Modeling the photocatalytic degradation of formic acid in a reactor with immobilized catalyst

Dijkstra, Marcel; Panneman, H.J.; Winkelman, Jozef G. M.; Kelly, John J.; Beenackers, A.A.C.M.

doi:10.1016/s0009-2509(02)00290-7

Cited by 111 publications

(65 citation statements)

References 36 publications

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“…Studies by Stokke et al [11], Dijkstra et al [16], Cen et al [17], Alberci and Jardin [18], Kim and Hong [19], and Jacboy [20] reported that a UV-C-irradiated ("-max = 254 nm) reactor resulted in greater photocatalytic oxidation ofVOCs than a reactor irradiated with UV -A light ("-max = 365 nm), implying that a shorter wavelength light source (i.e., higher energy photons) is more efficient. However, interpretation of the results from these studies on the effect of wavelength of TiOz-assisted photocatalysis is confounded with the influence of light intensity as these studies were conducted either at different light intensities or the light intensity was not well defined.…”

mentioning

confidence: 98%

“…Previously, UV light sources of various wavelengths ranging between 250-400 nm, and with various intensities, have been used in TiOz-catalyzed photocatalysis [1,11,[16][17][18][19][20]. Studies by Stokke et al [11], Dijkstra et al [16], Cen et al [17], Alberci and Jardin [18], Kim and Hong [19], and Jacboy [20] reported that a UV-C-irradiated ("-max = 254 nm) reactor resulted in greater photocatalytic oxidation ofVOCs than a reactor irradiated with UV -A light ("-max = 365 nm), implying that a shorter wavelength light source (i.e., higher energy photons) is more efficient.…”

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confidence: 99%

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The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite

Coutts¹,

Levine²,

Richards³

et al. 2011

Journal of Photochemistry and Photobiology A: Chemistry

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Abstract:The objective of this study was to distinguish the effect of photon flux (i.e., photons per unit time reaching a surface) from that of photon energy (i.e., wavelength) of a photon source on the silica-titania composite (STC)-catalyzed degradation of ethanol in the gas phase.Experiments were conducted in a bench-scale annular reactor packed with STC pellets and irradiated with either a UV-A fluorescent black light blue lamp (Amax=365 nm) at its maximum light intensity or a UV-C germicidal lamp (Amax=254 nm) at three levels of light intensity. The STC-catalyzed oxidation of ethanol was found to follow zero-order kinetics with respect to CO 2 production, regardless of the photon source. Increased photon flux led to increased EtOH removal, mineralization, and oxidation rate accompanied by lower intermediate concentration in the effluent. The oxidation rate was higher in the reactor irradiated by UV-C than by UV-A (38.4 vs. 31.9 nM S-I) at the same photon flux, with similar trends for mineralization (53.9 vs.43.4%) and reaction quantum efficiency (i.e., photonic efficiency, 63.3 vs. 50.1 nmol CO 2 ~mol photons-I). UV-C irradiation also led to decreased intermediate concentration in the effluent . compared to UV -A irradiation. These results demonstrated that STC-catalyzed oxidation is enhanced by both increased photon flux and photon energy.

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mentioning

confidence: 98%

mentioning

confidence: 99%

The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite

Coutts¹,

Levine²,

Richards³

et al. 2011

Journal of Photochemistry and Photobiology A: Chemistry

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“…This mass balance shows that the TOC present in the effluent (0.007 mg C/min) was accounted for by the methanol (0.004 mg C/min) and formaldehyde (0.003 mg C/min). The lack of the presence of measurable amounts of formic acid in the effluent can be attributed to the fact that only one electron hole is necessary for the total degradation of formic acid, which, according to other literature values, results in a high apparent quantum yield (0.45) compared to other compounds (0.06-0.001) (Dijkstra et al 2002). Since formic acid is degraded directly to carbon dioxide and water, the balance of the effluent carbon should be present as carbon dioxide (Dijkstra et al 2002).…”

Section: Simultaneous Adsorption and Oxidation Of Methanolmentioning

confidence: 67%

Final Report

Mazyck¹,

Lindner²,

Sheahan³

2007

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EXECUTIVE SUMMARYForest products provide essential resources for human civilization, including energy and materials. In processing forest products, however, unwanted byproducts, such as volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) are generated. The goal of this study was to develop a cost effective and reliable air pollution control system to reduce VOC and HAP emissions from pulp, paper and paperboard mills and solid wood product facilities. Specifically, this work focused on the removal of VOCs and HAPs from high volume low concentration (HVLC) gases, particularly methanol since it is the largest HAP constituent in these gases. Three technologies were developed and tested at the bench-scale: (1) A novel composite material of activated carbon coated with a photocatalyst titanium dioxide (TiO 2 ) (referred to as TiO 2 -coated activated carbon or TiO 2 /AC), (2) a novel silica gel impregnated with nanosized TiO 2 (referred to as silica-titania composites or STC), and (3) biofiltration. A pilot-scale reactor was also fabricated and tested for methanol removal using the TiO 2 /AC and STC.The technical feasibility of removing methanol with TiO 2 /AC was studied using a composite synthesized via a spay desiccation method. The removal of methanol consists of two consecutive operation steps: removal of methanol using fixed-bed activated carbon adsorption and regeneration of spent activated carbon using in-situ photocatalytic oxidation. Regeneration using photocatalytic oxidation employed irradiation of the TiO 2 catalyst with low-energy ultraviolet (UV) light. Results of this technical feasibility study showed that photocatalytic oxidation can be used to regenerate a spent TiO 2 /AC adsorbent. A TiO 2 /AC adsorbent was then developed using a dry impregnation method, which performed better than the TiO 2 /AC synthesized using the spray desiccation method. The enhanced performance was likely a result of the better distribution of TiO 2 particles on the activated carbon surface. A method for pore volume impregnation using microwave irradiation was also developed. A commercial microwave oven (800 W) was used as the microwave source. Under 2450 MHz microwave irradiation, TTIP was quickly hydrolyzed and anatase TiO 2 was formed in a short time (< 20 minutes). Due to the volumetric heating and selective heating of microwave, the solvent and by-products were quickly removed which reduced energy consumption and processing time.Activated carbon and TiO 2 /AC were also tested for the removal of hydrogen sulfide, which was chosen as the representative total reduced sulfur (TRS) species. The BioNuchar AC support itself was a good H 2 S remover. After coating TiO 2 by dry impregnation, H 2 S removal efficiency of TiO 2 /AC decreased compared with the virgin AC due to the change of surface pH. Under UV light irradiation, H 2 S removal efficiency of TiO 2 /AC composite doubled, and its sulfate conversion efficiency was higher than that of AC. The formation of sulfate is preferred since the sulfate can be remo...

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“…Various studies have identified the existence of mass transfer limitations in many immobilized systems, such as tubular reactors [7], [8], annular reactors [9]- [11], rotating disc reactors [9], [12], and packed-bed reactors [7], [13], among others [14]. A commonly used model equation derived from first principles is a Langmuir-type equation based on volumetric flowrate Q [15], [16]:…”

Section: Introductionmentioning

confidence: 99%

Design, Mass Transfer Studies, and Optimization of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue

Dalida¹,

Ramoso²

2017

IJCEA

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Abstract-An alternative process for the removal of organic pollutants in aqueous systems is photocatalysis. The challenges hindering its industrial use are electron-hole recombination and mass transfer limitations. In order to address these problems, the objective of this study is to introduce air by sparging, and design an air-sparged photocatalytic reactor using titanium dioxide immobilized on borosilicate glass. The performance of the reactor on the removal of the model pollutant, methylene blue (MB), was evaluated and compared against the reactor operated without sparging. The effect of mass transfer limitations on reactor performance was also investigated by regression using a Langmuir-type model equation. Reactor performance was optimized using Response Surface Methodology to determine the set of initial MB concentration, treatment time, initial pH, and sparging rate that would result to the highest removal of methylene blue. The sparged photocatalytic reactor was able to degrade 57% MB in 2 hours, an improvement of 40% compared to no sparging. Mass transfer limitation studies showed that the reactor operates near the reaction-limited regime, and that the extent of mass transfer limitation effects was reduced. The set of parameters that maximizes methylene blue removal were 2.0 ppm MB, 120 minutes treatment time, pH 9.95 and 2.0 L/min sparging rate, with a predicted removal of 55.5%. Validation experiments resulted to 57.2% MB removal, and that the present reactor is comparable to similar reactors in literature, but with the advantage of using less expensive materials of construction and simpler immobilization technique.Index Terms-Photocatalysis, response surface methodology, tubular photocatalytic reactor, wastewater treatment.

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Modeling the photocatalytic degradation of formic acid in a reactor with immobilized catalyst

Cited by 111 publications

References 36 publications

The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite

The effect of photon source on heterogeneous photocatalytic oxidation of ethanol by a silica–titania composite

Final Report

Design, Mass Transfer Studies, and Optimization of an Air-Sparged Tubular Photocatalytic Reactor for the Degradation of Methylene Blue

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