Fe-Doped TiO2-Carbonized Medium-Density Fiberboard for Photodegradation of Methylene Blue under Visible Light.

Justin Alfred Pe,Min Lee,Sung-Phil Mun

doi:10.3390/ma14174888

Justin Alfred Pe, Min Lee + Show 1 more

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https://doi.org/10.3390/ma14174888

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Abstract

Fe–doped titanium dioxide–carbonized medium–density fiberboard (Fe/TiO2–cMDF) was evaluated for the photodegradation of methylene blue (MB) under a Blue (450 nm) light emitting diode (LED) module (6 W) and commercial LED (450 nm + 570 nm) bulbs (8 W, 12 W). Adsorption under daylight/dark conditions (three cycles each) and photodegradation (five cycles) were separately conducted. Photodegradation under Blue LED followed pseudo-second-order kinetics while photodegradation under commercial LED bulbs followed pseudo-first-order kinetics. Photodegradation rate constants were corrected by subtracting the adsorption rate constant except on the Blue LED experiment due to their difference in kinetics. For 8 W LED, the rate constants remained consistent at ~11.0 × 10−3/h. For 12 W LED, the rate constant for the first cycle was found to have the fastest photodegradation performance at 41.4 × 10−3/h. After the first cycle, the rate constants for the second to fifth cycle remained consistent at ~28.5 × 10−3/h. The energy supplied by Blue LED or commercial LEDs was sufficient for the bandgap energy requirement of Fe/TiO2–cMDF at 2.60 eV. Consequently, Fe/TiO2–cMDF was considered as a potential wood-based composite for the continuous treatment of dye wastewater under visible light.

Highlights

Medium-density fiberboard (MDF), one of the wood-based panels with various physical properties and grades, is an extremely versatile building product that is commonly used in many home and professional projects including furniture, flooring, decorative projects, doors, and door frames
Anatase was the favored crystalline structure of the Ti-tip-treated Carbonized medium-density fiberboards (cMDFs) carbonized at 600–900 ◦C; carbonization beyond 900 ◦C preferred the formation of rutile [6]
The photodegradation experiments were performed without pre-adsorption using a fresh set of Fe/TiO2–cMDF slabs for five cycles

Summary

Introduction

Medium-density fiberboard (MDF), one of the wood-based panels with various physical properties and grades, is an extremely versatile building product that is commonly used in many home and professional projects including furniture, flooring, decorative projects, doors, and door frames. Lee et al prepared two different types of TiO2–cMDFs for the removal of aromatic VOCs, especially toluene: (1) one-step preparation of TiO2–cMDF through in situ formation from a titanium tetraisopropoxide precursor on the surface of MDF via carbonization [6] and (2) synthesis of TiO2 by sol-gel method and application to the surface of cMDF [7] These TiO2–cMDFs exhibited outstanding removal performance for formaldehyde, one of the major VOCs that cause sick house syndrome, and toluene, a hardly degradable aromatic VOC, through adsorption and photodegradation under UV irradiation [6,7]. No difference was observed between the toluene degradation performances of Fe and Co/TiO2–cMDF

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