scholarly journals Photo-Degradation of Orange G as an Environmental Pollutant with TiO2-ZnO Composite Material

2021 ◽  
pp. 29-38
Author(s):  
Md Abdullah Bin Samad ◽  
Md. Amjad Hossain ◽  
Tajmeri S. A. Islam ◽  
Waziha Farha

The increasing water pollution is a great concern as millions of people don't have access to pure water in Bangladesh. A considerable number of people are dying of contaminated water each year not only in Bangladesh but all over the world. Many industries, tanneries, companies, etc. are emitting lots of environmentally hazardous materials into the surrounding water. Many of these pollutants are industrial dyes. The dyes loss from the industrial water during dyeing operation damage the esthetic merit of surface water. They minimize light penetration, hamper aquatic lives and hinder photosynthesis. Some dyes may also have toxic, mutagenic, and carcinogenic characteristics. The purpose of this research is to get rid of the pollutant dye Orange G before the water is contaminated. A method named photo-degradation using different light sources is used to mineralize Orange G dye with composite materials including TiO2-ZnO. This composite was prepared by the hydrothermal method. The photocatalytic behavior of the prepared composite TiO2-ZnO helps in minimizing the effect of this dye to save the water from contamination. The composite compoundwas studied by experimenting on photo-degradation with Orange G under different light sources such as visible light, UV light, and sunlight. The photo-degradation percentage was found to maximum of 79.60 in the presence of sunlight. The percentages of photo-degradation under UV light and visible light were 48.0 and 18.40 respectively.

2020 ◽  
Author(s):  
Michael O'Hagan ◽  
Javier Ramos Soriano ◽  
Susanta Haldar ◽  
Juan Carlos Morales ◽  
Adrian Mulholland ◽  
...  

<div><p>Photoresponsive ligands for G-quadruplex oligonucleotides (G4) offer exciting opportunities for the reversible regulation of these assemblies with potential applications in biological chemistry and responsive nanotechnology. However, achieving the robust regulation of G4 ligand activity with low-energy visible light sources that are easily accessible and compatible with biological systems remains a significant challenge to realizing these applications. Herein, we report the G4-binding properties of a photoresponsive dithienylethene (DTE). We demonstrate the first example of G4-specific acceleration of the photoswitching kinetics of a small molecule and the visible-light mediated switching of the G4 ligand binding mode in physiologically-relevant conditions, which in turn allows control over the G4 tetrad structure of telomeric G4 in potassium buffer. The process is fully reversible and avoids the need for high-energy UV light. This affords an efficient, practical and biologically-relevant means of control that may be applied in the generation of new responsive G4/ligand supramolecular systems.</p></div><br>


2011 ◽  
Vol 287-290 ◽  
pp. 1735-1743 ◽  
Author(s):  
Yi Dong Shi ◽  
Qiong Guo ◽  
Yuan Song Xie

The C, N, S tri-doped TiO2 with high visible-light photo-catalysis effect was successfully prepared by mixing thiourea with the self-prepared TiO2 powder through calcining for 2h at 450°C. The TiO2 powder was obtained by homogeneous precipitation method using the metatitanic acid instead of expensive chemical reagents contained Ti as raw material. The effect of doping materials and methods on the photo-degradation rate of methylene blue and dyes was studied. The characterizations of the doped TiO2 were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectra (UV-vis). The results showed that this sample was the anatase TiO2 and contained elements C, N, S. The sample exhibited a significant response to ultraviolet and visible light. In the photo-degradation experiment, the C, N, S, tridoped-TiO2 could decolorize methylene blue and textile dyes quickly, and the photo-degradation rate of methylene blue could reach upward 98% after 3 hours under the different light sources.


2018 ◽  
Vol 3 (3) ◽  
pp. 76-78 ◽  
Author(s):  
Martin Hessling ◽  
Julian Schmid ◽  
Katharina Hoenes ◽  
Petra Vatter

Legionella infections caused by contaminated water are a widespread problem worldwide. Discharge lamps like mercury vapor lamps are widely known for the disinfection properties of their radiation, but they suffer technical disadvantages, like high voltages and toxic content, and are, therefore, not suitable for some infection control applications. New highintensity ultraviolet (UV) and violet LEDs offer new approaches for Legionella control, because these bacteria are significantly light sensitive compared to other pathogens. One of the most important infection pathways is the inhalation of Legionellacontaining aerosols during showering. This problem could be reduced by a single strong UV LED within the shower head, which irradiates the passing water for some milliseconds. This practice can be especially beneficial in hospitals and care facilities. UV light offers only a limited penetration depth, however, even in pure water. To disinfect larger water volumes, e.g., in water dispensers, visible violet LEDs are more appropriate. Unfortunately, up to now, neither approach has been given much attention by potential users.


2020 ◽  
Author(s):  
Michael O'Hagan ◽  
Javier Ramos Soriano ◽  
Susanta Haldar ◽  
Juan Carlos Morales ◽  
Adrian Mulholland ◽  
...  

<div><p>Photoresponsive ligands for G-quadruplex oligonucleotides (G4) offer exciting opportunities for the reversible regulation of these assemblies with potential applications in biological chemistry and responsive nanotechnology. However, achieving the robust regulation of G4 ligand activity with low-energy visible light sources that are easily accessible and compatible with biological systems remains a significant challenge to realizing these applications. Herein, we report the G4-binding properties of a photoresponsive dithienylethene (DTE). We demonstrate the first example of G4-specific acceleration of the photoswitching kinetics of a small molecule and the visible-light mediated switching of the G4 ligand binding mode in physiologically-relevant conditions, which in turn allows control over the G4 tetrad structure of telomeric G4 in potassium buffer. The process is fully reversible and avoids the need for high-energy UV light. This affords an efficient, practical and biologically-relevant means of control that may be applied in the generation of new responsive G4/ligand supramolecular systems.</p></div><br>


2020 ◽  
Author(s):  
Michael O'Hagan ◽  
Javier Ramos Soriano ◽  
Susanta Haldar ◽  
Juan Carlos Morales ◽  
Adrian Mulholland ◽  
...  

<div><p>Photoresponsive ligands for G-quadruplex oligonucleotides (G4) offer exciting opportunities for the reversible regulation of these assemblies with potential applications in biological chemistry and responsive nanotechnology. However, achieving the robust regulation of G4 ligand activity with low-energy visible light sources that are easily accessible and compatible with biological systems remains a significant challenge to realizing these applications. Herein, we report the G4-binding properties of a photoresponsive dithienylethene (DTE). We demonstrate the first example of G4-specific acceleration of the photoswitching kinetics of a small molecule and the visible-light mediated switching of the G4 ligand binding mode in physiologically-relevant conditions, which in turn allows control over the G4 tetrad structure of telomeric G4 in potassium buffer. The process is fully reversible and avoids the need for high-energy UV light. This affords an efficient, practical and biologically-relevant means of control that may be applied in the generation of new responsive G4/ligand supramolecular systems.</p></div><br>


Molekul ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 6
Author(s):  
Safni Safni ◽  
Mechy Rezita Wahyuni ◽  
Khoiriah Khoiriah ◽  
Yulizar Yusuf

Phenol (C6H5OH) is a common contaminant in wastewater. In certain concentrations, phenol can inhibit the activity of microorganisms and give adverse effects tohumanhealth, such as liver and kidney damage, perfect heart rate, and lower blood pressure. In this study, phenol was degraded with andwithoutN-doped TiO2under photolysis UV-light (10 Watts, λ = 365 nm) and visible-light (13 watt Philips, lux= 1400, λ = 465-640 nm)irradiation. The reductionof phenol concentrationwas measured by a UV-Vis spectrophotometer at a wavelength 200-400 nm. Some parameters such as catalyst dose, irradiation timesand type of light sources were studied. The XRD and DRS UV-Vis characterization confirmthat the nitrogen modified of titania catalyst potentially actives in visible-light. The N-doped TiO2is able to catalyze and improve the efficiency of phenol degradation in photocatalysissystem. Phenol with initialconcentration 8 mg/L was degraded by 33.89% and 30.51% without catalyst and increased to be 90.8% and 67.80%by additionof 15 mg N-doped TiO2catalyst under UV-light and visible-lightfor 210 minutes photolysis, respectively. From the results,irradiation using UV-light achieveshigherefficiency than visible-lightonphenol degradation.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012089
Author(s):  
B Usharani ◽  
V Manivannan ◽  
P Shanmugasundaram

Abstract Picric acid is a very dangerous environmental pollutant generated from chemical and dye industries due to its high toxicity. Therefore, efforts have been made to develop techniques for the efficient degradation of picric acid. A novel rGO-MnO2 nanocomposite has been synthesized by chemical method for the degradation of picric acid in various light medium. The rGO-MnO2 nanocomposite was characterized by X-ray Photoelectron Spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Energy dispersive X-ray (EDAX), Ultraviolet-visible (UV-Vis) and Scanning electron microscope (SEM). The synthesized, pure rGO, MnO2 and rGO-MnO2 nanocomposite catalyst have been studied for the activity of photocatalytic degradation against picric acid under different light sources such as UV light (254,365,390 nm), visible light and sunlight. It is found that rGO-MnO2 has achieved better performance compared to that of pure rGO, MnO2.


2021 ◽  
Vol 5 (1) ◽  
pp. 030-036
Author(s):  
Kearse Kelly P

The major use of alternative light sources (ALS) in the evaluation of bloodstains has been primarily focused on detection of whole blood, with relatively little attention to visualization of blood serum. Serum may become separated from blood pools during clotting, and because it is relatively invisible on certain backgrounds, go undetected by a perpetrator attempting to clean up a crime scene. Recently, Ultraviolet 365 (UV 365) was shown to be an effective tool in blood evaluation, useful for detection of even minute quantities of blood serum. Here the effects of environmental conditions on blood serum stain appearance were evaluated, including temperature, pH, protease sensitivity, solubility, and aging. Interestingly, it was found that the UV fluorescence of serum increases upon exposure to heat, which was accompanied by color changes under visible light and decreased solubility in multiple solvents. The efficiency of visualization of serum stains was somewhat variable, depending on the type of material on which it was dried. Finally, the current study documents the effect of heating on formation of fluorescent serum halo rings in dried bloodstains. Taken together, these data demonstrate that blood serum detection may be affected by certain conditions that influence its visualization under both visible and UV light.


2016 ◽  
Vol 12 (6) ◽  
pp. 4127-4133
Author(s):  
Nazmul Kayes ◽  
Jalil Miah ◽  
Md. Obaidullah ◽  
Akter Hossain ◽  
Mufazzal Hossain

Photodegradation of textile dyes in the presence of an aqueous suspension of semiconductor oxides has been of growing interest. Although this method of destruction of dyes is efficient, the main obstacle of applying this technique in the industry is the time and cost involving separation of oxides from an aqueous suspension. In this research, an attempted was made to develop ZnO films on a glass substrate by simple immobilization method for the adsorption and photodegradation of a typical dye, Remazol Red R (RRR) from aqueous solution. Adsorption and photodegradation of  RRR were performed in the presence of glass supported ZnO film. Photodegradation of the dye was carried out by varying different parameters such as the catalyst dosage, initial concentrations of RRR, and light sources. The percentage of adsorption as well as photodegradation increased with the amount of ZnO, reaches a maximum and then decreased. Maximum degradation has been found under solar light irradiation as compared to UV-light irradiation. Removal efficiency was also found to be influenced by the pre-sonication of ZnO suspension.


2020 ◽  
Author(s):  
Guifang Feng ◽  
Yanhong Hao ◽  
Liang Wu ◽  
Suming Chen

The photocycloaddition of olefins with carbonyls is of fundamental interest and practical importance in C=C bond location in unsaturated lipids. However, the traditional UV light activated [2+2] photocycloaddition reaction suffers side reactions and potential health damage. Here, we reported the first example of visible-light activated [2+2] photocycloaddition of anthraquinone with unsaturated lipids. This reaction showed great capability for locating the C=C bonds in various kinds of monounsaturated and polyunsaturated lipids by combining with tandem mass spectrometry (MS), such as fatty acids, phospholipids and glycerides. Based on this developed reaction, a workflow with liquid chromatography tandem MS method was developed for the global identification of unsaturated lipids in human serum, and 86 of monounsaturated and complicated polyunsaturated lipids were identified with definitive positions of C=C bonds. This approach provides new insights both on the photocycloaddition reactions and the structural lipidomics.


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