Wet oxidation of salicylic acid solutions

Environ Sci Technol. 2010 Nov 15;44(22):8629-35. doi: 10.1021/es1021944. Epub 2010 Oct 27.

Abstract

Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Hydrogen-Ion Concentration
  • Kinetics
  • Models, Chemical
  • Oxidation-Reduction
  • Pressure
  • Salicylic Acid / analysis
  • Salicylic Acid / chemistry*
  • Solutions / chemistry
  • Temperature
  • Waste Disposal, Fluid / methods*
  • Water Pollutants, Chemical / analysis
  • Water Pollutants, Chemical / chemistry*

Substances

  • Solutions
  • Water Pollutants, Chemical
  • Salicylic Acid