Hauv kev txhais dav dav, electrochemical oxidation txhais tau tias yog tag nrho cov txheej txheem ntawm electrochemistry, uas cuam tshuam nrog cov tshuaj electrochemical ncaj qha lossis tsis ncaj qha tshwm sim ntawm lub electrode raws li cov hauv paus ntsiab lus ntawm cov tshuaj oxidation-reduction. Cov tshuaj tiv thaiv no lub hom phiaj yog txo lossis tshem tawm cov pa phem ntawm cov dej khib nyiab.
Txhais tau tias nqaim, electrochemical oxidation yog hais txog cov txheej txheem anodic. Hauv cov txheej txheem no, cov kua organic lossis cov tshuaj ncua tau nkag mus rau hauv lub cell electrolytic, thiab los ntawm kev siv hluav taws xob ncaj qha, cov electrons raug rho tawm ntawm anode, ua rau oxidation ntawm cov organic compounds. Xwb, cov hlau qis-valence tuaj yeem raug oxidized rau cov hlau ions siab-valence ntawm anode, uas tom qab ntawd koom nrog hauv oxidation ntawm cov organic compounds. Feem ntau, qee cov pab pawg ua haujlwm hauv cov organic compounds qhia txog kev ua haujlwm electrochemical. Nyob rau hauv kev cuam tshuam ntawm lub teb hluav taws xob, cov qauv ntawm cov pab pawg ua haujlwm no hloov pauv, hloov cov khoom siv tshuaj lom neeg ntawm cov organic compounds, txo lawv cov tshuaj lom, thiab txhim kho lawv cov biodegradability.
Kev oxidation electrochemical muaj ob hom: oxidation ncaj qha thiab oxidation tsis ncaj qha. Kev oxidation ncaj qha (kev electrolysis ncaj qha) cuam tshuam nrog kev tshem tawm cov pa phem los ntawm cov dej khib nyiab los ntawm kev oxidizing lawv ntawm lub electrode. Cov txheej txheem no suav nrog ob qho tib si anodic thiab cathodic txheej txheem. Cov txheej txheem anodic cuam tshuam nrog kev oxidation ntawm cov pa phem ntawm qhov chaw anode, hloov lawv mus rau hauv cov tshuaj lom tsawg dua lossis cov tshuaj uas biodegradable dua, yog li txo lossis tshem tawm cov pa phem. Cov txheej txheem cathodic cuam tshuam nrog kev txo cov pa phem ntawm qhov chaw cathode thiab feem ntau yog siv rau kev txo thiab tshem tawm cov halogenated hydrocarbons thiab rov qab cov hlau hnyav.
Cov txheej txheem cathodic kuj tseem tuaj yeem raug xa mus rau electrochemical txo qis. Nws cuam tshuam nrog kev hloov pauv ntawm cov electrons los txo cov hlau hnyav ions xws li Cr6 + thiab Hg2 + mus rau hauv lawv cov xeev oxidation qis dua. Tsis tas li ntawd, nws tuaj yeem txo cov tshuaj chlorinated organic, hloov lawv mus rau hauv cov tshuaj lom tsawg dua lossis tsis muaj tshuaj lom, thaum kawg txhim kho lawv cov biodegradability:
R-Cl + H+ + e → RH + Cl-
Kev oxidation tsis ncaj qha (indirect electrolysis) cuam tshuam nrog kev siv cov tshuaj oxidizing lossis txo cov tshuaj electrochemical ua cov tshuaj reactants lossis catalysts los hloov cov pa phem mus rau hauv cov tshuaj lom tsawg dua. Kev electrolysis tsis ncaj qha tuaj yeem muab faib ua cov txheej txheem rov qab tau thiab tsis rov qab tau. Cov txheej txheem rov qab tau (mediated electrochemical oxidation) cuam tshuam nrog kev rov ua dua thiab rov ua dua ntawm cov hom redox thaum lub sijhawm electrochemical. Cov txheej txheem tsis rov qab tau, ntawm qhov tod tes, siv cov tshuaj tsim los ntawm cov tshuaj electrochemical tsis rov qab tau, xws li cov neeg sawv cev oxidizing muaj zog xws li Cl2, chlorates, hypochlorites, H2O2, thiab O3, los oxidize cov organic compounds. Cov txheej txheem tsis rov qab tau kuj tseem tuaj yeem tsim cov intermediates oxidative heev, suav nrog cov electrons solvated, · HO radicals, · HO2 radicals (hydroperoxyl radicals), thiab · O2- radicals (superoxide anions), uas tuaj yeem siv los rhuav tshem thiab tshem tawm cov pa phem xws li cyanide, phenols, COD (Chemical Oxygen Demand), thiab S2- ions, thaum kawg hloov lawv mus rau hauv cov tshuaj tsis muaj teeb meem.
Yog tias muaj kev oxidation ncaj qha los ntawm anodic, cov tshuaj reactant qis tuaj yeem txwv qhov kev cuam tshuam ntawm qhov chaw electrochemical vim muaj kev txwv kev hloov pauv loj, thaum qhov kev txwv no tsis muaj rau cov txheej txheem oxidation tsis ncaj qha. Thaum lub sijhawm ob qho tib si kev oxidation ncaj qha thiab tsis ncaj qha, cov tshuaj tiv thaiv sab uas cuam tshuam nrog kev tsim cov roj H2 lossis O2 yuav tshwm sim, tab sis cov tshuaj tiv thaiv sab no tuaj yeem tswj tau los ntawm kev xaiv cov khoom siv electrode thiab kev tswj hwm qhov muaj peev xwm.
Kev siv hluav taws xob oxidation tau pom tias muaj txiaj ntsig zoo rau kev kho cov dej khib nyiab uas muaj cov organic ntau, cov khoom sib xyaw ua ke, ntau yam khoom siv refractory, thiab xim siab. Los ntawm kev siv cov anodes nrog cov haujlwm electrochemical, cov thev naus laus zis no tuaj yeem tsim cov radicals hydroxyl oxidative siab heev. Cov txheej txheem no ua rau kev rhuav tshem cov kuab paug organic mus rau hauv cov khoom tsis muaj tshuaj lom, biodegradable thiab lawv cov mineralization tiav rau hauv cov tshuaj xws li carbon dioxide lossis carbonates.
Lub sijhawm tshaj tawm: Cuaj hlis-07-2023
