The oxidative degradation of 2-mercaptobenzothiazole at the interface of beta-MnO2 and water

J Hazard Mater. 2008 Jun 15;154(1-3):1098-105. doi: 10.1016/j.jhazmat.2007.11.015. Epub 2007 Nov 17.

Abstract

To investigate the oxidative degradation of organic pollutants at the interface of manganese oxides and water, beta-MnO2 was prepared and its crystal structure and the specific surface area were examined by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods, respectively. 2-Mercaptobenzothiazole (MBT) as a model chemical was used to study its oxidative degradation reaction in beta-MnO2 suspension. The experimental results showed that MBT was effectively degraded and mineralized into SO4(2-) and NO3- by beta-MnO2. In the meantime, it was found that beta-MnO2 could be reductively dissolved, and aqueous and adsorbed Mn2+ was generated. The kinetics of MBT degradation by beta-MnO2 is a function of initial MBT concentration, beta-MnO2 dosage and pH value. At pH 4.6, apparent reaction orders with respect to initial MBT concentration and beta-MnO2 dosage were determined to be 0.88 and 0.27, respectively. The initial reaction rate (rinit) is of pH dependence with a reaction order of -0.36. The thermodynamics of MBT degradation by beta-MnO2 was also investigated, and the apparent activation energy was calculated to be 5.62 kJ/mol. The inhibited effect of carboxylic acids (oxalic, citric, tartaric, and malic acids) or metal ions (Ni2+, Ca2+, Mn2+ and Cr3+) on the oxidative degradation of MBT by beta-MnO2 was also investigated. This investigation will give some new insights for understanding the interaction of organic pollutants with manganese oxides in natural soils and sediments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzothiazoles / chemistry*
  • Carboxylic Acids / chemistry
  • Hydrogen-Ion Concentration
  • Kinetics
  • Manganese Compounds / chemistry*
  • Metals / chemistry
  • Oxidation-Reduction
  • Oxides / chemistry*
  • Temperature
  • Waste Disposal, Fluid / methods*
  • Water / chemistry
  • Water Pollutants, Chemical / chemistry*
  • Water Purification / methods*

Substances

  • Benzothiazoles
  • Carboxylic Acids
  • Manganese Compounds
  • Metals
  • Oxides
  • Water Pollutants, Chemical
  • Water
  • manganese oxide
  • dibenzothiazyl disulfide