Recent progress of photocatalytic membrane reactors in water treatment and in synthesis of organic compounds. A review

Molinari, Raffaele; Lavorato, Cristina; Argurio, Pietro

doi:10.1016/j.cattod.2016.06.047

Cited by 237 publications

(111 citation statements)

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“…Heterogeneous photocatalysis processes have gained more attention in recent decades, attributed to their diverse applications in many fields, such as wastewater remediation, air purification, disinfection, hydrogen production, and catalysis of organic syntheses [1][2][3][4][5][6]. The performance of a photocatalyst mainly depends on two factors, namely band gap and redox potential.…”

Section: Introductionmentioning

confidence: 99%

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

Han

et al. 2017

Catalysts

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BiOX x Y 1−x (X, Y = Cl, Br, and I) solid solutions have been regarded as promising photocatalysts attributed to their unique layered structure, tunable band structure, and chemical and optical stability. In this study, BiOBr x I 1−x nanoplate solid solutions with a high exposure of {001} crystal facets were prepared by a facile alcoholysis method at room temperature and atmospheric pressure. X-ray diffraction (XRD) peaks exhibited a slight shift to lower diffraction angle with the increase of I content in BiOBr x I 1−x samples, which resulted in a gradual increase in their cell parameters. Field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM) images revealed that BiOBr x I 1−x samples exhibited 2D plate-like structure with the in-plane wrinkles. The regular changes in optical absorption threshold and E g value seen in UV-vis diffuse reflectance spectra (UV-vis DRS) indicated that the optical absorption property and band structure could be modulated by the formation of BiOBr x I 1−x solid solutions. The photocatalytic degradation of active dye Rhodamine B (RhB) over BiOBr x I 1−x solid solutions showed that BiOBr 0.75 I 0.25 had the best photocatalytic activity. The RhB photodegradation processes followed a pseudo-first-order kinetic model. The synergistic effect of structural factors (including amount of exposed {001} facets, interlayer spacing of (001) plane, and energy-level position of the valence band) determined the photocatalytic performance of BiOBr x I 1−x solid solutions.

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Section: Introductionmentioning

confidence: 99%

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

Han

et al. 2017

Catalysts

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“…For PMRs with immobilized photocatalyst, the enhanced hydrophilicity of modified membrane and the degradation of organic pollutants that form the gel layer or filtration cake would effectively mitigate membrane fouling, which is a major obstacle of suspended PMRs [32]. However, the immobilized PMRs require custom membranes with suitable pore size, effective dispersion of catalyst particles and high resistance to UV irradiation, posing a great challenge to the membrane manufacturing industry [33]. In addition, the active surface area of the photocatalyst is limited in immobilized PMRs, resulting in Coupling photocatalysis with dialysis has some advantages: (1) requires lower energy consumption; (2) maintains the photocatalyst in the photocatalytic compartment without a final filtration stage; (3) keeps the solid substance from feed solution away from the photoreactor, thus avoiding the light shielding effect.…”

Section: Evaluation Of Different Pmr Configurationsmentioning

confidence: 99%

“…Zhang et al [32] focused on the membrane fouling in PMRs for water treatment and discussed the relationship between photocatalysis and membrane fouling in detail. Molinari et al [33] paid attention to the application of PMRs in degradation of organic pollutants and in synthesis of organic compounds. These reviews concentrated on different aspects of PMR systems, however, the PMR configuration, which is also an important aspect, was rarely discussed at considerable length.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Membrane Reactors (PMRs) in Water Treatment: Configurations and Influencing Factors

et al. 2017

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Abstract:The lack of access to clean water remains a severe issue all over the world. Coupling photocatalysis with the membrane separation process, which is known as a photocatalytic membrane reactor (PMR), is promising for water treatment. PMR has developed rapidly during the last few years, and this paper presents an overview of the progress in the configuration and operational parameters of PMRs. Two main configurations of PMRs (PMRs with immobilized photocatalyst; PMRs with suspended photocatalyst) are comprehensively described and characterized. Various influencing factors on the performance of PMRs, including photocatalyst, light source, water quality, aeration and membrane, are detailed. Moreover, a discussion on the current problems and development prospects of PMRs for practical application are presented.

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“…Then, the hydrogen ions ( + H), instead of reacting with photogenerated electrons in the conduction band, they react in backward with the oxygen to produce again water molecules. To overcome this reverse reaction, it has been proposed to use electron donor, which can be co-catalysts or sacrificial agents [7,8] to trap the photogenerated holes and increase the probability of reaction between + H and the conduction band electrons of the semiconductor material. However, the yields of cocatalysts as IrO2 (RuOx) [7], Au [9], Rh [10] or CuO [11] are still low.…”

mentioning

confidence: 99%

“…However, the yields of cocatalysts as IrO2 (RuOx) [7], Au [9], Rh [10] or CuO [11] are still low. On the other hand, organic compound are excellent sacrificial agents due to the fact that most of the organic functional groups have an oxidation potential less positive than the valence band edges of the most common semiconductors materials [8], it means that by photocatalytic processes not only hydrogen can be obtained, but also organic compounds could be oxidized.…”

mentioning

confidence: 99%

Pd/TiO2-WO3 photocatalysts for hydrogen generation from water-methanol mixtures

Camacho

Rey

Hernández‐Alonso

et al. 2018

Applied Surface Science

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Solar light is inexhaustible; therefore, to take advantage of this energy, it is necessary to develop materials capable of absorbing in the widest range of the solar spectra. Although TiO2 is one of the most studied photocatalysts, it just absorbs in the UV range.With the purpose of increasing this absorption light towards visible range, different materials such as Pd and WO3 have been supported on bare TiO2, to study their photocatalytic properties for hydrogen generation from water-methanol mixtures under UVA and solar irradiation. Several parameters on the hydrogen production such as the amount of Pd, the catalyst amount and the influence of the water matrix have been studied. These catalytic materials were characterized by means of inductively coupled plasma with an optical emission spectrophotometer, nitrogen adsorption-desorption isotherms, X-ray diffraction, high resolutiontransmission electron microscopy, X-ray photoelectron spectroscopy and diffuse reflectance UV-Vis spectroscopy. Hydrogen evolution was monitored by on-line gas chromatography. The incorporation of a small amount of Pd (lower than 0.01 wt %) produced an important increase in the hydrogen production. Furthermore, the addition of WO3 on the bare titania also produced an increase in the hydrogen generation. The highest quantum efficiency obtained in this work under solar radiation was 7.7 % by the catalyst based on palladium supported on the nanotubes of titanium dioxide and tungsten trioxide (Pd/NT-WO3) using an aqueous solution of methanol (50 vol.%). PresentAddress: Repsol Technology Center, Agustín de Betancourt, s/n, 28935 Móstoles, Madrid, Spain Abbreviations: NT, nanotubes of TiO2; P25, commercial TiO2; Eg, Energy gapKeywords: photocatalysis; hydrogen; low palladium addition; sacrificial agents, quantum efficiency Graphical abstract Highlights: An efficient catalyst for hydrogen production under solar radiation has been obtained by doping Pd nanoparticles by photodeposition over a powdered support containing TiO2 and WO3. The addition of small Pd particles by photodeposition produces a strong increase in the hydrogen production decreasing the recombination of the electron hole pairs. The addition of WO3 nanoparticles allows the absorption of light of the catalysts in the visible region.

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Recent progress of photocatalytic membrane reactors in water treatment and in synthesis of organic compounds. A review

Cited by 237 publications

References 135 publications

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

Structure-Dependent Photocatalytic Performance of BiOBrxI1−x Nanoplate Solid Solutions

Photocatalytic Membrane Reactors (PMRs) in Water Treatment: Configurations and Influencing Factors

Pd/TiO2-WO3 photocatalysts for hydrogen generation from water-methanol mixtures

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