Comparative study of ozonation and synthetic goethite-catalyzed ozonation of individual NOM fractions isolated and fractionated from a filtered river water

Abstract

HON) and hydrophilic acid and base (HIA and HIB) were four major NOM fractions isolated from a filtered river water; so ozonation and catalytic ozonation were carried out on these fractions. Results indicate that in comparison to ozonation alone, catalytic ozonation can enhance ozone consumption, UV 254 and DOC reduction, fragmentation of fraction components with MW43000 Da, and formation of oxalic acid for these fractions under normal reaction conditions commonly adopted in water treatment plants. In addition, catalytic ozonation can enhance aldehydes formation and increase the percentage of easy biodegradable organic carbon compared with ozonation alone for HIA and HIB, but exert much less effect on these items for HOA and HON.

Formation of aldehydes and carboxylic acids in ozonated surface water and wastewater: A clear relationship with fluorescence changes

“…The total amount of the carboxylic acids was about five times higher than that of the aldehydes, constituting a major fraction of newly formed AOC by ozonation. Similar observations have been made for experiments with other forms of advanced oxidation processes (AOPs) including O 3 /FeOOH (Zhang et al, 2008), O 3 /H 2 O 2 (Wert et al, 2007) and UV/H 2 O 2 treatment (Sarathy and Mohseni, 2007).…”

Decomposition of 1,4-dioxane by vacuum ultraviolet irradiation: Study of economic feasibility and by-product formation

“…Additionally, some of the NOM th a t was not converted to form aldehyde during chlorination m ay have been transform ed to form aldehyde forming com pounds during VUV treatm ent, and therefore would also contribute to the increase in the form aldehyde concentration after chlorination. Glyoxal w as also observed in the lake w ater subjected to VUV/CI2 treatm ent, and this result agrees w ith previous results reported by (Zhang et al, 2008). However, w hen the VUV-treated lake w ater w as subse quently treated w ith BAC or virgin GAC, the form aldehyde and glyoxal concentrations observed after the final chlorination w ere substantially lower th a n before the carbon treatm ent.…”

“…Zhang et al (2008) reported th a t alde hydes are produced from NOM during a catalytic ozonation process, in w hich hydroxyl radicals play a critical role, and th a t am ong the aldehydes, form aldehyde w as produced in the largest am ounts. During VUV trea tm e n t in the present study, m ost of the reactions th a t occurred were caused by hydroxyl radicals, and this is likely the reason th a t a large am ount of form aldehyde w as produced.…”

Evaluation of disinfection by-products formation during chlorination and chloramination of dissolved natural organic matter fractions isolated from a filtered river water

“…The isolation and fractionation procedure was described in a former work [14]. Hydrophobic acid, hydrophobic neutral, hydrophobic base, hydrophilic acid, hydrophilic neutral and hydrophilic base were isolated by XAD-8, XAD-4, AG-MP-50 and Duolite A-7 resins.…”