても良い。
In the photocatalyst reaction tank, a reduction reaction in which the oxidant (A-Ox) becomes a reductant (A-Red) proceeds. In particular, a photocatalyst excellent in oxygen generation reaction can be used. As the semiconductor of the photocatalyst, a material whose conduction band level is more negative than the A-Ox / A-Red level and whose valence band level is more positive than the oxygen generation level can be used. Specifically, there are TiO 2 , WO 3 , BiVO 4 , Fe 2 O 3 , TaON, Ta 3 N 5 and the like.
Electrons generated by photoexcitation generate A-Red. Holes generated by photoexcitation may oxidize water to generate oxygen, or may add an easily reducing substance such as an organic substance and oxidatively decompose it.
光触媒は粉末状でも良いが、基板に固定して膜状にすることが好ましい。導電性基板に固定しても良い。助触媒を利用する場合、は半導体表面に付けても、導電性基板の一部に付けても良い。導電性基板の一面に半導体を成膜し、裏面に導通して助触媒を付けても良い。逆反応を防ぐために、半導体と助触媒をイオン交換膜で空間的に分離することもできる。 The photocatalyst may be in the form of a powder, but is preferably fixed to a substrate to form a film. You may fix to an electroconductive board | substrate. When a cocatalyst is used, it may be attached to the semiconductor surface or a part of the conductive substrate. A semiconductor may be formed on one surface of the conductive substrate, and the promoter may be attached to the back surface by conducting. In order to prevent the reverse reaction, the semiconductor and the cocatalyst can be spatially separated by an ion exchange membrane.
以下、本発明を実施例によりさらに具体的に説明するが、本発明はこれらの実施例によって何ら限定されるものではない。 EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
（実施例１、比較例１）
電気化学プロセスとして、ポテンショスタットおよび図１に図示する１枚のカチオン交換膜を付けた２室型電解槽を用いた。アノード電極とカソード電極にはＰｔ網とＰｔワイヤーを用いた。
実施例１として、光触媒反応後の溶液を想定し、アノード電極側にはＮａ2ＳＯ4(０.１Ｍ)とＨ2ＳＯ4(０.０２Ｍ)およびＦｅＳＯ4(０.０１Ｍ)の混合液を流入した。カソード電極側にはＮａ2ＳＯ4(０.１Ｍ)とＮａＯＨ(０.０４Ｍ)の混合液を流入した。生成した化合物の量を滴定で正確に測定することと、伝導度を高めるために、Ｎａ2ＳＯ4を最初にどちらの電極槽の溶液に入れているが、実際の反応では、目的の酸性と塩基性の化合物を入れておくことが望ましい。アノード電極側にＦｅ2+が存在しており、１ｍＡ一定で、０.５時間の平均で０.８Ｖの電解電圧であった。カソード電極側には電解効率９７％でＮａＯＨが生成していることを滴定実験で確認した。
比較例１として、アノード電極側にＦｅ2+が存在しない場合、１ｍＡ一定で、０.５時間の平均で１.６Ｖの電解電圧が必要であり、実施例１よりも高い電解電圧であった。カソード電極側には電解効率９７％でＮａＯＨが生成していることを滴定実験で確認した。
(Example 1, Comparative Example 1)
As the electrochemical process, a two-chamber electrolytic cell with a potentiostat and one cation exchange membrane shown in FIG. 1 was used. Pt nets and Pt wires were used for the anode electrode and the cathode electrode.
As Example 1, a solution after the photocatalytic reaction is assumed, and a mixed solution of Na 2 SO 4 (0.1M), H 2 SO 4 (0.02M) and FeSO 4 (0.01M) is provided on the anode electrode side. It flowed in. A mixed solution of Na 2 SO 4 (0.1M) and NaOH (0.04M) was introduced into the cathode electrode side. In order to accurately measure the amount of the compound formed by titration and increase the conductivity, Na 2 SO 4 is initially placed in the solution of either electrode tank. It is desirable to add a basic compound. Fe 2+ was present on the anode electrode side, the current was constant at 1 mA, and the electrolysis voltage was 0.8 V on average for 0.5 hours. It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 97% on the cathode electrode side.
As Comparative Example 1, when no Fe 2+ was present on the anode electrode side, an electrolytic voltage of 1.6 V was required on average at 0.5 mA and 0.5 hours on average, which was higher than that of Example 1. . It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 97% on the cathode electrode side.
（実施例２、比較例２）
電気化学プロセスとして、ポテンショスタットおよび図２に図示する１枚のカチオン交換膜と１枚のアニオン交換膜を付けた３室型電解槽を用いた。アノード電極とカソード電極にはＰｔ網とＰｔワイヤーを用いた。各イオン交換膜の間隔は２ｍｍである。
実施例２として、光触媒反応後の溶液を想定し、アノード電極側にはＮａ2ＳＯ4(０.１Ｍ)とＨ2ＳＯ4(０.０２Ｍ)およびＦｅＳＯ4(０.０１Ｍ)の混合液を流入した。カソード電極側にはＮａ2ＳＯ4(０.１Ｍ)とＮａＯＨ(０.０４Ｍ)の混合液を流入した。カチオン交換膜とアニオン交換膜の間にはＮａ2ＳＯ4(０.３Ｍ)を流入した。
生成した化合物の量を滴定で正確に測定することと、伝導度を高めるために、Ｎａ2ＳＯ4を最初にどの電極槽の溶液に入れているが、実際の反応では、目的の酸性と塩基性の化合物を入れておくことが望ましい。アノード電極側にＦｅ2+が存在しており、１ｍＡ一定で、０.５時間の平均で１.７Ｖの電解電圧であった。カソード電極側には電解効率９７％でＮａＯＨが生成していることを滴定実験で確認した。
比較例２として、アノード電極側にＦｅ2+が存在しない場合、１ｍＡ一定で、０.５時間の平均で２.５Ｖの電解電圧が必要であり、実施例２よりも高い電解電圧であった。カソード電極側には電解効率９７%でＮａＯＨが生成していることを滴定実験で確認した。
(Example 2, comparative example 2)
As the electrochemical process, a potentiostat and a three-chamber electrolytic cell with one cation exchange membrane and one anion exchange membrane shown in FIG. 2 were used. Pt nets and Pt wires were used for the anode electrode and the cathode electrode. The interval between the ion exchange membranes is 2 mm.
As Example 2, a solution after the photocatalytic reaction is assumed, and a mixed solution of Na 2 SO 4 (0.1M), H 2 SO 4 (0.02M) and FeSO 4 (0.01M) is provided on the anode electrode side. It flowed in. A mixed solution of Na 2 SO 4 (0.1M) and NaOH (0.04M) was introduced into the cathode electrode side. Na 2 SO 4 (0.3M) was allowed to flow between the cation exchange membrane and the anion exchange membrane.
In order to accurately measure the amount of the compound formed and to increase the conductivity, Na 2 SO 4 is initially placed in any electrode bath solution. It is desirable to store a sex compound. Fe 2+ was present on the anode electrode side, the current was constant at 1 mA, and the electrolysis voltage was 1.7 V on average for 0.5 hours. It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 97% on the cathode electrode side.
As Comparative Example 2, when Fe 2+ was not present on the anode electrode side, an electrolytic voltage of 2.5 V was required on average at 0.5 mA for 0.5 hours, which was higher than that of Example 2. . It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 97% on the cathode electrode side.
（実施例３、比較例３）
実施例３として、図２の１枚のカチオン交換膜と１枚のアニオン交換膜を付けた３室セルを用い、光触媒反応後の反応溶液をアノード電極側に流入した。
光触媒反応としては、Ｃｓ表面処理したＷＯ3粉末光触媒を懸濁した０.１Ｍ−ＨＣｌＯ4および０.０１Ｍ−Ｆｅ(ＣｌＯ4)3の混合水溶液に光照射を行い、Ｆｅ2+を生成させた。上澄みの光触媒反応後の反応溶液をアノード電極側に流入した。カソード電極側にはＮａＣｌ(０.１Ｍ)の水溶液を流入した。カチオン交換膜とアニオン交換膜の間にはＮａＣｌ(０.３Ｍ)を流入した。各イオン交換膜の間隔は２ｍｍである。
アノード電極側にＦｅ2+が存在しており、３ｍＡ一定で、０.５時間の平均で２.３Ｖの電解電圧であった。カソード電極側には電解効率７８％でＮａＯＨが生成していることを滴定実験で確認した。
比較例３として、アノード電極側に光照射を行わない光反応前の溶液を用い、Ｆｅ2+が存在しない場合、１ｍＡ一定で、０.５時間の平均で２.９Ｖの電解電圧が必要であり、実施例３よりも高い電解電圧であった。カソード電極側には電解効率７２％でＮａＯＨが生成していることを滴定実験で確認した。
(Example 3, Comparative Example 3)
As Example 3, a three-chamber cell with one cation exchange membrane and one anion exchange membrane in FIG. 2 was used, and the reaction solution after the photocatalytic reaction was flowed to the anode electrode side.
As the photocatalytic reaction, a mixed aqueous solution of 0.1M-HClO 4 and 0.01M-Fe (ClO 4 ) 3 in which a Cs surface-treated WO 3 powder photocatalyst was suspended was irradiated with light to generate Fe 2+ . . The reaction solution after the photocatalytic reaction of the supernatant flowed into the anode electrode side. An aqueous solution of NaCl (0.1 M) was flowed into the cathode electrode side. NaCl (0.3M) was allowed to flow between the cation exchange membrane and the anion exchange membrane. The interval between the ion exchange membranes is 2 mm.
Fe 2+ was present on the anode electrode side, the current was constant at 3 mA, and the electrolysis voltage was 2.3 V on average for 0.5 hours. It was confirmed by a titration experiment that NaOH was generated at an electrolytic efficiency of 78% on the cathode electrode side.
As Comparative Example 3, when a solution before photoreaction that does not irradiate light on the anode electrode side is used and Fe 2+ is not present, an electrolytic voltage of 2.9 V is required at an average of 0.5 mA at a constant 1 mA. Yes, the electrolysis voltage was higher than in Example 3. It was confirmed by a titration experiment that NaOH was generated at an electrolytic efficiency of 72% on the cathode electrode side.
（実施例４、比較例４）
実施例４として、図３に図示する、１枚のカチオン交換膜と、１枚のアニオン交換膜と、１枚のＨ+選択性カチオン交換膜とを付けた４室型電解槽を用い、光触媒反応後の反応溶液をアノード電極側に流入した。
光触媒反応としては、Ｃｓ表面処理したＷＯ3粉末光触媒を懸濁した０.１Ｍ−ＨＣｌＯ4および０.０１Ｍ−Ｆｅ(ＣｌＯ4)3の混合水溶液に光照射を行い、Ｆｅ2+を生成させた。上澄みの光触媒反応後の反応溶液をアノード電極側に流入した。カソード電極側にはＮａＣｌ(０.１Ｍ)の水溶液を流入した。カチオン交換膜とアニオン交換膜の間にはＮａＣｌ(０.３Ｍ)を流入した。アニオン交換膜とＨ+選択性カチオン交換膜の間にはＮａＣｌ(０.１Ｍ)を流入した。各イオン交換膜の間隔は２ｍｍである。
アノード電極側にＦｅ2+が存在しており、３ｍＡ一定で、０.５時間の平均で２.４Ｖの電解電圧であった。カソード電極側には電解効率７７％でＮａＯＨが生成していることを滴定実験で確認した。
比較例４として、アノード電極側に光照射を行わない光反応前の溶液を用い、Ｆｅ2+が存在しない場合、１ｍＡ一定で、０.５時間の平均で３Ｖの電解電圧が必要であり、実施例４よりも高い電解電圧であった。カソード電極側には電解効率７６％でＮａＯＨが生成していることを滴定実験で確認した。
(Example 4, comparative example 4)
As Example 4, a photocatalyst was used using a four-chamber electrolytic cell provided with one cation exchange membrane, one anion exchange membrane, and one H + selective cation exchange membrane shown in FIG. The reaction solution after the reaction flowed into the anode electrode side.
As the photocatalytic reaction, a mixed aqueous solution of 0.1M-HClO 4 and 0.01M-Fe (ClO 4 ) 3 in which a Cs surface-treated WO 3 powder photocatalyst was suspended was irradiated with light to generate Fe 2+ . . The reaction solution after the photocatalytic reaction of the supernatant flowed into the anode electrode side. An aqueous solution of NaCl (0.1 M) was flowed into the cathode electrode side. NaCl (0.3M) was allowed to flow between the cation exchange membrane and the anion exchange membrane. NaCl (0.1 M) was allowed to flow between the anion exchange membrane and the H + selective cation exchange membrane. The interval between the ion exchange membranes is 2 mm.
Fe 2+ was present on the anode electrode side, the current was constant at 3 mA, and the electrolysis voltage was 2.4 V on average for 0.5 hours. It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 77% on the cathode electrode side.
As Comparative Example 4, when a solution before photoreaction that does not irradiate light on the anode electrode side is used and Fe 2+ is not present, an electrolytic voltage of 3 V is necessary at an average of 0.5 hours at a constant 1 mA, The electrolysis voltage was higher than that in Example 4. It was confirmed by a titration experiment that NaOH was generated at an electrolytic efficiency of 76% on the cathode electrode side.
（実施例５、比較例５）
実施例５として、各イオン交換膜の間隔を５０ｍｍに広げた、前記の４室型電気反応槽を用いて、酸性および塩基性の化学品の定量を行った。光触媒反応としては、Ｃｓ表面処理したＷＯ3粉末光触媒を懸濁した０.１Ｍ−ＨＣｌＯ4および０.０１Ｍ−Ｆｅ(ＣｌＯ4)3の混合水溶液に光照射を行い、Ｆｅ2+を生成させた。上澄みの光触媒反応後の反応溶液をアノード電極側に流入した。カソード電極側にはＮａＣｌ(０.１Ｍ)水溶液を流入した。カチオン交換膜とアニオン交換膜の間にはＮａＣｌ(０.３Ｍ)を流入した。アニオン交換膜とＨ+択性カチオン交換膜の間にはＮａＣｌ(０.１Ｍ)を流入した。アノード電極側にＦｅ2+が存在しており、３ｍＡ一定で、３.５５Ｖの電解電圧であった。カソード電極側には電解効率８９％でＮａＯＨが生成していることを滴定実験で確認した。アニオン交換膜とＨ+選択性カチオン交換膜の間には、電解効率８９％でＨＣｌが生成していることを滴定実験で確認した。
比較例５として、アノード電極側に光照射を行わない光反応前の溶液を用い、Ｆｅ2+が存在しない場合、３ｍＡ一定で、３.８Ｖの電解電圧が必要であり、実施例５よりも高い電解電圧であった。カソード電極側には電解効率９２％でＮａＯＨが生成していることを滴定実験で確認した。アニオン交換膜とＨ+選択性カチオン交換膜の間には、電解効率９２％でＨＣｌが生成していることを滴定実験で確認した。
(Example 5, Comparative Example 5)
As Example 5, acidic and basic chemicals were quantified using the above-described four-chamber electric reaction tank in which the interval between each ion exchange membrane was increased to 50 mm. As the photocatalytic reaction, a mixed aqueous solution of 0.1M-HClO 4 and 0.01M-Fe (ClO 4 ) 3 in which a Cs surface-treated WO 3 powder photocatalyst was suspended was irradiated with light to generate Fe 2+ . . The reaction solution after the photocatalytic reaction of the supernatant flowed into the anode electrode side. A NaCl (0.1 M) aqueous solution was allowed to flow into the cathode electrode side. NaCl (0.3M) was allowed to flow between the cation exchange membrane and the anion exchange membrane. NaCl (0.1 M) was allowed to flow between the anion exchange membrane and the H + selective cation exchange membrane. Fe 2+ was present on the anode electrode side, and the electrolytic voltage was 3.55 V at a constant 3 mA. It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 89% on the cathode electrode side. It was confirmed by a titration experiment that HCl was generated at an electrolysis efficiency of 89% between the anion exchange membrane and the H + selective cation exchange membrane.
As Comparative Example 5, when a solution before photoreaction that does not irradiate light on the anode electrode side is used, and Fe 2+ is not present, an electrolytic voltage of 3.8 V is required at a constant 3 mA, which is higher than that in Example 5. The electrolysis voltage was high. It was confirmed by a titration experiment that NaOH was generated at an electrolysis efficiency of 92% on the cathode electrode side. It was confirmed by a titration experiment that HCl was generated at an electrolysis efficiency of 92% between the anion exchange membrane and the H + selective cation exchange membrane.
以上のように、アノード電極槽に光触媒反応で生成したレドックス媒体の還元体を流入させると、金属塩水素溶液から塩基性および酸性の化学品を合成のための電解電圧が低下できることがわかった。 As described above, it was found that when the reduced form of the redox medium produced by the photocatalytic reaction was allowed to flow into the anode electrode tank, the electrolysis voltage for synthesizing basic and acidic chemicals from the metal salt hydrogen solution could be reduced.
本発明は、酸化還元媒体(レドックス媒体)の光触媒反応と、イオン交換膜を用いた電気化学プロセスによる酸性および塩基性の化学品合成の低電圧化の方法、並びに当該方法を用いた反応装置に関するものであるが、それだけではなく脱塩やメッキなど様々な電気化学プロセスの省エネにも応用できる。 The present invention relates to a photocatalytic reaction of a redox medium (redox medium), a method for lowering the voltage of acidic and basic chemical synthesis by an electrochemical process using an ion exchange membrane, and a reaction apparatus using the method. However, it can also be applied to energy saving in various electrochemical processes such as desalting and plating.
Claims (12)
光触媒反応で生じたレドックス媒体の還元体を、アノード電極に接触させることにより電解電圧を低下させることを特徴とする光エネルギーを利用した化学品製造方法。 An electrochemical process that uses an aqueous solution of a metal salt as a raw material, moves a cation of the raw material metal to the cathode electrode side with a cation exchange membrane, produces a basic aqueous solution on the cathode electrode side, and produces an acidic aqueous solution on the anode electrode side In
A chemical production method using light energy, characterized in that an electrolysis voltage is lowered by bringing a reduced form of a redox medium generated by a photocatalytic reaction into contact with an anode electrode.
内部にアノード電極及びカソード電極並びに両電極間に配置されたカチオン交換膜を備えた電解槽と、光触媒を備えた光触媒反応槽とを有し、
該光触媒反応槽で生成されたレドックス媒体の還元体を含む溶液を、前記アノード電極側の電解槽に導入する手段を設けたことを特徴とする化学品製造装置。 A chemical production apparatus for producing a basic aqueous solution and an acidic aqueous solution by an electrochemical reaction using an aqueous solution of a metal salt as a raw material,
It has an electrolytic cell provided with a cation exchange membrane disposed between an anode and a cathode and both electrodes inside, and a photocatalytic reaction vessel equipped with a photocatalyst,
An apparatus for producing a chemical product, comprising means for introducing a solution containing a reductant of a redox medium produced in the photocatalytic reaction tank into the electrolytic cell on the anode electrode side.
前記光触媒反応槽で生成されたレドックス媒体の還元体を含む溶液を、前記アノード電極側の電解槽に導入する手段と、
前記金属塩の水溶液を、前記アニオン交換膜とカチオン交換膜の間の電解槽に導入する手段とを設けたことを特徴とする化学品製造装置。 The chemical product manufacturing apparatus according to claim 10, further comprising an anion exchange membrane between the anode electrode and the cation exchange membrane in the electrolytic cell,
Means for introducing a solution containing a reductant of the redox medium generated in the photocatalytic reaction tank into the electrolytic cell on the anode electrode side;
An apparatus for producing a chemical product, comprising means for introducing an aqueous solution of the metal salt into an electrolytic cell between the anion exchange membrane and the cation exchange membrane.
12. The chemical production apparatus according to claim 11, further comprising an H + selective cation exchange membrane between the anode electrode and the anion exchange membrane in the electrolytic cell.
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| CN110904465A (en) * | 2019-10-22 | 2020-03-24 | 新疆中泰创新技术研究院有限责任公司 | Device and method for treating byproduct mirabilite of viscose factory |
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| WO2018212513A3 (en) * | 2017-05-16 | 2019-01-17 | 경북대학교 산학협력단 | Complex system for water treatment, desalination, and chemical material production |
| KR101946029B1 (en) * | 2017-05-16 | 2019-04-17 | 경북대학교 산학협력단 | wastewater treatment, desalination and chemical production complex system |
| CN110636990A (en) * | 2017-05-16 | 2019-12-31 | 庆北大学校产学协力团 | Water treatment, desalination and chemical substance production combined system |
| US11629073B2 (en) | 2017-05-16 | 2023-04-18 | Kyungpook National University Industry-Academic Cooperation Foundation | Hybrid system for water treatment, desalination, and chemical production |
| CN110904465A (en) * | 2019-10-22 | 2020-03-24 | 新疆中泰创新技术研究院有限责任公司 | Device and method for treating byproduct mirabilite of viscose factory |
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |