Kinetic modeling of ZnO-rGO catalyzed degradation of methylene blue |
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| Authors: | Asif Nisar Muhammad Saeed Muhammad Usman Majid Muneer Muhammad Adeel Iltaf Khan Javaid Akhtar |
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| Affiliation: | 1. Department of Chemistry, Government College University Faisalabad, Faisalabad, Pakistan;2. Key Laboratory of Functional Inorganic Material Chemistry, Heilongjiang University, Harbin, People's Republic of China;3. Department of Chemical & Material Engineering, College of Engineering, King Abdul Aziz University, Jeddah, Kingdom of Saudi Arabia |
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| Abstract: | Photodegradation of organic pollutants strongly depends on design of metal oxide semiconductor photocatalysts. Graphene, if composited with ZnO, can effectively enhance its photocatalytic performance for the eradication of pollutants from aqueous medium. Here in, ZnO-rGO is reported as highly active catalyst for degradation of methylene blue. A 200-mg/L solution of methylene blue dye was completely degraded within 1 h in comparison to 74% and 56% degradation over ZnO and rGO, respectively. The commonly used mechanisms of heterogeneous catalytic reactions, the Langmuir-Hinshelwood mechanism, and the Eley-Rideal mechanisms, were used to describe the reaction kinetics. The Langmuir-Hinshelwood mechanism was found as more favorable in this study. Apparent activation energy, Eap, true activation energy, ET, entropy, ΔS, and enthalpy, ΔH were calculated as 36.2 kJ/mol, 13.1 kJ/mol, 197.5 J/mol, and 23.1 kJ/mol, respectively. |
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| Keywords: | Eley-Rideal mechanism graphene Langmuir-Hinshelwood mechanism methylene blue ZnO |
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