Magnetic Ni-Doped TiO2 Photocatalysts for Disinfection of Escherichia coli Bacteria (original) (raw)
Related papers
NiO/TiO2 Nanoparticles for Photocatalytic Disinfection of Bacteria under Visible Light
Journal of the …, 2011
NiO-TiO 2 composite nanoparticles have been prepared by a modified ammonia-evaporation-induced synthetic method, sintered at 4501C and characterized by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, UV-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electrochemical impedance spectroscopy. Doping shifts the optical absorption edge to the visible region but increases the charge-transfer resistance and decreases the capacitance. Under visible light, the composite nanoparticles effectively catalyze the Escherichia coli inactivation. The prepared oxide is selective in photocatalysis; with UV light, its photocatalytic activity to degrade sunset yellow, rhodamine B, and methylene blue dyes is less than that of the undoped one. However, it degrades phenol faster than TiO 2 P25.
2013
The photocatalytic activity of the as-prepared TiO 2 powders was tested by photodegradation of the organic dye Reactive Black 5 under UV and visible irradiation in an aqueous suspension. Antibacterial action of pure and Fe-modified titanium dioxide samples was tested using Escherichia coli ATCC 25922. The bacterial growth was examined in the presence of a synthesized preparations – in dark and with UV light. The photodisinfection activity was assessed by plotting of survival curves and calculation of removal efficiency. In order to estimate the post-irradiation effect, the behavior of the bacterial suspension in presence of each photocatalyst after 24 h dark period was tested. The optimal iron content was found to be 0.5 mol% for the photocatalytic decomposition of Reactive Black 5 dye under ultra violet (UV) and visible (Vis) irradiation, and also for antibacterial activity in the presence of UV light. At higher iron contents (1–2 mol%) the photocatalytic performance under both UV ...
2022
Visible light driven photocatalytically active mesoporous nanomaterials plays an indispensable role for antibacterial activity in low light applications. In this work, nanomaterials were handily prepared by varying the dopant concentrations from 0.25 to 1.0 Wt % using sol-gel method. All the prepared samples were characterized by Powdered X-ray diffraction (XRD), Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible diffuse reflectance spectroscopy (UV/Vis-DRS), Transmission electron microscopy (TEM) and Brauner-Emmett-Teller (BET). The characterization results revealed that a photocatalytically active phase i.e.; anatase and rutile mixed phase was observed for co-doped catalyst samples. Due to substitutional doping of Mn and Ni by replacing Ti, the frequency shift of Ti-O-Ti in the catalyst samples was observed by FTIR. Further the catalyst shows roughmorphology, irregular particle shape with less particle size having high surface area, and reduced band gap energy. The photocatalytically active materials antibacterial activity was discerned by using Sphingomonas paucimobilis and Pseudomonas fluorescence. The result of antibacterial activity shows that among all nanocatalysts, NMT2 catalyst shows optimum zone of inhibition at 25.1 ± 0.2 mm for Sphingomonas paucimobilis and 18.1 ± 0.2 mm for Pseudomonas fluorescence compared to standard (chloramphenicol) value at 24.1 ± 0.1 mm and 23.1 ± 0.05 mm at 100 µg/mL respectively. KEYWORDS nanomaterials, photocatalysis, Ni/Mn-TiO 2 , antibacterial activity, agar-well diffusion method FOR CITATION Miditana S.R., Tirukkovalluri S.R., Raju I.M. Synthesis and antibacterial activity of transition metal (Ni/Mn) co-doped TiO 2 nanophotocatalyst on different pathogens under visible light irradiation. Nanosystems:
Photocatalytic disinfection of E . coli using N-doped TiO 2 composite
2014
Heterogeneous photocatalysis is among an alternative technique for the inactivation of pathogenic microorganisms. Several researchers have achieved the successful killing of bacteria, viruses, fungi or protozoa by semiconductor photocatalysis. This study significantally provides a better understanding of the bactericidal properties of N-TiO2 by identifying specific bacterial targets and cell strcuture during disinfection in pure water. The photocatalytic inactivation of bacteria was investigated using E. coli, a well-known bacterial indicator. Firstly, the effects of the contact of N-doped TiO2 with bacterial cells in the dark on both the bacterial cultivability and the envelope integrity was carried out. Then, assessment of the deleterious effects of N-doped TiO2 on the bacteria’s permeability and cultivability was done under visible radiations exposure. In order to identify the cell structure during the inactivation of the bacteria, monitoring of atomic force microscopy was also c...
Photocatalytic Activity and Antibacterial Behavior of Fe3+-Doped TiO2/SnO2 Nanoparticles
Energy Research Journal, 2010
Problem statement: Since bacteria mainly causes damage on fresh vegetables and fruits during transportation to market, anti-bacterial TiO 2 photocatalyst was applied for their packaging films. However, it has been known that pure TiO 2 exhibits low photocatalytic property due to rapid recombination of photo-activated electrons and holes. Doping with metal or metal oxide shows the improvement of photocatalytic activity and disinfection effect. Approach: Fe 3+ was considered to dope into TiO 2 /3SnO 2 photocatalyst in order to enhance the photocatalytic property and bacterial inactivation efficiency. The Fe 3+ doped TiO 2 /3SnO 2 nanoparticles were prepared by sol-gel method and calcined at 400 °C for 2 h. The synthesized powders were characterized by XRD, BET and SEM. Photocatalytic activity and bacteria killing effect were determined by means of degradation of methylene blue solution and inactivation of E. coli bacteria, respectively. These tests were performed under UV and visible light irradiations. Results: Fe 3+ doping into TiO 2 /3SnO 2 has an effect on inhibition of anatase crystal growth, led to the enlargement of the composite specific surface area. Therefore, the photocatalytic activity of Fe 3+ doped TiO 2 /3SnO 2 composite in proper concentration was greater than those of pure TiO 2 and TiO 2 /3SnO 2 and 0.5 mol% Fe 3+ doping exhibited the highest photocatalytic activity and E.coli inactivation efficiency. The E. coli was completely killed within 90 min under UV irradiation or 99.7% inactivated under visible light exposure. Conclusion: Fe 3+ doped TiO 2 /3SnO 2 nanoparticles were successfully synthesized and identified as 100% anatase phase. The 0.5mol% Fe 3+ -doped TiO 2 /3SnO 2 which has particle size of 12.89 µm and specific surface area of 117.61 m 2 g −1 , exhibited the highest activity and disinfection efficiency. An attractive feature of Fe 3+ doped TiO 2 /3SnO 2 photocatalytic disinfection is its potential to be activated by visible light. Therefore, these composite TiO 2 nanoparticles can be utilized for fresh food packaging films.
Cu-doped TiO2 nanoparticles for photocatalytic disinfection of bacteria under visible light
Journal of Colloid and Interface Science, 2010
Two percent Cu-doped TiO 2 nanoparticles were prepared by a modified ammonia-evaporation-induced synthetic method, calcined at 450°C, and characterized by powder X-ray diffraction, energy dispersive X-ray analysis, ESR spectroscopy, scanning electron microscopy, UV-visible diffuse reflectance spectrum, photoluminescence spectroscopy, and electrochemical impedance spectroscopy. Doping shifts the optical absorption edge to the visible region but increases the charge-transfer resistance and decreases the capacitance. Under visible light, the composite nanoparticles very efficiently catalyze the disinfection of Escherichia coli. The prepared oxide is selective in photocatalysis; under UV light, its photocatalytic activity to degrade sunset yellow, rhodamine B, and methylene blue dyes is less than that of the undoped one.
Applied Catalysis B: Environmental, 2014
The present study deals with the inactivation of Escherichia coli and Klebsiella pneumoniae in water by means of heterogeneous photocatalysis under simulated solar irradiation. For this purpose, novel Mn-, Co-and Mn/Co-doped TiO 2 catalysts were prepared. A straightforward, simple and inexpensive process has been developed based on a co-precipitation method for the synthesis of metal-doped catalysts, which were subsequently assessed in terms of their disinfection efficiency. The effect of various operating conditions, such as metal dopant (Mn-, Co-and Mn/Co), dopant concentration (0.02-1 wt%), catalyst concentration (25-250 mg/L), bacterial concentration (10 2 -10 8 CFU/mL), treatment time (up to 60 min), toxic effects on bacteria and photon flux (4.93-5.8 × 10 −7 Einstein/(L s)), was examined under simulated solar irradiation. Metal-doped TiO 2 samples were prepared reproducibly and doping shifted the optical absorption edge to the visible region. Their activity was superior to the respective of commercially available P25 titania. The reference strains of E. coli and K. pneumoniae proved to be readily inactivated during photocatalytic treatment of aqueous samples, since disinfection occurred rapidly (i.e. after only 10 min of irradiation) with the dopant concentration affecting the overall process to a certain extent. Disinfection follows a pseudo-first order kinetic rate in terms of both bacteria removal. Inactivation of the bacteria is attributed to the oxidative degradation of their cells and increase of their cell permeability and not to the potential toxicity of the metal-doped semiconductors, which did not exhibit any bactericidal properties. It has been shown that the improved activity of the Mn-, Co-, and binary Mn/Co doped TiO 2 is accredited to the fact that they can be activated in the visible part of the spectrum, in the absence of UV light (i.e. >420 nm).
Springer Berlin Heidelberg, 2019
In the present work, Ni 2+ and Cu 2+ ions are doped with TiO 2 using sol-gel technique. The effects of Ni and Cu doping in TiO 2 matrix are characterized by XRD, Micro-Raman, FTIR, UV-DRS, PL, and FESEM with EDS. Furthermore, it is analyzed for photocatalytic activity and magnetic applications. From XRD analysis, it is observed that the peaks corresponding to the planes match with the JCPDS data [anatase: 89-4203] of TiO 2. The crystallite size of the doped samples is found to be greater than that of TiO 2. Micro-Raman analysis shows the confirmation of anatase phase of TiO 2. FTIR analysis confirms the presence of functional groups which are presented in the prepared samples. From UV-DRS, the band-gap values of TiO 2 and doped TiO 2 (Ni 2+ , Cu 2+) are found to be 3.25, 2.48, and 1.25 eV. Photoluminescence (PL) results show an emission edge of Ni-and Cu-doped TiO 2 is red shifted which is due to the vacancies of titanium and oxygen imported subsequently during doping. The surface morphology and the elemental composition of Ni-and Cu-doped TiO 2 nanoparticles are also analyzed. The photocatalytic activity of all the prepared samples are assessed by methylene blue dye as testing pollutant and visible radiation. The test reveals that Cu-TiO 2 , Ni-TiO 2 , and TiO 2 show the degradation efficiency of 68.14, 61.04, and 33.32%, thereby showing that the doped TiO 2 are more efficient in degrading the pollutant and can be applied for future photocatalytic applications. From VSM analysis, the saturation magnetization of Ni-TiO 2 and Cu-TiO 2 is found to be weak and can be improved by the synthesis process and the proportion of dopant.
Sains Malaysiana, 2012
Titanium dioxide nanoparticles were synthesized by using sol gel method and their physico-chemical properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectrophotometer. The photocatalytic property of TiO 2 nanoparticles was investigated by inactivation of Escherichia coli under irradiation of fluorescent lamp. The results showed that the size of TiO 2 was in the range of 3 to 7 nm with high crystallinity of anatase phase. The sharp peaks in FTIR spectrum determined the purity of TiO 2 nanoparticles and absorbance peak of UV-Vis spectrum showed the energy band gap of 3.2 eV. Optimum inactivation of E. coli was obtained at 1.0 g/L TiO 2 nanoparticles, with 80% of E. coli population was inactivated. The light scattering effect and insufficient concentration are the factors that cause the less effective inactivation reaction for 2.5 g/L and 0.1 g/L TiO 2 concentration.
Photocatalytic antibacterial performance of TiO 2 and Ag-doped TiO 2 against
Both N-doped and undoped thin films of 3SnO 2 /TiO 2 composite were prepared, by sol-gel and dip-coating methods, and then calcined at 600 ∘ C for 2 hours. The films were characterized by FTIR, XRD, UV-Vis, SEM, and XPS, and their photocatalytic activities to degrade methylene blue in solution were determined, expecting these activities to correlate with the inactivation of bacteria, which was confirmed. The doped and undoped films were tested for activities against Gram-negative Escherichia coli (E. coli) and Salmonella typhi (S. typhi), and Gram-positive Staphylococcus aureus (S. aureus). The effects of doping on these composite films included reduced energy band gap, high crystallinity of anatase phase, and small crystallite size as well as increased photocatalytic activity and water disinfection efficiency.