Maitiro eElectrogravimetric muAnalytical Chemistry
Electrogravimetry inzira yekare asi ichiri kukosha mukuongorora kemesitiri, kunyanya pakuyera ma ions esimbi mumushonga. Nzira iyi inosanganisa misimboti ye electrochemistry ne gravimetry: analyte inoiswa sesimbi pa electrode kuburikidza ne electrolysis, uye precipitate inobuda inozoyerwa kuverenga huwandu hwe analyte. Nekuti mhedzisiro yekupedzisira ndeyekuyera kwehukuru, electrogravimetry inozivikanwa nekururama kwakanaka kana mamiriro ekuyedza akadzorwa nemazvo.
Tsanangudzo uye Nheyo Dzekutanga
Muchidimbu, electrogravimetry inzira yekuongorora huwandu umo mhando (kazhinji metal cation) inoiswa paelectrode nemagetsi, uye kuwedzera kwehuremu hweelectrode kunoshandiswa kuona huwandu hwemhando iyoyo mumuenzaniso. Precipitate inowanzo kuumbwa pa cathode kuburikidza ne reduction reaction:
Mⁿ⁺ + ne⁻ → M(s)
Simbi yakagadzirwa M inonamira pamusoro pe cathode. Kana electrolysis yapera, electrode inogezwa, yoomeswa, yotonhodzwa mu desiccator, yozoyerwa. Musiyano wehukuru hwesimbi isati yasvika uye yapera ndeyehukuru hwesimbi yakachengetwa.
Kune rumwe rutivi, maitiro e oxidation anowanzoitika pa anode, akadai se oxidation yemvura kuti ibudise okisijeni. Muumbirwo we electrolyte inotsigira, pH, uye simba rinoshandiswa zvinofanira kusarudzwa kuti zvidzore maitiro anodiwa uye kuderedza maitiro akadai sekushanduka kwehydrogen pa cathode, izvo zvinogona kukanganisa kunaka kwe deposit.
Zvikamu neMidziyo
Seti yekuedza yakajairika ye electrogravimetric inosanganisira:
1. Simba rinobva: rinogona kuva DC power supply ine current regulation (galvanostatic) kana potential regulation (potentiostatic).
2. Sero reElectrolysis: mudziyo wegirazi unobata mhinduro yemuenzaniso uye unotsigira electrolyte.
3. Electrode inoshanda (cathode): panoiswa simbi, kazhinji platinum plate, nickel, kana electrode yakakosha yakaita se "platinum gauze" kuwedzera nzvimbo yepamusoro.
4. Electrode inopokana (anode): kazhinji isina simba (platinum kana graphite) kuitira kuti isanyunguduke.
5. Sisitimu yekukurunga: magnetic stirrer kana mechanical stirrer yekukurumidzira kutamiswa kwehuwandu (kuderedza miganhu yekupararira).
6. Kuenzanisa kwekuongorora: kunyatsorongeka kwakanyanya (kusvika ku0,1 mg kana kupfuura) kwemaerekitironi ekuyera.
Kuchena kwema electrode kwakakosha. Pamusoro pe electrode panofanira kunge pasina mafuta, ma oxide, uye tsvina kuitira kuti zvidimbu zvinamire zvakaenzana uye zvisapunzike.
Nzira Dzekudzora: Nguva Dzemagetsi Dzinochinja-chinja vs Nguva Dzemagetsi Dzinochinja-chinja
Electrogravimetry inogona kuitwa nenzira mbiri huru:
1. Electrogravimetry Yazvino Inogara Iripo (Galvanostatic)
Munzira iyi, simba remagetsi rinogara rakafanana mukati me electrolysis. Chakanakira chishandiso chiri nyore kushandisa. Zvisinei, sezvo huwandu hwe ion yesimbi huchiderera, cathode potential inogona kuchinja kuenda kune mamiriro asina kunaka, zvichikonzera mhedzisiro (semuenzaniso, kudzikira kweH⁺ kuenda kuH₂). Nekuda kweizvozvo, deposit inogona kushata, kuva nemaburi, kana kusanyatsonamira zvakanaka.
2. Electrogravimetry Inogara Ichikwanisa Kushandiswa (Potentiostatic)
Munzira iyi, simba remagetsi rinoshanda rinodzorwa nemutengo chaiwo kuitira kuti analyte reaction chete iitike nenzira yakasarudzwa. Nzira iyi inobatsira zvikuru pakuparadzanisa simbi dzakasiyana-siyana zvichibva pakusiyana kwesimba rekuderedza. Zvikanganiso ndezvekuti chishandiso chacho chakaoma (chinoda potentiostat), uye kusarudza mamiriro akakodzera kunoda kunzwisisa zviri nani electrochemistry.
Matanho eKuongororwa kweElectrogravimetric
Maitiro ese e electrogravimetry anosanganisira matanho anotevera:
1. Kugadzirira maerekitirodhi: erekitirodhi inocheneswa, inoomeswa, inotonhodzwa mu desiccator, yozoyerwa (huremu hwekutanga).
2. Kugadzirira mhinduro: sampuro inonyungudutswa uye pH inogadziriswa uye ma electrolyte anotsigira anowedzerwa (semuenzaniso H₂SO₄, HNO₃, kana munyu usina simba) kuti kuwedzere conductivity uye kugadzikana kwemamiriro ezvinhu.
3. Electrolysis: electrolysis inoiswa simba kana kuti potential apo mhinduro yacho inokurunga. Nguva yeelectrolysis inogadziriswa kusvika iyoni inotarirwa yaderera zvachose.
4. Kunyatsoongorora mvura: kunogona kuitwa nekutora mvura shoma woisa reagent kuti uve nechokwadi chekuti hapana ma ions esimbi aripo, kana kuona kuti mvura iri kudonha kusvika padyo ne zero pane imwe control.
5. Kushambidza ma electrode: electrode inosukurudzwa nemvura yakabviswa ion kuti ibvise electrolyte inonamatira, yozosukurudzwa nealcohol kana solvent inonyunguduka kuti iome nekukurumidza.
6. Kuomesa nekuyera: electrode inoomeswa patembiricha zvichienderana nerudzi rwekuiswa, yotonhodzwa mu desiccator, yozoyerwa (huremu hwekupedzisira).
7. Kuverenga zviri mukati: huremu hwe precipitate hunoshandiswa kuverenga mamoles esimbi uye huwandu huri mumuenzaniso.
Kuverenga kuri nyore ndekwekuti:
– huremu hwesimbi = huremu hwekupedzisira hweelectrode – huremu hwekutanga hweelectrode
– mamota esimbi = huremu hwesimbi / Mr wesimbi
– zviri mukati = mamota kana huremu hwesimbi pahuwandu hwemuenzaniso
Zvinhu Zvinokanganisa Hunhu hweMarara
Kubudirira kwe electrogravimetry kunoenderana zvakanyanya nemhando ye precipitate yakagadzirwa. Zvimwe zvinhu zvinosarudza ndeizvi:
– Kuwanda kwemagetsi: Mvura yakakwira zvakanyanya inokonzera kuparadzwa kwakasimba, kwakaita sesponji. Mvura yakaderera zvakanyanya inoita kuti mashandiro acho anonoke uye inogona kuwedzera njodzi yekusvibiswa.
– pH uye electrolyte composition: inokanganisa metal ion speciation uye reaction competition (semuenzaniso hydrogen evolution).
– Tembiricha: inowedzera reaction kinetics uye diffusion, asi inogona kukanganisa kugadzikana kwe precipitate kana trigger side reactions.
– Kukurunga: kunovandudza kutakurwa kwevhu kuitira kuti madhaka aenzane.
– Kuvapo kwezvinhu zvinobatanidza: mamwe ma ligand anogona kuderedza kuwanda kwema free ions nokudaro achichinja mukana wemvura uye achibatsira kupatsanurana kwekusarudza.
Chinangwa chikuru ndechekugadzira precipitate yakamanikana, inonamira zvakasimba, uye yakachena. Precipitate inodonha nyore nyore kana ine electrolytes dzakabatwa inokanganisa mhedzisiro yekuyera.
Zvikumbiro muAnalytical Chemistry
Electrogravimetry inoshandiswa zvakanyanya pakuongorora simbi dzakadai seCu, Ni, Ag, Zn, Pb, Cd, nedzimwe, mumienzaniso yeindasitiri neyezvakatipoteredza. Mashandisirwo akajairika anosanganisira:
- Kuziva huwandu hwemhangura mumushonga wekuisa simbi (electroplating bath).
- Kuongororwa kwe nickel ne cobalt mune mamwe ma alloys ane mukana wekupatsanurwa.
- Kuongororwa kwesirivha mumasampuli emifananidzo kana marara ane maAg⁺ ions.
- Kuongororwa kwesimbi dzinorema mukubvisa tsvina mumagadzirirwo esimbi.
Pamusoro pekuongororwa kwehuwandu humwe chete, electrogravimetry inogonawo kushandiswa sedanho rekuparadzanisa usati waenderera mberi nekuongorora, semuenzaniso kubvisa zvimwe zvinokanganisa simbi kuitira kuti kuyerwa kwespectrophotometric kana titration kuve kwakanyatsosarudzwa.
Zvakanakira uye Zvisina Kukwana
Zvakanakira zve electrogravimetry:
1. Yakarurama uye yakarurama nekuti chiyero chacho chinoenderana nehuremu.
2. Hazvidi muyero wetitrant sezvakaita mutitration.
3. Inogona kusarudza zvakanyanya nekugona kudzora.
4. Yakakodzera kushandiswa kwesimbi ine mwero kusvika yakakwira.
Miganhu ye electrogravimetry:
1. Zvinoda nguva ye electrolysis iyo inogona kutora nguva yakareba, kunyanya kana iri padanho rakaderera.
2. Inogona kukanganiswa nekukanganiswa kwemaitiro ekunze (semuenzaniso hydrogen) uye kusvibiswa kwevhu.
3. Inoda hunyanzvi mukugadzirira maerekitirodhi uye mamiriro ekudzora.
4. Hazvina kukodzera zvakanyanya kune vasiri simbi vanoongorora kana mhando dzisingakurumidzi kukanganiswa ne electrodeposition.
Mhedziso
Electrogravimetry inzira yekuongorora huwandu inoshandisa electrolytic precipitation uye huremu hwesimbi kuti ione zviri musimbi iri mumuenzaniso. Kunyangwe iri nzira yekare, electrogravimetry inoramba yakakosha mukuongorora makemikari nekuda kwekunyatsorongeka kwayo, misimboti yakajeka, uye kugona kwekuparadzanisa kwakasarudzwa nekudzora kwakakosha. Kubudirira kwenzira iyi kunonyanya kutsanangurwa nekudzora maparamita akadai se current/potential, pH, stirging, tembiricha, uye kuchena kwema electrode. Nekugadzirisa kwakakodzera, electrogravimetry inova chishandiso chakavimbika chekuongorora simbi munzvimbo dzakasiyana-siyana, kubva kuindasitiri ye plating kusvika pakutarisa simbi ine heavy metal.
Kana muchida, ndinogonawo kuwedzera mienzaniso yekuverenga nhamba (semuenzaniso, kuona Cu²⁺) kana kugadzira chinyorwa chine ruzivo rwakadzama chine magwaro nebhuku remabhuku.
