UV fluorescence, FTIR, and GC-MS analyses and resin fractionation procedures as indicators of the chemical treatability of olive mill wastewater

摘要

The organic matter content in original, untreated (COD=150,000mg/L; TOC=36,000mg/L; oil-grease=8,200mg/L; total phenols=3,800mg/L), and chemically treated olive mill wastewater was examined in detail by instrumental and analytical (resin fractionation) methods. For this purpose, two approaches were followed: (i) UV-fluorescence, FTIR, and GC-MS analyses as well as (ii) structural fractionation assessment employing XAD-8, XAD-4, AG-MP-50, and Duolite A-7 exchange resins to obtain hydrophobic-acidic, basic, neutral, and hydrophilic-acidic, basic, neutral fractions, respectively. Acid cracking (pH 2.0; T=70 degrees C), FeCl3 coagulation (pH 3.0; FeCl3=2,500mg/L) electrocoagulation with stainless steel electrodes (pH 2.0; T=65 degrees C; A=50mA/cm(2); t=120min), and the Fenton's reagent (pH 2.0; T=65 degrees C; 20mM Fe2+: 200mM H2O2; t=120min) were selected for convenient chemical treatment of the effluent. Resin fractionation analyses of the original wastewater sample indicated that the major organic content composed of hydrophobic moieties (75-95%). The percent relative inhibition of the original wastewater was concentrated in the hydrophobic neutral fraction (100%). By employing instrumental analyses, several organic compounds could be identified. Relatively low molecular weight chemicals were qualified via GC-MS analysis, whereas FTIR results revealed an appreciable loss of aliphatic moieties together with an increase in aromatic structures.