Skip to Main Content
Tables 2 and 3 show the effects of various parameters, such as different concentrations of titanium dioxide, on the removal efficiency of MB dye and COD. Comparing dye removal efficiency at different concentrations of titanium dioxide showed that the dye removal efficiency increased with the increase in photocatalyst concentration. However, dye removal efficiency showed a slight difference at concentrations of 0.9 and 1.2 of titanium dioxide. According to Table 2, dye removal efficiency in batch and tubular reactors was 15.2% and 3.5%, respectively, after 5 min of reaction time, while it was 100% and 93%, respectively, after 60 min of reaction time. The results of the present study showed that the removal efficiency of dye and COD increased with the increase in TiO2 concentration and reaction time (Figure 4). This result is consistent with the results of similar previous studies (Kuo 2001; An & Zhu 2002). Based on the obtained results, the removal efficiency of dye and COD was 99% and 37.7%, respectively, in the batch reactor at the concentration of 0.3 g/L of titanium dioxide, while it was 74.3 and 33.3% in the tubular reactor. Concerning concentration of 1.2 g/L of titanium dioxide and contact time of 60 min, the removal efficiency of dye and COD was 100% and 42.2%, respectively, in the batch reactor, while it was 93 and 47.8% in the tubular reactor. As indicated in Table 4, increased photocatalyst concentration (up to a certain concentration) played a role in increasing removal efficiency. If the photocatalyst concentration exceeded the optimal limit, it had a negative effect on the removal efficiency because catalyst particles prevented penetration of light photons (Chakrabarti & Dutta 2004). The increase of process efficiency with titanium dioxide dosage can be attributed to the increase in reactive radicals for degradation of dye and COD. Asgari et al. (2013) reported that the catalytic ozonation efficiency increased with bone charcoal dosage as a catalytic in the ozonation process.
Table 2

The effect of contact time on dye removal at different TiO2 concentrations (dye concentration: 60 mg/L, pH: 7)

TiO2 concentration (mg/L)Dye removal (%)
Time: 5 min
Time: 15 min
Time: 30 min
Time: 60 min
BatchTubularBatchTubularBatchTubularBatchTubular
0.3 10.2 0.4 42.2 86.6 38.2 99 74.3 
0.6 13.3 46.5 12.5 88.8 49.9 99.9 76.2 
0.9 15.1 54.4 20 90.1 56.6 100 90.7 
1.2 15.2 3.5 55 21.7 92.2 60 100 93 
TiO2 concentration (mg/L)Dye removal (%)
Time: 5 min
Time: 15 min
Time: 30 min
Time: 60 min
BatchTubularBatchTubularBatchTubularBatchTubular
0.3 10.2 0.4 42.2 86.6 38.2 99 74.3 
0.6 13.3 46.5 12.5 88.8 49.9 99.9 76.2 
0.9 15.1 54.4 20 90.1 56.6 100 90.7 
1.2 15.2 3.5 55 21.7 92.2 60 100 93 
Table 3

The effect of titanium dioxide concentration on COD removal at different contact time (dye concentration: 60 mg/L, pH: 7)

TiO2 concentration (mg/L)Dye removal (%)
Time: 5 min
Time: 15 min
Time: 30 min
Time: 60 min
BatchTubularBatchTubularBatchTubularBatchTubular
0.3 3.5 7.7 4.5 28.8 7.7 37.7 33.3 
0.6 2.7 4.7 30.3 7.8 39.9 39.8 
0.9 5.5 2.7 9.9 5.9 36.6 8.3 40.1 44 
1.2 5.5 3.3 10.2 6.4 38 42.2 47.8 
TiO2 concentration (mg/L)Dye removal (%)
Time: 5 min
Time: 15 min
Time: 30 min
Time: 60 min
BatchTubularBatchTubularBatchTubularBatchTubular
0.3 3.5 7.7 4.5 28.8 7.7 37.7 33.3 
0.6 2.7 4.7 30.3 7.8 39.9 39.8 
0.9 5.5 2.7 9.9 5.9 36.6 8.3 40.1 44 
1.2 5.5 3.3 10.2 6.4 38 42.2 47.8 
Table 4

The effect of initial dye concentration on dye removal (TiO2 concentration: 1.2 g/L, pH: 7)

Time (min)Dye removal (%)
Dye concentration: 15 mg/L
Dye concentration: 30 mg/L
Dye concentration: 60 mg/L
BatchTubularBatchTubularBatchTubular
48.8 22.5 30.8 8.3 15.2 3.5 
15 83.3 39.9 77.1 22 55 21.7 
30 97.7 66.7 94.2 64 92.2 60 
60 100 98.3 100 96 100 93 
Time (min)Dye removal (%)
Dye concentration: 15 mg/L
Dye concentration: 30 mg/L
Dye concentration: 60 mg/L
BatchTubularBatchTubularBatchTubular
48.8 22.5 30.8 8.3 15.2 3.5 
15 83.3 39.9 77.1 22 55 21.7 
30 97.7 66.7 94.2 64 92.2 60 
60 100 98.3 100 96 100 93 
Figure 4

(a) Dye removal change with TiO2 concentration change; (b) effect of TiO2 nanoparticle dose to one factor in batch reactor (C.Initial Dye: 60 mg/L, pH: 7).

Figure 4

(a) Dye removal change with TiO2 concentration change; (b) effect of TiO2 nanoparticle dose to one factor in batch reactor (C.Initial Dye: 60 mg/L, pH: 7).

Close Modal

or Create an Account

Close Modal
Close Modal