Chii chinonzi Oxidation uye Reduction Process muGeochemistry?
Mu geochemistry, shanduko dzakawanda dzinoitika muzvicherwa, matombo, pasi pevhu, uye kunyange zvinhu zvakanyungudutswa munzizi nemakungwa zvinokanganiswa nemaitiro emakemikari anosanganisira kutamiswa kwemaerekitironi. Maitiro maviri akakosha anotungamira kutamiswa kwemaerekitironi uku ndeye oxidation nekuderedza (zvinowanzonzi redox reactions). Kunzwisisa redox kwakakosha nekuti maitiro aya anosarudza kugadzikana kwemaminerari, kufamba kwesimbi, mhando yemvura, kuumbwa kweore, uye kunyange dynamics yezvinovaka muviri munharaunda. Chinyorwa chino chinokurukura kuti oxidation nekuderedza chii mumamiriro e geochemistry, mashandiro azvo, uye nei zvichiita basa rakakosha muhurongwa hwePasi.
Kunzwisisa Oxidation uye Kuderedza
Zvichitaurwa zviri nyore, oxidation inzira yekurasikirwa nemaerekitironi, nepo kuderedza kuri nzira yekuwana maerekitironi. Maitiro maviri aya anogara ari maviri: kana chinhu chikarasikirwa nemaerekitironi (chikasanganiswa), chimwe chinhu chinofanira kugamuchira maerekitironi iwayo (chinoderedzwa). Saka, redox reaction imhinduro inosanganisira kuchinjana kwemaerekitironi pakati pemarudzi maviri emakemikari.
Mukuita kwe geochemical, oxidation ne reduction zvinowanzobatanidzwa nekuchinja kwe oxidation number yechinhu. Kana oxidation number ikawedzera, chinhu chinooxidized; kana oxidation number ikaderera, inodzikira.
Muenzaniso uri nyore:
– Iron(II) kana Fe²⁺ inogona kuoxidized kuita Iron(III) kana Fe³⁺ (maerekitironi ari kurasikirwa).
– Kusiyana neizvi, Fe³⁺ inogona kuderedzwa kuita Fe²⁺ (kugamuchira maerekitironi).
Redox muSisitimu Yechisikigo: Kwete "Kungopindura Oxygen"
Izwi rekuti "oxidation" rinobva pakusangana neokisijeni, asi mu geochemistry, oxidation hairevi nguva dzose "kusangana neO₂." Oxidation inogona kuitika nekuda kwekusangana nezvimwe zvinhu zvinokonzera okisijeni zvakaita se nitrate (NO₃⁻), sulfate (SO₄²⁻), kana zvimwe zvicherwa zvinokwanisa kugamuchira maerekitironi.
Saizvozvowo, kudzikira hakuwanzobatanidzwa ne "kurasikirwa kweokisijeni." Kudzikira kunogona kuitika kuburikidza nekuwedzerwa kwemaerekitironi nezvinhu zvakasiyana-siyana zvinodzikisa, zvakaita sezvinhu zvakasikwa, hydrogen sulfide (H₂S), kana iron(II) ions, izvo zvinoderedza kusanganiswa kwezvimwe zvinhu.
Sei Maitiro eRedox Akakosha muGeochemistry?
Maitiro eRedox ndiwo "mainjini" anodzora zvinhu zvakawanda zvemakemikari ezvakatipoteredza uye geology, zvinosanganisira:
1. Kufamba kwezvinhu nesimbi dzinorema
Simbi zhinji (semuenzaniso, Fe, Mn, As, U, Cr) dzine kunyunguduka kwakasiyana pasi pemamiriro ekunyunguduka kana kuderedza. Pasi pemamiriro ekunyunguduka, dzimwe simbi dzinogadzira zvicherwa zve oxide/hydroxide zvisinganyunguduke; pasi pemamiriro ekunyunguduka, dzimwe dzinonyunguduka zvakanyanya uye dzinotakurwa zviri nyore nemvura yepasi pevhu.
2. Kuumbwa uye kugadziriswa kwezvicherwa
Zvicherwa zvesulfide zvakaita sepyrite (FeS₂) zvinogona kuoxida kana zvikasangana nemvura neokisijeni, zvichiburitsa sulfate neacidity. Iyi inzira huru mukugadzirisa matombo uye zvakare inokonzera matambudziko ezvakatipoteredza akadai sekuyerera kwemvura mumigodhi ine acid.
3. Hunhu hwemvura yepasi pevhu neyapamusoro pevhu
Mamiriro eRedox anokanganisa kana mvura ine iron yakanyungudutswa, manganese, ammonia, sulfide, kana nitrate uye oxygen yakanyungudutswa. Kuchinja kweRedox kunogona kuchinja kuravira, ruvara, kunhuhwirira, uye kuchengetedzeka kwemvura yekushandisa.
4. Kutenderera kwemakemikari emuviri
Kutenderera kwekabhoni, nitrogen, sarufa, uye iron kunonyanya kukanganiswa nemaitiro e redox anowanzo konzerwa netupukanana.
Pfungwa Huru: Redox Potential (Eh)
Mu geochemistry, mamiriro e oxidative kana reductive enzvimbo anowanzo tsanangurwa se Eh (redox potential), kazhinji mumayuniti e volts (V) kana millivolts (mV).
– High Eh → nzvimbo ine oxidative yakawanda (ma oxidant akawanda aripo, akadai seO₂).
– Low Eh → nzvimbo inodzikisa simba (oxygen shoma, chinhu chinoderedza simba, semuenzaniso zvinhu zvipenyu).
Eh haisi yega. Inoenderana ne pH, tembiricha, uye kuumbwa kwemakemikari emusanganiswa. Nokudaro, ma geochemist anowanzo shandisa dhayagiramu yeEh–pH (dhayagiramu yePourbaix) kufanotaura chimiro chemakemikari chakagadzikana chechinhu pasi pemamwe mamiriro ezvinhu—semuenzaniso, kana simbi ichagadzikana seFe²⁺ yakanyungudutswa, Fe³⁺, kana semaminerari akadai sehematite negoethite.
Mienzaniso yeMaitiro Akakosha eRedox muGeochemistry
1. Kubviswa kwePyrite Oxidation uye Kuyerera kweAcid Mine Drainage
Pyrite (FeS₂) imineral inonzi sulfide inowanikwa mumatombo egungwa nenzvimbo dzekuchera. Kana pyrite ikasangana neokisijeni nemvura, inogona kuoxidation kuti igadzire sulfate nehydrogen ions (H⁺), izvo zvinokonzera acidity.
Kazhinji (zvakareruka), mhinduro yacho inogona kuburitsa:
– sulfate ion (SO₄²⁻)
– Fe²⁺/Fe³⁺
– H⁺ (inoderedza pH)
Kukanganiswa kwacho kwakakura: pH yakaderera inonyungudutsa dzimwe simbi (Al, Mn, Zn, Cu), inosvibisa nzizi, uye inokuvadza nharaunda.
2. Kuderedza Sulfate uye Kuumbwa kweSulfide
Munzvimbo dzisina okisijeni yakawanda (dzisina chepfu) sedimentary, mabhakitiriya anoderedza sulfate anogona kushandisa sulfate semugamuchiri wemaerekitironi, zvichigadzira sulfide (H₂S). Maitiro aya anowanzoitika mumadhamu, mumakungwa, kana mumadhamu egungwa ane organic.
Mhedzisiro yacho:
- kunhuhwirira kwe "zai rakaora" kunoumbwa kubva kuH₂S
– masulfide anogona kuita neFe²⁺ kugadzira zvicherwa zvakaita seFeS kana pyrite (FeS₂), zvichivhara sarufa nesimbi muchimiro chakasimba.
3. Kuchinja kweSimbi neManganese mumvura yepasi
Mumvura yepasi pevhu ine oxygen yakanyungudika shoma, iron nemanganese zvinowanzovapo seFe²⁺ neMn²⁺ zvinonyungudika zvakanyanya. Kana mvura iyi ikapombwa pamusoro uye ikasangana neoxygen:
– Fe²⁺ inosanganiswa kuita Fe³⁺ uye inoumba precipitate yakatsvuka yebrown (iron oxide/hydroxide)
– Mn²⁺ inogona kugadzira madonhwe matema (manganese oxide)
Izvi zvinotsanangura chikonzero nei mamwe matsime achiburitsa mvura yakachena pakutanga asi yozochinja ruvara yosiya mavara.
4. Nitrogen Redox: Nitrate, Nitrite, uye Ammonium
Muvhu nemumvura:
– Kana paine mamiriro e oxidative, nitrogen inowanzo gadzikana se nitrate (NO₃⁻).
– Kana mamiriro ekuderedza simba, nitrate inogona kuderedzwa kuburikidza nekubvisa hunyoro kuita N₂ gasi (inoburitswa mumhepo), kana kuti inogona kuguma yava ammonium (NH₄⁺).
Izvi zvakakosha mukurima uye kusvibiswa kwemvura yepasi pevhu: nitrate inonyungudika uye inofambiswa, nepo ammonium inowanzo batana zvakanyanya kune zvimwe zvidimbu zvevhu.
Basa reZvipembenene muGeochemical Redox Reactions
Maitiro mazhinji e redox muzvisikwa anokurumidza zvikuru netupukanana tudiki. Anoshandisa maitiro e redox senzvimbo yesimba, semuenzaniso:
– mabhakitiriya anooxidation yesimbi (shandura Fe²⁺ kuita Fe³⁺)
– mabhakitiriya anoderedza simbi (shandura Fe³⁺ kuita Fe²⁺)
– mabhakitiriya anoderedza sulfate (SO₄²⁻ → H₂S)
- mabhakitiriya anokonzera nitrizing uye denitrizing (kuchinja kwenitrogen)
Kukanganiswa kwehutachiona uhu kunogona kukonzera kuti mamiriro e redox emadhaka kana pasi pevhu achinje nekukurumidza, kunyanya kana paine zvinhu zvipenyu zvinopihwa ne electron.
Mhedziso
Maitiro ekudzikisa okisijeni nekuderedza mu geochemistry maitiro ekuchinjana kwemaerekitironi anodzora chimiro chemakemikari, kunyungudika, uye kufamba kwezvinhu zvakawanda munzvimbo yePasi. Mamiriro eRedox (anowanzo kuyerwa neEh) anoona kana nzvimbo ichiita kuti maoxide, sulfides, kana mafomu akanyungudika echinhu chakati. Maitiro eRedox anoitawo basa guru mukuumbwa kwezvicherwa, kuumbwa kwematombo, kunaka kwemvura yepasi pevhu, kusvibiswa, uye kutenderera kwebiogeochemical kunosanganisira kabhoni, nitrogen, sarufa, iron, uye manganese. Nekunzwisisa redox, tinogona kufanotaura zviri nani shanduko dze geochemical muzvisikwa uye kugadzira nzira dzekutarisira nharaunda—semuenzaniso, kudzivirira kubuda kwemvura mumigodhi ine acid, kudzora kusvibiswa, kana kuvandudza kunaka kwemvura.
Kana muchida, ndinogona kuwedzera mufananidzo wedhayagiramu iri nyore yeEh–pH, muenzaniso wedambudziko rekuverenga nhamba dzeoxidation, kana shanduro yechinyorwa chinotarisa zvakanyanya pane zviitiko muIndonesia (semuenzaniso, mvura inoyerera mumigodhi yemarasha ine acid, peatlands, kana kusvibiswa kwearsenic mumvura yepasi pevhu).
