Document Type : Research Paper
Authors
1 Al-Nisour University College, Iraq
2 Al-Karkh University of Science, College of Science, Forensic Evidence Department/Iraq
3 college of science for women/ University of Babylon/Iraq
Abstract
Keywords
INTRODUCTION
Nanotechnology has been thriving to develop different main activities in recent years because the materials have unique properties, including nanomaterials. [1]. Nanostructured materials receive a great deal of attention, especially in biological and pharmaceutical applications, due to their potential for specific procedures and selectivity [2]. Photocatalysis is a flexible and highly versatile process that may be used for many water and air disinfection applications. Though, self-disinfection surfaces have been created and verified for usage in the form of goods being sold. [3] Chromium, iron, nickel, zinc, and copper are transition metals. [4,5] and Cu, copper with 0.52 V (Cu2+) and 0.16 V (Cu2+) (Cu1+). For several photocatalysts, redox potential was found to be an appropriate match [4]. (Cu2+) (0.73 Å), (Cu2+) (0.83 Å) and (Ti4+) (0.64 Å) have exact ionic density sizes (Cu2+) will be able to break through or eliminate the surrounding oxygen vacancy TiO2 and ZnO deep acceptor matrices (Zn2+) or (Cu1+) positions [6]. Nanotechnology has given rise to a new generation of biocidal agents, and they can even be tailor-made to produce microscopic particles of any shape and size. The results of various studies demonstrate that nanoparticulate formulations are powerful bactericidal agents. Suspensions that are lit up TiO2 support the research and development of photocatalytic techniques to eradicate Escherichia coli, the microorganism responsible for enteritis, hemorrhagic colitis, and diarrhoea. TiO2 in aqueous media [7]. The gram+ cocci-shaped staphylococcus aureus bacterium may be discovered on human skin, the nose, or the respiratory tract [8-10]. The two primary goals of this investigation are [1] to assess the use of visible laser diodes as a light source for photocatalytic degradation enhanced metal oxide photocatalytic activity and [2] to evaluate the catalytic capabilities of -> The overall goals of this study are to examine the use laser diodes for photocatalytic degradation that are visible to the naked eye enhanced metal oxide photocatalytic activity and to determine the catalytic capabilities of -> These are the two primary objectives of this study: [1] to examine the feasibility in the photocatalytic breakdown of enhanced metal oxide photocatalytic activity and [2] to determine the catalytic capabilities of -> TiO2, ZnO/ TiO2 and Cu: ZnO/ TiO2 NPs under laser light irradiation.
MATERIALS AND METHODS
The applied precursors can be listed as: The titanium trichloride (TiCl3 15% solution in HCl, Sigma–Aldrich, Germany), ammonium hydroxide (NH4OH 30-33% NH3), zinc chloride (ZnCl2 99%), sodium hydroxide (NaOH from Sigma–Aldrich, Germany). The cupric nitrate trihydrate was applied for doped samples.
Preparation (TiO2 , ZnO, ZnO/ TiO2, Cu: ZnO/ TiO2
TiO2 NPs have been produced using a sol-gel technique at PH=10. The reaction was performed at 50 °C under vigorous stirring at 700 rpm. Firstly, the “sol” was prepared by mixing TiCl3 with NH4OH as a procedure. Secondly, the “sol” grows into a gel phase system containing both a liquid and a solid phase. Thirdly, a drying process was used to remove the remaining liquid phase. The situation is often followed by substantial shrinkage. To finish, it’s common to need heat treatment, or calcination procedure, to acquire the finished product. The decline that often follows this scenario is typically significant. To finish, it’s common to need heat treatment, or calcination procedure, to acquire the finished product.
In contrast, the situation is often followed by substantial shrinkage. To finish, it’s common to need heat treatment, or calcination procedure, to acquire the finished product. Which is typically accompanied by a significant amount of shrinkage. Finally, a thermal treatment, or calcination process, is often necessary to obtain the final nanopowders. ZnO was prepared by the sol-gel method, where ZnCl2 and NaOH was analyzed in the presence of a controlled amount of ethanol as a 1: 2 solvent. We put the solutions on the ultrasound machine for five minutes, then put them on the stirring device at a temperature of 60 degrees Celsius for an hour; after the solutions are dried to get rid of the liquid materials, here the heat treatment or calcination is done to obtain the ZnO nanoparticles, and to preparation TiO2/ZnO After and ZnO reach the gel phase, equal amounts of titanium oxide and zinc oxide gel are taken and mixed and placed in one baker and on Stirrer at 60 ° C for one hour, then washed, dried and calcined at different temperatures(400, 500,600, and 700 °C), and to preparation Cu: ZnO/TiO2. After the preparation of ZnO/TiO2 nanoparticles and reach the pre-washing stage, dissolve the aqueous copper nitrate according to the molar equation and add it gradually to the two compounds, taking into account the constant stirring for 30 minutes, then wash, dry and calcination at a temperature of 500 to obtain a tinged nanomaterial.
RESULTS AND DISCUSSION
Properties of the structural
X-Ray Diffraction (XRD) of TiO2 measurement
The XRD of the TiO2 NPS at 400, 500,600, and 700 °C calcination identify the peaks of anatase (A) and rutile (R) phases. (400, 500, and 600 °C) show the anatase only 700 °C present anatase-rutile phase at (700 °C). However, the pattern shows that and at ( 400 °C) has three broad peaks at 2ϴ equal 27.757̊, 40.303̊, and 50.451̊, with (101), (004), and (200) diffraction planes, respectively. The sample calcination at (500 °C) has three broad peaks 2ϴ angle at 27.900̊, 40.451̊, and 50.602̊ with (101), (004), and (200) in the plane of diffraction, each time. The NPS of calcination at all the temperatures was determined as indicated in the Scheme. 1 that prove we get the perfect structure of TiO2 NPS. However, the slight change may be drawn to the interaction processor to combine two phases in the same part-scale (Fig. 1).
X-Ray Diffraction (XRD) of ZnO/ TiO2 measurement
Fig. 2 shows the XRD result of NPs prepare at different treatments, which reveals ZnO and TiO2 in all the samples. The ZnO may be found in the samples as zincite-phase TiO2 Titania is in the anatase phase with no polymorphs present. Polymorphic titanium dioxide was discovered by examination of the sample, but no additional polymorphs were found. It is clear that the TiZ400 pattern that (101) happened to be the most potent reflection of both ZnO and TiO2. A gradual reduction from TiZ400 up to TiZ700 for mole fraction is observed in Fig .2. According to Fig. 2, heat treatment from 400 up to 700 ◦C decreases the intensity of the (101) plane of Anatase, while (002) ZnO plane rises slowly. It shows that atoms of Zn on the (002) plane were ideally replaced by atoms of Ti and the formation of a ZnO/TiO2 the solid solution has been continued gradually by the increase of calcination temperature. By increasing temperature from 400 up to 700 ◦C, the intensity of ZnTiO3 is getting a gradual decrease.
X-Ray Diffraction (XRD) of Cu: ZnO/ TiO2 measurement
XRD showed the structures of Cu: ZnO/ TiO2 indifferent TiO2 and ZnO level and temp. Fig. 3 shows the XRD of the samples consist of 1–4 wt% copper, temp at 500 °C (Fig. 3). Zinc Oxide Quality JCPDS (reference code 98-002-9272), crystal phases of TiO2 including anatase (00-021-1272), Rutile (01-075-1750) and Brookite (00-029- 1360), Cu2O (00-05-0667) and CuO (00-48-1548) Are used to determining trends. Cu: ZnO/ TiO2 with copper loading of 1 wt% that temp at 500 °C. It crystallized in a matrix as Fig. 3, among TiO2 crystal structures, Anatase diffraction peaks showed the Strongest intensities at 500 ° C after calcination, Indicating their main phases inside the photocatalyst at this point. In the meantime, signs of rutile are also observed at 500 ° C in Cu: ZnO / TiO2 calcination. Using the sol-gel method, anatase structure is generally generated in TiO2 synthesis. However, rutile is stable, whereas brookite and Anatase are metastable. Besides TiO2 crystals, ZnO with peak intensities of intense diffraction are found in these photocatalysts. However, several ZnO In this study peaks based not identifiable on standard peaks. The findings proved that photo-depositional modification was successful. ZnO’s basic crystal structure and its transformation into ZnTiO3 or ZnTiO4. In this instance, it may be owing to the even dispersion of copper nanoparticles. ZnO surface. On the other hand, the presence of a high amount of zincite in the calcination of samples at 500 ° C indicated that the transformation mentioned above for photocatalysis at that temperature was not fully achieved. According to the Fig. 3, Signals of Cu2O (26.393 °) was detected, and the amplitude of these peaks increased with the concentration of copper, which explained the higher mass proportion of Cu2O with copper heating. However, Cu2O the o diffraction pattern is not observed as CuO Or due to the XRD detection cap, the limited size of Cu components. Another potential explanation may be a strong CuO dispersion inside the TiO2 frameworks.
Electron Scanning Microscopy for Field Emission (FESEM) of TiO2 measurements
Surface morphology and growth of the NPS is Reviewed by the Field Emission Scanning Electron Microscopy (FESEM)., Fig. 4 shows the surface morphology of the TiO2 NPS samples calcination at 500 °C at different magnification. The average particle size is calculated as shown in Table 1. The results show the larger particle size with a high uniform morphology for calcination of the samples at 500.
Field Emission Scanning Electron Microscopy of ZnO/ TiO2 Measurements
Fig. 5 shows the top surface of the ZnO/ TiO2 nanocomposites, which demonstrates the relationships to crystallography among the TiO2 nanoparticles and ZnO nanorods template. For the nanocomposites, TiO2 nanocomposites prepared by the thermal method at 500 °C, The average particle size of the composites is about 500 nm. The FESEM images show the uniform sizes of the nanocomposite particles prepared at 500 °C temperatures. Also, FESEM images provided additional information, including the structures and surface morphologies of the as-prepared nanomaterials. As shown in Fig. 5, by taking the best samples at temperatures on calcination (500 °C) with magnification (a-1µm),(b-3µm), (c-400µm), and (d-500µm) As for the as-prepared ZnO/ TiO2 nanocomposite (TiZ500, a-1µm), it can be seen that TiO2 nanoparticles are well distributed over ZnO nanorods (Fig. 5-a), which also indicated that the original Building and shape of the TiO2 nanoparticles and ZnO nanorods are well preserved during the preparation of the ZnO/TiO2 nanocomposites.
Field Emission Scanning Electron Microscopy of Cu: ZnO/TiO2 Measurements
According to the findings presented in Fig. 6, the Cu:ZnO/TiO2.photocatalyst morphology was affected by copper doping as demonstrated in Fig. 6 using FESEM. the impact of calcination temperature is shown in (1wt percent ) whereas the influence of calcium hydroxide solution concentration is shown in -> The effect of calcium hydroxide solution concentration is shown in (1wt percent ) as compared to (Fig.6-b). The XRD examination shows that the photocatalyst with 1.0 wt, as indicated, was produced at 500 °C and is primarily composed of amorphous crystals. This finding is further backed up by the FESEM picture shown below (Fig. 6-a). As shown, the catalyst’s surface is smooth and non-abrasive. The XRD results indicate that either the rutile nucleation sites or the adsorbed photocatalyst surface may be explained by the presence of an increased dopant concentration. The FESEM pictures showed crystalline lattice alterations in the photocatalyst array caused by the increase in dopant data (Fig. 6-b). The following image (Fig 6-c) demonstrates that when the magnification increased to 500μm, the crystallinity may have grown and become more pronounced. Cu doping also led to an improvement in crystallinity as a side effect of dopant concentration. This conclusion is consistent with the results of the XRD study. Cu–ZnO/TiO2.
Structures of the TiO2 UV–vis spectroscopy
Using the U.V.–vis spectroscopy for determining an optical property of TiO2. Fig. 7 shows the absorption of the TiO2 nanoparticles at any temp. The bandgap energy is measured depending on the equation [1]:
(1)
Eg is the Band gap and λ is the wavelength.
λ is the Bandgap was measured optically using the above method at several different temperatures as Table (2).
Fig. 7 shows TiO2 nanoparticle at temp (400) ◦C at (410) nanometer attributed to the band gap is 3.02 eV with delicate anatase phase and show highly crystalline nanomaterial. The TiO2 samples calcination at 500 ◦C, 600 ◦C and 700 ◦C show absorption at the wavelength (420) and (450) nanometer. At high temp, the TiO2 is change the absorption from UV to visible light.
UV–Vis spectroscopy of ZnO/ TiO2 structures
UV–Vis diffuse reflectance spectra analysis the optical absorption properties play an essential role in evaluating the photoabsorption ability of photocatalyst. Fig. 8 shows the U.V.–Vis diffuse reflectance spectra of as-prepared samples ZnO/ TiO2 at (400-700) ◦C temperatures. U.V. absorption was dominant across the span of nearly the whole U.V. spectrum. (λ=233 nm) at 700 ◦C, and the weak absorption happened in the visible region for ZnO/TiO2 at 400 ◦C . Furthermore, the absorption edge spread into the visible light range when temperatures increased. Furthermore, when temperatures increase, the absorption edge spreads into the visible light range. ZnO/TiO2 at 500◦C and 600 ◦C. Notably, the absorbance intensity of ZnO/TiO2 at 600 ◦C in the visible light region is more vital than that of ZnO/TiO2 500 ◦C, which illustrated those doping zinc elements facilitated the extending of optical absorption toward the visible light region.
UV–vis spectroscopy of Cu: ZnO/ TiO2 nanoparticles structures
The absorption spectra of undoped and doped samples were measured in the UV-visible range. Cu: ZnO/ TiO2 nanoparticles are shown in Fig. 9. It can be seen in Fig. 9 that there is a strong excitonic absorption peak in all samples. This peak is attributed to the large binding energy of excitons and the good optical quality of nanoparticles. With the increasing Cu content, the redshift is slight in band edge absorption peak. The calculated bandgap of the Cu:ZnO nanoparticle are 3.297, 3.28, 3.263, and 3.53, TiO2 nanoparticle are 3.02, 2.95, 2.75, and 2.55 for 1%, 2% , 3% and 4% doping respectively. The bandgap decrease with Cu doping concurs with previous studies on Cu doping. ZnO/ TiO2. Two leading causes may contribute to variations in bandgap energies, namely quantum size effect and electronic structure modifications. Because of the Bohr radius of ZnO and TiO2 is in the range 0.9–2.4 nm, the decrease of the band gap in Fig. 9 is not likely due to samples of as-synthesized material exhibit diameters greater than 60 nm. It is reasonable to expect the slight band gap (Eg ), decrease with Raising in concentrations of Cu as possibly due to doping induced band edge Bowing.
Antibacterial activity of TiO2, ZnO/TiO2, Cu: ZnO/TiO2 NPs Measurements
The pictures of antibacterial activity shown in Fig. 10 were seen using the zone of inhibition analysis, with or without laser treatment. TiO2, ZnO2/TiO2, Cu: ZnO/TiO2 against Staphylococcus aureus. Table (3) for the four specimens in the test, this image illustrates the antibacterial activity findings. (400-700 °C). The inhibition zone diameter was measured in mm, and Table (4) show the results of the antibacterial activity test for Cu: ZnO/ TiO2 specimen with temperatures on calcination (500 °C) at 1%, 2%, 3%, and 4%. The inhibition zone diameter was measured in mm.
When the temp of TiO2 N.P.s become more leads to the decreasing of the inhibition. The cause of increasing inhibition was attributed to increasing the surface area of the reaction as the particle size of TiO2 NPs decreased.
Disc diffusion to measure the antibacterial activity of nanoparticles, it was completed. ZnO/ TiO2. Inhibition zone diameter indicated that ZnO/ TiO2 in 500 °C had a more significant antimicrobial effect against bacteria compared to the combination of individual nanoparticles with 400 °C, 600 °C, and 700 °C. Based on the results, S. aureus bacteria were more sensitive to the antimicrobial agents in ZnO/ TiO2 more than. The primary purpose of using ZnO as a nanocomposite with TiO2 Is to control their release of and increase the antimicrobial activity. The permeability of both the cell wall and the cell membrane is disrupted by nanoparticles, thereby interfering with DNA replication and protein synthesis.
Photocatalytic activity and antibacterial experiments were executed Cu doped ZnO/ TiO2 at 1%, 2%, 3%, and 4% with a temperature of 500 ° C.In addition, this data was compared to new results. TiO2 and ZnO/ TiO2. The samples were evaluated with bacterial strains S. aureus. The bacterial Inhibition zone diameter significantly Is increasing at 1%, 2%, and 4%. The bacterial reduction was achieved in the presence of Cu doped samples in 3%. the inactivation observed is a synergetic effect of TiO2 As well as Cu ions in the presence of visible light were introduced and led to enhanced absorption efficiency, which made bacterial inactivation faster, as shown in comparison to control samples.
CONCLUSION
The crystalline lattice strengthened with an increase in the dopant matrix content and temp. Both TiO2 Anatase and ZnO Wurztzite phases were obtained without impurity compounds, as shown in the XRD patterns. After calcination, the anatase peaks (004) and (101) in the nanocomposite respectively appeared at 400, 500, and 600 °C, while the Rutile peaks appeared in the 700 °C. FTSEM results showed that spherical TiO2 rod-like ZnO particles were obtained. TEM results confirmed that the spherical TiO2 particles were embedded in the lattice and attached to the ZnO rod-like surface. The activity of Cu: ZnO/TiO2 photocatalyst was influenced by such dopant content and calcination temperature.
CONFLICT OF INTEREST
The authors declare that there are no conflicts of interest regarding the publication of this manuscript.