In situ generation of a hydroxyl radical by nanoporous activated carbon derived from rice husk for environmental applications: kinetic and thermodynamic constants.
The objective of this investigation is to evaluate the hydroxyl radical (˙OH) generation using nanoporous activated carbon (NPAC), derived from rice husk, and dissolved oxygen in water. The in situ production of the ˙OH radical was confirmed through the DMPO spin trapping method in EPR spectroscopy and quantitative determination by a deoxyribose assay procedure. NPAC served as a heterogeneous catalyst to degrade 2-deoxy-d-ribose (a reference compound) using hydroxyl radical generated from dissolved oxygen in water at temperatures in the range 313-373 K and pH 6, with first order rate constants (k = 9.2 × 10(-2) min(-1), k = 1.2 × 10(-1) min(-1), k = 1.3 × 10(-1) min(-1) and k = 1.68 × 10(-1) min(-1)). The thermodynamic constants for the generation of hydroxyl radicals by NPAC and dissolved oxygen in water were ΔG -1.36 kJ mol(-1) at 313 K, ΔH 17.73 kJ mol(-1) and ΔS 61.01 J mol(-1) K(-1).
Environmental Technology Division, Council of Scientific & Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Adyar, Chennai-600 020, Tamilnadu, India. ganesansekaran@gmail.com karthik.keyan02@gmail.com.
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D002606:Charcoal / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D058608:Nanopores / Q000648:ultrastructure; D012275:Oryza / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D019097:Spin Trapping; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
C045076:Fenton's reagent; D014867:Water; D002606:Charcoal; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; D010100:Oxygen