Visible light caffeic acid degradation by carbon-doped titanium dioxide

Area of Science:

• Environmental Chemistry
• Materials Science
• Photocatalysis

Background:

• Phenolic compounds, like caffeic acid, are common pollutants in wastewater.
• Olive mill wastewater (OMW) poses environmental challenges due to high organic load.
• Effective removal of phenolic compounds is crucial for environmental remediation.

Purpose of the Study:

• To investigate the photodegradation of caffeic acid using carbon-doped titanium dioxide (TiO2) under visible light.
• To elucidate the role of adsorption in the overall removal process.
• To assess the potential application for treating olive mill wastewater.

Main Methods:

• Photocatalytic degradation experiments using carbon-doped TiO2 under visible light.
• UV-vis absorption spectroscopy and gas chromatography-ion trap mass spectrometry for analysis.
• Kinetic analysis using a second-order kinetic adsorption model.
• Adsorption isotherm studies, zeta potential, and scanning electron microscopy (SEM) to evaluate adsorption.

Main Results:

• Caffeic acid removal showed a dependence on substrate concentration.
• The photodegradation process followed a second-order kinetic adsorption model.
• Adsorption was identified as a key mechanism, confirmed by isotherm studies and surface analysis (zeta potential, SEM).
• A synergistic mechanism involving both adsorption and photodegradation governed the overall removal.

Conclusions:

• Carbon-doped TiO2 is effective for caffeic acid photodegradation under visible light.
• Adsorption plays a critical role, working synergistically with photodegradation.
• This photocatalytic approach shows significant potential for removing phenolic compounds from olive mill wastewater.