Dabaru na Electrogravimetric a fannin Kimiyyar Nazari
Electrogravimetry wata dabara ce ta gargajiya amma har yanzu tana da mahimmanci a fannin nazarin sinadarai, musamman don auna ions na ƙarfe a cikin maganin. Wannan hanyar ta haɗa ƙa'idodin electrochemistry da gravimetry: ana ajiye analyte ɗin a matsayin ƙarfe akan electrode ta hanyar electrolysis, sannan a auna abin da ya haifar da shi don ƙididdige adadin analyte ɗin. Saboda sakamakon ƙarshe shine ma'aunin taro, an san cewa electrogravimetry yana da kyakkyawan daidaito lokacin da aka sarrafa yanayin gwaji yadda ya kamata.
Ma'anar da Ka'idoji na Asali
A taƙaice dai, electrogravimetry hanya ce ta nazarin adadi inda ake sanya nau'in halitta (yawanci ƙarfe cation) a kan wani lantarki ta hanyar wutar lantarki, sannan a yi amfani da ƙaruwar nauyin electrode don tantance adadin wannan nau'in a cikin samfurin. Yawanci ana samar da ruwan da ke fitowa a cathode ta hanyar rage amsawar:
Mⁿ⁺ + ne⁻ → M(s)
Karfe M da aka samar yana manne da saman cathode. Bayan an kammala electrolysis, ana wanke electrode ɗin, a busar da shi, a sanyaya shi a cikin na'urar bushewa, sannan a auna shi. Bambancin da ke tsakanin nauyi kafin da bayan electrolysis shine nauyin ƙarfe da aka ajiye.
A gefe guda kuma, halayen iskar shaka yawanci suna faruwa ne a anode, kamar iskar shaka da ruwa ke fitarwa don samar da iskar shaka. Dole ne a zaɓi abun da ke cikin electrolyte mai tallafawa, pH, da ƙarfin da aka yi amfani da shi don mamaye amsawar da ake so da kuma rage halayen da ba su dace ba kamar juyin halittar hydrogen a cathode, wanda zai iya yin illa ga ingancin ajiya.
Kayan aiki da Kayan aiki
Tsarin gwajin electrogravimetric na yau da kullun ya haɗa da:
1. Tushen wutar lantarki: zai iya zama tushen wutar lantarki na DC tare da tsarin wutar lantarki na yanzu (galvanostatic) ko kuma tsarin wutar lantarki mai yuwuwa (potentiostatic).
2. Tarin lantarki: wani jirgin ruwa mai gilashi wanda ke ɗauke da maganin samfurin da kuma mai tallafawa electrolyte.
3. Wutar lantarki mai aiki (cathode): inda ake ajiye ƙarfe, sau da yawa farantin platinum, nickel, ko lantarki na musamman kamar "gauze na platinum" don ƙara girman saman.
4. Na'urar auna wutar lantarki (anode): gabaɗaya ba ta narkewa (platinum ko graphite) ta yadda ba za ta narke ba.
5. Tsarin juyawa: na'urar motsa maganadisu ko na'urar motsa jiki ta injiniya don hanzarta canja wurin taro (rage iyakokin yaɗuwa).
6. Daidaiton nazari: babban daidaito (har zuwa 0,1 mg ko mafi kyau) don auna na'urorin lantarki.
Tsaftar electrode yana da matuƙar muhimmanci. Dole ne saman electrode ya kasance babu mai, oxides, da gurɓatattun abubuwa domin tabbatar da cewa ma'adanai suna manne daidai gwargwado kuma suna tsayayya da fashewa.
Hanyoyin Sarrafawa: Na'urar Wuta Mai Dorewa vs Na'urar Da Ke Dawowa
Ana iya yin electrogravimetry ta amfani da manyan hanyoyi guda biyu:
1. Tsarin Electrogravimetry na Yanzu Mai Dorewa (Galvanostatic)
A cikin wannan hanyar, ana kiyaye wutar lantarki a ko'ina cikin electrolysis. Fa'idar ita ce na'urar da ta fi sauƙi. Duk da haka, yayin da yawan ion na ƙarfe ke raguwa, ƙarfin cathode na iya canzawa zuwa yanayi mafi muni, yana haifar da halayen gefe (misali, rage H⁺ zuwa H₂). Sakamakon haka, ajiyar na iya zama mai kauri, mai ramuka, ko kuma mara kyau.
2. Tsarin Electrogravimetry Mai Sauƙi (Potentiostatic)
A wannan hanyar, ana sarrafa ƙarfin lantarki mai aiki a wani ƙima ta yadda amsawar mai nazari kawai ke faruwa a zahiri. Wannan hanyar tana da matuƙar amfani wajen rabuwa Zaɓi ƙarfe da yawa bisa ga bambance-bambancen da ke cikin yuwuwar ragewa. Abin da ke haifar da hakan shi ne cewa kayan aikin sun fi rikitarwa (suna buƙatar potentiostat) kuma ƙayyade yanayin da ya fi dacewa yana buƙatar fahimtar electrochemistry sosai.
Matakai na Nazarin Electrogravimetric
Tsarin aikin electrogravimetry gabaɗaya ya haɗa da matakai masu zuwa:
1. Shirya electrode: ana tsaftace electrode, a busar da shi, a sanyaya shi a cikin na'urar bushewa, sannan a auna shi (nauyin farko).
2. Shirya maganin: an narkar da samfurin kuma an daidaita pH ɗin kuma an ƙara electrolytes masu tallafawa (misali H₂SO₄, HNO₃, ko gishiri mara aiki) don ƙara yawan aiki da daidaita yanayi.
3. Electrolysis: ana amfani da wutar lantarki ko ƙarfin lantarki yayin da ake motsa ruwan. Lokacin electrolysis yana daidaita har sai ion ɗin da aka nufa ya kusan rage gaba ɗaya.
4. Cikakken gwajin ruwan sama: ana iya yin sa ta hanyar ɗaukar ƙaramin adadin ruwan da kuma ƙara wani abu mai aiki don tabbatar da cewa babu wani ƙarfe da ya rage, ko kuma lura da raguwar wutar lantarki zuwa kusan sifili a wani takamaiman iko.
5. Wankewar electrode: ana wanke electrode da ruwan da aka cire daga ion don cire duk wani electrolyte da ke manne, sannan a wanke da barasa ko kuma sinadarin da ke canzawa don hanzarta bushewa.
6. Busarwa da aunawa: ana busar da na'urar lantarki a zafin jiki bisa ga nau'in ajiya, a sanyaya ta a cikin na'urar busarwa, sannan a auna (nauyin ƙarshe).
7. Lissafin abun ciki: ana amfani da nauyin abin da ya fashe don ƙididdige ƙwayoyin ƙarfe da yawansu a cikin samfurin.
Lissafi mafi sauƙi shine:
– nauyin ƙarfe = nauyin ƙarshe na lantarki – nauyin farko na lantarki
– moles na ƙarfe = nauyin ƙarfe / Mr na ƙarfe
– abun ciki = moles ko nauyin ƙarfe a kowace samfurin girma
Abubuwan da ke Shafar Ingancin Laka
Nasarar electrogravimetry ta dogara ne sosai akan ingancin ruwan da ya fito. Wasu abubuwan da ke tantancewa sune:
– Yawan wutar lantarki: Yawan wutar lantarki yana haifar da tarin mai datti da kuma mai kauri. Rashin wutar lantarki sosai yana sa tsarin ya yi jinkiri kuma yana iya ƙara haɗarin gurɓatawa.
- pH da abun da ke cikin electrolyte: yana shafar bambancin ion na ƙarfe da gasar amsawa (misali juyin halittar hydrogen).
– Zafin jiki: yana ƙara yawan motsin amsawa da yaɗuwa, amma yana iya shafar kwanciyar hankalin abin da ya haifar ko kuma tasirin sakamako masu illa.
– Juyawa: yana inganta jigilar jama'a ta yadda laka zai zama iri ɗaya.
– Kasancewar sinadaran da ke ƙara wa sinadaran ƙarfi: wasu ligands na iya rage yawan ions masu 'yanci ta haka suna canza yuwuwar hazo da kuma taimakawa wajen rabuwar da zaɓaɓɓu.
Babban burin shine a samar da wani abu mai kama da ruwa ...
Aikace-aikace a cikin Kimiyyar Nazarin Bayanai
Ana amfani da electrogravimetry sosai don nazarin karafa kamar Cu, Ni, Ag, Zn, Pb, Cd, da sauransu, duka a cikin samfuran masana'antu da muhalli. Aikace-aikacen gama gari sun haɗa da:
– Tabbatar da abun da ke cikin jan ƙarfe a cikin maganin shafawa (baho mai amfani da wutar lantarki).
– Binciken nickel da cobalt a wasu karafa tare da yiwuwar raba su.
- Tantance azurfa a cikin samfuran daukar hoto ko sharar da ke ɗauke da ions na Ag⁺.
- Binciken ƙarfe masu nauyi a cikin hanyoyin fitar da ruwa a cikin hanyoyin ƙarfe.
Baya ga tantance adadi ɗaya, ana iya amfani da electrogravimetry a matsayin matakin rabuwa kafin ƙarin bincike, misali don cire wasu tsangwama na ƙarfe ta yadda ma'aunin spectrophotometric ko titration zai zama zaɓi mafi kyau.
Fa'idodi da Iyakoki
Amfanin electrogravimetry:
1. Daidai kuma daidai domin ma'aunin ya dogara ne akan yawan abu.
2. Ba ya buƙatar ma'aunin titrant kamar yadda yake a cikin titration.
3. Zai iya cimma babban zaɓi tare da yuwuwar iko.
4. Ya dace da matsakaicin yawan ƙarfe zuwa babban taro.
Iyakokin electrogravimetry:
1. Yana buƙatar lokacin electrolysis wanda zai iya ɗaukar lokaci mai tsawo, musamman a ƙananan matakan.
2. Yana iya kamuwa da tsangwama daga halayen gefe (misali hydrogen) da gurɓatar laka.
3. Yana buƙatar ƙwarewa wajen shirya na'urorin lantarki da kuma sarrafa yanayi.
4. Bai dace da masu nazarin da ba na ƙarfe ba ko nau'ikan da ba sa haifar da matsala ta hanyar lantarki.
Kammalawa
Electrogravimetry wata hanya ce ta nazarin adadi wadda ke amfani da ruwan sama da nauyin nauyi na electrolytic don tantance abubuwan da ke cikin ƙarfe a cikin samfurin. Duk da cewa dabara ce ta gargajiya, electrogravimetry ta kasance mai mahimmanci a cikin ilmin sunadarai na nazari saboda daidaitonta, ƙa'idodi bayyanannu, da ikon rabuwa da zaɓi tare da yuwuwar iko. Nasarar wannan hanyar galibi ana ƙaddara ta ne ta hanyar sarrafa sigogi kamar halin yanzu/mai yiwuwa, pH, motsawa, zafin jiki, da tsabtar lantarki. Tare da ingantaccen haɓakawa, electrogravimetry ya zama kayan aiki mai aminci don nazarin ƙarfe a fannoni daban-daban, daga masana'antar plating zuwa sa ido kan ƙarfe mai nauyi.
Idan kuna so, zan iya ƙara misalan lissafin lambobi (misali, ƙayyade Cu²⁺) ko ƙirƙirar sigar ilimi ta labarin tare da ambato da kuma littafin tarihi.
