Platinum-supported aluminum oxide on activated carbon filter media for removal of formaldehyde in the indoor condition

Abstract

Formaldehyde is one of the hazardous indoor air pollutants which have harmful effects on humans, domestic animals, and environmental health. The goal of this study was to synthesize a Pt/Al2O3 coated on granular activated carbon (GAC), which is easily recoverable and can be used as an absorbent for formaldehyde removal from polluted indoor air. Moreover, the Pt/Al2O3 catalyst could achieve complete and stable HCHO oxidation at ambient temperature. The characteristic properties of the Pt/Al2O3/GAC sample were analyzed using scanning electron microscopy, energy-dispersive spectrometer, Fourier-transform infrared spectroscopy, and Brunauer–Emmett–Teller techniques. The Pt/Al2O3/GAC catalyst was investigated to determine the catalytic performance with regard to formaldehyde (HCHO) oxidation under different face velocity and initial formaldehyde concentration applicable to a building environment. It was revealed that the removal capacity of Pt/Al2O3 catalyst reached a maximum of 2.23 mg g−1 during 0.1 m s−1 face velocity and 0.75 ppm HCHO inlet concentration. Among zero-, first- and second-order reaction kinetic model, the correlation coefficient of the first-order reaction kinetic model (0.7948 < R2 < 0.9249) and second-order reaction kinetic model (0.6056 < R2 < 0.8146) is lower than zero-order reaction kinetic model (0.9352 < R2 < 0.9921) of Pt/Al2O3 catalyst. The oxidation kinetic of HCHO was well fitted with the zero-order reaction for Pt/Al2O3 catalyst. This study provides some instructions for the design and manufacture of environmentally harmless and cost-effective catalysts with excellent catalytic oxidation properties to remove HCHO at room temperature.