Can environmental pharmaceuticals be photocatalytically degraded and completely mineralized in water using g-C3N4/TiO2 under visible light irradiation?—Implications of persistent toxic intermediates

Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.

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“…In another study, Li et al [97] reported the 100% degradation of Acyclovir in 90 min. using g-C 3 N 4 /TiO 2 under visible light irradiation.…”

Section: Tio 2 /G-c 3 Nmentioning

confidence: 94%

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

et al. 2020

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“…In addition to this, the transfer of holes from the VB of ZnO to the VB of g-C 3 N 4 further contribute towards limiting hole oxidation. In another study, graphitic carbon nitride (g-C 3 N 4 )/TiO 2 hybrid photocatalyst was tested for degrading acyclovir under visible light [295].…”

Section: Other Nano Photocatalystsmentioning

confidence: 99%

Removal of Pharmaceutical Contaminants in Wastewater Using Nanomaterials: A Comprehensive Review

Chauhan

Sillu

Agnihotri

2019

CDM

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Background: The limitless presence of pharmaceutical contaminants in discharged wastewater has emerged as a threat to aquatic species and humans. Their presence in drinking water has although raised substantial concerns, very little is known about the fate and ecological impacts of these pollutants. As a result, these pollutants are inevitably introduced to our food chain at trace concentrations. Unfortunately, the conventional wastewater treatment techniques are unable to treat pharmaceuticals completely with practical limitations. The focus has now been shifted towards nanotechnology for the successful remediation of these persistent pollutants. Thus, the current review specifically focuses on providing readers brief yet sharp insights into applications of various nanomaterials for the removal of pharmaceutical contaminants. Methods: An exhaustive collection of bibliographic database was done with articles having high impact and citations in relevant research domains. An in-depth analysis of screened papers was done through standard tools. Studies were categorized according to the use of nanoscale materials as nano-adsorbents (graphene, carbon nanotubes), nanophotocatalysts (metal, metal oxide), nano-filtration, and ozonation for promising alternative technologies for the efficient removal of recalcitrant contaminants. Results: A total of 365 research articles were selected. The contemporary advancements in the field of nanomaterials for drinking and wastewater treatment have been thoroughly analyzed along with their future perspectives. Conclusion: The recommendations provided in this article will be useful to adopt novel strategies for on-site removal of the emerging contaminants in pharmaceutical effluents and related industries.

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“…Apart from the intrinsic characteristics of disinfection materials, environment parameters are key factors that govern the performance of photocatalysts . Even in similar photocatalysis system, the outcomes of organic degradation and bacterial inactivation could be different . This is because in comparison with organics, microorganisms are more sensitive to the composition of reaction media and the nature of catalysts in photocatalytic oxidation .…”

Section: Influence Of Water Matrix To Photocatalytic Sterilizationmentioning

confidence: 99%

“…124 Even in similar photocatalysis system, the outcomes of organic degradation and bacterial inactivation could be different. 135 This is because in comparison with organics, microorganisms are more sensitive to the composition of reaction media and the nature of catalysts in photocatalytic oxidation. 136 Characteristics of the water matrix, such as ionic strength, oxygen, pH value, humic acid concentration, or even intracellular organic matter released from bacteria inactivation, etc., are of direct relevance to antibacterial efficiency 20,137 by influencing the RS generation process and surface contact between cells and photocatalysts.…”

Section: Influence Of Water Matrix To Photocatalytic Sterilizationmentioning

confidence: 99%

Two‐dimensional nanomaterials for photocatalytic water disinfection: recent progress and future challenges

Liu

Zeng

et al. 2018

J of Chemical Tech & Biotech

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Photocatalysis has received ever‐growing attention as a promising alternative to traditional water treatment technologies for waterborne biohazard inactivation. Due to unique optical, electronic, physicochemical properties and feasibility of functional architecture assembly, two‐dimensional (2D) nanomaterials have become important in developing novel photocatalysts. This review summarizes the recent progress in configuring nanostructures with 2D materials as building blocks for photocatalytic water disinfection. In this review, five categories of 2D nanomaterials, that is, graphene, graphitic carbon nitride, 2D metal oxides and metallates, metal oxyhalides and transition metal dichalcogenides, for photocatalytic pathogen inactivation are introduced. First, the synthesis process, nanostructure engineering and disinfection performance of 2D‐based photocatalysts are reviewed in categories. In the following section, the bacteria destruction mechanism based on the generation and roles of reactive species (RSs) is presented. Moreover, the effects of the chemical characteristics of the water matrix on photocatalytic bactericidal performance are discussed. Finally, the challenges regarding the development and application of 2D‐based photocatalysts for highly efficient water sterilization are highlighted. © 2018 Society of Chemical Industry

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Can environmental pharmaceuticals be photocatalytically degraded and completely mineralized in water using g-C3N4/TiO2 under visible light irradiation?—Implications of persistent toxic intermediates

Cited by 162 publications

References 56 publications

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Removal of Pharmaceutical Contaminants in Wastewater Using Nanomaterials: A Comprehensive Review

Two‐dimensional nanomaterials for photocatalytic water disinfection: recent progress and future challenges

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