Water disinfection using hydrogen peroxide with fixed bed hematite catalyst - kinetic and activity studies

Area of Science:

• Environmental Science
• Catalysis
• Water Treatment

Background:

• Effective water disinfection is crucial for public health.
• Hydrogen peroxide (H₂O₂) is a potential disinfectant but requires efficient catalytic decomposition.
• Hematite (Fe₂O₃) shows promise as a Fenton-like catalyst.

Purpose of the Study:

• To design and evaluate a lab-scale fixed-bed reactor with a hematite catalyst for H₂O₂ decomposition and bacterial inactivation.
• To investigate the kinetics of bacterial inactivation and H₂O₂ decomposition.
• To assess catalyst stability and iron leaching during water disinfection.

Main Methods:

• Design of a fixed-bed reactor utilizing a hematite catalyst.
• Experiments conducted with varying initial bacterial counts (E. coli) and H₂O₂ concentrations.
• Kinetic analysis using first-order reaction models for H₂O₂ and the modified Weibull model for bacterial inactivation.
• Catalyst characterization using XRD, FTIR, SEM, and ICP-OES.

Main Results:

• Significant bacterial reduction (3.5-4 log) achieved with 5 mM H₂O₂ and a 104-min residence time.
• H₂O₂ decomposition followed first-order kinetics; bacterial inactivation kinetics were described by the Weibull model (n < 1).
• Catalyst stability confirmed, with minimal iron leaching below WHO limits for drinking water.

Conclusions:

• Technical-grade hematite is an effective Fenton-like catalyst for water disinfection.
• The fixed-bed reactor design is suitable for mobile water purification applications.
• The system offers a promising solution for emergency water treatment.