2.4. Photocatalytic experiment
The photocatalytic experiment was carried out in a photochemical
reactor. A xenon lamp (1000 W) simulates sunlight. Weigh 50 mg of
photocatalyst, scatter it into a beaker with 50 ml of 10 mg/L methyl
orange, put it in the photochemical reactor, close the box door to avoid
alternating light and dark, stir and adsorb for 20 minutes, turn on the
light source, take 4 ml of samples every 5 minutes, and take the
supernatant after centrifugation. The absorbance of the methyl orange
solution before and after the reaction was measured by a UV-Vis
spectrophotometer at 464 nm. During the reaction, hold the reaction
suspension at about 10 °C. Beer Lambert’s Law was used to calculate the
degradation rate of photocatalytic degradation of MO. Characterization
of photocatalytic degradation of MO using the kinetic equation method:
\(\frac{\complement_{t}}{\complement_{0}=}\frac{A_{t}}{A_{0}}\) (1)
\(A_{t}+Kt=-ln(\frac{C_{t}}{C_{0}})\) (2)
A0 and At show the absorbance of the
solution at the initial and post-irradiation times, and
C0 and Ct show the corresponding initial
concentration of the solution and the solution concentration after t
time.
Catalyst cycle stability analysis: collect the photocatalyst after each
use, wash and dry it many times, and repeat the above steps twice to
investigate its cycle stability.
Free radical capture experiment: Using isopropanol (IPA) as hydroxyl
radical (OH·) trapping agent, triethanolamine (TEOA) as hole
(h+) trapping agent, and p-benzoquinone (BQ) as
superoxide radical (O- 2· ) trapping agent, the active
factors in the catalytic degradation process of the objective
contaminant were analyzed through the change in degradation efficiency
before and after the addition of trapping agent.
3.
Results and Discussion