Monitoring the physicochemical and chemical treatment of textile wastewater using GC/MS, LC/MS and -MS/MS techniques

Abstract

Conventional biological wastewater treatment processes often fail in the elimination of finishing agents contained in textile wastewater such as dyes, surfactants, and softeners. Therefore, discharges from the textile industry are known as a major source of water pollution reaching groundwater and even drinking water treatment. Physicochemical treatment and advanced treatment processes (AOP) were applied to eliminate the pollutants prior to discharge. Ozone (O3), O3/UV, hydrogen peroxide/UV (H2O2/UV), Fenton's reagent (Fe2+/H2O2) were applied to eliminate by oxidation while ultrasonication (US) alone, US/UV or powdered activated carbon (PAC) were used for the physicochemical treatment. Elimination was monitored by a conventional sum parameter analyses (COD, BOD, DOC) while gas chromatography/mass spectrometry (GC/MS) and liquid chromatography coupled with MS and tandem mass spectrometry (LC/MS and -MS/MS) was applied for follow-up of pollutants and their degradation products. The application of PAC, Fenton, and O3/UV resulted in the highest dissolved organic carbon elimination. A complete or partial elimination and/or degradation of non-polar or polar pollutants was observed by GC/MS or flow injection analysis/MS (FIA/MS) respectively. LC/MS and MS/MS analyses confirmed that ethoxylated surfactants (AEO) present in the original wastewater could be oxidized or destroyed resulting in carboxylated AEO and polyethylene glycol (PEG) or even carboxylated PEG.