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Qixing Zhou - One of the best experts on this subject based on the ideXlab platform.
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the combination of rotating disk Photocatalytic Reactor and tio2 nanotube arrays for environmental pollutants removal
Journal of Hazardous Materials, 2011Co-Authors: Aiyong Zhang, Minghua Zhou, Lu Han, Qixing ZhouAbstract:A combined Photocatalytic system on one single TiO(2)-nanotube (TNT)/Ti photocatalyst, which was indeed the functional combination of photon-efficient thin-film and conventional bulk-phase photocatalysis processes, was effectively developed in rotating disk Photocatalytic Reactor for environmental purification applications. The TNT/Ti rotating disk, of uniform size and well-aligned, was successfully prepared by direct anodic oxidation on a dominantly large surface area of 38 cm(2), compared to the typical 1 cm(2) in available literature. To estimate the potentials of combined Photocatalytic system for environmental applications, the degradation of rhodamine B was carried out under the optimized conditions, a substrate removal efficiency of nearly 90% and a mineralization efficiency of 56% were observed for initial 20 mg/L solution after 3 h treatment. Compared with the combined Photocatalytic system on TiO(2) nanoparticle disk, a significant improvement in substrate removal efficiency of about 25-40% was observed on TNT/Ti disk. It was confirmed that the main degradation of rhodamine B occurred on the upper half of TNT/Ti disk above the heavily colorized sample solution, which was attributed to the superior UV utilization efficiency and the resultant high interfacial photoactivity.
Jean Michel Laine - One of the best experts on this subject based on the ideXlab platform.
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effect of hydrogen peroxide on the destruction of organic contaminants synergism and inhibition in a continuous mode Photocatalytic Reactor
Applied Catalysis B-environmental, 2004Co-Authors: Dionysios D Dionysiou, Makram T Suidan, Isabelle Baudin, Jean Michel LaineAbstract:Abstract The effect of hydrogen peroxide on the Photocatalytic degradation of organic contaminants in water was investigated using a TiO 2 -rotating disk Photocatalytic Reactor (RDPR) operated in a continuous-mode and at steady state. The experiments were performed at pH 3.0, in the presence of near-UV radiation, and using 4-chlorobenzoic acid (4-CBA) as a model non-volatile organic contaminant at influent concentration of 300 μmol l −1 . Experiments were performed at concentrations of hydrogen peroxide in the range 0–10.74 mmol l −1 . Addition of hydrogen peroxide at small concentrations ( −1 ) had a synergistic effect and increased considerably the rates of Photocatalytic reactions. An optimum influent hydrogen peroxide concentration was observed at 1.6 mmol l −1 , which caused an increased in the rates of 4-CBA degradation and total organic carbon (TOC) mineralization by 1.72 and 2.13 times, respectively. This corresponded to an optimum oxidant to contaminant molar ratio of 5.33. At higher concentrations, hydrogen peroxide was found to cause an inhibiting effect on the Photocatalytic reactions. The synergistic and inhibiting effects of hydrogen peroxide were rationalized based on the reaction rate constants between relevant radical species.
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rotating disk Photocatalytic Reactor development characterization and evaluation for the destruction of organic pollutants in water
Water Research, 2000Co-Authors: Dionysios D Dionysiou, Ganesh Balasubramanian, Makram T Suidan, Amid P Khodadoust, Isabelle Baudin, Jean Michel LaineAbstract:This work focuses on the development, characterization and evaluation of the TiO2 Rotating Disk Photocatalytic Reactor (RDPR) for the treatment of organic pollutants in water. A commercial TiO2-based catalyst in the form of composite ceramic balls was used as the immobilized photocatalyst on the rotating disk. LiCl tracer studies conducted at different disk angular velocities, ranging from 20 to 5 rpm, proved that the mixing in the RDPR is close to that of an ideal CSTR. Two different techniques, an overflow method and the potassium ferrioxalate actinometry method were employed for determining the liquid holdup and turnover time of the rotating disk with glass beads substituted for TiO2 coated beads. The two methods were in agreement and only the overflow method was employed for determining the same parameters for the rotating disk when loaded with TiO2 composite ceramic balls. Power law correlations were obtained in all cases. TiO2-assisted Photocatalytic degradation of 4-chlorobenzoic acid (4-CBA) was investigated in the RDPR at a specified angular velocity of the rotating disk (4 rpm), initial pH=3.0, and room temperature using near-UV radiation.
Gianluca Li Puma - One of the best experts on this subject based on the ideXlab platform.
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novel pebble bed Photocatalytic Reactor for solar treatment of textile wastewater
Chemical Engineering Journal, 2012Co-Authors: N N Rao, Vibha Chaturvedi, Gianluca Li PumaAbstract:Abstract A novel, low cost, pebble bed Photocatalytic Reactor (PBPR) having a horizontal or inclined solar trough collector is presented. The collector contains TiO 2 coated, silica rich, white pebbles fixed on a flat surface in an ordered configuration to facilitate the contact between the liquid and the photocatalyst. The Reactor efficiency was evaluated for the decolorization of selected reactive dye solutions: Reactive Black 5 (RB5), Reactive Orange 16 (RO16), Reactive Red 2 (RR2), Reactive Red 141(RR141), Reactive Yellow 84 (RY84) and Reactive Violet 13 (RV13) as well as, for the treatment of textile wastewater (synthetic dye house effluents) under sunlight. The rate of decolorization of chlorotriazine reactive dyes was found to be faster than that of vinylsulfone based dyes. The decolorization rate of the dyes followed pseudo first-order kinetics. The first order rate constant of color removal was in the range from 2.479 × 10 −2 to 7.858 × 10 −2 min −1 , with a maximum mineralization efficiency ( k TOC / k dye ) of 28%. The figure of merit of this Reactor as recommended by IUPAC (the collector area per mass A CM ) and (the collector area per order A CO ) was in the range of 0.30–0.37 m 2 /g dye and 8.6–12.2 m 2 /m 3 /order, respectively, with the exception of RO16 which degraded at a much slower rate. The treatment of simulated textile wastewater showed 72% (Batch I) and 54% (Batch-II) color reduction and 3–35% total organic carbon (TOC) reduction. The results indicate that the PBPR can be successfully used for the decolorization of dyes from dyeing wastewater under sunlight.
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Modeling of an annular Photocatalytic Reactor for water purification: oxidation of pesticides.
Environmental Science & Technology, 2004Co-Authors: Gianluca Li Puma, Jen Nee Khor, Alberto BrucatoAbstract:Photocatalytic oxidation (PCO) over titanium dioxide (TiO2) is a “green” sustainable process for the treatment and purification of water and wastewater. However, the application of PCO for wastewater treatment on an industrial scale is currently hindered by a lack of simple mathematical models that can be readily applied to Reactor design. Current models are either too simplistic or too rigorous to be useful in Photocatalytic Reactor design, scale-up, and optimization. In this paper a simple mathematical model is presented for slurry, annular, Photocatalytic Reactors that still retains the essential elements of a rigorous approach while providing simple solutions. The model extends the applicability of the thin-film model of Photocatalytic Reactors previously presented to include the case of geometrically thick photoReactors (i.e., those Reactors in which the thickness of the annular zone is significant as compared to the outer radius of the Reactor). The model uses a novel six-flux absorption-scattering ...
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A novel fountain Photocatalytic Reactor: model development and experimental validation
Chemical Engineering Science, 2001Co-Authors: Gianluca Li Puma, Po Lock YueAbstract:The application of photocatalysis for water treatment and purification on an industrial scale can be accelerated by the development of both new photoReactor designs and mathematical models. A novel, pilot-plant, thin-film, slurry Photocatalytic Reactor for water treatment and purification is presented in this paper. The Reactor is a “fountain” Photocatalytic Reactor, consisting of a flattened water bell irradiated from above. Such a Reactor configuration is particularly suitable for large-scale solar applications of photocatalysis. A dimensionless mathematical model for the fountain Photocatalytic Reactor is presented in this paper. The model was developed using parameters that can be estimated easily from real systems and model solutions can be obtained with little computational effort. The model was validated with experimental results from the Photocatalytic oxidation of salicylic acid in a pilot-scale Reactor using titanium dioxide (TiO2) as the photocatalyst. Experiments were performed under a number of different conditions by varying substrate concentration, intensity of the incident radiation, catalyst loading, flow rate, recycle ratio and water fountain diameter. The model results were found to fit the experimental data well in all cases. The modeling approach can be extended to other thin-film slurry Photocatalytic Reactors.
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The modeling of a fountain Photocatalytic Reactor with a parabolic profile
Chemical Engineering Science, 2001Co-Authors: Gianluca Li Puma, Po Lock YueAbstract:Abstract A dimensionless mathematical model for a novel, thin film, slurry fountain Photocatalytic Reactor for water or wastewater treatment is presented. The model extends the applicability of the horizontal water fountain model previously presented to include water fountains with a parabolic profile. The model was developed using parameters that can be easily estimated for real systems. The model was successfully validated with experimental results from the Photocatalytic oxidation of indigo carmine dye in a pilot-scale Reactor using titanium dioxide (TiO 2 ) as the photocatalyst.
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A laminar falling film slurry Photocatalytic Reactor. Part I—model development
Chemical Engineering Science, 1998Co-Authors: Gianluca Li Puma, Po Lock YueAbstract:Abstract The application of photocatalysis for wastewater treatment on an industrial scale has been partially impeded by the lack of simple mathematical models and optimisation studies. In this paper, a mathematical model (LSSE-LSPP model) for a laminar falling film slurry (LFFS) Photocatalytic Reactor is presented. The model is expressed in terms of five dimensionless parameters and can be solved with a minimal number of simple integrations. Model predictions are presented for different reaction kinetics and model parameters. As the parameters used in the model can be readily estimated from real systems, the model may be used for scale-up. A study of the sensitivity of the model to variations of the model parameters and validation of the model with experimental results of the oxidation of salicylic acid in a pilot-scale LFFS Photocatalytic Reactor are presented in Part II of this paper.
Ajay K. Ray - One of the best experts on this subject based on the ideXlab platform.
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Photocatalytic Reactor Configurations for Water Purification: Experimentation and Modeling
Advances in Chemical Engineering - Photocatalytic Technologies, 2009Co-Authors: Ajay K. RayAbstract:Abstract Heterogeneous photocatalysis on semiconductor particles has been shown to be an effective means of removing toxic organic pollutants as well as toxic metal ions from water. The problem of scale-up of multiphase Photocatalytic Reactors is considerably more complex than that of conventional chemical Reactors. The demand for catalyst illumination is an additional engineering factor in the Reactor design, besides conventional Reactor scale-up factors such as mixing and mass transfer, reactant–catalyst contacting, fluid flow patterns, and catalyst installation. Photocatalytic Reactor design must address important parameters, such as uniform light distribution, providing high illuminated catalyst surface area, and mixing inside the Reactor. Several novel Reactor designs (multiple tube Reactor, tube light Reactor, rotating tube Reactor, Taylor vortex Reactor) addressing the above issues as well as other important challenges are discussed in this chapter.
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Experimental investigation of Taylor vortex Photocatalytic Reactor for water purification
Chemical Engineering Science, 2004Co-Authors: Paritam K. Dutta, Ajay K. RayAbstract:A Taylor vortex Photocatalytic Reactor was developed that creates unsteady Taylor–Couette flow in between the two co-axial cylinders by re-circulating fluids form bulk to the inner cylinder wall, which was coated with TiO2. Systematic investigation for flow development as well as Photocatalytic degradation of three different organic compounds was carried out. The effect of Reynolds number and catalyst loading on Photocatalytic degradation were compared for both slurry and fixed catalyst system. The experimental results demonstrate that Taylor vortex Photocatalytic Reactor is promising for water purification even when catalyst is fixed, as there is no significant difference in overall degradation rate between slurry and immobilized systems.
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design modelling and experimentation of a new large scale Photocatalytic Reactor for water treatment
Chemical Engineering Science, 1999Co-Authors: Ajay K. RayAbstract:Recent literature has demonstrated on a laboratory scale the potential of semiconductor photocatalysis technology to completely destroy organic pollutants present in water. However, to date no viable pilot plant exists using this technology. In this paper, a new Reactor design is presented that addresses the two most important parameters, namely, light distribution inside the Reactor and high specific surface area of catalyst. The Reactor consists of several hollow tubes employed as a means of light delivery to the catalyst present on the outside surface of the tubes. Simple model calculations were performed to evaluate the radial light intensity profile as a function of input light intensity and angle of incidence, diameter, length, wall thickness and surface roughness of tubes. A Reactor was designed and constructed based on the modelling results, and when experiments were conducted showed very promising results. The new Reactor aims at developing a technical solution to the design of a commercial scale Photocatalytic Reactor.
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development of a new Photocatalytic Reactor for water purification
Catalysis Today, 1998Co-Authors: Ajay K. Ray, Antonie A. C. M. BeenackersAbstract:The purification of water by heterogeneous photocatalysis is one of the most rapidly growing areas of interest to both research workers and water purification plants. Recent literature has demonstrated on a laboratory scale the potential of this promising technology to completely destroy organic pollutants dissolved or dispersed in water into harmless substances. However, to date no viable pilot plant exists using this technology. New Reactor design ideas are necessary that must be able to address the two most important parameters, namely, light distribution inside the Reactor through the absorbing and scattering liquid to the catalyst, and providing high surface areas for catalyst per unit volume of Reactor. In this paper, a new Reactor design addressing the solution to both the above problems is proposed for water treatment. The Reactor consists of several hollow tubes coated on its outside surface with the catalysts. The hollow tubes have been employed as a means of light delivery to the catalyst. Experiments performed in a Reactor containing 54 densely packed hollow tubes of 0.006 m diameter showed promising results. The new Reactor aims at developing a technical solution to the design of a commercial Photocatalytic Reactor. # 1998 Elsevier Science B.V.
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Novel Photocatalytic Reactor for water purification
AIChE Journal, 1998Co-Authors: Ajay K. Ray, Antonie A. C. M. BeenackersAbstract:A novel Photocatalytic Reactor design for water treatment is characterized by the use of new extremely narrow diameter lamps, thus allowing for much higher surface area for catalyst coating per unit Reactor volume and consequently for much higher specific Reactor capacity. Experiments in a Reactor containing 21 novel U-shaped lamps coated with catalyst showed a 695% increase in efficiency of the Reactor performance in comparison with a classical annular Reactor and 259% in comparison with a slurry Reactor. Both a classical annular Reactor and a slurry Reactor cannot be scaled up for large-scale applications due to the low values of illuminated catalyst surface area per unit volume of liquid treated inside the Reactor while this configuration is flexible enough for large-scale applications.
Nur Hanis Hayati Hairom - One of the best experts on this subject based on the ideXlab platform.
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Industrial textile wastewater treatment via membrane Photocatalytic Reactor (MPR) in the presence of ZnO-PEG nanoparticles and tight ultrafiltration
Journal of Water Process Engineering, 2019Co-Authors: Amira Liyana Desa, Nur Hanis Hayati Hairom, Mohd Khairul Ahmad, Abdul Wahab MohammadAbstract:Abstract In the present study, the degradation of industrial textile wastewater (SDWW) was investigated using a membrane Photocatalytic Reactor (MPR) in the presence of zinc oxide capped with polyethylene glycol (ZnO-PEG) nanoparticles and polypiperazine-amide (PPA) tight ultrafiltration membrane (UF-PPA). The optimum operating conditions of MPR were obtained under initial pH 11, 0.10 g/L of ZnO-PEG nanoparticles, and 75% dilution of SDWW. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) analyses confirmed that ZnO-PEG nanoparticles and the UF-PPA membrane have great potential as an alternative treatment to meet the stringent discharge limits. The mechanisms of membrane fouling for the optimum operational condition were investigated using model fitting according to the Wiesner and Aptel equations. It was revealed that cake formation occurred rapidly at both stages of the fouling mechanism. Hence, it is believed that this integrated approach has a great potential to be implemented in the industrial textile wastewater treatment sector to ensure the environmental cleanliness for future generations.
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effect of various zinc oxide nanoparticles in membrane Photocatalytic Reactor for congo red dye treatment
Separation and Purification Technology, 2014Co-Authors: Nur Hanis Hayati Hairom, Abdul Wahab Mohammad, Abdul Amir H KadhumAbstract:The utilisation of titanium dioxide (TiO2) in a coupling system membrane Photocatalytic Reactor (MPR) has been widely investigated. However, there have been very few studies regarding the zinc oxide (ZnO) photocatalyst in MPR, although it has been shown to provide better efficiency than TiO2 in certain cases, mainly for dye photodegradation. In this study, the influence of ZnO nanoparticles in MPR has been investigated for Congo red (CR) dye treatment. Four types of ZnO were synthesised via the precipitation of oxalic acid and zinc acetate solutions. The X-ray diffractometry (XRD) and transmission electron microscopy (TEM) results showed that precipitation is a valuable method for producing the smallest particle size (7–30 nm) of ZnO without any agglomerations, especially under stirring conditions in the presence of PVP (ZnO-PVP-St). As expected, the ZnO-PVP-St presented the great potential in MPR in terms of the highest photodegradation efficiency and lesser membrane flux decline, which was supported by the FESEM results. From the EDX analysis, it was confirmed that the small amount of ZnO-PVP-St did not pass through the membrane pores to the final stream. It was believed that the other remaining ZnO was reused in the Photocatalytic Reactor, for the continuous process of MPR. Due to the effective surface area of ZnO-PVP-St and adsorption of UV light, the optimum photocatalyst loading for the system was 0.3 g L-1 under 20 mg L-1 dye concentration and pH 7 of the initial CR dye solution.