Photocatalytic production of 1O2 and OH mediated by silver oxidation during the photoinactivation of Escherichia coli with TiO2

Castro, Camilo A.; Osorio, Paula; Sienkiewicz, Andrzej; Pulgarín, C.; Centeno, Aristóbulo; Giraldo, Sonia A.

doi:10.1016/j.jhazmat.2011.08.076

Cited by 34 publications

(18 citation statements)

References 53 publications

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“…5.55 eV; this value is slightly lower than that of the pristine TiO 2 (ca. 6.0 eV) 50 51 52 . The slight change in energy difference of the Ti2p peaks can be attributed to the formation of a mixed phase of rutile and anatase in the sample TiO 2 -4 53 .…”

Section: Resultsmentioning

confidence: 99%

Controllable Synthesis and Tunable Photocatalytic Properties of Ti3+-doped TiO2

Ren

Wen

Cui

et al. 2015

Sci Rep

168

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Photocatalysts show great potential in environmental remediation and water splitting using either artificial or natural light. Titanium dioxide (TiO2)-based photocatalysts are studied most frequently because they are stable, non-toxic, readily available, and highly efficient. However, the relatively wide band gap of TiO2 significantly limits its use under visible light or solar light. We herein report a facile route for controllable synthesis of Ti3+-doped TiO2 with tunable photocatalytic properties using a hydrothermal method with varying amounts of reductant, i.e., sodium borohydride (NaBH4). The resulting TiO2 showed color changes from light yellow, light grey, to dark grey with the increasing amount of NaBH4. The present method can controllably and effectively reduce Ti4+ on the surface of TiO2 and induce partial transformation of anatase TiO2 to rutile TiO2, with the evolution of nanoparticles into hierarchical structures attributable to a high pressure and strong alkali environment in the synthesis atmosphere; in this way, the photocatalytic activity of Ti3+-doped TiO2 under visible-light can be tuned. The as-developed strategy may open up a new avenue for designing and functionalizing TiO2 materials for enhancing visible light absorption, narrowing band gap, and improving photocatalytic activity.

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Section: Resultsmentioning

confidence: 99%

Controllable Synthesis and Tunable Photocatalytic Properties of Ti3+-doped TiO2

Ren

Wen

Cui

et al. 2015

Sci Rep

168

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“…Degraded nanoparticles also have the potential to cause toxicity. Nanomaterials that have been shown to induce toxicity include nano-TiO 2 (Castro et al, 2012;Lewicka et al, 2013), nano-ZnO (He et al, 2014;Lewicka et al, 2013), and carbon-based nanomaterials, such as carbon nanotubes (Schlagenhauf et al, 2015;Guo et al, 2011;Ju et al, 2014). Moreover, increasing use of nanomaterials in volume and types of food packaging may be a cause for concern that the release of NPs from the package would migrate to food or the environment.…”

Section: Introductionmentioning

confidence: 99%

Evaluating weathering of food packaging polyethylene-nano-clay composites: Release of nanoparticles and their impacts

et al. 2018

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Nano-fillers are increasingly incorporated into polymeric materials to improve the mechanical, barrier or other matrix properties of nanocomposites used for consumer and industrial applications. However, over the life cycle, these nanocomposites could degrade due to exposure to environmental conditions, resulting in the release of embedded nanomaterials from the polymer matrix into the environment. This paper presents a rigorous study on the degradation and the release of nanomaterials from food packaging composites. Films of nano-clay-loaded low-density polyethylene (LDPE) composite for food packaging applications were prepared with the spherilene technology and exposed to accelerated weathering of ultraviolet (UV) irradiation or low concentration of ozone at 40 °C. The changes in the structural, surface morphology, chemical and physical properties of the films during accelerated weathering were investigated. Qualitative and quantitative changes in properties of pristine and aged materials and the release of nano-clay proceeded slowly until 130 hr irradiation and then accelerated afterward resulting complete degradation. Although nano-clay increased the stability of LDPE and improved thermal and barrier properties, they accelerated the UV oxidation of LDPE. With increasing exposure to UV, the surface roughness, chemiluminescence index, and carbonyl index of the samples increased while decreasing the intensity of the wide-angle X-ray diffraction pattern. Nano-clay particles with sizes ranging from 2-8 nm were released from UV and ozone weathered composite. The concentrations of released nanoparticles increased with an increase in aging time. Various toxicity tests, including reactive oxygen species generation and cell activity/viability were also performed on the released nano-clay and clay polymer. The released nano-clays basically did not show toxicity. Our combined results demonstrated the degradation properties of nano-clay particle-embedded LDPE composites toxicity of released nano-clay particles to A594 adenocarcinomic human alveolar basal epithelial cells was observed, which will help with future risk based-formulations of exposure.

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“…As the Fermi level of TiO2 is very high as compared to silver, the electron transfer from the conduction band of the semiconductor to the silver nanoparticles is thermodynamically feasible [50,51]. The LSPR properties can be tuned depending on the size and shape of the metallic Ag nanoparticles (AgNPs) [52]. However, silver exhibits LSPR under visible-light where the collective oscillation of its electrons can yield an inter band excitation, providing enough energy to electrons that move to the interface to surmount the Schottky barrier [51].…”

Section: Non-metal-and Metal-tio2 Systemsmentioning

confidence: 99%

An approach to the photocatalytic mechanism in the TiO2-nanomaterials microorganism interface for the control of infectious processes

Rodríguez-González

Obregón

Patrón-Soberano

et al. 2020

Applied Catalysis B: Environmental

141

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J o u r n a l P r e -p r o o f 2 Graphical Abstract Highlights  Photoactive TiO2 nanomaterials can solve the actual microbial infectious defies  The microbial cell/TiO2 surface approach is key to get the photo-kill mechanism  Microbial preparation requires a reproducible protocol for proper characterization  Advanced surface characterization techniques can unravel the photo-kill mechanism  Generation of ROS, physical injuries and biocidal features confirm the annihilation J o u r n a l P r e -p r o o f Abstract The approach of this timely review considers the current literature that is focused on the interface nanostructure/cell-wall microorganism to understand the annihilation mechanism. Morphological studies use optical and electronic microscopes to determine the physical damage on the cell-wall and the possible cell lysis that confirms the viability and microorganism death. The key parameters of the tailoring the surface of the photoactive nanostructures such as the metal functionalization with bacteriostatic properties, hydrophilicity, textural porosity, morphology and the formation of heterojunction systems, can achieve the effective eradication of the microorganisms under natural conditions, ranging from practical to applications in environment, agriculture, and so on. However, to our knowledge, a comprehensive review of the microorganism/nanomaterial interface approach has rarely been conducted. The final remarks point the ideal photocatalytic way for the effective prevention/eradication of microorganisms, considering the resistance that the microorganism could develop without the appropriate regulatory aspects for human and ecosystem safety. Introduction and background 1. TiO 2 based materials obtained from TiO 2 and its composites J o u r n a l P r e -p r o o f previous studies have demonstrated that photocatalysis can be considered a promising tool in anticancer therapies, since the photocatalyst can kill cancer cells such as HeLa cells, which cause cervical cancer [7]. The energy absorbed by the photocatalyst comprises the range of ultraviolet and/or visible light, even natural sunlight. When the photocatalyst absorbs light, if the energy of the photons is enough to excite the electrons J o u r n a l P r e -p r o o f 6in the valence band (VB), then they migrate to a higher energy level in the conduction band (CB) of the material, as it is illustrated in Fig. 1. This phenomenon generates the charge carriers known as hole-electron pairs. The photogenerated hole can migrate to the surface of the material and react with water molecules or hydroxyl ions to produce hydroxyl radicals, while the photoexcited electron in the conduction band can react with the adsorbed molecular oxygen to produce superoxide ions [8]. Since the report of Fujishima and Honda about the water splitting process using a TiO2 electrode under UV irradiation, numerous studies have exploited the photoactive properties of this material [9,10]. Several reviews have studied the relationship between the electronic properties of TiO2 with...

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Photocatalytic production of 1O2 and OH mediated by silver oxidation during the photoinactivation of Escherichia coli with TiO2

Cited by 34 publications

References 53 publications

Controllable Synthesis and Tunable Photocatalytic Properties of Ti3+-doped TiO2

Controllable Synthesis and Tunable Photocatalytic Properties of Ti3+-doped TiO2

Evaluating weathering of food packaging polyethylene-nano-clay composites: Release of nanoparticles and their impacts

An approach to the photocatalytic mechanism in the TiO2-nanomaterials microorganism interface for the control of infectious processes

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