Novel synthesis of ZnO/PMMA nanocomposites for photocatalytic applications | Scientific Reports

 

photocatalytic application of zno

Request PDF on ResearchGate | ZnO for application in photocatalysis: From thin films to nanostructures | In this research work, we report the photocatalytic properties of ZnO synthesized in. A Green and Facile Hydrothermal Synthesis of ZnO Nanorods for Photocatalytic Application. JOJ Material Sci. ; 4(1): DOI: /JOJMS Juniper Online ournal aterial Science On the basis of studies mentioned above, it can be concluded that the formation of such rod-like structure was achieved via. The main objectives of the current review is to evaluate the employment of ZnO nanoparticles as solar photocatalysts, application of ZnO nanoparticles in water treatment, solar-photodegradation mechanisms of zinc oxide photocatalysis, synthesis methods of ZnO nanoparticles, comparisons between photocatalytic membrane reactor and the suspended Cited by:



Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to photocatalytic application of zno continued support, we are displaying the site without styles and JavaScript. A Nature Research Journal. The incorporation of nanostructured photocatalysts in polymers is a strategic way to obtain novel water purification systems.

This approach takes the advantages of: 1 the presence of nanostructured photocatalyst; 2 the flexibility of polymer; 3 the immobilization of photocatalyst, that avoids the recovery of the nanoparticles after the water treatment.

Here we present ZnO-polymer nanocomposites with high photocatalytic performance and stability, photocatalytic application of zno. The remarkable photocatalytic efficiency of the nanocomposites was demonstrated by the degradation of methylene blue MB dye and phenol in aqueous solution under UV light irradiation, photocatalytic application of zno.

The composites also resulted reusable and stable, since they maintained an unmodified photo-activity photocatalytic application of zno several MB discoloration runs. Water was taken for granted for centuries, until increasing pollution and reduction of potable water supplies delineated a need to protect our water reserve and develop new technologies to purify water for consumption.

For example, it is imperative that pollutants in wastewater effluents, from both industrial and domestic sources, have to be removed before their discharge in the environment. These pollutants are produced as by-products of industrialization and social development, and include conventional and emergent contaminants, such as toxic dye photocatalytic application of zno, pharmaceuticals, personal care products, phenols, etc. Conventional water treatment technologies fail in removing the emergent environmental pollutants, generating the need for the development of novel methods.

Nanotechnology offers practical solutions photocatalytic application of zno the problems associated with the production of drinking water and with the protection of natural water for being contaminated 123. Radically, a high surface to volume ratio implies a significant increase in the surface reactivity.

Thus, nanotechnology can be used to safeguard our water resources by providing different tools and technology for water treatment and purification. An innovative purification method involves the combined use of nanostructures and photocatalysts.

The heterogeneous photocatalysis is effective in degrading a wide range of refractory organics, eventually mineralizing them in innocuous carbon dioxide and water 45678910 Among the semiconductor photocatalysts, ZnO has received a great interest in the field of photocatalytic technology. At present, the main technological barrier preventing the commercialization of nanostructured photocatalyst is the post-recovering of the catalyst particles after the water treatment.

As a consequence, further efforts consist of the immobilization of the photocatalyst. The incorporation of the active nano-material in a polymeric matrix is a promising approach to overcome this problem. Nanocomposites have attracted considerable research attention in recent years, because they combine low weight and easy formability, photocatalytic application of zno.

Several papers report on nano-ZnO photocatalytic application of zno to different polymers, such as: poly N-isopropylacrylamide 19polyester 20hybrid polymers 2122photocatalytic application of zno, polyethylene glycol or Pluronic F Among the available polymers, poly methyl methacrylate PMMA is frequently employed in many applications, photocatalytic application of zno its transparency to visible light, its mechanical properties and chemical stability; it is also a low-cost and hydrophobic polymer suitable for contact with food and drinks.

Despite its remarkable properties the PMMA has been rarely coupled with ZnO nanoparticles in order to obtain nanocomposites 24 The photocatalytic performance of the nanocomposites was tested by the degradation of methylene blue MB dye, and phenol in water under UV light irradiation. The stability and reusability of the composites was checked for several MB discoloration runs.

The effect of the pH of the aqueous solution on the efficiency of dye photo-degradation process was investigated, too. In the ALD process the highly reactive precursors are pulsed into the reactor alternatively and separated by purging steps with an inert gas.

This results in a stepwise surface-saturated and self-limiting gas-solid reaction mechanism with many advantages, such as good reproducibility, excellent conformality and uniformity over large area, simple and precise control of film thickness, easy composition tuning, and low deposition temperature, photocatalytic application of zno.

These ALD features are very practical in designing and preparing photocatalytic thin films, which enables uniform and conformal deposition also on three-dimensional substrate structures. As a consequence, even porous powders can be easily coated by ALD Diethyl zinc DEZ, purity The pulse and purge time were kept constant at 0. After that, the film was peeled off from the Petri dish and used for the morphological, structural and chemical characterization, and the photocatalytic tests. A similar synthesis process was simultaneously performed only with the PMMA powders i.

It is worth to note that both the ALD and the sonication and solution casting processes are easily scalable at industrial level 27 The photocatalytic application of zno structure was investigated by XRD analyses, with a Bruker D diffractometer detector scan mode at 0. Calibration, procedures to account for the steady-state charging effect, and background photocatalytic application of zno were already described 30photocatalytic application of zno, The photocatalytic activity of the samples was evaluated by the degradation of MB dye in water under light irradiation.

The pH of the solution was fixed at 7. The decomposition of the MB dye in the absence of any photocatalyst materials was also checked as a reference. The stability of the nanocomposites was checked by repeating seven times the MB degradation measurements. The effect of the pH of the dye aqueous solution on the photo-degradation of MB was investigated by varying the pH values from 3 to 12by adding few drops of HCl or NaOH.

The starting solution included phenol in de-ionized water, with a concentration of 1. The variation of the concentration of phenol was measured spectrophotometrically Hach DR spectrophotometerusing the LCK cuvette tests.

The Photocatalytic application of zno on polymers is a challenging process due to the absence of hydroxyl groups on their surface, that are in principle necessary to activate the growth As an example, Sinha et al. On the other hand, the ALD of Al 2 O 3 films on polymers polyethylene, polystyrene, polypropylene, PMMA, and poly vinyl chloride was successfully reported 3637 Wilson et al. All the ZnO films resulted polycrystalline, irrespective of the low temperature.

The ZnO films showed a significant photocatalytic activity independently of the substrate used, i. Since the PMMA and resin are both insulators, we observed the ad-hoc prepared specimen at low magnification conventional BF TEM, and by lowering the beam electron dose as much as possible to minimize the induced electric charge of the specimen itself.

Albeit this setup entailed images with a low signal to noise ratio and low resolution, photocatalytic application of zno, the image resolution showed to be still good for measuring the ZnO thickness.

Figure 2 a reports a TEM photocatalytic application of zno in cross-view of the coated powders. The ZnO film clearly followed the morphology of the polymer, since the conformality of the deposition. The EDS analysis, reported in Fig. Being the oxygen not only present into the ZnO film but also into the PMMA and into the resin the O X-ray peak intensity is obviously much higher that that one expected for the ZnO film only. The crystallographic structure of the powders was investigated by Photocatalytic application of zno. Figure 4 shows the evolution of the residual concentration of MB versus the time.

The first test was performed under dark conditions for 1 hr reported in grey colour in Fig. Furthermore, it is clear that the investigated materials exhibited a negligible adsorption of MB. When the UV light was switched on, no discoloration was obtained neither with the MB alone squares in Fig. The photo-degradation reaction rate k of the MB contaminant was estimated according to the Langmuir-Hinshelwood model 6 :.

In the case of aqueous powder dispersion, as reported above, one significant drawback hindering its applications in water treatment is the cost of separating the powder from the water after the treatment. To overcome this obstacle, the immobilization of the photocatalyst powder is a solution.

The magnification reported in the inset of Fig. The PMMA film showed broad bands related to the amorphous structure of the polymer, as expected. As a consequence, the sonication and solution casting methodology, applied to synthesize the composite, did not cause any alteration of the crystallographic structure of the ALD ZnO films.

The most evident difference between the binding energy BE values of the present system with respect to the PMMA reference lies in the slight higher BE value of the last ionization peak, that is 0.

Again the higher 0. These features are almost identical to those already reported for photocatalytic application of zno ZnO system 43 The photocatalytic degradation of the MB dye caused by the composites is reported in Fig.

Indeed, on one hand the photocatalytic performance improves with the film thickness, as a consequence of the higher number of charge carriers generated by the light irradiation in thicker films; on another hand the photocatalysis is strongly affected by the charge diffusion length for major details the reader can refer to ref.

It is worth noting that the photo-corrosion of ZnO during the photocatalytic process is a commonly observed phenomenon As a consequence, the photo-stability of the ZnO in the composite during the photocatalytic process was tested, by repeating the photo-degradation measurements seven times.

The results for the third left triangles and seventh right triangles test are reported in Fig. The nanocomposites were again characterized by XRD after the photocatalytic tests, in order to verify the stability of the material. The XRD pattern shows the Bragg peaks corresponding to the planes,andtypical of the wurtzite crystal structure of the ZnO.

Comparing this spectrum with the one obtained before the MB tests see Fig. The pH of the aqueous solution is one of the most important operating parameter that affect the heterogeneous photocatalysis, since it influences the surface-charge properties of the photocatalyst, and the position of the conductance and valence bands 67.

Furthermore, the pH of industrial wastewater can be very acidic or basic. As a consequence, the effect of the pH needs to be considered. For these reasons, we carried out an experiment at several pH values of the MB aqueous solution: 3, 7. Figure 12 indicates an increase of the photocatalytic efficiency for higher pH up triangles for pH 3, circles for pH 7. The decrease in the photocatalytic degradation at acidic pH null at pH 3 is probably due to the dissolution of ZnO at low pH On the contrary, at high pH there is an excess of hydroxyl ions, which facilitate the photo-generation of hydroxyl radicals 46 This result demonstrates that ZnO was not released in the MB solution, since we did not detect any photo-degradation.

The phenols are one of the most important class of pollutants discharged in the environment. The principal sources of phenol pollution in the aquatic environment are wastewaters from paint, pesticides, photocatalytic application of zno, coal conversion, polymeric resin, photocatalytic application of zno, petroleum and petrochemical industries The phenols are considered primary pollutants since they are harmful for organisms also at low concentrations At high concentration photocatalytic application of zno are even toxic and mutagenic, and may be absorbed through the skin The photocatalytic response of a control solution only containing phenol and de-ionized water i.

This blank solution showed a negligible degradation of phenol, as expected, photocatalytic application of zno.

The evolution of the materials, from the form of powders to the form of composites was deeply morphologically, structurally, and chemically investigated. In addition, the photocatalytic performance in degrading MB dye and phenol in water was tested under UV light irradiation, showing significant efficiency. The synthesized nanocomposites are also reusable and stable in the water environment, as demonstrated by several MB discoloration tests.

 

 

photocatalytic application of zno

 

Request PDF on ResearchGate | ZnO for application in photocatalysis: From thin films to nanostructures | In this research work, we report the photocatalytic properties of ZnO synthesized in. Jan 18,  · The photocatalytic activity of the ZnO/PMMA powders was tested by the degradation of the MB dye, a chemical compound commonly used to evaluate the photocatalytic efficiency of Cited by: The main objectives of the current review is to evaluate the employment of ZnO nanoparticles as solar photocatalysts, application of ZnO nanoparticles in water treatment, solar-photodegradation mechanisms of zinc oxide photocatalysis, synthesis methods of ZnO nanoparticles, comparisons between photocatalytic membrane reactor and the suspended Cited by: