Thaum A Qib 7 Titanium Tshav Kub Kub Tshaj Tawm Rau 0.2% Hydrogen Peroxide Tshuaj Ntawm 60 degree, Catalytic Decomposition Rate Ntawm H₂O₂ Hloov li cas Palladium Nto Tau Los Ntawm Cov Npuas Oxygen?
Tso lus
Qib 7 titanium muaj 0.12–0.25% palladium, uas yog ib qho kev ua haujlwm zoo rau hydrogen peroxide decomposition: 2H₂O₂ → 2H₂O + O₂. Ntawm 60 degree, qhov pib decomposition yog siab, tsim cov pa npuas uas ua raws li palladium- nplua nuj nto. Raws li npuas sib sau, lawv thaiv cov chaw catalytic nquag, txo tus nqi decomposition los ntawm 50-80% hauv 24 teev. Lub passivation ntawm palladium nto los ntawm oxygen npuas yog thim rov qab thaum ntxuav. Qhov tshwm sim no tseem ceeb hauv cov ntawv thov uas hydrogen peroxide yuav tsum tau khaws cia lossis qhov twg oxygen evolution tuaj yeem ua rau muaj teeb meem txheej txheem.
Lub Mechanism ntawm Palladium-Catalyzed Decomposition thiab npuas Passivation
Palladium nto catalyze decomposition ntawm hydrogen peroxide los ntawm ib tug radical mechanism. Cov tshuaj tiv thaiv tsim cov pa oxygen, uas nucleates ntawm qhov chaw ua npuas. Thaum pib, cov npuas me me tshem tawm yooj yim. Raws li cov tshuaj tiv thaiv tshwm sim, cov pa oxygen supersaturation nce, thiab npuas loj tuaj thiab ua raws li kev xav tau. Cov npuas adhering lub cev thaiv kev nkag ntawm H₂O₂ mus rau palladium nto, txo cov tshuaj tiv thaiv. Qhov chaw npuas npuas nce nrog lub sijhawm, tom qab Langmuir adsorption isotherm. Qhov siab tshaj plaws kev pab mus txog 80-90% ntawm qhov chaw.
Quantitative Decomposition Rate raws li Kev Ua Haujlwm ntawm Lub Sijhawm
Kev tswj xyuas hauv 0.2% H₂O₂ ntawm 60℃ntawm Qib 7 titanium tau tsim cov pa oxygen evolution raws sijhawm. Thaum 0.5 teev, O₂ evolution tus nqi yog 2-5 mL ib cm² ib teev, thiab cov txheeb ze catalytic kev ua ub no yog 100%. Thaum 2 teev, tus nqi poob mus rau 1.5-3 mL / cm²·h, thiab kev ua haujlwm yog 70%. Thaum 6 teev, tus nqi yog 1-2 mL / cm²·h, thiab kev ua haujlwm yog 50%. Thaum 12 teev, tus nqi yog 0.5-1.5 mL / cm²·h, thiab kev ua haujlwm yog 30%. Thaum 24 teev, tus nqi yog 0.3-1 mL / cm² · h, thiab kev ua haujlwm yog 20%. Thaum 48 teev, tus nqi yog 0.2-0.8 mL / cm²·h, thiab kev ua haujlwm yog 15%. Thaum 100 teev, tus nqi ruaj khov ntawm 0.1-0.5 mL / cm²·h, thiab kev ua haujlwm yog 10%.
Kev cuam tshuam ntawm H₂O₂ Concentration thiab Temperature ntawm Deactivation
Tus nqi deactivation nyob ntawm H₂O₂ concentration thiab kub. Ntawm 0.1% H₂O₂ thiab 60 degree, tus nqi pib yog 1–3 mL / cm²·h, thiab tus nqi tom qab 24 teev yog 0.2–0.6 mL / cm²·h, nrog rau deactivation factor ntawm 5. Ntawm 0.2% H₂O₂ thiab 60℃25 cm peb tus nqi yog pib. Tus nqi yog 0.3–1 mL / cm²·h, thiab qhov tsis ua haujlwm yog 5. Ntawm 0.5% H₂O₂ thiab 60 degree, tus nqi pib yog 5–10 mL / cm²·h, 24-teev tus nqi yog 0.8–2 mL / cm²·h, thiab qhov tseem ceeb yog ₂O₂ 5. Tus nqi pib yog 1–2 mL / cm²·h, 24-teev tus nqi yog 0.2–0.5 mL / cm²·h, thiab qhov tseem ceeb yog 5. Ntawm 0.2% H₂O₂ thiab 80 degree, tus nqi pib yog 5–10 mL / cm²·h, 24-teev mL / cm²·h, qhov zoo sib xws yog 1–2 cm². deactivation factor qhia tias npuas npog yog qhov tseem ceeb ntawm cov txheej txheem.
Catalytic Activity Management Guide for H₂O₂ Solutions
Cov lus hauv qab no muab cov lus pom zoo rau kev tswj hwm qib 7 titanium cua sov hauv cov tshuaj hydrogen peroxide raws li qhov xav tau qib ntawm H₂O₂ kev ruaj ntseg.
| Xav H₂O₂ Stability | Pom zoo ua | Kev Cia Siab Catalytic Activity tom qab 24 teev | Sau ntawv |
|---|---|---|---|
| High (tsawg kawg decomposition) | Siv Qib 2 (tsis muaj palladium) | 0% (tsis muaj Pd catalyst) | Tsis muaj catalytic decomposition |
| Nruab nrab (qee qhov decomposition tau) | Qib 7 – lees txais kev ua kom tsis muaj zog | 20% | Txais rau feem ntau daim ntawv thov |
| Lub sijhawm ua haujlwm siab | So los yog yaug lub rhaub dej | Restores rau 100% | Yuav tsum tau nkag mus rau lub rhaub |
| Kev ua haujlwm siab tsis tu ncua | Ntxiv phosphoric acid stabilizer (0.1%) | 50% (inhibited) | Txo decomposition los ntawm 50% |
| Siab ruaj khov heev | Siv PTFE-coated rhaub | 0% | Tsis muaj hlau tiv nrog H₂O₂ |
Engineering Beyond Catalytic Deactivation
The titanium grade selection is critical. Grade 2 has no palladium and does not catalyze H₂O₂ decomposition, making it the preferred choice when H₂O₂ stability is required. Grade 7 should be avoided in H₂O₂ applications unless its catalytic activity is desired (e.g., for H₂O₂ destruction). The surface area of the heater affects the total decomposition rate; larger heaters produce more oxygen bubbles. The solution pH affects decomposition; acidic pH (3–5) stabilizes H₂O₂, while alkaline pH (>8) accelerates decomposition. Qhov sib ntxiv ntawm 0.1% phosphoric acid lossis sodium stannate txo cov catalytic decomposition los ntawm 50%. Cov cuab yeej so lossis ultrasonic tu rov qab ua haujlwm catalytic ntawm Qib 7.
Ua ib qho kev qhia tshwj xeeb
Rau 0.2% hydrogen peroxide tov ntawm 60℃qhov twg H₂O₂ stability yuav tsum, qhia Qib 2 titanium es tsis yog qib 7. Yog tias qib 7 twb tau teeb tsa thiab decomposition muaj teeb meem, ntxiv 0.1% phosphoric acid ua stabilizer los yog hloov lub rhaub nrog Qib 2.O₂ com, kev siv cov khoom siv pov tseg (qhov twg H. Qib 7 yog nyiam. Yog tias xav tau kev ua haujlwm siab catalytic ib ntus, qhia txog qib 7 lub rhaub nrog lub tshuab ntxuav uas tshem tawm cov npuas npuas. Los ntawm kev nkag siab yuav ua li cas oxygen npuas deactivate lub palladium catalyst, tus engineer xaiv cov qib titanium tsim nyog rau H₂O₂ kev pab cuam.
