This study focusses on the photocatalytic degradation of caffeine (CAF) a stimulating drug and environmental contaminant that pose threat to humans and the environment. The effect of operating parameters such as; CAF initial concentration (5–20 mg/L), catalyst dosage (0.1–0.9 g/L) and pH (3.0–9.0) were explored in detail. The experimental results showed the maximum CAF and chemical oxygen demand (COD) removals of 87.2% and 66.7% respectively. The optimized parameters were; CAF initial concentration – 5 mg/L, catalyst dosage – 0.5 g/L and pH – 7.2. The photocatalytic degradation of CAF followed pseudo-first order kinetics. The obtained experimental data were analysed with response surface methodology (RSM) using Design Expert Software.

  • The optimized parameters were; [CAF]=5 mg/L, [TiO2]=0.5 g/L, pH=7.2.

  • The maximum CAF and COD removals were 86.7 and 66.7% respectively.

  • CAF and COD removals followed pseudo-first-order kinetics.

  • Good agreement between experimental and predicted data.

  • All operating parameters were significant in CAF and COD removals.

Graphical Abstract

Graphical Abstract
Graphical Abstract
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