A pilot-scale photocatalyst-membrane hybrid reactor: performance and characterization.

Area of Science:

• Environmental Engineering
• Materials Science
• Chemical Engineering

Background:

• Photocatalysis and membrane filtration are advanced oxidation processes for water treatment.
• Developing integrated systems can enhance pollutant removal efficiency and operational stability.
• Titanium dioxide (TiO2) is a widely studied photocatalyst for degrading organic contaminants.

Purpose of the Study:

• To develop and evaluate a pilot-scale photocatalyst-membrane hybrid reactor for water treatment.
• To assess the reactor's performance in degrading various organic pollutants.
• To investigate the impact of operating conditions, particularly suction modes, on reactor efficiency and membrane fouling.

Main Methods:

• A pilot-scale hybrid reactor combining photocatalysis (using TiO2) and membrane filtration was constructed and tested.
• Performance was evaluated by monitoring the degradation of humic acids, methylene blue, rhodamine B, and 4-chlorophenol.
• Membrane suction pressure was monitored under continuous and intermittent suction modes to assess fouling.

Main Results:

• The hybrid reactor demonstrated efficient degradation of 4-chlorophenol (100 ppb fully degraded in 2 hours).
• Humic acid concentration initially increased then decreased due to photoinduced desorption from TiO2.
• Methylene blue decolorization was faster than rhodamine B, but mineralization rates were reversed.
• Continuous suction led to TiO2 cake layer formation and increased pressure; intermittent suction (9 min suction, 3 min pause) prevented fouling.

Conclusions:

• The photocatalyst-membrane hybrid reactor is a promising technology for micropollutant removal in water.
• The intermittent suction mode is crucial for mitigating membrane fouling and ensuring sustained operation.
• This integrated system offers an attractive solution for advanced water purification and contaminant control.