Deposition Of ZnO Nanoparticles Research Articles

Self-assembly method assisted synthesis of g-C3N4/ZnO heterostructure nanocomposites with enhanced photocatalytic performance

Designing heterostructure photocatalysts by simple and efficient methods has attracted increasing attention nowadays, since the heterojunction between two different semiconductors would promote the separation of photogenerated electron-hole pairs, and improve the photocatalytic activity. In this study, the efficient g-C3N4/ZnO nanocomposite photocatalysts with outstanding separation ability of photogenerated carriers were synthesized via a facile approach of electrostatic self-assembly combined with low-temperature precipitating method. The treatment of concentrated sulphuric acid endows g-C3N4 with more negative polarity and more active sites, which serves the deposition of ZnO nanoparticles. Besides, the in-situ growth way produces a tight and perfect heterojunction for speedy electron transfer between g-C3N4 and ZnO. The g-C3N4/ZnO composite samples exhibited much ehanced photocatalytic performance than single catalysts, and the degradation efficiency of the optimal product for decomposition of methylene blue (MB) reached to 60% within 120 min, of which the total reaction rate constant was about 3.9 times higher than that of pure ZnO. The trapping experiments showed that the •OH radical was the major reactive oxygen species for degradation of MB, and it dropped approximate 50% of the degradation efficiency after the addition of the scavengers of ·OH. The Z-scheme mechanism is employed to explain the electron transfer pathway, which is a main reason for the enhancement of photocatalytic activity. This work provides a facile synthetic method and new sight for constructing heterojunctions for photocatalytic decompositing organic pollutants.

ZnO supported on Cu2O{1 0 0} enhances charge transfer in dimethyldichlorosilane synthesis

In this work, three types of ZnO/Cu2O heterostructures were synthesized by depositing ZnO nanoparticles on the supports of Cu2O cubes, Cu2O octahedrons and Cu2O dodecahedrons with different exposed facets. These catalysts were used for the Rochow reaction, which is an important industrial process for the synthesis of organosilicon polymers. It was demonstrated that Cu2O cubes-supported ZnO catalyst is the most active toward dimethyldichlorosilane formation, while Cu2O dodecahedrons-supported ZnO catalyst is the least active. Both experimental results and density functional theory calculations show that, in the three cases, the charge transfer efficiency between the ZnO nanoparticle and the Cu2O{1 0 0} plane is the highest, which enhances the dissociative adsorption of methylchloride at Cu2O{1 0 0}, the subsequent reduction of Cu+ into Cu0 and the final formation of the Cu3Si active phases. This work reveals essential information about how the Rochow reaction proceeds on the ZnO/Cu2O catalyst and demonstrates a practical strategy to rationally design highly efficient catalytic system in heterogeneous catalysis.

Improvement in corrosion resistance of WE43 magnesium alloy by the electrophoretic formation of a ZnO surface coating

A highly active Mg alloy, WE43, was electrophoretically coated by ZnO nanoparticles followed by heat treatment with the aim of decreasing its initial corrosion resistance for possible applications as biodegradable body implants. The investigation of the corrosion behavior of the coated WE43 surface was performed by electrochemical impedance spectroscopy in a phosphate-buffered saline solution (PBS). It was found that the highest corrosion protection resistance was achieved when the coating was formed at a cell voltage of 3 V during a 210 min deposition time. The corrosion protection efficiency of this coating was excellent, above 99.9% during a 6 h of immersion in PBS. The coating was found to be polycrystalline with a preferential growth direction along the c-axis, and the outer layer was composed of complex compounds containing oxides, carbonates, and hydroxides of Zn and Mg. The deposited ZnO nanoparticles were observed to be fused to an integral coating by heat treatment and thus provided excellent physical barrier against transport of corrosion species.

Modification of a polypropylene feed spacer with metal oxide-thin film by chemical bath deposition for biofouling control in membrane filtration

Surface modification of polypropylene feed spacers typical of spiral wound membrane modules was studied by generation of crystalline ZnO nanorods. A seeding layer made by deposition of ZnO nanoparticles (20–40–60 nm diameter) from aqueous dispersions served as nucleation centers for crystallization. A uniform layer of ZnO nanorods was grown on the seeding layer by chemical bath deposition from a zinc acetate solution. Biocidal activity was estimated by antibacterial tests in static liquid culture against Escherichia coli and antibiofouling tests in flow-through/cross-flow mode against a mixture of Pseudomonas fluorescens and Bacillus subtilis. Best biocidal activity was displayed by 20 nm ZnO particles, suggesting a tradeoff between surface coverage, roughness and particle size. Although the seed layer itself displayed acceptable antibacterial activity, a marked improvement was achieved by the nanorods, proving that the morphology of the deposition layer was involved in the antibacterial mechanism. Antibiofouling activity was further improved by superhydrophobic over-coating of the nanorods with octadecyl-phosphonic acid. Modified spacers reduced permeate flux decay by at least 40% compared to controls. The enhanced antibiofouling activity of crystalline ZnO nanorods, compared with amorphous ZnO nanoparticles, can be explained by a combination of the abrasive surface of the crystalline nanorods, hydrophobic repulsion and cumulative oxidation.

Fabrication of zinc oxide nanostructure coated membranes for efficient oil/water separation

A hierarchically structured membrane was fabricated for oil/water separation by effectively depositing ZnO nanoparticles on a glass fiber (GF) membrane. Simple potassium permanganate solution treatment of the GF membranes resulted in the formation of an Mn–(hydroxy)oxide deposit seed layer on the membranes, and then, chemical bath deposition was applied to deposit zinc oxide nanoparticles on the membranes. The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) showed that ZnO nanostructures were effectively deposited on the membrane surfaces. The ZnO coated membranes were underwater superoleophobic with oil contact angles greater than 150°. An oil-water separation process driven by gravity demonstrated that the membranes could maintain a permeation flux greater than 250 L/m2-h with separation efficiencies above 98%. In addition, the ZnO coated membranes exhibited excellent oil/water separation performance in the reusability and durability tests. The results suggest that the ZnO coated membranes possess not only stability but also comprehensive applicability.

Zinc–diethanolamine complex: synthesis, characterization, and formation mechanism of zinc oxide via thermal decomposition

Zn(OAc)2(H2DEA) was synthesized by the reaction of zinc acetate dihydrate (Zn(OAc)2•2H2O) with diethanolamine (H2DEA), and was characterized using single-crystal X-ray structural analysis, nuclear magnetic resonance spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and elemental analysis. Zn(OAc)2(H2DEA) had a trigonal bipyramidal geometry comprised of one zinc atom, two acetate groups, and one H2DEA as a neutral tridentate ligand to form two five-membered rings. The states of Zn(OAc)2(H2DEA) heated at various temperatures were determined by FT-IR spectroscopy. At 270 °C, the H2DEA ligand dissociated and was removed. The absorption bands assigned to Zn–O stretching vibration of Zn4O core such as the zinc-oxo cluster appeared. When heated at 500 °C, the absorption bands of μ4-oxozincate and the acetate group disappeared completely and hexagonal wurtzite structural ZnO was formed at 550 °C. A possible thermal decomposition pathway from Zn(OAc)2(H2DEA) to ZnO was proposed. The ZnO film was highly transparent and formed by the deposition of ZnO nanoparticles with size ~40 nm.

Nanostructure depositions on alumina hollow fiber membranes for enhanced wetting resistance during membrane distillation

Omniphobic alumina hollow fiber membranes were developed for direct contact membrane distillation (DCMD) with a low surface tension feed in this study. Alumina hollow fiber (HF) membranes were prepared as the membrane substrates, and chemical bath deposition methods were applied to deposit ZnO nanorods and nanoparticles on the HF membranes. The SEM, EDX, and AFM analyses showed that the ZnO nanostructures were effectively deposited on the membrane surfaces and able to increase the surface roughness. After surface fluorination by FAS17, the HF membranes deposited by ZnO nanorods and nanoparticles demonstrated contact angles of 128.7° and 138.1° for a 90% v/v ethanol/water mixture, both of which were higher than 114.8° for the pristine HF membrane without ZnO nanostructures. In the DCMD experiments with the sequential addition of SDS from 0.2 to 2.0 mM, the HF membranes with ZnO nanostructures exhibited superior wetting resistances with low surface tension feeds compared to that of the pristine HF membranes. Moreover, the HF membranes with the deposited ZnO nanoparticles had the best wetting resistance, and the permeate water flux was maintained for 24 h using a 2.0 mM SDS (70 °C 1 M NaCl) solution as an initial feed. The results not only suggested that the deposition of nanostructures enhanced the wetting resistance of the alumina hollow fiber membranes to low surface tension liquids but also showed the promise of utilizing these membranes for the desalination of low surface tension wastewaters.

Solvothermal Synthesis of ZnO-Nitrogen Doped Graphene Composite and its Application as Catalyst for Photodegradation of Organic Dye Methylene Blue

A facile one step solvothermal method is designed for the synthesis of visible light-sensitive ZnO-nitrogen doped graphene (ZNG) nano photocatalysts using ethylene glycol as a solvent as well as an agent to prevent aggregation of graphene layers. The deposition of ZnO nanoparticles onto the NG layers was confirmed by high resolution transmission electron microscope (HR-TEM), scanning electron microscope (SEM), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). UV-Vis spectroscopy (UV-Vis) was used to study the enhanced photocatalytic activity, which shows the red-shift of the band-edge as compared to ZnO nano particles. The enhancement in photocatalytic activity is possibly due to the synergistic effect of improved adsorptivity of dyes, enhanced visible light absorption and effective charge separation.

In situ generation and deposition of ZnO nanoparticles on cotton surface to impart hydrophobicity: investigation of antibacterial activity

ABSTRACTThe study of ZnO nanoparticles was prepared and deposited onto cotton fabrics surface via a simple and rapid hydrothermal approach successfully. Fluorosurfactant has been used to stabilize, homogenize the coated ZnONPs and control their shape. The use of fluorosurfactant has improved the durability of ZnONPs dipped on the cotton surface and decreased it’s leaching in a particular surfactant. The surface morphology, crystalline Structure and hydrophobic nature of the uncoated and coated cotton fabric were investigated by scanning electron microscope, X-Ray diffraction, Energy dispersive X-ray spectroscopy and water drop stability with contact angle measurement. SEM and XRD analysis revealed information about the shape and size of the coated ZnO nanoparticles is about 50–80 nm wurtzite ZnO nanoparticles. ZnONPs coated cotton fabric showed the highest antibacterial activity against Bacillus subtilis and Escherichia coli.

Exploring the Feasibility of Adsorptive Removal of ZnO Nanoparticles from Wastewater.

This study tested the feasibility of adsorptive removal of ZnO nanoparticles using activated carbon from wastewater. The effects of pH (5, 6, 7, 8, and 9) and nanoparticle/activated carbon concentration ratios (10, 1, 0.1, 0.01, and 0.001) on the removal were studied in batch kinetic studies in both deionized water and wastewater. The adsorption capacity of activated carbon for ZnO nanoparticles were found to be 9.3 ± 0.8 mg/g (93% removal) and 8.2 ± 3.7 mg/g (85% removal) at 640 and 780 min in deionized and wastewater respectively at optimum conditions (pH 8; 10g/L activated carbon concentration, 100mg/L ZnO nanoparticle concentration). The rate constant was lowest at ratio 0.01 and pH 8, and highest at ratio 10 and 1 and pH 5 and 6. Pseudo-second-order and the Weber-Morris model best described the adsorption process. Characterization analysis also confirmed the deposition of ZnO nanoparticles onto activated carbon. Overall activated carbon successfully removed ZnO nanoparticles using the adsorptive process.

Carbon dioxide capture using an omniphobic membrane for a gas-liquid contacting process

An omniphobic membrane has been successfully prepared to ensure high efficiency as well as long-term stability in a CO2 absorption process. This omniphobic membrane was fabricated by creating a multilevel re-entrant structure via depositing ZnO nanoparticles (NPs) on a porous glass fiber (GF) membrane through chemical bath deposition (CBD). The membrane coated with ZnO NPs was then functionalized with 1 H,1 H,2 H,2H-perfluorodecyltriethoxysilane (FAS17) and coated with a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer. A variety of techniques such as capillary flow porometry (CFP), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle goniometry, atomic force microscope (AFM) and CO2 absorption trials were conducted to explore the surface structure, chemistry and performance of the membrane. The omniphobic membrane surface with a high fluorine concentration had a strong resistance to wetting by water and organic liquids (γ = 72.8–22.1 mN/m) and showed a contact angle with an amine absorbent as high as 147.8 ± 0.8°. In the CO2 absorption trials, the omniphobic membrane exhibited a stable absorption flux of 2.10 ± 0.07 mmol/m2s for 96 h. The results indicate that the omniphobic membrane outperforms hydrophobic membranes. Thus, the omniphobic membrane has shown potential for application in large-scale CO2 absorption in thermal power plants.

Omniphobic membranes for direct contact membrane distillation: Effective deposition of zinc oxide nanoparticles

An omniphobic membrane was fabricated for membrane distillation (MD) by effectively depositing ZnO nanoparticles on a hydrophilic glass fiber (GF) membrane using a chemical bath deposition method to create hierarchical re-entrant structures, followed by surface fluorination and the addition of a polymer coating to lower the surface energy of the membrane. The omniphobic membranes possessed a particulate membrane morphology and an extremely high fluorine concentration on the surface. The omniphobicity of the fabricated membrane was indicated by the contact angles for water and ethanol, which were as high as 152.8±1.1° and 110.3±1.9°, respectively. Compared to hydrophobic GF membranes without deposited ZnO nanoparticles, the omniphobic membrane revealed a higher wetting resistance to low surface tension feed solutions in direct membrane distillation (DCMD) experiments. The water flux was stably maintained in a 0.3mM sodium dodecyl sulfate (SDS) solution (60°C 1M NaCl) with salt rejection rate higher than 99.99%. The results suggest that the omniphobic membrane exhibited not only superior wetting resistance to low surface tension liquids but also promise for desalinating low surface tension wastewaters.

Rational design of multi-layered superhydrophobic coating on cotton fabrics for UV shielding, self-cleaning and oil-water separation

It remains a great challenge to prepare multi-functional fabrics using a low-cost and scalable method with fluorine-free materials. In this paper, we report a new procedure for producing fluorine-free super hydrophobic cotton fabrics, via a simple dip-coating process. Firstly, a polydimethylsiloxane (PDMS) adhesive layer is deposited onto the cotton substrate, followed by the subsequent deposition of ZnO nanoparticles to enhance the surface roughness through an oil bath process. Finally, a second PDMS dip-coating is applied to construct a multi-layered PDMS-ZnO-PDMS composite coating on the cotton fabrics. The multi-layer coated samples display superhydrophobic properties, with a water contact angle (CA) exceeding 160°. Additionally, the new PDMS-ZnO-PDMS@cotton fabric exhibits excellent multi-functions, including UV-blocking, self-cleaning and oil-water separation. The prepared superhydrophobic fabric can withstand a large number of abrasion cycles and 20cycles of accelerated washing without obvious decline in the water contact angle. This facile preparation method is of low-cost, environmentally friendly, and suitable for large-scale production of a series of specialty fabrics including sports clothing.

ZnO nanoparticles loaded different mesh size of porous activated carbon prepared from Pinus eldarica and its effects on simultaneous removal of dyes: Multivariate optimization

In this work, mesoporous activated carbon in different mesh size (35–200) was prepared from Pinus eldarica stalks (PES) as good, cheap and useful support for deposition of ZnO nanoparticles. This new material was characterized by FTIR, XRD, BET, BJH, SEM and EDS-mapping techniques and subsequently was used for the simultaneous ultrasound assisted removal of azure II (AZ-II) and auramine O (AO) dyes from aqueous solutions in batch method. The influence of operational parameters such as the sonication time, adsorbent mass, pH and initial AZ-II and AO concentration on adsorption efficiency were investigated and optimized via central composite design (CCD). Optimal conditions of adsorption experiments at desirability value of 0.98 were set as at 4.0min of sonication time, 25mgL−1 of AZ-II and AO concentration, 0.05g of adsorbent and pH 7.0 which provides removal percentage of 90.42 and 98.14% for AO and AZ-II, respectively. The experimental equilibrium data for all mesh size showed that the Langmuir model is a good and suitable model for evaluation and the actual behavior of adsorption of understudy dyes. Kinetic studied of experimental data for all mesh size revealed that adsorption processes were good followed by pseudo-second-order. These results clearly demonstrated that this material is an efficient and low cost adsorbent for treatment of wastewater containing AZ-II and AO dyes.

In-situ sonosynthesis of cobblestone-like ZnO nanoparticles on cotton/polyester fabric improving photo, bio and sonocatalytic activities along with low toxicity and enhanced mechanical properties

For the first time in this study, in-situ sonosynthesis and deposition of ZnO nanoparticles under ultrasound irradiation was used to prepare multifunctional cotton/polyester fabric. The process was carried out at 80 °C in ultrasonic bath and was free from final heating of fabrics to convert zinc hydroxide to zinc oxide nanoparticles. This was due to the physical and chemical effects of ultrasound promoting the involved reactions and facilitating the nucleation and growth of ZnO nanoparticles. Central composite design was also used to statistically analyze the process, optimizing the applied condition including zinc precursor concentration, pH and the effect of dispersing agent namely cetyltrimethylammonium bromide surfactant (CTAB). The treated samples were further characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDX). Photocatalytic activities of the treated samples were assessed based on the ability of fabrics to degrade Methylene Blue dye stain under sunlight irradiation. The effect of synthesis parameters on photocatalytic activities (self-cleaning) was statistically optimized. Moreover, for evaluating the sonocatalytic efficiencies of the samples Reactive Blue 2 was applied and the activities were studied by visible spectroscopy. The cotton/polyester samples possessed multifunctional properties including self-cleaning, sonocatalytic, antibacterial, antifungal, low cytotoxicity and enhanced mechanical properties.

Stable dual-wavelength erbium-doped fiber laser using novel fabricated side-polished arc-shaped fiber with deposited ZnO nanoparticles

A dual-wavelength fiber laser operating at the 1550 nm region using a side-polished arc-shaped fiber with deposited ZnO nanoparticles is proposed and demonstrated. The arc-polished fiber is fabricated by using a simple but novel approach in which a silicon carbide paper polishes one side of a conventional single-mode fiber. An arc-polished fiber with a length of 2.25 mm and an insertion loss of 0.95 dB is obtained and deposited with ZnO nanoparticles by the drop-cast method. A stable dual-wavelength output is obtained at 1562.5 and 1563.4 nm at peak powers of −9.3 and −10.1 dBm, respectively, as well as a signal-to-noise ratio of 28.4 dB and a channel spacing of 0.9 nm. Both lasing wavelengths also have narrow linewidths of between 0.045 and 0.049 nm and show little to no wavelength or power fluctuations over continued testing.

Coating ZnO nanoparticle films with DNA nanolayers for enhancing the electron extracting properties and performance of polymer solar cells.

Here we present for the first time polymer solar cells that incorporate biological material that show state of the art efficiencies in excess of 8%. The performance of inverted polymer solar cells was improved significantly after deposition of ZnO nanoparticles (ZnO-NPs) together with a thin deoxyribonucleic acid nanolayer and used as an electron extraction layer (EEL). The ZnO-NPs/DNA double layer improved the rectifying ratio, shunt resistance of the cells as well as lowering the work function of the electron-collecting contact. Importantly, the ZnO-NPs/DNA bilayer enhanced the power conversion efficiency of cells considerably compared to cells with EELs made of only DNA (improvement of 56% in relative terms) or only ZnO-NPs (improvement of 19% in relative terms) reaching a best power conversion efficiency of 8.5%. The ZnO-NPs/DNA double layer cells also outperformed ones made with one of the most efficient previous synthetic composite EELs (i.e. ZnO/PEIE(poly(ethyleneimine)-ethoxylated)). Since all fabrication procedures were carried out at low (<150 °C) or room temperature, we have applied the findings to flexible substrates as well as on glass obtaining a high PCE of 7.2%. The solar cells with the biological/metal-oxide composite EELs also delivered an improvement in the stability (∼20% in relative term) compared to that with ZnO-NPs only. All these findings show that natural materials, in this case DNA, the premium biological material, can be incorporated in organic semiconductor devices in tandem with inorganic devices delivering uncompromising levels of performance as well as significant improvements.

Performance of RF sputtered p-Si/n-ZnO nanoparticle thin film heterojunction diodes in high temperature environment

In this article, temperature-dependent current-voltage characteristics of n-ZnO/p-Si nanoparticle thin film heterojunction diode grown by RF sputtering technique are analyzed in the temperature range of 300–433k to investigate the performance of the device in high temperature environment. The microstructural, morphological, optical and temptrature dependent electrical properties of as-grown nanoparticle thin film were characterized by X-ray diffractometer (XRD), atomic force microscopy (AFM), field emmision scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), variable angle ellipsometer and semiconductor device analyzer. XRD spectra of as-grown ZnO films are exhibited that highly c-axis oriented ZnO nanostructures are grown on p- Si〈100〉 substrate whereas AFM and FESEM images confirm the homogeneous deposition of ZnO nanoparticles on surface of Si substratewith minimum roughness.The optical propertiesof as-grown ZnO nanoparticles have been measured in the spectral range of 300–800nm using variable angle ellipsometer.To measure electrical parameters of the device prototype in the temperature range of room temperature (300K) to 433K, large area ohmic contacts were fabricated on both side of the ZnO/Si heterostructure. From the current-voltage charcteristics of ZnO/Si heterojunction device, it is observed that the device exhibits rectifing nature at room temperature. However, with increase in temperature, reverse saturation current and barrier height are found to increase, whereas ideality factor is started decreasing. This phenomenon confirms that barrier inhomogeneities are present at the interface of ZnO/Si heterojunction, as a result of lattice constant and thermal coefficient mismatch between Si and ZnO. Therefore, a modified value of Richardson constant [33.06Acm−2K−2] has been extracted from the temperature-dependent electrical characteristics after assuming the Gaussian distribution of special barrier height inhomogeneities across the Si/ZnO interface which is close to its theoretical value [32Acm−2K−2]. This result indicates that regardless of presence of barrier height inmogeneities, ZnO/Si heterojunction diode still hasability to perform well in high temperature environment.

Anti-microbial surfaces: An approach for deposition of ZnO nanoparticles on PVA-Gelatin composite film by screen printing technique

Initially micro-organisms get exposed to the surfaces, this demands development of anti-microbial surfaces to inhibit their proliferation. Therefore, herein, we attempt screen printing technique for development of PVA-GE/ZnO nanocomposite (PG/ZnO) films. The synthesis of PG/ZnO nanocomposite includes two steps as: (i) Coating of Zinc Oxide nanoparticles (ZnO NPs) by poly ethylene glycol in order to be compatible with organic counterparts. (ii) Deposition of coated nanoparticles on the PG film surface. The results suggest the enhancement in anti-microbial activity of PG/ZnO nanocomposite over pure ZnO NPs against both Gram positive Bacillus subtilis and Gram negative Escherichia coli from zone of inhibition. The uniformity in deposition is further confirmed by scanning electron microscopy (SEM) images. The phase identification of ZnO NPs and formation of PG/ZnO nanocomposite has been confirmed by X-ray diffraction (XRD) analysis and UV–vis spectroscopy (UV–vis). The Attenuated total reflection Spectroscopy (ATR) analysis indicates the ester bond between PVA and gelatin molecules. The thermal stability of nanocomposite is studied by thermogravimetric analysis (TGA) revealing increase in crystallinity due to ZnO NPs which could be utilized to inhibit the growth of micro-organisms. The tensile strength is found to be higher and percent elongation is double of PG/ZnO nanocomposite than PG composite film.

Polypropylene – zinc oxide nanorod hybrid material for applications in separation processes

Abstract Hybrid filter material was obtained via modification of polypropylene (PP) nonwoven with nanosize zinc oxide particles of a high aspect ratio. Modification was conducted as a three-step process, a variant of hydrothermal method used for synthesis of nano-ZnO, adopted for coating three dimensional polymeric nonwoven filters. The process consisted of plasma treatment of nonwoven to increase its wettability, deposition of ZnO nanoparticles and low temperature hydrothermal growth of ZnO rods. The modified nonwovens were investigated by a high resolution scanning electron microscopy (HR-SEM). It has been found that the obtained hybrid filters offer a higher filtration efficiency, in particular for so called most penetrating particle sizes.