Ngā Tauhohenga Matū i roto i te Tukanga Waikura
Ko te waikura tētahi o ngā āhuatanga matū e tino pā ana ki te oranga o ia rā, engari he nui rawa atu tōna pānga. Mai i te waikura o ngā taiapa ki te ngoikore o ngā anga waka ki te turuturu o ngā paipa ahumahi—ka tīmata katoa i te tukanga waikura. He māmā noa iho, ka taea te mārama ki te waikura ko te pirau o ngā rauemi (ina koa ko ngā konganuku) nā ngā tauhohenga matū, hikohiko rānei ki te taiao. Ahakoa e whakaarohia ana he "waikura", ko te waikura he raupapa matatini o ngā tauhohenga e pāngia ana e te wai, te hāora, te tote, te waikawa, me ngā rerekētanga pūmanawa hiko puta noa i te mata konganuku.
Te Waikura hei Tukanga Hikohiko
I te nuinga o te wā, ka puta te waikura whakarewa mā roto i ngā tikanga hikohiko, arā, ko te tikanga ko te rere o ngā irahiko e puta mai ana i te hanganga o tētahi pūtau hiko-iti i runga i te mata whakarewa. E rua ngā wāhanga matua o tēnei pūtau: te rohe anode me te rohe cathode. Ahakoa te āhua ōrite o te whakarewa, he maha ngā wā kei roto i tōna mata ngā hapa, ngā ahotea o roto, ngā rerekētanga o te hanganga moroiti, te pā atu rānei ki ētahi atu whakarewa e meinga ai tētahi wāhanga o te mata hei anode, me tētahi atu wāhanga hei cathode.
– I te anode, ka waikuratia te konganuku (ka tukuna ngā irahiko).
– I te katote, ka puta he tauhohenga whakaiti (te tango i ngā irahiko), ko te nuinga o te wā ka uru mai ngā katote hāora, hauwai rānei.
Ara, ka taea te tiro i te waikura hei "pāhiko iti" e mahi tonu ana i runga i te mata whakarewa, mena kei reira he irahiko (hei tauira, te wai) hei reo mō te kawe i ngā katote.
Ngā Tauhohenga Taketake o te Waikura Rino: Ngā Pūtake o te Waikura
Ko te rino (Fe) te tauira tino kitea i roto i ngā kōrero mō te waikura nā te mea he ngāwari te waikura. He ranunga matatini te waikura, ko te nuinga he waikura rino kua whakamakukuhia (hei tauira, Fe₂O₃·nH₂O), engari ka tīmatahia tōna hanganga e ētahi taahiraa tauhohenga.
1. Tauhohenga Anodic: Waikura Rino
I te anode, ka rewa te rino mā te tuku i ngā irahiko:
Fe(s) → Fe²⁺(aq) + 2e⁻
Nā tēnei tauhohenga ka puta ngā iona Fe²⁺, ka ngaro te papatipu o te konganuku i te pūwāhi anodic. Koinei te tīmatanga o te tukanga "waikura" i roto i te konganuku.
2. Tauhohenga Katorika: Whakaitinga Hāora
I roto i ngā taiao kūpapa, i ngā taiao kawakore rānei (pērā i te wai māori), ko te tauhohenga katote e tino kitea ana ko te whakaiti i te hāora rewa:
O₂(g) + 2H₂O(l) + 4e⁻ → 4OH⁻(aq)
Ka tukuna ngā irahiko mai i te anode ki te rohe cathode, ā, ka whakamahia hei whakaiti i te hāora. Ko te noho mai o te wai me te hāora ngā mea matua e rua.
3. Te Hanganga o te Matū Takawaenga: Fe(OH)₂
Ka tauhohe ngā iona Fe²⁺ i hangaia ki te anode ki ngā iona OH⁻ mai i te tauhohenga katote hei hanga i tētahi matūriki:
Fe²⁺(aq) + 2OH⁻(aq) → Fe(OH)₂(s)
Ehara ēnei putunga i te waikura whakamutunga, engari he "hua waikura tōmua" ka taea te whakarerekē haere.
4. Te Whakahāora Anō ki te Fe(OH)₃ me te Waikura Rino Whakahāora
Ka taea te whakahāwea i te Fe(OH)₂ e te hāora ki te Fe(OH)₃:
4Fe(OH)₂(s) + O₂(g) + 2H₂O(l) → 4Fe(OH)₃(s)
Kātahi ka pāngia te Fe(OH)₃ e te maroketanga ā-wāhanga, ā, ka hurihia te hanganga hei waikura rino kua whakamakukuhia e tātou e mōhiotia nei ko te waikura:
Fe(OH)₃(s) → Fe₂O₃·nH₂O(s) + (wai)
He pūwero ngā hua waikura, ā, kāore e piri pai, nō reira kāore e tiaki i ngā paparanga whakarewa o raro. Nō reira, ka haere tonu te waikura o te rino, ā, ka kino haere.
Te Pānga o ngā Irahiko me ngā Katote Tote
Ka tere ake te waikura i te aroaro o tētahi irahiko pai, pērā i te wai moana, i te wai rānei kei roto te tote. Ko ngā katote hauota (Cl⁻) tētahi o ngā whakatere waikura tino morearea. Ka whakanuia e te tote te kawe hiko o te otinga, ka whakanuia te iahiko hiko i te mata whakarewa. Hei tāpiri, ka taea e te hauota te kino i te paparanga kore mahi i runga i ētahi whakarewa, ā, ka puta te waikura ā-rohe pērā i te waikura kapiti me te waikura poka.
I roto i te rino, ka taea hoki e te taiao kei roto ko te Cl⁻ te whakatenatena i te hanganga o ngā hua waikura kāore i te pumau, me te whakateretere i te hanganga o ngā ira anode iti, hohonu, ka hua ake he poka waikura e uaua ana ki te kitea mai i waho.
Te Waikura i roto i ngā Taiao Waikawa: Te Whakaiti i te Hauota Hauwai
I roto i te taiao waikawa, ka rerekē pea te tauhohenga katote. Mena he teitei te kukū o te H⁺, ko te tauhohenga whakaiti matua ko te hanganga o te hau hauwai:
2H⁺(aq) + 2e⁻ → H₂(g)
Ahakoa ko te tauhohenga anodic ko te whakarewatanga o te konganuku:
Fe(s) → Fe²⁺(aq) + 2e⁻
Mā tēnei huinga ka tere ake te memeha o te rino i roto i te waikawa. Nō reira, ka taea e te konganuku te memeha me te kore he nui o te hāora rewa. Koia te take he nui ake te mōrearea o te waikura tere o ngā paipa, ngā tāke rānei e pāngia ana e ngā wai waikawa mēnā kāore i pania, kāore rānei i te whakahaeretia te pH.
Te Waikura Pūnaha: Ina Tūtaki Ngā Konganuku E Rua
Ehara i te mea ko te taiao anake te take o te waikura, engari ko ngā konganuku e pā ana hoki. Ina honoa ngā konganuku rerekē e rua ki te hiko i roto i te irahiko, ka hangaia he pūtau karawaka. Ko te konganuku kaha ake (he ngāwari ake te waikura) ka mahi hei anode, ā, ka tere ake te waikura, ko te konganuku rangatira ia ka mahi hei cathode, ā, he āhua tiakina.
Hei tauira, ki te pā te rino ki te parahi i ngā āhuatanga makuku, ka mahi te rino hei anode, ā, ka tere ake te waikura. Nā te rerekētanga o te pūmanawa hiko paerewa i waenga i ngā konganuku e rua tēnei, e whakatau ana i te ahunga o te rere o te irahiko.
Ngā Paparanga Āhuakore me te Waikura i runga i Ētahi Atu Konganuku
Kāore ngā konganuku katoa e waikura pērā i te rino. Hei tauira, ko te konumohe me te maitai kore waikura ka hanga i tētahi paparanga waikura angiangi, matotoru, piri tonu e kiia nei ko te paparanga kore waikura. Ka ārai tēnei paparanga i te horapa o te hāora me te wai ki te mata o te konganuku, ā, ka whakaiti i te tere o te waikura. I runga i te konumohe, he tino pumau te paparanga Al₂O₃. I roto i te maitai kore waikura, ka tautokona te paparanga kore waikura e te chromium, ka hanga i te Cr₂O₃.
Heoi, ka taea te pakaru o te paparanga kore mahi i ētahi āhuatanga, pērā i te nui o te kukū o te hauhā, ngā āhuatanga kore-hāora i roto i ngā āputa whaiti, ngā rerekētanga rānei o te hauhautanga (ngā pūtau kukū hāora). Ina pakaru te paparanga kore mahi i ngā wāhi iti, ka tere te pirau ā-rohe, ka mōrearea hoki.
Ngā Take e Pā Ana ki ngā Tauhohenga Waikura
Ko ētahi o ngā āhuatanga matua e whakatau ana i te tere o te waikura ko:
1. Te wātea o te wai me te hāora: Ka mahi te wai hei irahiko me te reo tauhohenga, ko te hāora ia ka mahi hei ākena waikura i roto i te tauhohenga katote.
2. pH taiao: Ka tere ake te memeha o te konganuku i ngā taiao waikawa. I ētahi wā ka āwhina ngā taiao kawakore ki te hanga i tētahi paparanga tiaki i runga i ētahi konganuku.
3. Te kukū o te katote (ina koa ko te Cl⁻): Ka whakanui ake i te kawe hiko, ā, ka puta te waikura ā-rohe.
4. Te Pāmahana: I te nuinga o te wā, ka piki ake te tere o ngā tauhohenga matū me te pāmahana, nō reira ka tere ake te waikura i ngā pāmahana tiketike.
5. Te tere o te rere o te wai: Ka taea e te rere te whakangaro i te paparanga tiaki me te whakateretere i te tuku hāora, ka puta ai te pirau me te waikura.
6. Te whakapā atu ki waenga i ngā konganuku: Ka puta te waikura konukōre mena he rerekētanga pūmanawa.
Te Katinga
Ko te waikura he raupapa o ngā tauhohenga waikura-whakaiti e puta noa ana i te wā e taunekeneke ana te konganuku me tōna taiao. I roto i te rino, ka tīmata te tukanga me te waikura o Fe ki Fe²⁺ i te anode me te whakahekenga o te hāora (ngā iona hauwai rānei i roto i ngā āhuatanga waikawa) i te cathode. Ko te hua whakamutunga ko te waikura rino waikura, e mōhiotia ana ko te waikura. Ko te noho mai o te wai, te hāora, te tote, me ngā āhuatanga pH ka whakatau nui i te tere o tēnei tauhohenga , me ngā āhuatanga rauemi pēnei i te hononga konganuku me te kaha ki te hanga i tētahi paparanga kore mahi. Mā te mārama ki ngā tauhohenga matū e uru ana ki te tukanga waikura, ka taea e tātou te hoahoa i ngā rautaki ārai tika—mai i ngā paninga, te whakamahinga aukati, te tiaki cathodic, ki te kōwhiringa rauemi—kia taea ai te whakaiti i ngā mate nā te waikura.
