Commercial ZnO Research Articles

Sacrificial Zinc Oxide Strategy-Enhanced Mesoporosity in MIL-53-Derived Iron–Carbon Composite for Methylene Blue Adsorption

MOF-derived carbon-based materials have attracted widespread attention due to their relatively large surface area, morphology, and their stability in water. Considering these advantages, these materials present themselves as excellent adsorbents. In this work, a novel method was designed for the fabrication of a nano zero-valent-iron (nZVI) carbon composite. The utilization of zinc oxide nanorods (ZnONRs) in the role of sacrificial consumable nuclei for the synthesis of MIL-53 sacrificial zinc oxide nanorods (MIL-53-SNR) and the subsequent pyrolysis at 700 °C in the inert atmosphere led to a graphitic-supported nZVI material (Fe-C-SNR). Fe-C-SNR was compared with a commercial zinc oxide bulk (MIL-53-SB) and with a pristine MIL-53. By virtue of the ZnONRs, Fe-C-SNR exhibited a greatly improved mesoporous structure. Consequently, the pyrolyzed materials were applied as adsorbents for methylene blue. Fe-C-SNR’s performance increased to more than double of the pyrolyzed MIL-53 (Fe-C), with a remarkably fast adsorption time (10 min) for a concentration of 10 mg L−1 with only 200 mg L−1 adsorbent required. This functional composite also displayed exceptional recyclability; after ten complete cycles, Fe-C-SNR was still capable of completely adsorbing the methylene blue. The utilization of ZnONRs proves itself advantageous and could further be extended to other MOFs for a wide range of applications.

Preparation and characterization of carboxymethyl cellulose capped zinc oxide nanoparticles: A proof-of-concept study

Zinc oxide (ZnO) is one of the promising food additives, which adds nutrients and provides antimicrobial properties when incorporated into various food matrices. In this study, carboxymethyl cellulose capped ZnO (ZnO-CMC) were developed via a low-energy and cost-effective technique without calcination or grinding. The fabrication involved two steps: crosslinking Zn2+ ions with CMC through electrostatic interactions and generation of ZnO nanoparticles with CMC as capping agent. After mild heating, the crystalline structure of ZnO-CMC was confirmed by WAXS. Both FTIR and AFM studies illustrated that ZnO was physically trapped by CMC molecules, resulting in a physical barrier to prevent aggregation. SEM verified that the ZnO-CMC had a size of 50–80 nm with comparable morphology to commercial ZnO. Overall, CMC played a key role in controlling growth and inhibiting agglomeration of ZnO. Given the small and uniform particle size, the obtained ZnO-CMC is ready to be incorporated into different food matrices.

Precise control of surface oxygen vacancies in ZnO nanoparticles for extremely high acetone sensing response

ZnO has been studied intensely for chemical sensors due to its high sensitivity and fast response. Here, we present a simple approach to precisely control oxygen vacancy contents to provide significantly enhanced acetone sensing performance of commercial ZnO nanopowders. A combination of H2O2 treatment and thermal annealing produces optimal surface defects with oxygen vacancies on the ZnO nanoparticles (NPs). The highest response of ∼27,562 was achieved for 10 ppm acetone in 0.125 M H2O2 treated/annealed ZnO NPs at the optimal working temperature of 400 °C, which is significantly higher than that of reported so far in various acetone sensors based on metal oxide semiconductors (MOSs). Furthermore, first-principles calculations indicate that pre-adsorbed O formed on the surface of H2O2 treated ZnO NPs can provide favorable adsorption energy, especially for acetone detection, due to strong bidentate bonding between carbonyl C atom of acetone molecules and pre-adsorbed O on the ZnO surface. Our study demonstrates that controlling surface oxygen vacancies by H2O2 treatment and re-annealing at optimal temperature is an effective method to improve the sensing properties of commercial MOS materials.

Kinetic modelling of the photocatalytic degradation of Diisobutyl phthalate and coupling with acoustic cavitation

Phthalates are widely used plasticizers, but have endocrine-disrupting effects, which cause harm to both humans and the wider environment. Photocatalytic technologies have been shown to be promising methods for removal of a range of environmental pollutants in water. In this paper the photocatalytic oxidation of Diisobutyl phthalate (DiBP) using two common commercial catalysts, TiO2 and ZnO is assessed. Both photocatalysts proved to be effective in removing > 90% of the compound in less than 25 min of treatment. Pseudo-first kinetics were initially used to describe the kinetics of the process, but were found to poorly describe the kinetics, which was believed to be a result of not accounting for the influence of intermediates. A new kinetic model is proposed to account for intermediate formation, which described the experimental data better. In addition, the incorporation of acoustic cavitation (AC) with photocatalysis (PC) was tested for DiBP degradation. The hybrid process enhanced the DiBP degradation rate and a synergistic index of 1.5 and 2.2 observed for TiO2 and ZnO respectively. The effect of pH on DiBP degradation was investigated and it showed that on both photocatalysts, reaction rates were higher when pH was greater than the point of zero charge for the photocatalyst. These results demonstrated the feasibility of photocatalysis for DiBP removal and the potential of AC to enhance the PC process for removal of phthalates from water. This new kinetic model proposed will be useful for the design of AOP based water treatment as it predicts the kinetics of the process more accurately than the commonly used pseudo first order kinetic model.

Effective control of microbial spoilage in soybeans by water-soluble ZnO nanoparticles

The microbial spoilage of soybeans during soaking process severely deteriorates the quality of soybean products and threatens human health. Herein, water-soluble aminated zinc oxide nanoparticles (ZnO NPs) were developed to effectively control the microbial spoilage in soybeans during soaking. ZnO NPs achieved significant inactivation of three dominant spoilage bacteria (bacillus cereus, bacillus megaterium and enterococcus faecium) isolated from the deteriorated soybeans, which could adhere to the bacterial surface and damage the cell wall/membrane, but also generate large amounts of reactive oxygen species (ROS). Compared to two commercial ZnO, water-soluble ZnO exhibited superior antibacterial properties due to producing more ROS and bacteria-adhered ability. After ZnO NPs treatment, the content of the residual Zn (51.1 mg/kg) in soybeans was the safety standards of Zn element in soybeans products for human). Therefore, the water-soluble ZnO NPs showed great potentials as efficient and safe antimicrobial agents for soybeans preservation during soaking process.

Epoxy Composites Reinforced with ZnO from Waste Alkaline Batteries.

The zinc alkaline battery is one of the most popular sources of portable electrical energy, with more than 300,000 tons being consumed per year. Accordingly, it is critical to recycle its components. In this work, we propose the use of zinc oxide (ZnO) microparticles recovered from worn-out batteries as fillers of epoxy resins. These nanocomposites can be used as protective coatings or pigments and as structural composites with high thermal stability. The addition of ceramic nanofillers, such as ZnO or/and TiO2, could enhance the thermal and mechanical properties, and the hardness and hydrophobicity, of the epoxy resins, depending on several factors. Accordingly, different nanocomposites reinforced with recycled ZnO and commercial ZnO and TiO2 nanoparticles have been manufactured with different nanofiller contents. In addition to the different ceramic oxides, the morphology and size of fillers are different. Recycled ZnO are“desert roses” such as microparticles, commercial ZnO are rectangular parallelepipeds nanoparticles, and commercial TiO2 are smaller spherical nanoparticles. The addition of ceramic fillers produces a small increase of the glass transition temperature (<2%), together with an enhancement of the barrier effect of the epoxy resin, reducing the water diffusion coefficient (<21%), although the maximum water uptake remains constant. The nanocomposite water absorption is fully reversible by subsequent thermal treatment, recovering its initial thermomechanical behavior. The water angle contact (WCA) also increases (~12%) with the presence of ceramic particles, although the highest hydrophobicity (35%) is obtained when the epoxy resin reinforced with recycled flowerlike ZnO microparticles is etched with acid stearic and acetic acid, inducing the corrosion of the ZnO on the surface and therefore the increment of the surface roughness. The presence of desert rose ZnO particles enhances the de lotus effect.

Preparation and characterization of N-doped ZnO and N-doped TiO2 beads for photocatalytic degradation of phenol and ammonia

N-doped ZnO beads (NZB) and N-doped TiO2 beads (NTB) were synthesized via a modified sol–gel technique utilizing chitosan (CS)/polyvinyl alcohol (PVA) hydrogel beads as basic support for photocatalyst. Urea was used as a source of nitrogen in the preparation of N-doped ZnO beads, while ammonium acetate, CH3COONH4, was used as a nitrogen source in the production of N-doped TiO2 beads. The characteristics of synthesized beads were identified by scanning electron microscope (SEM), X-ray photoelectron spectroscopy analysis (XPS), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, BET surface area, Fourier transform infrared (FT-IR) measurements, and diffuse reflectance spectroscopy (DRS) studies. The use of the nitrogen doping method for photocatalyst was performed to adjust the bandgap and electrical properties of ZnO and TiO2 by establishing acceptor defects. NZB and NTB with the intrinsic donor defect of oxygen vacancy and the nitrogen-to-oxygen acceptor defect could be activated by a less-energy UV consumption for efficient pollutant degradation. The results indicated that the as-synthesized NZB achieved much higher degradation activity than NTB, commercial ZnO, and TiO2 in the decomposition of a binary mixture composed of ammonia and phenol under UV light irradiation.

Revealing the Influence of the Shape, Size, and Aspect Ratio of ZnO Nanoparticles on Antibacterial and Mechanical Performance of Cellulose Fibers Based Paper

AbstractThe discovery and characterization of nanoparticles represent a multidisciplinary issue. Their properties and applications within many fields depend on their size, shape, aspect ratio, and so on. No single methodology can currently analyze all characteristics and reveal their influence on the specific performance. Here, antibacterial and mechanical properties are investigated of three different ZnO nanoparticles (cubes, rods, and pellets) incorporated in the cellulose matrix in order to examine the correlation between the physical and chemical characteristics and antibacterial/mechanical activities. Therefore, various particles of ZnO with different sizes, shapes, and aspect ratios are synthesized via simple precipitation method in an aqueous solution and evaluated as an antimicrobial agent against Gram‐positive and Gram‐negative model bacteria alongside the commercial ZnO powder. The bactericidal activity is evaluated as prepared cellulose/ZnO nanocomposites in the form of paper sheets. Additionally, the tests of mechanical properties of the fabricated paper sheets are carried out according to ISO 5270 standard. Microscopic and spectroscopic methods are utilized to investigate the psychic‐chemical properties of the products. This study highlights that there is a strong impact of the shape, size, and aspect ratio of ZnO particles on the antibacterial efficacy and mechanical response of the fabricated cellulose‐based paper.

Photocatalytic activity of graphene oxide/zinc oxide nanocomposite derived from rice husk for the degradation of phenanthrene under ultraviolet-visible light

Environmental concerns have arisen due to the persistent nature and carcinogenicity of polycyclic aromatic hydrocarbons (PAHs). This study used the doping approach to successfully develop a nanocomposite photocatalyst based on graphene oxide (GO) and zinc oxide (ZnO). The nanocomposites were investigated by Fourier transform infrared (FTIR) spectroscopy, UV–Visible diffuse reflectance spectroscopy (UV–Vis DRS), x-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive x-ray (EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and Raman spectroscopy. GO/ZnO nanocomposite showed excellent ability to degrade 25 ppm of phenanthrene (86.06%) in 120 min under UV–Visible light exposure followed by photolysis (no photocatalyst) (15.56%), GO/ZnO without stirring (40.28%), GO/ZnO in the dark with stirring (47.40%), and commercial ZnO (62.84%). This is due to the largest surface area, which was enhanced by the doping of GO in commercial ZnO. Phenanthrene photodegradation by GO/ZnO nanocomposite followed first-order kinetics with a rate constant of 0.0375 min−1. The smaller byproducts like (Z)-3-hydroxy acrylic acid (1b; m/z = 88) and (Z)-4-oxobut-2-enoic acid (1c; m/z = 100) identified in GC–MS, clearly demonstrated e− excitement from encapsulated nanocatalyst followed by OH (active species) based oxidation of phenanthrene. Consequently, the GO/ZnO nanocomposite could be a versatile photocatalyst for the photodegradation of phenanthrene in wastewater treatment.

Superficial sonication synthesis of a highly sunshine active metal modified ZnO photocatalyst and its multiple applications

Hexagonal and spherical-like SrO/Ag/ZnO nanostructures have been successfully synthesized by a simple sonication method. The structure and composition of the samples were analyzed by XRD, FE-SEM, EDX, TEM, DRS, PL, XPS and BET surface area measurements. In this present work, the photocatalytic degradation of Trypan blue dye with prepared heterogeneous photocatalyst for SrO/Ag/ZnO under the natural sun light. The behavior of operational parameters such as pH, catalyst dosage, dye concentration and stability of the catalyst on photo mineralization of TB dye has been investigated. The Sr/Ag/ZnO stability was studied by its antiphotocorrosion property. The result shows that antiphotocorrosive property of SrO/Ag/ZnO is better than bare ZnO because of their reusability and photostability behavior. The antibacterial activity was also tested by SrO/Ag/ZnO, pure ZnO, and commercial ZnO. The mineralization of Trypan Blue dye has been confirmed by COD measurements.

Facile one-pot solid-state fabrication of a novel binary nanocomposite of commercial ZnO and commercial PbCrO4 with enhanced photocatalytic degradation of Rhodamine B dye

Lead chromate, PbCrO4, is a semiconductor material exhibiting narrow bandgap energy indicating its promising visible-light-driven photocatalytic activity. However, very few papers reported the utilization of PbCrO4 as a photocatalyst. Herein, we report a simple one-pot room-temperature method that was employed for the synthesis of a novel PbCrO4/ZnO binary nanocomposite, for the first time, based on solid-state mixing of commercial Zinc oxide nanoparticles and commercial PbCrO4 nanorods to enhance the optical properties and photocatalytic performance of ZnO. The as-synthesized nanocomposite was characterized by FE-SEM, XRD, FTIR, DRS, and PL. The results confirmed that the anchoring of PbCrO4 nanorods on the surface of ZnO nanoparticles achieved a significant enhancement in their optical properties such as decreasing the bandgap energy and reducing the e-h recombination rate as well as the enhanced photocatalytic performance toward Rhodamine B photodegradation. Finally, the mechanism of the enhanced photocatalytic performance of the as-synthesized novel PbCrO4/ZnO nanocomposite was suggested.

Analysis of the ZnO/Cu2O and CdSe/Cu2O Thin Film Hetero-structure Electrode for Photo Electro chemical Solar Cell Applications

This paper proposes an economical route to the production of CdSe/Cu2O and ZnO/Cu2Obased on commercial ZnO, CdSe corpuscle. The deposition of CdSe thin films was prepared by partial thermal oxidation method, Powder Vaporization method, and microwave oven method on the cleaned Cu2O substrate at room temperature. The solar cell fabrication process is greatly simplified by this method and opens a door in the direction of inexpensive techniques based on saleable available materials. The results show that the solar cell based on the mixture of CdSe/Cu2O has electron transportability, better light absorption, and high power conversion efficiency (PCE) of 0.7 was obtained. These materials have been characterized using FTIR, at which numerous peaks are present in the sample, and were assessed in detail. Multiple current-voltage characteristic curves were plotted, an open-circuit voltage VOC, a short circuit current Isc, and the maximum power points Pmax were also noted. This work throws off more light in enhancing the photo response of the electrode in both solar H2generation and photo electro chemical solar cell

Facile fabrication of chitin/ZnO composite hydrogels for infected wound healing.

When ordinary wounds are infected, the skin's self-healing capacity declines; thus appropriate dressings with both antibacterial ability and healing ability for bacteria-associated wounds are indispensable. In this work, multifunctional chitin/ZnO composite hydrogels have been designed as an infected full-thickness skin wound-healing material. The hydrogels are fabricated by a facile one-pot strategy through the sequential addition of commercial ZnO powders into aqueous alkaline chitin solutions, crosslinking and regeneration. The regenerated nanoscale ZnO particles aggregate into microscale particles and are embedded in the chitin matrix with tight interactions, including hydrogen bonding and coordination interactions. The decoration of ZnO endows the chitin/ZnO composite hydrogels with excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with acceptable biocompatibility. More importantly, the chitin/ZnO composite hydrogels show an outstanding accelerated infectious full-thickness wound-healing performance with more fibroblast proliferation, more collagen deposition, and more neogenesis of the epithelium and granulation tissue. Therefore, it is expected that the chitin/ZnO composite hydrogels can serve as competitive skin wound dressings for the prevention and control of infections.

Facile Synthesis of Zn2+‐Based Hybrid Nanoparticles as a New Paradigm for the Treatment of Internal Bacterial Infections

AbstractTransition metal ions such as Ag+, Cu2+, and Zn2+are utilized as sterile agents thousands of years ago. Unfortunately, these metal ions in the form of traditional metal or metal oxide nanoparticles cannot be directly medicated into human body due to the potential toxicity. Herein, novel Zn2+–ε‐poly(l‐lysine) (EPL)–protocatechuic aldehyde (PCA)‐based hybrid nanoparticles (ZEP NPs) with on‐demand release capability are synthesized for the first time by one‐step coordination self‐assembly of Zn2+, EPL, and PCA to address this issue. The ZEP NPs can effectively adhere on bacterial cells and release Zn2+in situ due to the decomposition of ZEP NPs in acidic infection microenvironment. More importantly, ZEP NPs exhibit excellent bactericidal ability in a protein‐rich environment, in which free Zn2+completely loses its bactericidal ability. The excellent bactericidal effect of ZEP NPs is confirmed in a skin infection model and a lung infection model, demonstrating the great potential to deal with internal infections. Meanwhile, ZEP NPs exhibit negligible toxicity since the dose of Zn2+can be significantly reduced compared to the commercial zinc oxide nanoparticles (ZnO NPs). The outstanding bactericidal ability as well as negligible toxicity of ZEP NPs makes it ideal candidate of next generation antibacterial agents in treating internal infections.

Apple-like Zinc-Oxide Mesocrystals as Robust and Versatile Photocatalysts for Efficient Degradation of Eight Different Organic Dyes.

The discovery of efficient photocatalysts is a promising key approach to solve the environmental crisis caused by hazardous organic dyes. Herein, we have for the first time created ZnO mesocrystals with a novel apple-like morphology. We have developed a one-pot biomineralization route to synthesize ZnO nanostructures at room temperature by using the rod-like protein collagen as the template. The shape of ZnO mesocrystals can be conveniently tuned from fusiform-like and kiwi-like to orange-like, apple-like, and snack-like structures. The apple-like ZnO mesocrystals show a significantly better photodegradation efficiency than the commercial ZnO powder as well as other nanostructured ZnO materials for both rhodamine B (RhB) and methyl orange (MO). Furthermore, the apple-like zinc-oxide mesocrystals can degrade all of the tested eight different types of organic dyes (RhB, rhodamine 6G, methylene blue, Coomassie brilliant blue R250, BPB, MO, Li Chunhong S, and carmine) simply under the exposure of sunlight, demonstrating their superior photodegradation prowess, environmental amiability, and energy-saving features. The novel robust and versatile photocatalyst has greatly advanced our abilities for the elimination of organic dyes. The green, one-pot strategy provides a convenient method for the construction of novel metal-oxide nanostructures with promising applications in environmental protection.

Fabrication of microcrystalline cellulose/zinc oxide hybrid composite by hydrothermal synthesis and its application in rubber compounding

AbstractWith great concern of environmental threats, attempts have been made to reduce the consumption of zinc oxide (ZnO) in rubber products. This research aims at fabricating a new type of ZnO by depositing ZnO on microcrystalline cellulose (MCC) surface using an ultrasonic‐assisted hydrothermal process. The concentration ratio of Zn(NO3)2 to NaOH is varied from 1:1 to 1:4. The obtained products, namely MCC‐ZnO, are characterized by various techniques such as field emission scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, Brunauer–Emmett–Teller, and Thermogravimetric analysis. Results show that the amount of deposited ZnO and the specific surface area of MCC‐ZnO increase continuously with increasing NaOH concentration. The MCC‐ZnO (1:3) containing approximately 55.6 wt% of deposited ZnO is selected for investigating the curing efficiency in natural rubber (NR) and compared with the commercial ZnO (C‐ZnO). Obviously, the state of cure progressively increases with increasing either MCC‐ZnO or C‐ZnO content. At the same content, MCC‐ZnO exhibits a significantly higher crosslink density than C‐ZnO leading to the superior elasticity and mechanical properties. This could be explained by the greater specific surface area and, thus, the higher reactivity of MCC‐ZnO. Clearly, a considerably lower quantity of MCC‐ZnO is required to attain a similar level of crosslink density or mechanical properties as compared to C‐ZnO.

Green Synthesis and Characterization of a ZnO-ZrO2 Heterojunction for Environmental and Biological Applications

The zinc oxide–zirconium dioxide (ZnO-ZrO2) heterojunction was prepared by a green method using rubber leaves as reducing and capping agents. Various physicochemical techniques were used to study the chemical composition and the structural and optical properties of the synthesized nanocomposite. The nature of the heterojunction was confirmed through X-ray diffraction and the average sizes of ZnO and ZrO2 crystallites were found to be 70 and 24 nm, respectively. The photocatalytic potential of the ZnO-ZrO2 heterojunction was examined against rhodamine 6G (Rh-6G), and 97.30 percent of the dye was degraded due to the synergistic effect of the light and the catalyst. The commercial ZnO nanopowder was used as a reference catalyst and 86.32 percent degradation was noted under the same reaction conditions. The in vitro antioxidant activity was also performed to scavenge the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals, where the activity of the ZnO-ZrO2 heterojunction was found to be higher than the ascorbic acid.

Insecticidal Effect of Zinc Oxide Nanoparticles against Spodoptera frugiperda under Laboratory Conditions.

Simple SummaryFall armyworm has devastated several crops around the world, especially maize that is widely grown and utilized globally. Also, it has been known to cause a lot of damage in rice fields. However, controlling this pest has been a challenge to farmers due to its ability to reproduce faster and its development of resistance to synthetic chemicals, among other factors. Moreover, synthetic chemicals are a threat to the environment and humanity. For these reasons, we are constantly looking for safer yet effective means of controlling this pest, and nanotechnology comes in handy. Zinc Oxide nanoparticles have proved to be efficacious to several insect pests, of which some are in the same genus as Spodoptera frugiperda. This study aimed to find out the insecticidal effects of ZnO nanoparticles on S. frugiperda under laboratory conditions. We observed body deformations, reduced fecundity, reduced oviposition, and mortality when insects were fed on food treated with several concentrations of ZnO nanoparticles, yet the ones fed on control were normal in all the aspects. Therefore, we recommend ZnO nanoparticles for further studies with the aim of using them as an alternative control agent against fall armyworm under field conditions.Fall armyworm Spodoptera frugiperda is a major pest of corn, rice, and sorghum among other crops usually controlled using synthetic or biological insecticides. Currently, the new invention of nanotechnology is taking root in the agricultural industry as an alternative source of pest management that is target-specific, safe, and efficient. This study sought to determine the efficacy of commercial Zinc Oxide (ZnO) nanoparticles (NPs) towards S. frugiperda under laboratory conditions. ZnO NPs were diluted into different concentrations (100–500 ppm), where the baby corn used to feed the S. frugiperda larvae was dipped. The development of the insect feeding on food dipped in ZnO solution was significantly (p < 0.05) affected, and the number of days that the insect took to complete its life cycle had a significant difference compared to the control. There was a significant difference in the adults’ emergence in all the concentrations of ZnO NPs compared to the control, with over 90% of the eggs successfully going through the life cycle until adult emergence. Additionally, several body malformations were observed throughout the lifecycle of the insect. Also, the fecundity of the females was greatly affected. The findings of this study suggest the possibility of exploitation of ZnO nanoparticles not only to manage S. frugiperda but to significantly reduce their population in the ecosystem through body deformations, reduced fecundity, reduced oviposition, and hatchability of eggs. It will be a valuable tool in integrated pest management regimens.

In situ formation of ZnOx species for efficient propane dehydrogenation

Propane dehydrogenation (PDH) to propene is an important alternative to oil-based cracking processes, to produce this industrially important platform chemical1,2. The commercial PDH technologies utilizing Cr-containing (refs. 3,4) or Pt-containing (refs. 5–8) catalysts suffer from the toxicity of Cr(vi) compounds or the need to use ecologically harmful chlorine for catalyst regeneration9. Here, we introduce a method for preparation of environmentally compatible supported catalysts based on commercial ZnO. This metal oxide and a support (zeolite or common metal oxide) are used as a physical mixture or in the form of two layers with ZnO as the upstream layer. Supported ZnOx species are in situ formed through a reaction of support OH groups with Zn atoms generated from ZnO upon reductive treatment above 550 °C. Using different complementary characterization methods, we identify the decisive role of defective OH groups for the formation of active ZnOx species. For benchmarking purposes, the developed ZnO–silicalite-1 and an analogue of commercial K–CrOx/Al2O3 were tested in the same setup under industrially relevant conditions at close propane conversion over about 400 h on propane stream. The developed catalyst reveals about three times higher propene productivity at similar propene selectivity.

An investigation of the effects of synthesized zinc oxide nanoparticles on the properties of water-based drilling fluid

The deterioration of drilling fluid properties during deep drilling causes problems like inefficient cutting removal, fluid invasion, and shale swelling, which increases non-productive time (NPT) and cost. Recently nanoparticles (NPs) based drilling fluid are introduced to address these impediments since these particles prove their advantages in different stages of petroleum exploration and recovery. Previous developments are concerned with the use of commercial zinc oxide (ZnO) NPs in inorganic KCl salt-based drilling fluid, although application of KCl in drilling fluid arouses environmental complications. In this study, ZnO NPs prepared in the laboratory are used in water-based drilling fluid (WBDF) to assess the effect of nanoparticles on the properties of drilling fluid at two temperature conditions of 40 °C and 80 °C. A base mud is formulated, and ZnO NPs with five different concentrations of 0.05, 0.1, 0.5, 1.0, and 2.0 wt% are mixed with the base mud. The experimental analysis shows that NPs improve the rheological properties of WBDF. When the concentration of NPs was 0.1 wt%, the yield point increased by 61.54% at 40 °C, and when the concentration of NPs was 0.05 wt%, the yield point increased by 60% at 80 °C. Besides, when the concentration of NPs is 0.05 wt%, 10-sec gel strengths are enhanced by 25% and 50% at 40 °C and 80 °C, respectively. The API low-pressure low-temperature (LPLT) filter volume is not significantly affected by the addition of NPs in WBDF. However, mud cake thickness continuously reduces with the increase of NPs concentrations. This result reveals that a superior rheological improvement is achieved at low NPs concentration (0.05 wt%) at higher temperature.