Oxidative transformation of carbamazepine by manganese oxides

Environ Sci Pollut Res Int. 2012 Nov;19(9):4206-13. doi: 10.1007/s11356-012-0949-2. Epub 2012 May 8.

Abstract

This study presents oxidative transformation of carbamazepine by synthetic manganese oxide (δ-MnO(2)) as well as impact of variables including initial MnO(2) loading, pH, coexisting metal ions, and humic acid (HA) on transformation. Manganese oxide (δ-MnO(2)) was synthesized and stored in the form of suspension. The oxidative reactions were conducted in 50 mL polyethylene (PE) centrifuge tubes with constant pH maintained by buffers. The kinetic experiment was carried out in the solution of pH 2.72 containing 5.0 mg/L of carbamazepine and 130.5 mg/L of MnO(2). Effects of initial MnO(2) loading (0-130.5 mg/L), pH (2.72-8.58) and 0.01 M of coexisting solutes (metal ions and HA) on carbamazepine oxidation were also determined. Reaction kinetics indicated that carbamazepine was rapidly degraded in the first 5 min, and approximately 95 % of carbamazepine was eliminated within 60 min. The reaction exhibited pronounced pH dependence and increased with decreasing pH values. The transformation of carbamazepine was also accelerated with increasing MnO(2) loadings. Coexisting metal ions competed with carbamazepine for reactive sites leading to reduced carbamazepine removal, and the inhibitive capacity followed the order of Mn(2+) > Fe(3+) > Ca(2+) ≈ Mg(2+). Presence of HA in aqueous solution caused a significant reduction on the magnitude of carbamazepine transformation. This study indicated that carbamazepine can be effectively degraded by δ-MnO(2), and transformation efficiency was strongly dependent on reaction conditions. It suggests that amendment of soil with MnO(2) be a potential alternative to solve carbamazepine pollution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbamazepine / analysis
  • Carbamazepine / chemistry*
  • Environmental Restoration and Remediation / methods
  • Humic Substances
  • Hydrogen-Ion Concentration
  • Kinetics
  • Manganese Compounds / analysis
  • Manganese Compounds / chemistry*
  • Oxidation-Reduction
  • Oxides / analysis
  • Oxides / chemistry*
  • Soil Pollutants / analysis
  • Soil Pollutants / chemistry*

Substances

  • Humic Substances
  • Manganese Compounds
  • Oxides
  • Soil Pollutants
  • Carbamazepine
  • manganese oxide