Titanium(IV) Oxide Modified with Activated Carbon and Ultrasounds for Caffeine Photodegradation: Adsorption Isotherm and Kinetics Study
Piotr Zawadzki 1  
,   Edyta Kudlek 2  
,   Mariusz Dudziak 2  
 
More details
Hide details
1
Central Mining Institute
2
Silesian University of Technology, Institute of Water and Wastewater Engineering, Konarskiego 18, 44-100 Gliwice, Poland
CORRESPONDING AUTHOR
Piotr Zawadzki   

Central Mining Institute
Publication date: 2020-11-01
 
J. Ecol. Eng. 2020; 21(8):137–145
 
KEYWORDS
TOPICS
ABSTRACT
In this paper the adsorption and photodegradation of caffeine (CAF) using modified photocatalysts were studied. The laboratory synthesis method of commercial titanium(IV) oxide, activated carbon and ultrasound was proposed. The adsorption effect of caffeine was described by the Langmuir and Freundlich isotherms. The effectiveness of CAF photocatalytic decomposition was evaluated as well as the parameters of the pseudo-first-order and pseudo-second-order reaction kinetics were estimated. It was determined that the caffeine adsorption fit both the Langmuir and Freundlich isotherms. The value of the experimental maximum adsorption capacity (qe) was the highest for TiO2 modified with activated carbon and ultrasounds (TiO2/AC/Us). The highest removal degree (over 99.0%) of CAF was observed for titanium(IV) oxide modified with activated carbon. Both photodegradation kinetics models show good or very good fit; however, the pseudo-first-order model shows better fit to the experimental data (R2 = 97-99%). After 20 minutes of the photodegradation process, the following efficiency order was determined: TiO2 < TiO2/AC < TiO2/AC/US. The results indicate that the combination of TiO2, activated carbon and ultrasound is an interesting alternative for the efficient degradation of caffeine, comparing to commercial TiO2.