Special Issue "Photocatalytic Wastewater Treatment"

A special issue of Catalysts (ISSN 2073-4344).

Deadline for manuscript submissions: closed (15 April 2016)

Special Issue Editors

Guest Editor
Prof. Dr. Dionysios (Dion) Demetriou Dionysiou

Professor of Environmental Engineering, Center of Sustainable Urban Engineering, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA
Website | E-Mail
Interests: advanced oxidation technologies and chemical oxidation for water treatment; drinking water treatment and purification; environmental nanotechnology; transition-metal oxidation and reverse electron transfer reactions; the use of ionic liquids in environmental applications; destruction of biological toxins in water; physicochemical phenomena on particle-water interfaces
Guest Editor
Dr. Giusy Lofrano

Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, 84084 Salerno, Italy
E-Mail
Interests: advanced oxidation process, industrial pollution control, high strenght wastewater treatment, emerging contaminants removal, nanotechnology
Guest Editor
Dr. Polycarpos Falaras

Division of Physical Chemistry, NCSR “Demokritos”, 15310 Aghia Paraskevi, Attiki, Greece
Website | E-Mail
Phone: +30-210-6503644
Fax: +30-210-6511766
Guest Editor
Dr. Suresh C. Pillai

Centre for Precision Engineering, Materials and Manufacturing Research &Nanotechnology Research Group, Department of Environmental Science,Institute of Technology Sligo, Ash Lane, Sligo, Ireland
E-Mail
Phone: +353-71-9305816
Guest Editor
Dr. Adrián M.T. Silva

Laboratory of Catalysis and Materials (LCM). Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, s/n, 4200-465, PORTO - Portugal
Website | E-Mail
Phone: +351-22-041-4908
Interests: nano- and macro-structured materials; magnetic nanocatalysts; separation and oxidation reactions; environmental catalysis
Guest Editor
Prof. Dr. Xie Quan

School of Environmental Science and Technology, Dalian University of Science and Technology, Dalian, China
Website | E-Mail
Phone: +86-411-8407-6140

Special Issue Information

Photocatalytic processes have shown great potential in recent years as environmentally friendly and sustainable treatment technologies to align with the “zero” waste scheme in the wastewater industry. At present, the main technical barriers that prevent their commercialisation remain: a) the costs associated with the UV source capital, b) the post-recovery of the catalysts after water treatment, and c) the efficiency of the photocatalytic treatment process, especially for new emerging/recalcitrant pollutants.

In order to meet and solve these technical challenges, research efforts have been focused on the development of catalysts with a broader range of light absorption for better utilization of sunlight and its integration through nanostructured films on different supports in integrated photocatalytic reactor systems (e.g., membrane-photocatalytic reactors which could combine two treatments, photocatalysis and filtration, in one unit). To date, several methods for achieving visible-light-driven photocatalysis or for increasing the lifetime of the photoproduced electron-hole pairs are widely investigated. These include modification of TiO2, the most popular photocatalyst, and several other commercially available nanocrystalline semiconductors (e.g., ZnO or CuO) by various metal ions or non-metallic species (N, C, S, B, P, F, or I), as well as by combination of these semiconductors with carbon materials. However, the stability and long-term efficacy of these alternative photocatalysts have not been tested. In terms of integration of these nanostructured photocatalytic films on membranes, research is still in its beginning and a great deal remains to be done. Judicious engineering of the semiconductor nanostructured materials may significantly enhance the development of a green, cost effective, and efficient technology for the removal of contaminants of emerging concern.

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Synthesis, characterisation and test applications of catalysts in Advanced Oxidation and Reduction Processes (AOPs, AORs) for the removal of emerging contaminants
  • Applications of photocatalytic processes in disinfection treatments
  • New generation photocatalysts for decontamination and disinfection applications
  • Operation mechanism clarification(s)
  • Process engineering (including modeling) for up-scaling materials and devices (photoreactors)
  • Green chemistry considerations for the development and application of photocatalytic processes in water and wastewater treatment
  • Economics of the photocatalytic technologies in water and wastewater remediation
  • Fate of catalysts in wastewater treatment plants
  • Challenges around the development of photocatalysis for beneficial ends in water/wastewater treatment

Published Papers (9 papers)

View options order results:
result details:
Displaying articles 1-9
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle TiO2 Nanotubes Supported Cu Nanoparticles for Improving Photocatalytic Degradation of Simazine under UV Illumination
Catalysts 2016, 6(11), 167; doi:10.3390/catal6110167
Received: 15 August 2016 / Revised: 20 October 2016 / Accepted: 21 October 2016 / Published: 29 October 2016
Cited by 2 | PDF Full-text (13858 KB) | HTML Full-text | XML Full-text
Abstract
Nano size Copper (Cu) incorporated TiO2 nanotubes was successfully synthesized via the anodic oxidation technique in ethylene glycol (EG) containing 0.5 wt % NH4F and 1.6 wt % KOH for the photocatalytic degradation of Simazine (2-chloro-4, 6-diethylamino-1,3,5-triazine) under Ultraviolet (UV)
[...] Read more.
Nano size Copper (Cu) incorporated TiO2 nanotubes was successfully synthesized via the anodic oxidation technique in ethylene glycol (EG) containing 0.5 wt % NH4F and 1.6 wt % KOH for the photocatalytic degradation of Simazine (2-chloro-4, 6-diethylamino-1,3,5-triazine) under Ultraviolet (UV) illumination. In the present study, the influence of different loading Cu concentrations on the formation of Cu-TiO2 nanotubes film towards the photocatalytic degradation of Simazine is reported. Based on our study, it was found that the optimum Cu loading concentration was about 0.45 wt % on TiO2 nanotubes film for approximately 64% photocatalytic degradation of Simazine after 4 h under UV illumination. This finding was mainly attributed to the uniform surface covering of the Cu loaded TiO2NTs which acted as electron traps, preventing the recombination of electron hole pairs, eventually leading to higher photocatalytic activity of our photocatalyst in degrading the targeted organic pollutant, Simazine. Moreover, an increased kinetic rate of the degradation to 0.0135 h−1 was observed in the presence of Cu in TiO2NTs. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Open AccessArticle A Highly Efficient Dual Rotating Disks Photocatalytic Fuel Cell with Wedged Surface TiO2 Nanopore Anode and Hemoglobin Film Cathode
Catalysts 2016, 6(8), 114; doi:10.3390/catal6080114
Received: 15 April 2016 / Revised: 19 July 2016 / Accepted: 19 July 2016 / Published: 4 August 2016
Cited by 1 | PDF Full-text (6402 KB) | HTML Full-text | XML Full-text
Abstract
In this study, a dual rotating-disk photocatalytic fuel cell using TiO2 on Ti plate with a wedged surface as the anode and hemoglobin (Hb) on graphite as the cathode was investigated and found to show excellent performance of simultaneous organic pollutant degradation
[...] Read more.
In this study, a dual rotating-disk photocatalytic fuel cell using TiO2 on Ti plate with a wedged surface as the anode and hemoglobin (Hb) on graphite as the cathode was investigated and found to show excellent performance of simultaneous organic pollutant degradation and electricity generation. This study is based on a well-developed photocatalytic fuel cell equipped with dual rotating disks for wastewater treatment that we developed previously, and the innovation of this new device is using a hemoglobin on graphite cathode for in situ hydrogen peroxide (H2O2) generation. The result proved with confidence that H2O2 was generated in situ on a cathode surface with the exited electron transferred from organic oxidation in a photoanodic half cell, and the organic pollutants were removed by the reaction with H2O2 and ·OH in a cathodic half cell. This design uses the invalid excited electron from the photoanode and enhances the overall performance of Rhodamine B degradation compared with the cells using the cathode without Hb. Compared with traditional photocatalytic reactors, the photocatalytic fuel cell developed above shows much better utilization efficiency of incident light and a higher degradation performance of organic pollutants and a larger photocurrent. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Open AccessArticle Highly Crystallized C-Doped Mesoporous Anatase TiO2 with Visible Light Photocatalytic Activity
Catalysts 2016, 6(8), 117; doi:10.3390/catal6080117
Received: 14 April 2016 / Revised: 22 July 2016 / Accepted: 25 July 2016 / Published: 1 August 2016
Cited by 9 | PDF Full-text (5100 KB) | HTML Full-text | XML Full-text
Abstract
Highly crystallized C-doped mesoporous anatase TiO2 is prepared using a multi-walled carbon nanotube (MWCNT) mat as both a “rigid” pore template and a carbon doping source. SEM and TEM characterization shows that the MWCNT template imposed a pore structure in reverse of
[...] Read more.
Highly crystallized C-doped mesoporous anatase TiO2 is prepared using a multi-walled carbon nanotube (MWCNT) mat as both a “rigid” pore template and a carbon doping source. SEM and TEM characterization shows that the MWCNT template imposed a pore structure in reverse of that of the MWCNT mat. The pore walls are formed by chain-like interconnected TiO2 nanocrystals with an average diameter about 10 nm, and pores are derived from spaces occupied by MWCNTs before removal. XRD characterization shows that TiO2 is crystallized with a pure anatase phase. XPS characterization reveals that the relative carbon content in the TiO2 is related to the duration of TiO2/MWCNT composite annealing before removal of MWCNT template. Three samples prepared contain 2.3%, 2.8% and 3.9% carbon; show a ~30 nm red shift and a plateau of adsorption from 450–800 nm in UV–Vis spectra in comparison to that of P25; and display visible light photocatalytic activity for decomposition of methyl orange (MO) in relationship with the carbon content and crystallinity of the anatase TiO2. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Open AccessArticle Fabrication of Hierarchically Porous Reduced Graphene Oxide/SnIn4S8 Composites by a Low-Temperature Co-Precipitation Strategy and Their Excellent Visible-Light Photocatalytic Mineralization Performance
Catalysts 2016, 6(8), 113; doi:10.3390/catal6080113
Received: 11 June 2016 / Revised: 5 July 2016 / Accepted: 12 July 2016 / Published: 29 July 2016
Cited by 1 | PDF Full-text (14251 KB) | HTML Full-text | XML Full-text
Abstract
Hierarchically porous reduced graphene oxide/SnIn4S8 (RGO/SnIn4S8) composites with visible-light response and strong mineralization ability were first successfully prepared by a facile low-temperature co-precipitation method, and were characterized by X ray diffraction (XRD), scanning electron microscope (SEM),
[...] Read more.
Hierarchically porous reduced graphene oxide/SnIn4S8 (RGO/SnIn4S8) composites with visible-light response and strong mineralization ability were first successfully prepared by a facile low-temperature co-precipitation method, and were characterized by X ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmet-Teller (BET), UV-Visible spectrophotometer (UV-Vis), Raman spectra and Photoluminescence (PL) techniques. RGO/SnIn4S8 composite exhibits strong absorption in UV and visible-light range. The optimized 5% RGO/SnIn4S8 possesses the optimal photocatalytic degradation efficiency and the best mineralization performance with complete degradation of Rhodamine B (RhB) within 70 min and 73.17% mineralization yield within 160 min under visible-light irradiation, which is much higher than that of pure SnIn4S8. The main reactive species, which play crucial roles in the degradation and mineralization of RhB, follow the order of h+ > ·O2 > ·OH. The intermediate products of RhB degradation were analyzed by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS), and the possible degradation pathways and mechanism were proposed. Moreover, 5% RGO/SnIn4S8 exhibits excellent reusability and stability without an obvious decrease in photocatalytic activity after four consecutive photocatalytic degradation-regeneration experiments. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Open AccessArticle Photocatalytic Removal of Microbiological Consortium and Organic Matter in Greywater
Catalysts 2016, 6(6), 91; doi:10.3390/catal6060091
Received: 15 April 2016 / Revised: 6 June 2016 / Accepted: 13 June 2016 / Published: 22 June 2016
PDF Full-text (1780 KB) | HTML Full-text | XML Full-text
Abstract
This study aimed to investigate TiO2 photocatalytic degradation of synthetically-prepared greywater samples with differing compositional contents of organic matter (OM), anion concentration, and microbiological consortium. Treatment efficiency was followed through removal of organic matter content in terms of dissolved organic carbon (DOC),
[...] Read more.
This study aimed to investigate TiO2 photocatalytic degradation of synthetically-prepared greywater samples with differing compositional contents of organic matter (OM), anion concentration, and microbiological consortium. Treatment efficiency was followed through removal of organic matter content in terms of dissolved organic carbon (DOC), specific spectroscopic parameters, and bacterial inactivation. Photocatalytic degradation kinetics were expressed by pseudo first-order kinetic modeling. The best DOC removal rates were attained for greywater samples containing OM with lower molecular size fractions. In addition, either enhancing or reducing the effect of common anions as radical scavengers were observed depending on the composition and concentration of variables in the greywater matrix. Moreover, possibility of a photocatalytic disinfection process was found to be of a bacteria type specific in OM-loaded synthetic greywater samples. Photocatalytic destruction of fecal streptococci required longer irradiation periods under all conditions. Bacterial removal rates were found to be in the order of total coliform > fecal coliform > fecal streptococci, for low organic load greywater, and fecal coliform > total coliform > fecal streptococci, for high organic load greywater. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Open AccessArticle Kinetic Model for Simultaneous Adsorption/Photodegradation Process of Alizarin Red S in Water Solution by Nano-TiO2 under Visible Light
Catalysts 2016, 6(6), 84; doi:10.3390/catal6060084
Received: 15 April 2016 / Revised: 26 May 2016 / Accepted: 1 June 2016 / Published: 8 June 2016
Cited by 1 | PDF Full-text (4616 KB) | HTML Full-text | XML Full-text
Abstract
The simultaneous adsorption and visible light photodegradation of Alizarin Red S in water solutions were studied in real time mode by using nano-TiO2, such as Anatase and Aeroxide P-25, supported on polypropylene strips. Kinetic results of the overall process were compared
[...] Read more.
The simultaneous adsorption and visible light photodegradation of Alizarin Red S in water solutions were studied in real time mode by using nano-TiO2, such as Anatase and Aeroxide P-25, supported on polypropylene strips. Kinetic results of the overall process were compared with those obtained from separated steps of adsorption and photodegradation previously studied; kinetic advantages were evidenced with the simultaneous approach. From the study of different dye concentrations, a kinetic model has been proposed which describes the overall process. This model considered two consecutive processes: The adsorption of dye on TiO2 surface and its photodegradation. The obtained results were in good agreement with experimental data and can predict the profiles of free dye, dye adsorbed on TiO2 and photoproduct concentrations during the total process. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Open AccessArticle Synthesis and Characterization of Ag-Ag2O/TiO2@polypyrrole Heterojunction for Enhanced Photocatalytic Degradation of Methylene Blue
Catalysts 2016, 6(6), 76; doi:10.3390/catal6060076
Received: 30 March 2016 / Revised: 13 May 2016 / Accepted: 17 May 2016 / Published: 25 May 2016
Cited by 9 | PDF Full-text (3081 KB) | HTML Full-text | XML Full-text
Abstract
Hybrid multi-functional nanomaterials comprising two or more disparate materials have become a powerful approach to obtain advanced materials for environmental remediation applications. In this work, an Ag-Ag2O/TiO2@polypyrrole (Ag/TiO2@PPy) heterojunction has been synthesized by assembling a self-stabilized Ag-Ag
[...] Read more.
Hybrid multi-functional nanomaterials comprising two or more disparate materials have become a powerful approach to obtain advanced materials for environmental remediation applications. In this work, an Ag-Ag2O/TiO2@polypyrrole (Ag/TiO2@PPy) heterojunction has been synthesized by assembling a self-stabilized Ag-Ag2O (p type) semiconductor (denoted as Ag) and polypyrrole (π-conjugated polymer) on the surface of rutile TiO2 (n type). Ag/TiO2@PPy was synthesized through simultaneous oxidation of pyrrole monomers and reduction of AgNO3 in an aqueous solution containing well-dispersed TiO2 particles. Thus synthesized Ag/TiO2@PPy was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and UV-Vis diffuse reflectance spectroscopy (UV-vis DSR). The photocatalytic activity of synthesized heterojunction was investigated for the decomposition of methylene blue (MB) dye under UV and visible light irradiation. The results revealed that π-conjugated p-n heterojunction formed in the case of Ag/TiO2@PPy significantly enhanced the photodecomposition of MB compared to the p-n type Ag/TiO2 and TiO2@PPy (n-π) heterojunctions. A synergistic effect between Ag-Ag2O and PPy leads to higher photostability and a better electron/hole separation leads to an enhanced photocatalytic activity of Ag/TiO2@PPy under both UV and visible light irradiations. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Open AccessArticle A Novel Delafossite Structured Visible-Light Sensitive AgFeO2 Photocatalyst: Preparation, Photocatalytic Properties, and Reaction Mechanism
Catalysts 2016, 6(5), 69; doi:10.3390/catal6050069
Received: 23 February 2016 / Revised: 29 April 2016 / Accepted: 4 May 2016 / Published: 10 May 2016
Cited by 2 | PDF Full-text (3252 KB) | HTML Full-text | XML Full-text
Abstract
This work presents a systematic study of a novel efficient visible-light sensitive AgFeO2 photocatalyst. The photocatalysts were prepared via simple hydrothermal procedure at 160 °C with different reaction time. The structures, morphologies, specific surface areas, and optical properties of the photocatalysts were
[...] Read more.
This work presents a systematic study of a novel efficient visible-light sensitive AgFeO2 photocatalyst. The photocatalysts were prepared via simple hydrothermal procedure at 160 °C with different reaction time. The structures, morphologies, specific surface areas, and optical properties of the photocatalysts were explored by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) model, and UV-vis diffuse reflectance spectra (DRS). Photoluminescence and photocurrent analysis were conducted for the understanding of photogenerated electron-hole pair separation. AgFeO2 with a six-hour hydrothermal procedure demonstrated the most efficient photocatalytic performance which resulted in 97% degradation of methyl orange (MO) within 180 min. The enhanced photocatalytic activity was attributed to the combined effect of its relatively large surface area and high separation electron-hole pair efficiency. Holes and ·O2 were the dominant reactive species responsible for MO degradation and holes played the leading role according to the quenching effects analysis and detection of active species. The conduction and valence band position of AgFeO2 were calculated to be −0.5 V and 1.32 V, respectively. Based on active species detection, along with the band structure, the photocatalytic mechanism was proposed. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Review

Jump to: Research

Open AccessReview Advances in Magnetically Separable Photocatalysts: Smart, Recyclable Materials for Water Pollution Mitigation
Catalysts 2016, 6(6), 79; doi:10.3390/catal6060079
Received: 16 April 2016 / Revised: 12 May 2016 / Accepted: 18 May 2016 / Published: 20 June 2016
Cited by 7 | PDF Full-text (4718 KB) | HTML Full-text | XML Full-text
Abstract
Organic and inorganic compounds utilised at different stages of various industrial processes are lost into effluent water and eventually find their way into fresh water sources where they cause devastating effects on the ecosystem due to their stability, toxicity, and non-biodegradable nature. Semiconductor
[...] Read more.
Organic and inorganic compounds utilised at different stages of various industrial processes are lost into effluent water and eventually find their way into fresh water sources where they cause devastating effects on the ecosystem due to their stability, toxicity, and non-biodegradable nature. Semiconductor photocatalysis has been highlighted as a promising technology for the treatment of water laden with organic, inorganic, and microbial pollutants. However, these semiconductor photocatalysts are applied in powdered form, which makes separation and recycling after treatment extremely difficult. This not only leads to loss of the photocatalyst but also to secondary pollution by the photocatalyst particles. The introduction of various magnetic nanoparticles such as magnetite, maghemite, ferrites, etc. into the photocatalyst matrix has recently become an area of intense research because it allows for the easy separation of the photocatalyst from the treated water using an external magnetic field. Herein, we discuss the recent developments in terms of synthesis and photocatalytic properties of magnetically separable nanocomposites towards water treatment. The influence of the magnetic nanoparticles in the optical properties, charge transfer mechanism, and overall photocatalytic activity is deliberated based on selected results. We conclude the review by providing summary remarks on the successes of magnetic photocatalysts and present some of the future challenges regarding the exploitation of these materials in water treatment. Full article
(This article belongs to the Special Issue Photocatalytic Wastewater Treatment)
Figures

Journal Contact

MDPI AG
Catalysts Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
E-Mail: 
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Catalysts Edit a special issue Review for Catalysts
logo
loading...
Back to Top