Heterogeneous Fenton Oxidation of Caffeine Using Zeolite-Supported Iron Nanoparticles

The current study aimed at exploring the potential of iron-embedded zeolites to serve as heterogeneous Fenton catalyst for the treatment of caffeine. Synthetic zeolites were modified through co-precipitation and subsequent deposition of iron precipitates on the zeolites. Catalyst was characterized through chemical composition, particle size and its distribution, BET specific surface area, FTIR, and XRD techniques. Batch mode studies were carried out, and process parameters including pH, contact time, and iron to hydrogen peroxide ratio (Fe+2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Fe}^{+2}$$\end{document}:H2O2)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{2}\hbox {O}_{2})$$\end{document} were optimized. Response surface methodology was employed for this purpose using Design Expert 10.0 software. Fe+2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Fe}^{+2}$$\end{document}:H2O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{2}\hbox {O}_{2}$$\end{document} ratio was found to be the most important parameter affecting the removal of caffeine. Significant interaction between pH and Fe+2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text {Fe}^{+2}$$\end{document}:H2O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{2}\hbox {O}_{2}$$\end{document} ratio was also observed. More than 80% removal of caffeine was achieved when the pH was in the range of 5.8–7 and Fe+2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\text {Fe}^{+2}$$\end{document}:H2O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {H}_{2}\hbox {O}_{2}$$\end{document} ratio in the range of 2.5–3. Catalyst was found stable, and negligible loss of iron under experimental conditions was observed. Moreover, the catalyst could be reused for at least three successive runs of treatment without significant loss in the activity of the catalyst.