Plate Photocatalytic Reactor Research Articles

The design of novel swash plate photocatalytic reactor with PAN/BiInOCl membrane photocatalyst for excellent RhB degradation

The low recovery efficiency and secondary pollution of traditional powder photocatalysts are the main problems restricting the practical application of photocatalysis technology. Therefore, PAN/BiInOCl membrane photocatalysts were prepared by simple electrospinning technology, and the swash plate photocatalytic reactor was designed according to the utilization characteristics of the membrane photocatalyst. By cooperating membrane photocatalyst with the swash plate photocatalytic reactor, the rapid and effective photocatalytic degradation of RhB simulated wastewater by PAN/BiInOCl membrane photocatalyst can be achieved, and the rapid and non-destructive recovery of photocatalysts can be realized. PAN/BiInOCl-3 membrane photocatalyst with the best photocatalytic degradation efficiency can realize the complete degradation of RhB within 30 min and has good stability under the actual sunlight irradiation. Radical trapping experiments confirmed that hydroxyl radicals and holes play a major role in the photocatalytic degradation of RhB. The preparation of PAN/BiInOCl membrane photocatalyst and the design of swash plate photocatalytic reactor lay a theoretical foundation for the design and preparation of efficient membrane photocatalyst and the application of photocatalytic technology in wastewater treatment.

A high-performance solar chimney in building integrated with photocatalytic technology for atmospheric methane removal

The techniques for the removal of methane from the atmosphere are highly challenging due to its stable chemical properties, dispersed sources, and low concentrations. This paper proposes a practical small-scale solar chimney (SC) in buildings with photocatalytic reactors (PCRs) for atmospheric methane removal. Two comprehensive numerical models on photocatalytic reaction and indoor ventilation are developed. The numerical simulation considers the performance of methane removal and indoor air ventilation of the proposed system, as well as its specific crucial parameters such as the type of PCRs, solar radiation, and flow channel width. The obtained results show that the SC with honeycomb photocatalytic reactor (HPCR) is more able to remove atmospheric methane than SC with plate photocatalytic reactor (PPCR) under the premise of meeting the ventilation standards. In addition, there is a maximum methane purification rate of 57.27 μg/s under the condition that the air gap width is 0.3 m, the length of the HPCR is 1.5 m, and the porosity is 0.85. It is then proved that the SC in buildings with PCRs can allow small-scale, zero-energy consumption, continuable, and decentralized low-concentration atmospheric methane removal while improving the indoor ventilation.

Modelling and analysis of hydrodynamics and flow phenomena of fluid with formic acid as pollutant in the reactive area of a flat plate photocatalytic reactor with top and bottom turbulence promote

The inadequate mixing of pollutant and its low mass transfer in the reactive surface reduces the efficiency of photocatalytic reactor. A computational model is developed, and numerical analysis is conducted to examine the effect of top and bottom baffles on the mass transfer and hydrodynamic performance of the reactor compared to reactor without baffle in this study. The hydrodynamic flow phenomena such as local streamlines, velocity, turbulence characteristic, pressure-drops, and wall shear stress were investigated. The experiment was done in a lab-scale flat-plate photocatalytic reactor using Formic Acid as pollutant in feed water for model validation. The FA concentration versus feed flow rate and velocity as a function of time showed good agreement between simulation and experimental results (only about 5 % variation). From the simulation, it was found that the pressure drops increase with increase in baffle height and the lowest was found to be 0.1 kPa and 0.4 kPa when the baffle height was 5 mm at velocity of 0.15 m/s and 0.5 m/s respectively. The highest turbulent kinetic energy and the dissipation was found 0.215 m2/s2 and 46 m2/s3 respectively when the baffle height was 12 mm in the present simulation. Baffles significantly changes the hydrodynamic performance such as turbulence, velocity, mass of pollutant and the pressure drops. The velocity magnitude also increases and the highest was found to be 9.2 times of the free stream velocity when 12 mm top baffle was used. Similar trends were found for bottom baffles. The highest magnitude of turbulent kinetic energy was found to be four times higher than the plain reactor without baffle. Therefore, baffle will significantly promote turbulence and improve the hydrodynamic performance thus enhance the photocatalytic rector performance.

Phenol degradation of waste and stormwater on a flat plate photocatalytic reactor with TiO2 on glass slide: An experimental and modelling investigation

Heterogeneous photocatalytic oxidation process using TiO2 (titanium dioxide) and UV light is a promising method to degrade a wide variety of recalcitrant organic substances such as phenol, pesticides, herbicides, etc. from waste and stormwater. Due to lack of suitable computational fluid dynamics (CFD) model, the industrial-scale application of this technique poses a few challenges indicating the need to clearly understand the hydrodynamic behaviour of the photocatalytic system and investigate the ways of improving their performance. Inadequate mixing and turbulence in a fixed photocatalytic reactor limit the performance of the reactor in terms of pollutant mass transport to the catalyst surface and pollutant degradation. In this study, a 3D flat plate photocatalytic reactor was designed and developed, and numerically analysed using CFD code FLUENT to investigate the performance of the reactor. The CFD modelling results were validated against the experimental data at various flow conditions. The CFD results including velocity and phenol concentration was found in strong agreement with the experimental results with R2 value of 0.998. The experimental results shows that the phenol degradation was 85.5% when the irradiation was 70.6 Wm−2 and initial concentration of phenol was 20 PPM The experimental results also show that the phenol degradation increases with the increase of irradiation but decreases with the increase of initial concentration. The results show that phenol degradation of the reactor decreases with the increase in flow rate as expected. The CFD model can accurately predict the velocity and the concentration of phenol at different flow rates.

Rate of Photocatalytic Degradation of Acid Orange 7 Azo Dye on TiO2 Coated Layers: Role of pH and Initial Dye Concentration

This paper examined the role of pH and initial dye concentration on the rate of Acid Orange 7 photocatalytic degradation. A batch mode plate photocatalytic reactor fitted with a TiO2 coated layer of dimensions (10cm×15cm) immobilized on microscopic glass was used. The coated layer was prepared by sedimentation from an aqueous suspension of 5 g.L-1 phase and annealed at 300°C. Polychromatic sun beds lamps were used as a source of Ultra Violet (UV) light with maximum intensity at wavelength λ= 365 nm. An appropriate dye solution flow rate of 50 lit/hr was used. A UV-Vis spectrophotometer monitored changes in dye concentrations at λ_max= 485 nm. From changes in dye concentration during irradiation the rate of photocatalytic degradation was determined. The findings reveal that pH range 5 to 9 the degradation rate is almost constant, for pH values lower than 5 it marginally increases while for pH values above 9 it significantly decreases. Additionally the degradation rate increased significantly with increasing initial dye concentration in the range from (1×10-5 mol.L-1 to 8×10-5 mol. L-1). The amount of adsorbed Acid Orange 7 increases with increased dye concentration, however for concentrations greater than 1×10-4 mol. L-1 it was observed that the increase was marginal. The findings confirm a direct correlation between the amount of dye adsorbed and resultant degradation rate. The optimum pH and initial dye concentration were determined ;[( pH= 3, r=1.6×10-7 mol.m-2.s-1); (initial concentration = 8×10-5 mol.L-1 to 1×10-4 mol.L-1, r= 3×10-7 mol.m-2.s-1)]. A shift in dye solution pH from acidic to basic in the range 3 to 11.5 reduced photocatalytic degradation rates by 56.3%.

CFD + DoE optimization of a flat plate photocatalytic reactor applied to NOx abatement

This paper illustrates the optimization of a flat plate photocatalytic reactor through a computational framework coupling CFD, taking into account the radiation field modeling, and design of experiments (DoE). The CFD-based DoE approach was used to analyze the influence of the reactor’s height (H) and inlet velocity (vx,in) on the NO conversion (XNO), the integral rate of NO consumption and the pressure drop with Box-Cox power transformation (ΔP-0.15). Results showed that XNO increases when decreasing H and vx,in. A critical point of maximum was observed for the integral rate of NO consumption. However, the pressure drop decreases with the increase of H. Additionally, an optimization strategy based on the desirability function approach was used to optimize the process, and the optimum values were H = 7.78 mm and vx,in = 68 mm·s−1. The values predicted by the metamodel and the CFD code showed promising results for this methodology.

A corrugated plate photocatalytic reactor for degradation of waterborne organic contaminants

AbstractA UV‐C/titanium dioxide (TiO2) plate coated photocatalytic reactor using a corrugated frame system was designed for water borne organic contaminant degradation. The anticipated advantages of using the corrugated layout include a larger photocatalytic surface area per unit volume and improved photocatalytic activity. The water distribution system was designed to assist effective interactions among the water pollutant, photocatalyst, and photons. The degradation of a methylene blue solution, as a model water contaminant, was carried out at room temperature (22 °C) at different concentrations and flowrates. With an 11 mg/L methylene blue solution, 70 % was degraded within the first 10 min using TiO2 coated corrugated plates, whereas under the same conditions the degradation rate was only 12 % for a corrugated reactor without a catalyst coating, and 4 % for a no‐plate reactor. The methylene blue degradation was described by the Langmuir‐Hinshelwood model, and the apparent photonic efficiency of the corrugated arrangement was found to be in the range of 1.53–2.83 % when half the initial concentration was degraded.The local area specific rate of energy absorption (LASREA) profile over the plates was determined from a model developed based on UV‐C light irradiation distribution and plate configuration. Light intensity measurements were carried out and were found to correlate with this model. A set of corrugated plate photocatalytic reactors with different geometries, but with the same coated area, were then analyzed and absorbed UV light intensities were integrated to determine the best geometry.

Solar assisted degradation of carbendazim in water using clay beads immobilized with TiO2 & Fe doped TiO2

The current work emphasized on the sunlight based photocatalytic application of TiO2 and iron doped TiO2 (Fe-TiO2), immobilized over the novel, eco-friendly support material developed as clay beads (CL), and placed in a newly developed Flat Plate Photocatalytic Reactor (FPPR). For catalyst immobilization, simple heat attachment method was applied using double distilled water as solvent for 2% (by weight) of TiO2 and Fe-TiO2 separately. Clay beads were characterized by Scanning Electron Microscope (SEM), Electron Dispersive Spectroscopy (EDS) and Brunauer Emmett Teller (BET) analysis for their structural, electronic & textural properties respectively; whereas characterization of Fe-TiO2 was performed using Field Emission Scanning Electron Microscope (FESEM), EDS, Transmission Electron Microscopy (TEM), X-ray Diffraction spectroscopy (XRD) and Diffuse reflectance spectrometer (DRS). A benzimidazole fungicide, Carbendazim (CBZ) was taken as the reference water pollutant and catalyst coated beads were further applied for its degradation using the FPPR. Remarkable degradation (87 ± 1% average) of CBZ was observed for 40 successful cyclic studies over the Fe-TiO2 coated CL beads under sunlight, without performing any reactivation of catalyst. Whereas highest degradation of CBZ achieved under sunlight conditions was 93 ± 4.65%. Effect of various reaction parameters was analyzed using UV–Visible spectroscopy, and the mineralization of CBZ was confirmed by Chemical oxygen demand (COD) and Gas Chromatography Mass Spectroscopy (GC–MS) analysis.

Mathematical model of a flat plate photocatalytic reactor irradiated by solar light

Mathematical model of a flat plate photocatalytic reactor irradiated by solar light

Modeling and Experimental Verification of a Corrugated Plate Photocatalytic Reactor Using Computational Fluid Dynamics

Heterogeneous photocatalysis is a suitable technology for eliminating indoor pollutants at low concentration ranges. In this work we deal with the modeling and experimental evaluation of a continuo...

Photodegradation of cellulose under UV light catalysed by TiO2

AbstractBACKGROUND: Since natural cellulose is an insoluble, crystalline microfibril, which is difficult to react with other compounds, most reactions related with cellulose are heterogeneous. The methods of cellulose degradation include acid hydrolysis, thermal degradation, alkaline degradation and catalytic degradation. Photocatalysis is a very powerful process.RESULTS: With 10 g cellulose dissolved in 100 mL ZnCl2 solution (66%), the 5‐hydroxymethyl furfural yield in the corrugated plate photocatalytic reactor reached 3.87 g L−1 under the following experimental conditions: 2 h irradiation under ultraviolet (UV) lamp (power—21 W), nine TiO2 coating cycles, and 42° corrugated plate angle.CONCLUSION: Owing to the enhancement of catalyst surface area illuminated by UV light and the large number of photons captured on the catalyst surface, the energy efficiency per mass (EE/M) of the corrugated plate photocatalytic reactor for photocatalytic degradation of cellulose was 10.9 kWh kg−1. This is therefore an effective technology for 5‐HMF preparation from cellulose. Copyright © 2011 Society of Chemical Industry

Three‐dimensional CFD model for a flat plate photocatalytic reactor: Degradation of TCE in a serpentine flow field

AbstractComputational fluid dynamics (CFD) simulation was applied to a photocatalytic reactor with surface reaction for trichloroethylene (TCE) oxidation at various pollutant concentrations, and flow rates. First‐order and Langmuir‐Hinshelwood kinetics for TCE removal rate were considered. The results were compared with those from experiments of Demeestere et al. (Appl Catal B Environ. 2004;54:261–274) in a flat plate photocatalytic reactor with serpentine geometry. The flow regime was laminar. Through the CFD simulation, the velocity field and the concentration gradient of TCE in the reactor were studied in detail. At Reynolds numbers around 900, the laminar flow becomes unstable. Under such a condition, when flow passes the 180° sharp turns, due to formation of secondary flow and consequently vortices, there is a lot of cross‐sectional mixing in the reactor. This kind of studies can help us to model the photocatalytic reactor as accurately as possible. © 2008 American Institute of Chemical Engineers AIChE J, 2009

Nonuniform radiation modeling of a corrugated plate photocatalytic reactor

AbstractCorrugated plate photocatalytic reactors provide a promising photoreactor design due to its potential in enhancing energy efficiency. A detailed model of such reactors is needed for engineering applications and process design. The model for the light absorption in a corrugated plate reactor using a nonuniform radiation source is developed based on first principles. The local area‐specific rate of energy absorption (LASREA) distribution on the corrugated plates is examined via simulation. The effect of the design parameters on LASREA is investigated. The results from this research provide feasible basis for design and optimization of corrugated plate photoreactors. © 2005 American Institute of Chemical Engineers AIChE J, 2005

Experimental analysis of a corrugated plate photocatalytic reactor

A corrugated plate reactor configuration was developed and assessed using 4-chlorophenol degradation experiments and mass transfer tests. Two other reactor systems, a flat plate reactor and a slurry reactor, were examined for comparative purposes. The corrugated plate reactor was found to be up to 150% faster and more energy-efficient than a similar flat plate reactor. Its electrical energy per order of concentration reduction (EE/O) was estimated to be as low as 37 kWh/m 3 and was close to that of a slurry system. Mass transfer rates in corrugated plate reactors were found to be up to 600% higher than those in the flat plate reactor. The superior performance of this reactor is due primarily to its large illuminated catalyst surface area per unit volume, and its ability to effectively deliver both photons and reactants to the catalyst surfaces.

Modeling of radiation absorption in a flat plate photocatalytic reactor

The radiation field inside a flat-plate photocatalytic reactor has been modeled. The solid-liquid heterogeneous reactor is irradiated by two tubular lamps and two parabolic reflectors. The model accounts for absorption and scattering effects by the solid suspension. From the lamp and reflector characteristics, the catalyst properties and concentration, and the reactor dimensions, the model provides a detailed description of the spatial and angular direction distributions of radiation intensities inside the reactor. These results permit to calculate at each point of the reactor the local value of the volumetric rate of radiation energy absorption (LVREA), a property that is always required to formulate the initiation rate of any photocatalytic process.