Ozone facilitated degradation of caffeine using Ce-TiO₂ catalyst

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Caffeine is a common pharmaceutical pollutant in wastewater.
• Ozonation is a potential water treatment method, but its efficiency can be limited.
• Developing effective catalysts is crucial for advanced oxidation processes.

Purpose of the Study:

• To investigate the catalytic effect of cerium (Ce) on titanium dioxide (TiO2) for caffeine degradation.
• To optimize catalyst properties and reaction conditions (pH, ceria loading) for enhanced ozonation.
• To elucidate the degradation pathway and identify reaction products.

Main Methods:

• Synthesis of Ce/TiO2 nano-catalysts using the sol-gel method.
• Characterization of catalysts using SEM, TEM, BET, and XRD.
• Experimental ozonation of caffeine in water samples under varying conditions, followed by TOC analysis and LC-MS identification of products.

Main Results:

• Ce/TiO2 significantly enhanced caffeine degradation compared to uncatalyzed ozonation, proceeding via a free radical mechanism.
• Optimal performance (60% TOC removal in 2h) was achieved with 0.5 wt% Ce/TiO2 at pH 6 in natural water samples.
• One reaction intermediate and one final degradation product were identified using LC-MS.

Conclusions:

• Ce/TiO2 is an effective catalyst for the ozonation and degradation of caffeine in wastewater.
• The catalyst's mesoporous structure and large surface area contribute to its high activity.
• This catalytic ozonation process shows promise for removing pharmaceutical pollutants from water.