Separations 2023 , 10 , 148
12of 15
Table3. Cont.
Relative Content (%)
Organic Compound
RT
Wastewater
Ozonation Catalytic Ozonation Pure TiO 2 /O 3
18.581 18.841 19.082 19.186 19.448 19.502 19.726 19.856 20.092 20.607 20.871 21.096 21.133 21.311 21.448 21.615 21.696 21.703 22.147 23.188 23.548 23.655 24.699 24.724 26.219 23.51
Dimethyl phthalate 2-Pentadecanone
-
-
0.11 0.21 0.37
0.09 0.65 0.32
2.46
1.35 0.21
Eicosane
-
Stearamide Palmitic acid
0.19 5.67 0.24 0.48 1.45 0.59 0.84 -
-
- - - - - - -
-
2.21
0.09
Dibutyl phthalate
- - - - - -
- - - - - -
Ethyl oleate
N-Pentadecanenitrile
0.05
2,2 -Methylenebis(4-methyl-6- tert-butylphenol) N,N-Dimethyldodecanamide 9,12-Octadecadienoic acid (Z,Z)- Pentadecanoic acid Stearyl Nitrile 1-Chlorononane (5E)-5-Octadecene Cyclohexadecane Oleic acid Oleic acid amide Ditetradecane Eruvic acid amide 6-Ethyl-3-octanol Nonyl hexanoate Dihexadecanoic acid N,N-Dimethyloctanamide 1-21 Alcohol
-
1.82 2.32
2.11 1.73
1.76 2.11
4.17
0.5
- - - - - -
- -
- -
2.15 1.22 1.07
0.54
0.14
0.22
-
-
- -
0.33 0.34
0.14 0.17 0.43 1.23 - 0.12 3.22 0.34 -
0.25
1.45
-
-
0.4
7.51 2.34
3.25
0.64
-
- -
1.1
0.64 1.15 0.32
- -
1.64 0.48
Nineteen alkane
When pure titanium dioxide powder was used to catalyze the ozonation treatment, in- termediates produced by the degradation of fatty acids such as tetradecanol and tetradecyl aldehyde were detected. At the same time, palmitic acid was not completely degraded after treatment, and styrene was completely degraded, but the intermediate styrene still existed. This shows that the degree of mineralization of pure titanium dioxide powder catalytic ozonation treatment is not high, and some compounds cannot be completely degraded, which may be caused by the fact that titanium dioxide powder is easy to agglomerate in water, resulting in a serious decline in activity. 3.7. Analysis of Degradation Mechanism of Two Kinds of DCSs As shown in Figure 8, according to the results of FT-IR and GC-MS, the degradation mechanisms of two kinds of DCSs are analyzed and the possible reaction paths are deduced. Under the strong oxidation of hydroxyl radicals, the palmitic acid is first decarboxylated to a radical with the release of the first C atom to CO; the C 14 H 29 radical is then oxidized to pentadecanol (C 15 H 32 O). The alcohol C 15 H 32 O is then oxidized to pentadecanal (C 15 H 30 O), followed by oxidation to pentadecanoic acid (C 15 H 30 O 2 ) [33]. Subsequently, the acid undergoes chain reactions to release the second and additional CO 2 until the pentadecanoic acid achieves complete mineralization into CO 2 andH 2 O [29]. Alcohols and aldehydes, the intermediate products of pentadecanoic acid, are not detected by GC-MS, which may be attributed to their rapid decomposition and oxidation.
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