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Patrick S.M. Dunlop
NIBEC, School of Engineering, Ulster University, Newtownabbey BT37 0QB, UK

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Review
Published: 18 February 2021 in Clean Technologies
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Billions of litres of wastewater are produced daily from domestic and industrial areas, and whilst wastewater is often perceived as a problem, it has the potential to be viewed as a rich source for resources and energy. Wastewater contains between four and five times more energy than is required to treat it, and is a potential source of bio-hydrogen—a clean energy vector, a feedstock chemical and a fuel, widely recognised to have a role in the decarbonisation of the future energy system. This paper investigates sustainable, low-energy intensive routes for hydrogen production from wastewater, critically analysing five technologies, namely photo-fermentation, dark fermentation, photocatalysis, microbial photo electrochemical processes and microbial electrolysis cells (MECs). The paper compares key parameters influencing H2 production yield, such as pH, temperature and reactor design, summarises the state of the art in each area, and highlights the scale-up technical challenges. In addition to H2 production, these processes can be used for partial wastewater remediation, providing at least 45% reduction in chemical oxygen demand (COD), and are suitable for integration into existing wastewater treatment plants. Key advancements in lab-based research are included, highlighting the potential for each technology to contribute to the development of clean energy. Whilst there have been efforts to scale dark fermentation, electro and photo chemical technologies are still at the early stages of development (Technology Readiness Levels below 4); therefore, pilot plants and demonstrators sited at wastewater treatment facilities are needed to assess commercial viability. As such, a multidisciplinary approach is needed to overcome the current barriers to implementation, integrating expertise in engineering, chemistry and microbiology with the commercial experience of both water and energy sectors. The review concludes by highlighting MECs as a promising technology, due to excellent system modularity, good hydrogen yield (3.6–7.9 L/L/d from synthetic wastewater) and the potential to remove up to 80% COD from influent streams.

ACS Style

A Islam; Patrick Dunlop; Neil Hewitt; Rose Lenihan; Caterina Brandoni. Bio-Hydrogen Production from Wastewater: A Comparative Study of Low Energy Intensive Production Processes. Clean Technologies 2021, 3, 156 -182.

AMA Style

A Islam, Patrick Dunlop, Neil Hewitt, Rose Lenihan, Caterina Brandoni. Bio-Hydrogen Production from Wastewater: A Comparative Study of Low Energy Intensive Production Processes. Clean Technologies. 2021; 3 (1):156-182.

Chicago/Turabian Style

A Islam; Patrick Dunlop; Neil Hewitt; Rose Lenihan; Caterina Brandoni. 2021. "Bio-Hydrogen Production from Wastewater: A Comparative Study of Low Energy Intensive Production Processes." Clean Technologies 3, no. 1: 156-182.

Review
Published: 09 January 2021 in Catalysts
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The presence of pharmaceutical products in the water cycle may cause harmful effects such as morphological, metabolic and sex alterations in aquatic organisms and the selection/development of organisms resistant to antimicrobial agents. The compounds’ stability and persistent character hinder their elimination by conventional physico-chemical and biological treatments and thus, the development of new water purification technologies has drawn great attention from academic and industrial researchers. Recently, the electro-Fenton process has been demonstrated to be a viable alternative for the removal of these hazardous, recalcitrant compounds. This process occurs under the action of a suitable catalyst, with the majority of current scientific research focused on heterogeneous systems. A significant area of research centres working on the development of an appropriate catalyst able to overcome the operating limitations associated with the homogeneous process is concerned with the short service life and difficulty in the separation/recovery of the catalyst from polluted water. This review highlights a present trend in the use of different materials as electro-Fenton catalysts for pharmaceutical compound removal from aquatic environments. The main challenges facing these technologies revolve around the enhancement of performance, stability for long-term use, life-cycle analysis considerations and cost-effectiveness. Although treatment efficiency has improved significantly, ongoing research efforts need to deliver economic viability at a larger scale due to the high operating costs, primarily related to energy consumption.

ACS Style

Jessica Meijide; Patrick S. M. Dunlop; Marta Pazos; María Angeles Sanromán. Heterogeneous Electro-Fenton as “Green” Technology for Pharmaceutical Removal: A Review. Catalysts 2021, 11, 85 .

AMA Style

Jessica Meijide, Patrick S. M. Dunlop, Marta Pazos, María Angeles Sanromán. Heterogeneous Electro-Fenton as “Green” Technology for Pharmaceutical Removal: A Review. Catalysts. 2021; 11 (1):85.

Chicago/Turabian Style

Jessica Meijide; Patrick S. M. Dunlop; Marta Pazos; María Angeles Sanromán. 2021. "Heterogeneous Electro-Fenton as “Green” Technology for Pharmaceutical Removal: A Review." Catalysts 11, no. 1: 85.

Journal article
Published: 21 October 2020 in Journal of Water Process Engineering
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In regions where houses are sparsely located, traditional centralized water treatment plants are not economically feasible, with household water treatment (HWT) systems commonly used to provide potable water for a range of household activities. Filtration prior to disinfection is essential, and due to their ease of use and small footprint, cartridge filters are commonly employed. In this work, readily available commercial filter types (spun, wound and pleated) of different micron ratings (10, 5 and 1) were tested for the removal of turbidity either alone or in series via simulated large volume pilot trials. Water with an initial turbidity of 40 ± 10 NTU was prepared using fine test dust (ISO 12103-1, A2) with the turbidity removal efficiency, pressure drop, total capacity and lifespan of the filters evaluated. To increase useable filter lifetime upon reaching the 1 bar pressure limit, a series of washing steps were employed to regenerate the filters. Whilst pleated filters could be efficiently cleaned, spun and wound filters could not, and were discarded after single use. In pilot trials, the volume of turbid water filtered varied from 0.85 m3 with a 1 micron wound filter to 6 m3, with 5 and 1 micron pleated filters in series, which following regeneration could be used for three filtration cycles. For pleated filters, turbidity removal efficiency improved over time as a cake built up resulting in the effluent turbidity reaching acceptable quality (<5 NTU). This criterion continued to be achieved with repeated cycles of washed pleated filters, thereby significantly reducing the cost and improving sustainability of the HWT system. Field trials were carried out with a similar HWT system (5 and 1 micron spun filters) installed in households of rural communities in Curiti, Colombia. Turbidity was effectively removed from natural water (reduction to <1.2 NTU) with improved efficacy in comparison to synthetic water samples due to the large particle size distribution observed in the natural water.

ACS Style

Arsalan Afkhami; Mattia Marotta; Dorian Dixon; Nigel G. Ternan; Luis Javier Montoya-Jaramillo; Margarita Hincapie; Laila Galeano; Pilar Fernandez-Ibanez; Patrick S.M. Dunlop. Assessment of low-cost cartridge filters for implementation in household drinking water treatment systems. Journal of Water Process Engineering 2020, 39, 101710 .

AMA Style

Arsalan Afkhami, Mattia Marotta, Dorian Dixon, Nigel G. Ternan, Luis Javier Montoya-Jaramillo, Margarita Hincapie, Laila Galeano, Pilar Fernandez-Ibanez, Patrick S.M. Dunlop. Assessment of low-cost cartridge filters for implementation in household drinking water treatment systems. Journal of Water Process Engineering. 2020; 39 ():101710.

Chicago/Turabian Style

Arsalan Afkhami; Mattia Marotta; Dorian Dixon; Nigel G. Ternan; Luis Javier Montoya-Jaramillo; Margarita Hincapie; Laila Galeano; Pilar Fernandez-Ibanez; Patrick S.M. Dunlop. 2020. "Assessment of low-cost cartridge filters for implementation in household drinking water treatment systems." Journal of Water Process Engineering 39, no. : 101710.

Journal article
Published: 10 October 2020 in Water
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In keeping with the circular economy approach, reclaiming greywater (GW) is considered a sustainable approach to local reuse of wastewater and a viable option to reduce household demand for freshwater. This study investigated the mineralization of total organic carbon (TOC) in GW using TiO2-based advanced oxidation processes (AOPs) in a custom-built stirred tank reactor. The combinations of H2O2, O3, and immobilized TiO2 under either dark or UVA irradiation conditions were systematically evaluated—namely TiO2/dark, O3/dark (ozonation), H2O2/dark (peroxidation), TiO2/UVA (photocatalysis), O3/UVA (Ozone photolysis), H2O2/UVA (photo-peroxidation), O3/TiO2/dark (catalytic ozonation), O3/TiO2/UVA (photocatalytic ozonation), H2O2/TiO2/dark, H2O2/TiO2/UVA, H2O2/O3/dark (peroxonation), H2O2/O3/UVA (photo-peroxonation), H2O2/O3/TiO2/dark (catalytic peroxonation), and H2O2/O3/TiO2/UVA (photocatalytic peroxonation). It was found that combining different treatment methods with UVA irradiation dramatically enhanced the organic mineralization efficiency. The optimum TiO2 loading in this study was observed to be 0.96 mg/cm2 with the highest TOC removal (54%) achieved using photocatalytic peroxonation under optimal conditions (0.96 mg TiO2/cm2, 25 mg O3/min, and 0.7 H2O2/O3 molar ratio). In peroxonation and photo-peroxonation, the optimal H2O2/O3 molar ratio was identified to be a critical efficiency parameter maximizing the production of reactive radical species. Increasing ozone flow rate or H2O2 dosage was observed to cause an efficiency inhibition effect. This lab-based study demonstrates the potential for combined TiO2-AOP treatments to significantly reduce the organic fraction of real GW, offering potential for the development of low-cost systems permitting safe GW reuse.

ACS Style

Dheaya Alrousan; Arsalan Afkhami; Khalid Bani-Melhem; Patrick Dunlop. Organic Degradation Potential of Real Greywater Using TiO2-Based Advanced Oxidation Processes. Water 2020, 12, 2811 .

AMA Style

Dheaya Alrousan, Arsalan Afkhami, Khalid Bani-Melhem, Patrick Dunlop. Organic Degradation Potential of Real Greywater Using TiO2-Based Advanced Oxidation Processes. Water. 2020; 12 (10):2811.

Chicago/Turabian Style

Dheaya Alrousan; Arsalan Afkhami; Khalid Bani-Melhem; Patrick Dunlop. 2020. "Organic Degradation Potential of Real Greywater Using TiO2-Based Advanced Oxidation Processes." Water 12, no. 10: 2811.

Journal article
Published: 04 August 2020 in Journal of Environmental Chemical Engineering
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Reclaiming non-conventional water sources such as greywater is gaining more attention in the light of current and expected water shortage due to the global trend of continued population growth, urbanization, and the impact of climate change. In this work, the degradation of organic matter measured as total organic carbon (TOC) and biochemical oxygen demand (BOD5) in real greywater samples using different ozone-based oxidation and solar advanced oxidation treatments was investigated in a custom-built glass tube reactor combined with a concentrated parabolic collector (CPC). The evaluated processes included ozonation (O3), solar ozonation (O3/solar irradiation), hydrogen peroxide oxidation (H2O2), hydrogen peroxide under solar irradiation (H2O2/solar irradiation), peroxonation (H2O2/O3), and solar peroxonation (H2O2/O3/solar irradiation). Combining different treatment methods with/without exposure to solar irradiation enhanced overall treatment efficiency. The efficiency of the examined processes followed the order: solar peroxonation > solar ozonation > peroxonation > ozonation, while the other processes showed a negligible effect. The highest TOC reduction (58.6 %) was observed using solar peroxonation at 41.7 mg O3/min and 0.2 H2O2/O3 molar ratio; the highest BOD5 reduction (29.4 %) was observed using solar peroxonation at 41.7 mg O3/min and 0.4 H2O2/O3 molar ratio. We conclude that low-cost advanced oxidation technologies can be effective to remove organic materials providing efficient greywater remediation for reuse applications.

ACS Style

D.M.A. Alrousan; P.S.M. Dunlop. Evaluation of ozone-based oxidation and solar advanced oxidation treatment of greywater. Journal of Environmental Chemical Engineering 2020, 8, 104309 .

AMA Style

D.M.A. Alrousan, P.S.M. Dunlop. Evaluation of ozone-based oxidation and solar advanced oxidation treatment of greywater. Journal of Environmental Chemical Engineering. 2020; 8 (5):104309.

Chicago/Turabian Style

D.M.A. Alrousan; P.S.M. Dunlop. 2020. "Evaluation of ozone-based oxidation and solar advanced oxidation treatment of greywater." Journal of Environmental Chemical Engineering 8, no. 5: 104309.

Journal article
Published: 01 May 2017 in Chemical Engineering Journal
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ACS Style

Brenda R. Cruz-Ortiz; Jeremy W.J. Hamilton; Cristina Pablos; Lourdes Diaz Jimenez; Dora Alicia Cortés-Hernández; Preetam Kumar Sharma; María Castro-Alférez; Pilar Fernandez-Ibañez; Patrick Dunlop; John Byrne. Mechanism of photocatalytic disinfection using titania-graphene composites under UV and visible irradiation. Chemical Engineering Journal 2017, 316, 179 -186.

AMA Style

Brenda R. Cruz-Ortiz, Jeremy W.J. Hamilton, Cristina Pablos, Lourdes Diaz Jimenez, Dora Alicia Cortés-Hernández, Preetam Kumar Sharma, María Castro-Alférez, Pilar Fernandez-Ibañez, Patrick Dunlop, John Byrne. Mechanism of photocatalytic disinfection using titania-graphene composites under UV and visible irradiation. Chemical Engineering Journal. 2017; 316 ():179-186.

Chicago/Turabian Style

Brenda R. Cruz-Ortiz; Jeremy W.J. Hamilton; Cristina Pablos; Lourdes Diaz Jimenez; Dora Alicia Cortés-Hernández; Preetam Kumar Sharma; María Castro-Alférez; Pilar Fernandez-Ibañez; Patrick Dunlop; John Byrne. 2017. "Mechanism of photocatalytic disinfection using titania-graphene composites under UV and visible irradiation." Chemical Engineering Journal 316, no. : 179-186.

Journal article
Published: 28 April 2017 in Molecules
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TiO2 photocatalysis is considered as an alternative to conventional disinfection processes for the inactivation of waterborne microorganisms. The efficiency of photocatalysis is limited by charge carrier recombination rates. When the photocatalyst is immobilized on an electrically conducting support, one may assist charge separation by the application of an external electrical bias. The aim of this work was to study electrochemically assisted photocatalysis with nitrogen doped titania photoanodes under visible and UV-visible irradiation for the inactivation of Escherichia coli. Aligned TiO2 nanotubes were synthesized (TiO2-NT) by anodizing Ti foil. Nanoparticulate titania films were made on Ti foil by electrophoretic coating (P25 TiO2). N-doped titania nanotubes and N,F co-doped titania films were also prepared with the aim of extending the active spectrum into the visible. Electrochemically assisted photocatalysis gave higher disinfection efficiency in comparison to photocatalysis (electrode at open circuit) for all materials tested. It is proposed that electrostatic attraction of negatively charged bacteria to the positively biased photoanodes leads to the enhancement observed. The N-doped TiO2 nanotube electrode gave the most efficient electrochemically assisted photocatalytic inactivation of bacteria under UV-Vis irradiation but no inactivation of bacteria was observed under visible only irradiation. The visible light photocurrent was only a fraction (2%) of the UV response.

ACS Style

Cristina Pablos; Javier Marugán; Rafael Van Grieken; Patrick Stuart Morris Dunlop; Jeremy William John Hamilton; Dionysios D. Dionysiou; John Anthony Byrne. Electrochemical Enhancement of Photocatalytic Disinfection on Aligned TiO2 and Nitrogen Doped TiO2 Nanotubes. Molecules 2017, 22, 704 .

AMA Style

Cristina Pablos, Javier Marugán, Rafael Van Grieken, Patrick Stuart Morris Dunlop, Jeremy William John Hamilton, Dionysios D. Dionysiou, John Anthony Byrne. Electrochemical Enhancement of Photocatalytic Disinfection on Aligned TiO2 and Nitrogen Doped TiO2 Nanotubes. Molecules. 2017; 22 (5):704.

Chicago/Turabian Style

Cristina Pablos; Javier Marugán; Rafael Van Grieken; Patrick Stuart Morris Dunlop; Jeremy William John Hamilton; Dionysios D. Dionysiou; John Anthony Byrne. 2017. "Electrochemical Enhancement of Photocatalytic Disinfection on Aligned TiO2 and Nitrogen Doped TiO2 Nanotubes." Molecules 22, no. 5: 704.

Journal article
Published: 30 September 2016 in Journal of Molecular Catalysis A: Chemical
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Although UV-induced TiO2 photocatalysis involves the generation of several reactive oxygen species (ROS), the formation of hydroxyl radicals is generally associated with the degradation of persistent organic contaminants in water. In this study, a variety of radical scavengers were employed to discriminate the roles of different ROS during visible light-activated (VLA) photocatalysis using nitrogen and fluorine doped TiO2 (NF-TiO2) in the degradation of the hepatotoxin, microcystin-LR (MC-LR) in water. The addition of hydroxyl radical scavengers, methanol and tert-butyl alcohol to the reaction mixture resulted in negligible inhibition of NF-TiO2 photocatalytic degradation of MC-LR at pH 3.0 and only partial inhibition at pH 5.7 under visible light. While hydroxyl radicals (OH) generally play the primary role in UV-TiO2 photocatalysis, the minimal influence of MeOH and t-BuOH on the degradation process under these experimental conditions indicates that OH are not crucial in VLA NF-TiO2 photocatalysis. However, strong inhibition was observed in VLA NF-TiO2 photocatalytic degradation of MC-LR in the presence of superoxide dismutase, benzoquinone and catalase at pH 3.0 and 5.7 indicating that O2− and H2O2 play critical roles in the degradation process. Similar degradation rates were observed in the presence of deuterium oxide, which enhances singlet oxygen mediated processes further suggesting singlet oxygen is not a key species in the degradation of MC-LR. Formic acid and cupric nitrate were added to probe the roles of the valence band holes and conduction band electrons, respectively. Under UV–vis light irradiation, almost complete inhibition of MC-LR removal is observed with NF-TiO2 in the presence of OH scavengers at pH 5.7. These results demonstrate that the solution pH plays a major role in the formation and reactivity of ROS during VLA NF-TiO2 photocatalysis. The adsorption strength of scavengers and MC-LR onto NF-TiO2 as well as the speciation of ROS as a function of pH needs to be carefully considered since they also play a major role in the efficiency of the process. These results indicate that the reduction of molecular oxygen by photo-generated electrons rather than hydroxyl radicals produced by oxidative reactions of photo-generated holes is the key factor in the VLA NF-TiO2 photocatalytic degradation of MC-LR.

ACS Style

Miguel Pelaez; Polycarpos Falaras; Vlassis Likodimos; Kevin O’Shea; Armah A. de la Cruz; Patrick Dunlop; John Byrne; Dionysios D. Dionysiou. Use of selected scavengers for the determination of NF-TiO2 reactive oxygen species during the degradation of microcystin-LR under visible light irradiation. Journal of Molecular Catalysis A: Chemical 2016, 425, 183 -189.

AMA Style

Miguel Pelaez, Polycarpos Falaras, Vlassis Likodimos, Kevin O’Shea, Armah A. de la Cruz, Patrick Dunlop, John Byrne, Dionysios D. Dionysiou. Use of selected scavengers for the determination of NF-TiO2 reactive oxygen species during the degradation of microcystin-LR under visible light irradiation. Journal of Molecular Catalysis A: Chemical. 2016; 425 ():183-189.

Chicago/Turabian Style

Miguel Pelaez; Polycarpos Falaras; Vlassis Likodimos; Kevin O’Shea; Armah A. de la Cruz; Patrick Dunlop; John Byrne; Dionysios D. Dionysiou. 2016. "Use of selected scavengers for the determination of NF-TiO2 reactive oxygen species during the degradation of microcystin-LR under visible light irradiation." Journal of Molecular Catalysis A: Chemical 425, no. : 183-189.

Editorial
Published: 05 June 2016 in International Journal of Photoenergy
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ACS Style

Wanjun Wang; Po Keung Wong; Suresh C. Pillai; Tian Ming; Patrick S. M. Dunlop. Photocatalysis in Environment, Energy, and Sustainability. International Journal of Photoenergy 2016, 2016, 1 -2.

AMA Style

Wanjun Wang, Po Keung Wong, Suresh C. Pillai, Tian Ming, Patrick S. M. Dunlop. Photocatalysis in Environment, Energy, and Sustainability. International Journal of Photoenergy. 2016; 2016 ():1-2.

Chicago/Turabian Style

Wanjun Wang; Po Keung Wong; Suresh C. Pillai; Tian Ming; Patrick S. M. Dunlop. 2016. "Photocatalysis in Environment, Energy, and Sustainability." International Journal of Photoenergy 2016, no. : 1-2.

Book chapter
Published: 30 March 2016 in Energy and Environment Series
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It is estimated that there are 748 million people throughout the world without access to improved water sources for drinking and many more rely on water that is not safe to drink due to contamination with pathogenic microorganisms. Furthermore, the reuse of wastewater is becoming increasingly important due to water scarcity throughout the globe, and it is vitally important to ensure that water for reuse is free from pathogenic microorganisms. Solar energy is free and ubiquitous on the Earth's surface. The combination of solar disinfection and photocatalysis technology offers real possibilities for removing lethal pathogenic microorganisms from polluted water and drinking water. The treatment time taken for the solar disinfection of drinking water can be greatly reduced by utilizing heterogeneous photocatalysis. This chapter reviews and compares the fundamental mechanisms of solar and solar photocatalytic inactivation of microorganisms. The complexity of the mechanisms, involving reactive oxygen species and their effects on the cell wall, membrane and internal components of microorganism, are discussed. Furthermore, the photocatalytic inactivation of antibiotic resistant bacteria is discussed. The development of visible light active photocatalytic materials for solar disinfection is reviewed and, finally, there is a short discussion concerning photo-reactors specifically for the solar photocatalytic disinfection of water.

ACS Style

Pilar Fernández-Ibáñez; J. Anthony Byrne; M. Inmaculada Polo-López; Patrick S. M. Dunlop; Popi Karaolia; Despo Fatta-Kassinos. CHAPTER 3. Solar Photocatalytic Disinfection of Water. Energy and Environment Series 2016, 72 -91.

AMA Style

Pilar Fernández-Ibáñez, J. Anthony Byrne, M. Inmaculada Polo-López, Patrick S. M. Dunlop, Popi Karaolia, Despo Fatta-Kassinos. CHAPTER 3. Solar Photocatalytic Disinfection of Water. Energy and Environment Series. 2016; ():72-91.

Chicago/Turabian Style

Pilar Fernández-Ibáñez; J. Anthony Byrne; M. Inmaculada Polo-López; Patrick S. M. Dunlop; Popi Karaolia; Despo Fatta-Kassinos. 2016. "CHAPTER 3. Solar Photocatalytic Disinfection of Water." Energy and Environment Series , no. : 72-91.

Journal article
Published: 01 September 2015 in Advanced Science, Engineering and Medicine
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ACS Style

S. Wadhwa; A. Mathur; J. W. J. Hamilton; P. S. M. Dunlop; J. A. Byrne. Photo-Electrochemical Properties of Anodised Titania Nanotube Arrays Annealed in Nitrogen Atmosphere. Advanced Science, Engineering and Medicine 2015, 7, 761 -770.

AMA Style

S. Wadhwa, A. Mathur, J. W. J. Hamilton, P. S. M. Dunlop, J. A. Byrne. Photo-Electrochemical Properties of Anodised Titania Nanotube Arrays Annealed in Nitrogen Atmosphere. Advanced Science, Engineering and Medicine. 2015; 7 (9):761-770.

Chicago/Turabian Style

S. Wadhwa; A. Mathur; J. W. J. Hamilton; P. S. M. Dunlop; J. A. Byrne. 2015. "Photo-Electrochemical Properties of Anodised Titania Nanotube Arrays Annealed in Nitrogen Atmosphere." Advanced Science, Engineering and Medicine 7, no. 9: 761-770.

Review
Published: 30 March 2015 in Molecules
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Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

ACS Style

John Anthony Byrne; Patrick Stuart Morris Dunlop; Jeremy William John Hamilton; Pilar Fernández-Ibáñez; Inmaculada Polo-López; Preetam Kumar Sharma; Ashlene Vennard. A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection. Molecules 2015, 20, 5574 -5615.

AMA Style

John Anthony Byrne, Patrick Stuart Morris Dunlop, Jeremy William John Hamilton, Pilar Fernández-Ibáñez, Inmaculada Polo-López, Preetam Kumar Sharma, Ashlene Vennard. A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection. Molecules. 2015; 20 (4):5574-5615.

Chicago/Turabian Style

John Anthony Byrne; Patrick Stuart Morris Dunlop; Jeremy William John Hamilton; Pilar Fernández-Ibáñez; Inmaculada Polo-López; Preetam Kumar Sharma; Ashlene Vennard. 2015. "A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection." Molecules 20, no. 4: 5574-5615.

Journal article
Published: 15 January 2015 in Applied Physics A
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Titania nanostructures have been prepared by anodisation in aqueous solution assisted by focused ion beam (FIB) milling. The structures formed are bi-periodic, a disordered “native” nanotube array, with characteristics similar to those formed by the standard anodisation process and an ordered array of tubes with larger diameters, guided by the positioning of the FIB concave pits. Low kV EDX analysis shows implanted Ga in FIB-treated titanium which is efficiently removed by the anodisation process. Following thermal annealing, the FIB-treated regions also crystallise to the same anatase phase as the native regions. This result is in stark contrast to previous FIB-assisted anodisation studies which only produced nanostructured arrays of native dimensions. This singularity is discussed in terms of the stable FIB-induced crystalline defects which, in an aqueous electrolyte, can result in the growth of a weaker barrier layer and larger tubes. This novel process gave hexagonal and square arrays with tailored cross-sectional dimensions and therefore has potential for the synthesis of novel meta-materials.

ACS Style

Pradeep K. Yadav; Patrick Lemoine; Graham Dale; Jeremy W. J. Hamilton; Patrick S. M. Dunlop; John A. Byrne; Pascal Mailley; Colin Boxall. Hierarchical titania nanostructures prepared with focused ion beam-assisted anodisation of titanium in an aqueous electrolyte. Applied Physics A 2015, 119, 107 -113.

AMA Style

Pradeep K. Yadav, Patrick Lemoine, Graham Dale, Jeremy W. J. Hamilton, Patrick S. M. Dunlop, John A. Byrne, Pascal Mailley, Colin Boxall. Hierarchical titania nanostructures prepared with focused ion beam-assisted anodisation of titanium in an aqueous electrolyte. Applied Physics A. 2015; 119 (1):107-113.

Chicago/Turabian Style

Pradeep K. Yadav; Patrick Lemoine; Graham Dale; Jeremy W. J. Hamilton; Patrick S. M. Dunlop; John A. Byrne; Pascal Mailley; Colin Boxall. 2015. "Hierarchical titania nanostructures prepared with focused ion beam-assisted anodisation of titanium in an aqueous electrolyte." Applied Physics A 119, no. 1: 107-113.

Journal article
Published: 03 July 2014 in Chemical Engineering Journal
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Interest has grown in the modification of titanium dioxide with graphene to improve the photocatalytic behaviour. In this work, titanium dioxide–reduced graphene oxide (TiO2–RGO) composites were synthesised by the photocatalytic reduction of exfoliated graphene oxide (GO) by TiO2 (Evonik P25) under UV irradiation in the presence of methanol as a hole acceptor. The composite materials were characterised using high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman and XPS analysis provided evidence that GO was converted to RGO by photocatalytic reduction. The TiO2–RGO composites were compared to TiO2 in suspension reactors for the disinfection of water contaminated with Escherichia coli and Fusarium solani spores under real sunlight. Very rapid water disinfection was observed with both E. coli and F. solani spores. An enhancement in the rate of inactivation of E. coli was observed with the TiO2–RGO composite compared to P25 alone. The rate of inactivation of F. solani spores was similar for both the TiO2–RGO and P25. When the major part of the solar UVA was cut-off (λ > 380 nm) using a methacrylate screen, there was a marked increase in the time required for inactivation of E. coli with P25 but no change in the inactivation rate for the TiO2–RGO. There is evidence of singlet oxygen production with visible light excitation of the TiO2–RGO composites which would lead to E. coli inactivation.

ACS Style

Pilar Fernandez-Ibañez; M.I. Polo-López; S. Malato; Shikha Wadhwa; J.W.J. Hamilton; P.S.M. Dunlop; R. D’Sa; E. Magee; K. O’Shea; D.D. Dionysiou; J.A. Byrne. Solar photocatalytic disinfection of water using titanium dioxide graphene composites. Chemical Engineering Journal 2014, 261, 36 -44.

AMA Style

Pilar Fernandez-Ibañez, M.I. Polo-López, S. Malato, Shikha Wadhwa, J.W.J. Hamilton, P.S.M. Dunlop, R. D’Sa, E. Magee, K. O’Shea, D.D. Dionysiou, J.A. Byrne. Solar photocatalytic disinfection of water using titanium dioxide graphene composites. Chemical Engineering Journal. 2014; 261 ():36-44.

Chicago/Turabian Style

Pilar Fernandez-Ibañez; M.I. Polo-López; S. Malato; Shikha Wadhwa; J.W.J. Hamilton; P.S.M. Dunlop; R. D’Sa; E. Magee; K. O’Shea; D.D. Dionysiou; J.A. Byrne. 2014. "Solar photocatalytic disinfection of water using titanium dioxide graphene composites." Chemical Engineering Journal 261, no. : 36-44.

Journal article
Published: 30 May 2014 in The Journal of Physical Chemistry C
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Jeremy W.J. Hamilton; J. Anthony Byrne; Patrick S.M. Dunlop; Dionysios D. Dionysiou; Miguel Pelaez; Kevin O’Shea; Damian Synnott; Suresh C. Pillai. Evaluating the Mechanism of Visible Light Activity for N,F-TiO2 Using Photoelectrochemistry. The Journal of Physical Chemistry C 2014, 118, 12206 -12215.

AMA Style

Jeremy W.J. Hamilton, J. Anthony Byrne, Patrick S.M. Dunlop, Dionysios D. Dionysiou, Miguel Pelaez, Kevin O’Shea, Damian Synnott, Suresh C. Pillai. Evaluating the Mechanism of Visible Light Activity for N,F-TiO2 Using Photoelectrochemistry. The Journal of Physical Chemistry C. 2014; 118 (23):12206-12215.

Chicago/Turabian Style

Jeremy W.J. Hamilton; J. Anthony Byrne; Patrick S.M. Dunlop; Dionysios D. Dionysiou; Miguel Pelaez; Kevin O’Shea; Damian Synnott; Suresh C. Pillai. 2014. "Evaluating the Mechanism of Visible Light Activity for N,F-TiO2 Using Photoelectrochemistry." The Journal of Physical Chemistry C 118, no. 23: 12206-12215.

Journal article
Published: 18 April 2014 in Catalysis Today
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The widespread use and abuse of antibiotics in human and animal medicine has produced a reservoir of antibiotic resistant bacteria (ARB) which persist and spread within many environments including natural and wastewater systems. This paper reports the first investigation into the effect of advanced oxidation technologies, photocatalysis, on the potential to induce antibiotic resistant gene transfer within sub-lethally injured ARB. The impact of photocatalytic disinfection (PCD) treatments on three strains of Escherichia coli, an antibiotic sensitive strain (K12) and two antibiotic resistant strains (J-53R (rifampicin resistant) and HT-99 (chloramphenicol resistant), within an immobilised titanium dioxide stirred tank reactor. When suspended in distilled water, viable cell numbers (CFU mL−1) of both ARB declined from 3 log10 to 0.5 log10 with 180 min PCD treatment. However, subsequent recovery to 3 log10 of both ARB was observed during post treatment incubation at 37 °C for 24 h. No E. coli K12 were recovered immediately after 150 min treatment, or after post treatment incubation. These observations suggest that the ARB are less sensitive to the oxidative stresses involved in PCD treatment than the antibiotic sensitive strain. Gene pair conjugant numbers in PCD treated mixtures of J-53R and HT-99 cells (a 9:1 ratio) were calculated to be four-fold greater than in the (no treatment) control experiments. Both surviving bacterial cell numbers and conjugant pair numbers were lower when ARB were PCD treated in final effluent from an urban wastewater treatment plant. In conclusion, the results of this study confirm the efficacy of PCD, but also highlight the importance of applying PCD treatment “long enough” to avoid post treatment recovery from sub-lethal injury and the highly undesirable transfer of antibiotic resistant genes amongst bacteria during wastewater treatment.

ACS Style

P.S.M. Dunlop; M. Ciavola; L. Rizzo; D.A. McDowell; John Byrne. Effect of photocatalysis on the transfer of antibiotic resistance genes in urban wastewater. Catalysis Today 2014, 240, 55 -60.

AMA Style

P.S.M. Dunlop, M. Ciavola, L. Rizzo, D.A. McDowell, John Byrne. Effect of photocatalysis on the transfer of antibiotic resistance genes in urban wastewater. Catalysis Today. 2014; 240 ():55-60.

Chicago/Turabian Style

P.S.M. Dunlop; M. Ciavola; L. Rizzo; D.A. McDowell; John Byrne. 2014. "Effect of photocatalysis on the transfer of antibiotic resistance genes in urban wastewater." Catalysis Today 240, no. : 55-60.

Research article
Published: 15 January 2014 in Journal of Catalysts
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Supported titanium dioxide (TiO2) was investigated for the photodegradation of the insecticide fenamiphos in water. The photocatalyst was immobilised on borosilicate glass plates and the kinetics of degradation were studied in a stirred tank reactor under UV irradiation. Two types of TiO2, for example, Millennium PC500 (100% anatase) and Degussa P25 (80% anatase, 20% rutile), were used. Their activities have been based on the rates of insecticide disappearance. Experiments were investigated to evaluate the effect of pH and initial concentrations of fenamiphos as well as catalyst doses on the photocatalytic degradation of fenamiphos. Kinetic parameters were experimentally determined and an apparent first-order kinetic was observed. For photolysis process of fenamiphos, two photoproducts were identified and characterized using high performance liquid chromatography/mass spectrometry (HPLC/MS). The plausible mechanism of photolysis involved is the oxidation of sulfonamide group. In presence of photocatalyst TiO2, photodegradation was observed. Under identical conditions, Degussa P25 shows higher photocatalytic activity in regard to PC500 Millennium and complete degradation was observed after 180 min.

ACS Style

A. El Yadini; H. Saufi; P. S. M. Dunlop; J. Anthony Byrne; M. El Azzouzi; S. El Hajjaji. Supported TiO2 on Borosilicate Glass Plates for Efficient Photocatalytic Degradation of Fenamiphos. Journal of Catalysts 2014, 2014, 1 -8.

AMA Style

A. El Yadini, H. Saufi, P. S. M. Dunlop, J. Anthony Byrne, M. El Azzouzi, S. El Hajjaji. Supported TiO2 on Borosilicate Glass Plates for Efficient Photocatalytic Degradation of Fenamiphos. Journal of Catalysts. 2014; 2014 ():1-8.

Chicago/Turabian Style

A. El Yadini; H. Saufi; P. S. M. Dunlop; J. Anthony Byrne; M. El Azzouzi; S. El Hajjaji. 2014. "Supported TiO2 on Borosilicate Glass Plates for Efficient Photocatalytic Degradation of Fenamiphos." Journal of Catalysts 2014, no. : 1-8.

Journals
Published: 01 January 2014 in Catalysis Science & Technology
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This comprehensive review addresses the fundamentals of photocatalytic mechanism, recent developments in materials synthesis and reactor design.

ACS Style

Donal A. Keane; Kevin McGuigan; Pilar Fernandez-Ibañez; Maria Inmaculada Polo López; John Byrne; Patrick Dunlop; Kevin E Oshea; Dionysios D. Dionysiou; Suresh C. Pillai. Solar photocatalysis for water disinfection: materials and reactor design. Catalysis Science & Technology 2014, 4, 1211 -1226.

AMA Style

Donal A. Keane, Kevin McGuigan, Pilar Fernandez-Ibañez, Maria Inmaculada Polo López, John Byrne, Patrick Dunlop, Kevin E Oshea, Dionysios D. Dionysiou, Suresh C. Pillai. Solar photocatalysis for water disinfection: materials and reactor design. Catalysis Science & Technology. 2014; 4 (5):1211-1226.

Chicago/Turabian Style

Donal A. Keane; Kevin McGuigan; Pilar Fernandez-Ibañez; Maria Inmaculada Polo López; John Byrne; Patrick Dunlop; Kevin E Oshea; Dionysios D. Dionysiou; Suresh C. Pillai. 2014. "Solar photocatalysis for water disinfection: materials and reactor design." Catalysis Science & Technology 4, no. 5: 1211-1226.

Research article
Published: 26 February 2013 in Industrial & Engineering Chemistry Research
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Innovative sol–gel synthesis based on the self-assembling template method has been applied to synthesize mesoporous anion-doped TiO2 with N–F, S and C atoms using suitable surfactants and reagents, to improve simultaneously the structural, morphological, and electronic properties of TiO2 nanomaterials and achieve anion doping of titania with high visible light photoinduced reactivity. The incorporation of anion species in the titania structure resulted in the effective extension of TiO2 optical absorption in the visible range through the formation of intragap energy states. The anion-doped titania materials immobilized in the form of nanostructured thin films on glass substrates exhibited high photocatalytic efficiency for the degradation of the microcystin-LR (MC-LR) cyanotoxin, a hazardous water pollutant of emerging concern, under visible light irradiation. The development of these visible light-activated nanocatalysts has the potential of providing environmentally benign routes for water treatment.

ACS Style

Vlassis Likodimos; ChangSeok Han; Miguel Pelaez; Athanassios G. Kontos; Guanglong Liu; Duanwei Zhu; Shuijiao Liao; Armah A. De La Cruz; Kevin O’Shea; Patrick Dunlop; John Byrne; Dionysios D. Dionysiou; Polycarpos Falaras. Anion-Doped TiO2 Nanocatalysts for Water Purification under Visible Light. Industrial & Engineering Chemistry Research 2013, 52, 13957 -13964.

AMA Style

Vlassis Likodimos, ChangSeok Han, Miguel Pelaez, Athanassios G. Kontos, Guanglong Liu, Duanwei Zhu, Shuijiao Liao, Armah A. De La Cruz, Kevin O’Shea, Patrick Dunlop, John Byrne, Dionysios D. Dionysiou, Polycarpos Falaras. Anion-Doped TiO2 Nanocatalysts for Water Purification under Visible Light. Industrial & Engineering Chemistry Research. 2013; 52 (39):13957-13964.

Chicago/Turabian Style

Vlassis Likodimos; ChangSeok Han; Miguel Pelaez; Athanassios G. Kontos; Guanglong Liu; Duanwei Zhu; Shuijiao Liao; Armah A. De La Cruz; Kevin O’Shea; Patrick Dunlop; John Byrne; Dionysios D. Dionysiou; Polycarpos Falaras. 2013. "Anion-Doped TiO2 Nanocatalysts for Water Purification under Visible Light." Industrial & Engineering Chemistry Research 52, no. 39: 13957-13964.

Book chapter
Published: 01 January 2013 in ACS Symposium Series
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This book chapter discusses the syntheses of various nanomaterials, for green nanotechnology applications in detail. Special attention is given to the development of emerging areas, such as environmental as well as energy materials. Various approaches for preparing nanostructured photocatalysts, such as titanium dioxide, zinc oxide, iron oxide, and metal sulfides, different conventional methods and novel methods, including sol-gel methods, hydrothermal methods, microwave-assisted methods and sonochemical methods are introduced. The use of nanomaterials as photocatalysts, supporting materials for solar cells, and disinfectants is reported for environmental remediation and energy applications. Advanced applications of nanomaterials for water detoxification, air purification, and the inactivation of pathogenic microorganisms in water as well as dye-sensitized solar cells is also discussed. The enhancement of selectivity of photocatalysis, especially TiO2 systems, for the destruction of target contaminants in water is comprehensively presented. Finally, the role of reactive oxygen species (ROS), such as hydroxyl radical (•OH), superoxide anion radical (O2 •-), singlet oxygen (1O2) and hydrogen peroxide (H2O2), in semiconductor photocatalysis is introduced and various experimental techniques to detect ROS are also discussed.

ACS Style

ChangSeok Han; Joel Andersen; Suresh C. Pillai; Rachel Fagan; Polycarpos Falaras; John Byrne; Patrick Dunlop; Hyeok Choi; Wenjun Jiang; Kevin O’Shea; Dionysios D. Dionysiou. Chapter Green Nanotechnology: Development of Nanomaterials for Environmental and Energy Applications. ACS Symposium Series 2013, 201 -229.

AMA Style

ChangSeok Han, Joel Andersen, Suresh C. Pillai, Rachel Fagan, Polycarpos Falaras, John Byrne, Patrick Dunlop, Hyeok Choi, Wenjun Jiang, Kevin O’Shea, Dionysios D. Dionysiou. Chapter Green Nanotechnology: Development of Nanomaterials for Environmental and Energy Applications. ACS Symposium Series. 2013; ():201-229.

Chicago/Turabian Style

ChangSeok Han; Joel Andersen; Suresh C. Pillai; Rachel Fagan; Polycarpos Falaras; John Byrne; Patrick Dunlop; Hyeok Choi; Wenjun Jiang; Kevin O’Shea; Dionysios D. Dionysiou. 2013. "Chapter Green Nanotechnology: Development of Nanomaterials for Environmental and Energy Applications." ACS Symposium Series , no. : 201-229.