Photocatalytic degradation of organophosphorus pesticides using floating photocatalyst TiO2 · SiO2/beads by sunlight
TL;DR: In this article, the feasibility of photocatalytic degradation of organophosphorus pesticides using TiO 2 ǫ·SiO 2 beads as a floating photocatalyst by sunlight is studied.
About: This article is published in Solar Energy.The article was published on 2005-07-01. It has received 129 citations till now. The article focuses on the topics: Photocatalysis.
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TL;DR: This paper presents a critical review of recent achievements in the modification of ZnO photocatalyst for organic contaminants degradation and recommends improvements in the heterogeneous photocatalysis under UV/visible/solar illumination.
1,646 citations
TL;DR: It is evident from the literature survey that photocatalysis has good potential to remove a variety of organic pollutants, however, there is still a need to determine the practical utility of this technique on a commercial scale.
711 citations
Cites background from "Photocatalytic degradation of organ..."
...The positive holes are considered as the major oxidation steps at low pH, whereas hydroxyl radicals are considered as the predominant species at neutral or high pH levels (Shifu and Gengyu 2005; Mathews 1986)....
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...Shifu and Gengyu 2005 studied the SiO2 content on the photocatalytic activity of TiO2....
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TL;DR: An exhaustive examination of current research trends with a focus on nanomaterials (NMs) to considerably improve the performance of classical wastewater treatment technologies, e.g. adsorption, catalysis, separation, and disinfection is undertaken.
Abstract: The efficient handling of wastewater pollutants is a must, since they are continuously defiling limited fresh water resources, seriously affecting the terrestrial, aquatic, and aerial flora and fauna. Our vision is to undertake an exhaustive examination of current research trends with a focus on nanomaterials (NMs) to considerably improve the performance of classical wastewater treatment technologies, e.g. adsorption, catalysis, separation, and disinfection. Additionally, NM-based sensor technologies are considered, since they have been significantly used for monitoring water contaminants. We also suggest future directions to inform investigators of potentially disruptive NM technologies that have to be investigated in more detail. The fate and environmental transformations of NMs, which need to be addressed before large-scale implementation of NMs for water purification, are also highlighted.
397 citations
TL;DR: In this article, a comprehensive study on the preparation, photocatalytic activity and reuse of polymeric-based TiO 2 /polymer photocatalyst is presented, and the scope for future work and challenges for commercialization of polymer-supported TiO2/polymeric photocatalysers in visible and/or solar light are highlighted.
Abstract: Since the past two decades, immobilization of titanium dioxide (TiO 2 ), a popular photocatalyst, on different substrates has been drawing a lot of attention because it eliminates the need of costly post-treatment separation processes. Considering the various substrates that have been tried for supporting TiO 2 photocatalysts, polymer substrate seems to be very promising due to its several advantages such as flexible nature, low-cost, chemical resistance, mechanical stability, low density, high durability and ease of availability. This review covers over a hundred published papers in the field of polymer-based photocatalysts and presents a comprehensive study on the preparation, photocatalytic activity and reuse of TiO 2 /polymer photocatalysts. Polymer-supported buoyant TiO 2 photocatalysts and biodegradable polymer-supported TiO 2 photocatalysts are also discussed. Finally, the scope for future work and challenges for commercialization of polymer-supported TiO 2 photocatalysts in visible and/or solar light have been highlighted.
343 citations
TL;DR: In this paper, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, mode of catalyst application, and calcinations temperature.
Abstract: The heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works in the field of photocatalytic oxidation of toxic organic compounds such as phenols and dyes, predominant in wastewater effluent. In this review, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented. Recent findings suggested that different parameters, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, mode of catalyst application, and calcinations temperature can play an important role on the photocatalytic degradation of organic compounds in water environment. Extensive research has focused on the enhancement of photocatalysis by modification of TiO2 employing metal, non-metal, and ion doping. Recent advances in TiO2 photocatalysis for the degradation of various phenols and dyes are also highlighted in this review.
303 citations
Cites background from "Photocatalytic degradation of organ..."
...The positive holes are considered as the major oxidation steps at low pH, whereas hydroxyl radicals are considered as the predominant species at neutral or high pH levels (Shifu and Gengyu 2005, Mathews 1986)....
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References
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TL;DR: The slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses as discussed by the authors, which is a serious problem.
Abstract: The civilian, commercial, and defense sectors of most advanced industrialized nations are faced with a tremendous set of environmental problems related to the remediation of hazardous wastes, contaminated groundwaters, and the control of toxic air contaminants. For example, the slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses. Over the last 10 years problems related to hazardous waste remediation have emerged as a high national and international priority.
17,188 citations
TL;DR: In this paper, the presence of transition metal ions in photocatalytic reactions is reviewed according to two main approaches: (a) the influence of metal ions on the rate of photocatalysis and (b) the transformation of the ions to less toxic species or their deposition on the semiconductor catalyst surface for recovery of expensive and useful metals.
Abstract: The presence of transition metal ions in photocatalytic reactions is reviewed according to two main approaches: (a) the influence of transition metal ions on the rate of photocatalytic reactions (mainly oxidation) and (b) the transformation of the ions to less toxic species or their deposition on the semiconductor catalyst surface for recovery of expensive and useful metals. Most of the proposed mechanisms are discussed, together with experimental physicochemical evidences that support the involved pathways. Practical applications related to environmental protection and industrial processes are described.
1,294 citations
TL;DR: In this article, the characterization of mixed oxides of TiO2/SiO2 and TiO 2/Al2O3 prepared by sol−gel methods is described.
Abstract: The characterization of mixed oxides of TiO2/SiO2 and TiO2/Al2O3 prepared by sol−gel methods is described. Application of the TiO2/Al2O3 material for the photocatalytic decomposition of salicylic acid gave improved activity relative to TiO2-only materials. The photocatalytic activity of TiO2/SiO2, TiO2/Al2O3, and TiO2 toward the photocatalytic decomposition of phenol demonstrated the enhancement of local TiO2 sites on TiO2/SiO2 materials relative to the other materials. The characterization of the catalysts indicates that the TiO2/SiO2 materials consist of matrix-isolated TiO2 quantum particles, while the TiO2/Al2O3 materials do not.
551 citations
TL;DR: It is concluded that solar light induced degradation of textile dye in wastewater is a viable technique for wastewater treatment.
480 citations
TL;DR: Transparent anatase mesoporous (MTiO2) and TiO2 nanometer thin films were prepared on soda-lime glass and fused quartz via the reverse micellar method and sol-gel method, respectively as mentioned in this paper.
Abstract: Transparent anatase mesoporous TiO2 (MTiO2) and TiO2 nanometer thin films were prepared on soda-lime glass and fused quartz via the reverse micellar method and sol–gel method, respectively. The as-prepared MTiO2 and TiO2 films were then treated by dipping them in a H2SO4 solution. The MTiO2 and TiO2 films before and after surface acid treatment were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), BET surface area and UV–VIS spectrophotometry. The photocatalytic activity of the samples was evaluated by photocatalytic oxidation of acetone in air. It was found that MTiO2 thin films showed higher photocatalytic activity than that of the TiO2 thin films. This was attributed to the fact that MTiO2 thin films were composed of smaller monodisperse spherical particles about 15 nm and had higher specific surface areas. Furthermore, the monodispersity of TiO2 particles was beneficial to transfer and separation of photo-generated electrons and holes in the inner of and on the surface of TiO2 particle and reduced the recombination of photo-generated electrons and holes. The films deposited on quartz showed the highest photocatalytic activity because films deposited on quartz exhibited a better crystallization and had no sodium contaminant. The photocatalytic activity of MTiO2 and TiO2 thin films deposited on different substrates after treated with H2SO4 solution was significantly enhanced. Acid treatment was particularly effective for MTiO2/glass and TiO2/glass, which showed activity enhancement of four and over two times, respectively. This increase in activity has been correlated with the reduction of sodium ions and the increase in the adsorbed hydroxyl content on the surface of TiO2 films.
471 citations