Effect of concentrated NaCl on catalytic wet oxidation (CWO) of short chain carboxylic acids

Abstract

The effect of concentrated NaCl (200 g L−1) on CWO of oxalic acid and acetic acid over MnCeOx was investigated at 110 °C and 0.5 MPa O2 to explore the potential of using CWO for shale gas wastewater treatment. The presence of concentrated NaCl hindered oxalic acid conversion, which from ATR-IR spectroscopy was attributed to the salting out effect increasing the oxalic acid surface coverage with formation of strongly adsorbed intermediates, slowing oxalic acid mineralisation. In addition, the weak adsorption of acetic acid on MnCeOx was proposed to be responsible for the insignificant conversion with or without NaCl present.

Keywords

• Catalytic wet oxidation (CWO)
• MnCeOx
• Salt effect
• In situ ATR spectroscopy