Tio2 P90 (Evonik, Germany) As The Photocatalyst
Aeroxide® TiO2 P90 (Evonik, Germany) was used in all experiments as the photocatalyst. The properties of TiO2 nanoparticles are given in Table 3.1 according to the supplier. The suspensions were prepared by dispersion of the desired amount of TiO2 in deionized water. The suspension was magnetically mixed at the stirrer speed of 500 – 600 rpm.
Table 3.1. Characteristic physicochemical data of Aeroxide® TiO2 P90
Properties Unit
Primary particle size µm 14
Specific surface area (BET) m2/g 90 ± 20 Tamped density g/L Approx.. 1220 pH (in 4% dispersion) 3.2 – 4.5
TiO2 - content wt.% ≥ 99.50 80% anatase, 20% rutile
The nature pH of TiO2 suspension was 4.9 ± 0.2 and adjusted to the desired value by addition of H3PO4 (10%) or NaOH (0.1 M) if …show more content…
Turbidity measurement
The concentration of TiO2 suspension was determined based on the concentration – turbidity calibration curve prepared with known concentrations (Figure 3.11). The turbidity of the suspension was measured using a turbidity meter WTW-Turb 550 (Germany). Figure 3.11. Calibration graph between TiO2 concentration and turbidity
3.5.3. TOC analysis
The amount of total organic carbon (TOC) in the aqueous sample was measured by the Multi N/C 2100 (Analytik Jena, Germany). The samples of the reaction mixture were collected at regular time intervals. Prior to TOC analysis, the samples were filtered through a CHROMAFIL® O-20/15MS filter to remove the particles. The volume of the samples ranged from 5 to 10 mL.
The TOC degradation as the photocatalytic degradation efficiency was determined according to Equation (24).
TOC degradation =(〖TOC〗_t-〖TOC〗_0)/〖TOC〗_0 .100 (%) (24)
The reaction rate was also calculated as Equation (25): r=(〖TOC〗_t-〖TOC〗_0)/∆t (25)
where r is the degradation rate (mgTOC/L/min), TOCt and TOC0 are the TOC concentration in the bulk reaction mixture at the end and at the beginning of the irradiation (mg/L), respectively and Δt is the irradiation time (min). Furthermore, the apparent rate constant k was determined as the slope of the plot between ln(TOC/TOC0) and irradiation
Table 3.1. Characteristic physicochemical data of Aeroxide® TiO2 P90
Properties Unit
Primary particle size µm 14
Specific surface area (BET) m2/g 90 ± 20 Tamped density g/L Approx.. 1220 pH (in 4% dispersion) 3.2 – 4.5
TiO2 - content wt.% ≥ 99.50 80% anatase, 20% rutile
The nature pH of TiO2 suspension was 4.9 ± 0.2 and adjusted to the desired value by addition of H3PO4 (10%) or NaOH (0.1 M) if …show more content…
Turbidity measurement
The concentration of TiO2 suspension was determined based on the concentration – turbidity calibration curve prepared with known concentrations (Figure 3.11). The turbidity of the suspension was measured using a turbidity meter WTW-Turb 550 (Germany). Figure 3.11. Calibration graph between TiO2 concentration and turbidity
3.5.3. TOC analysis
The amount of total organic carbon (TOC) in the aqueous sample was measured by the Multi N/C 2100 (Analytik Jena, Germany). The samples of the reaction mixture were collected at regular time intervals. Prior to TOC analysis, the samples were filtered through a CHROMAFIL® O-20/15MS filter to remove the particles. The volume of the samples ranged from 5 to 10 mL.
The TOC degradation as the photocatalytic degradation efficiency was determined according to Equation (24).
TOC degradation =(〖TOC〗_t-〖TOC〗_0)/〖TOC〗_0 .100 (%) (24)
The reaction rate was also calculated as Equation (25): r=(〖TOC〗_t-〖TOC〗_0)/∆t (25)
where r is the degradation rate (mgTOC/L/min), TOCt and TOC0 are the TOC concentration in the bulk reaction mixture at the end and at the beginning of the irradiation (mg/L), respectively and Δt is the irradiation time (min). Furthermore, the apparent rate constant k was determined as the slope of the plot between ln(TOC/TOC0) and irradiation