Removal of organic pollutants from 2,2',5,5'-tetrachlorobenzidine (TCB) industrial wastewater by micro-electrochemical oxidation and air-stripping

J Hazard Mater. 2007 Jun 1;144(1-2):159-63. doi: 10.1016/j.jhazmat.2006.10.028. Epub 2006 Oct 13.

Abstract

A feasible method for treatment of the wastewater from the two-staged neutralization in 2,2',5,5'-tetrachlorobenzidine (TCB) manufacturing processes, a refractory dye intermediate effluents, based on combined micro-electrochemical oxidation or iron-chipping filtration (ICF) and air-stripping reactor (ASR), was developed. On conditions of HRT 1h, pH 3.0 in ICF and HRT 38 h, gas-liquid ratio 15, pH 6.0-8.65, temperature 26 degrees C in ASR, the overall COD, color, TCB and NH(4)(+)-N removal were 96.8%, 91%, 87.61% and 62%, respectively, during the treatment of TCB wastewater from the two-staged neutralization dissolved by methanol. The averaged 18.3%, 81.7% of the total degraded COD, 35.2%, 64.8% of TCB were carried out in ICF and ASR, respectively. NH(4)(+)-N removal was finished mainly in ASR. The experimental results indicated that the combined micro-electrochemical oxidation and air-stripping process performed good treatment of COD, color, TCB and NH(4)(+)-N removal in TCB wastewater from the two-staged neutralization dissolved by ethanol or acetone, came up the discharge standard in China. But the TCB wastewater from the two-staged neutralization dissolved by methanol should be deeply treated before discharged.

MeSH terms

  • Benzidines / chemistry*
  • Color
  • Electrochemistry
  • Industrial Waste
  • Iron / chemistry
  • Oxidation-Reduction
  • Quaternary Ammonium Compounds / chemistry
  • Waste Disposal, Fluid / methods
  • Water Pollutants, Chemical / chemistry*
  • Water Purification / methods*

Substances

  • Benzidines
  • Industrial Waste
  • Quaternary Ammonium Compounds
  • Water Pollutants, Chemical
  • Iron
  • 2,2',5,5'-tetrachlorobenzidine