Impact of O₃ or O₃/H₂O₂ treatment via a membrane contacting system on the composition and characteristics of the natural organic matter of surface waters

Journal
Environmental science and pollution research  
Volume
25
Issue
13
Start Page
12246
End Page
12255
Citation
Environmental Science and Pollution Research 13 (25): 12246-12255 (2018-05)
Publisher DOI
10.1007/s11356-017-9554-8
Scopus ID
2-s2.0-85021263432
The present study aims to evaluate changes in the structure-composition of natural organic matter (NOM) that occur after the application of bubbleless ozonation or peroxone treatment of surface waters. The oxidation experiments (using 0.5–2 mg O₃/mg DOC, or 2:1 O₃:H₂O₂ molar ratio) were performed in a continuous mode, using a tubular ceramic membrane contactor. Fluorescence spectroscopy (emission-excitation matrix) and liquid chromatography-organic carbon detection (LC-OCD) were mainly used for the detailed DOC characterization. In brief, the application of single ozonation resulted to high reduction of humic-like peak fluorescence intensities (50–85%) and also to the formation of two new peaks in the region of protein-like components. The co-addition of H2O2 did not present the anticipated increase in the reduction of fluorescence intensity; however, it resulted to the further oxidation of protein-like fluorophores. LC-OCD measurements confirmed the decrease of average molecular weight of NOM during ozone treatment, due to the gradual degradation of biopolymers (14–23%) and humic substances (11–17%) towards building blocks and low molecular weight (LMW) neutrals. Advanced oxidation process (AOP) treatment by the mixture O₃/H₂O₂ resulted in the simultaneous decrease of building blocks and LMW neutral concentrations. Conventional batch ozonation and AOP experiments were conducted using ozone-saturated solutions to investigate the effect of different contacting patterns. The results revealed that the different reaction pathways followed during bubbleless and conventional batch experiments may also influence the formation of NOM oxidation intermediates.
Subjects
Advanced oxidation processes (AOP)
EEMs
LC-OCD
Natural organic matter (NOM)
Ozonation
Peroxone
Reaction pathways
Biopolymers
Chromatography, Liquid
Humic Substances
Hydrogen Peroxide
Membranes, Artificial
Organic Chemicals
Oxidation-Reduction
Ozone
Spectrometry, Fluorescence
Water Pollutants, Chemical
Water Purification