Doxycycline Degradation by the Oxidative Fenton Process
Table 1
Experimental conditions of tests of doxycycline degradation carried out according to the experimental RCCD, coded and uncoded values of the independent variables, and results of residual doxycycline () and total organic carbon (TOC) concentrations at the end of the Fenton process.
Test
(mg/L)
(mg/L)
(°C)
(mg/L)
TOC (mg/L)
1
−1
−1
−1
28.3
262
8.1
28.6
38.4
2
+1
−1
−1
96.7
262
8.1
5.8
45.8
3
−1
+1
−1
28.3
738
8.1
18.5
45.0
4
+1
+1
−1
96.7
738
8.1
4.3
41.7
5
−1
−1
+1
28.3
262
31.9
13.6
41.9
6
+1
−1
+1
96.7
262
31.9
2.6
40.7
7
−1
+1
+1
28.3
738
31.9
7.8
36.0
8
+1
+1
+1
96.7
738
31.9
3.0
40.6
9
−1.68
0
0
5.0
500
20.0
4.4
47.4
10
+1.68
0
0
120.0
500
20.0
3.3
45.3
11
0
−1.68
0
62.5
100
20.0
55.8
46.6
12
0
+1.68
0
62.5
900
20.0
4.7
38.8
13
0
0
−1.68
62.5
500
0.0
21.4
40.7
14
0
0
+1.68
62.5
500
40.0
2.6
40.4
15
0
0
0
62.5
500
20.0
0.0
40.4
16
0
0
0
62.5
500
20.0
0.2
45.6
17
0
0
0
62.5
500
20.0
2.0
45.2
18
0
0
0
62.5
500
20.0
0.0
41.2
19
0
0
0
62.5
500
20.0
0.0
39.2
20
0
0
0
62.5
500
20.0
0.4
38.5
Mean results at the central point
0.43
41.7
Standard deviation at the central point
0.52
3.0
Variation coefficient at the central point
1.21
0.073
= initial concentration of ferrous ion; = initial concentration of hydrogen peroxide; = temperature; = coded values of ; = coded values of ; = coded values of .
