scholarly journals Zinc Oxide Nanoparticles Preparation for Pd2+ Ions Adsorption From Aqueous Wastewaters: A Green Technique

2021 ◽  
Author(s):  
Reza Davarnejad ◽  
Kourosh Nikandam
Keyword(s):  
Contact Time ◽  
Zinc Nitrate ◽  
Sem Analysis ◽  
Hexagonal Structure ◽  
Ambient Conditions ◽  
Zno Nps ◽  
Isothermal Model ◽  
Initial Concentration ◽  
Centaurea Cyanus ◽  
The Impact

Abstract ZnO nanoparticles (NPs) were easily synthesized using zinc nitrate through centaurea cyanus extract (as a reducing agent) at ambient conditions. XRD results demonstrated that ZnO NPs have a high-crystalline hexagonal structure with an average size of 48 nm in diameter. FT-IR spectral analysis indicated an active contribution of centaurea cyanus-derived biomolecules in zinc ions bioreduction. According to SEM analysis, ZnO NPs were properly dispersed and had a hexagonal shape. Batch experiments were performed to investigate the impact of several process parameters such as initial pH of solution, adsorption dosage, Pd2+ ions initial concentration and contact time on the Pd2+ ions adsorption from the solution. The Freundlich isothermal model could excellently legitimize a multilayer adsorption. Furthermore, the adsorption process followed a pseudo-second-order reaction kinetic. The maximum adsorption (99.24%) was experimentally found at pH of 5.5, adsorption dosage of 1.63 g.L-1, Pd2+ ions initial concentration of 77.5 mg.L-1 and contact time of 91.25 min.

scholarly journals Synthesis of ZnO Nanoparticles by Precipitation Method with Their Antibacterial Effect

2018 ◽  
Vol 16 (2) ◽  
pp. 117 ◽  
Author(s):  
Muhammad Fajri Romadhan ◽  
Nurgaha Edhi Suyatma ◽  
Fahim Muchammad Taqi
Keyword(s):  
Antimicrobial Activity ◽  
Particle Size ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Zinc Nitrate ◽  
Sem Analysis ◽  
Precipitation Method ◽  
Average Particle ◽  
Zno Nps

The aim of this study was to synthesize and characterize Zinc oxide nanoparticles (ZnO-NPs) prepared by precipitation method. Zinc nitrate and sodium hydroxide was used as starting materials with biopolymer pectin as capping agent. ZnO-NPs were synthesized at three levels of temperatures (60, 80 and 100 °C) without or with calcinations (500 °C). Particle size analyzer (PSA) analysis results showed that the samples without calcination (T60, T80 and T100) having an average particle size respectively 105.13, 78.53, and 76.43 nm, whereas at the samples by calcination (T60C, T80C and T100C) each have average particle size of 88.73, 44.30 and 543.77 nm. The results showed that preparation of ZnO-NPs by using heating at 80 °C followed with calcinations at 500 °C (T80C) produced the smallest size. T80C samples further were analyzed using XRD, SEM and the antimicrobial activity compared with the ZnO-NPs commercials. XRD analysis confirmed that ZnO-NPs were successfully obtained and have form of pure nanostructure. SEM analysis showed that ZnO-NPs obtained has a spherical shape. Furthermore, this ZnO-NPs (T80C) has a better antimicrobial activity compared than commercial ZnO-NPs in market.

scholarly journals Green approach in fabrication of photocatalytic, antimicrobial, and antioxidant zinc oxide nanoparticles – hydrothermal synthesis using clove hydroalcoholic extract and optimization of the process

2020 ◽  
Vol 9 (1) ◽  
pp. 375-385 ◽  
Author(s):  
Mahvash Anvarinezhad ◽  
Afshin Javadi ◽  
Hoda Jafarizadeh-Malmiri
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Bioactive Compound ◽  
Bactericidal Effect ◽  
Zinc Nitrate ◽  
Sem Analysis ◽  
Zinc Salt ◽  
Oxide Nanoparticles ◽  
Zno Nps ◽  
Clove Extract

AbstractZinc oxide nanoparticles (ZnO NPs) were hydrothermally fabricated, using hydroalcoholic clove extract. GC-MS analysis demonstrated that Eugenol is the main bioactive compound of the prepared extract. Experiments were designed, based on the central composite design. The effects of different amounts of zinc nitrate (2–6 g) and clove extract (10–30 mL) were evaluated for antioxidant and bactericidal properties of the formed ZnO NPs using the response surface methodology. The attained results demonstrated that more desirable NPs with maximum antioxidant activity (85.23%) and bactericidal effect, against Escherichia coli and Staphylococcus aureus, as manifested in the diameter of formed clear zones of 11.12 and 12.11 mm, respectively, were resulted using 3.98 g of the zinc salt and 20.30 mL of the clove extract. Furthermore, XRD and SEM analysis results revealed that the fabricated ZnO NPs had a hexagonal shape with a particle size of 50 nm and could degrade 70% of methylene blue during UV radiation.

Impact of Particulate Matter on Distribution System Disinfection Efficacy

2008 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Linda Wojcicka ◽  
Carole Baxter ◽  
Ron Hofmann
Keyword(s):  
Helicobacter Pylori ◽  
Particulate Matter ◽  
Distribution System ◽  
Contact Time ◽  
Water Disinfection ◽  
Sphingomonas Paucimobilis ◽  
Soil Corrosion ◽  
Log Reduction ◽  
Drinking Water Disinfection ◽  
The Impact

Abstract Microorganisms have been shown to survive drinking water disinfection and remain viable in disinfected waters despite the presence of disinfectant residuals. This may be partially attributed to protection by particulate matter. The aim of this study was to determine the effects of the presence of particulate matter on disinfection kinetics. Sphingomonas paucimobilis ATCC 10829 and Helicobacter pylori ATCC 43504 were used in inactivation experiments in the presence and absence of soil, corrosion, and wastewater particles. The results showed that the presence of such particles tended to inhibit chlorine and monochloramine inactivation, although the magnitude of the impact under the conditions tested was small (e.g., 1-log reduction in inactivation for several minutes of contact time in the presence of less than 1 mg/L of disinfectant).

Ferro-nanofluid squeeze film lubrication with heat transfer

2021 ◽  
pp. 135065012110276
Author(s):  
Manimegalai Kavarthalai ◽  
Vimala Ponnuswamy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Contact Time ◽  
Transfer Rate ◽  
Fluid Layer ◽  
Darcy Law ◽  
Squeeze Film ◽  
Mean Temperature ◽  
Special Cases ◽  
The Impact

A theoretical study of a squeezing ferro-nanofluid flow including thermal effects is carried out with application to bearings and articular cartilages. A representational geometry of the thin layer of a ferro-nanofluid squeezed between a flat rigid disk and a thin porous bed is considered. The flow behaviours and heat transfer in the fluid and porous regions are investigated. The mathematical problem is formulated based on the Neuringer–Rosensweig model for ferro-nanofluids in the fluid region including an external magnetic field, Darcy law for the porous region and Beavers–Joseph slip condition at the fluid–porous interface. The expressions for velocity, fluid film thickness, contact time, fluid flux, streamlines, pathlines, mean temperature and heat transfer rate in the fluid and porous regions are obtained by using a perturbation method. An asymptotic solution for the fluid layer thickness is also presented. The problem is also solved by a numerical method and the results by asymptotic analysis, perturbation and numerical methods are obtained assuming a constant force squeezing state and are compared. It is shown that the results obtained by all the methods agree well with each other. The effects of various parameters such as Darcy number, Beavers–Joseph constant and magnetization parameter on the flow behaviours, contact time, mean temperature and heat transfer rate are investigated. The novel results showing the impact of using ferro-nanofluids in the two applications under consideration are presented. The results under special cases are further compared with the existing results in the literature and are found to agree well.

scholarly journals Optimizing Adsorption of 17α-Ethinylestradiol from Water by Magnetic MXene Using Response Surface Methodology and Adsorption Kinetics, Isotherm, and Thermodynamics Studies

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3150
Author(s):  
Mengwei Xu ◽  
Chao Huang ◽  
Jing Lu ◽  
Zihan Wu ◽  
Xianxin Zhu ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Quadratic Model ◽  
Adsorption Efficiency ◽  
Process Variables ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Independent Variables ◽  
The Impact ◽  
Adsorbent Dose

Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.

The influence of Hanok experience on tourists’ attitude and behavioral intention: An interplay between experiences and a Value-Attitude-Behavior model

2021 ◽  
pp. 135676672110117
Author(s):  
Choong-Ki Lee ◽  
Yvette Reisinger ◽  
Muhammad Shakil Ahmad ◽  
Yae-Na Park ◽  
Choong-Won Kang
Keyword(s):  
Behavioral Intention ◽  
Sem Analysis ◽  
Experience Economy ◽  
A Value ◽  
Functional Value ◽  
Experienced Utility ◽  
Attitude Behavior ◽  
Tourism And Hospitality ◽  
The Impact ◽  
Value Functional

This study examines the impact of Hanok experience on tourists’ attitude and behavioral intention using the experience economy ( Pine and Gilmore, 1998 ) and the experienced utility theory ( Kahneman et al., 1997 ). Specifically, the study explores how tourists’ experiences are associated with a Value-Attitude-Behavior (VAB) model in the context of a heritage tourism attraction such as Jeonju Hanok Village in South Korea. A total of 323 responses were examined using SEM analysis. The results revealed that educational, entertainment, and escapism experiences significantly influenced functional value. Functional value had a significant relationship with attitude, which was positively related to behavioral intention. The results indicate the interplay of tourists’ experiences with the VAB model. The study provides theoretical and practical implications for tourism and hospitality academics and practitioners.

scholarly journals Nanoparticles induce genetic, biochemical, and ultrastructure variations in Salvadora persica callus

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Manar S. Fouda ◽  
Mohamed H. Hendawey ◽  
Ghada A. Hegazi ◽  
Hayat M. Sharada ◽  
Nagwa I. El-Arabi ◽  
...  
Keyword(s):  
Folk Medicine ◽  
Antimicrobial Activities ◽  
In Vitro Production ◽  
Salvadora Persica ◽  
Zno Nps ◽  
Active Constituent ◽  
Benzyl Isothiocyanate ◽  
Stress Markers ◽  
The Impact

Abstract Background Salvadora persica is an endangered medicinal plant due to difficulties in its traditional propagation. It is rich in bioactive compounds that possess many pharmaceutical, antimicrobial activities and widely used in folk medicine. The current study aims at in vitro propagation of Salvadora persica and the application of different nanoparticles (NPs) to induce the synthesis of bioactive and secondary metabolites within the plant. The cellular and genetic responses to the application of different NPs were evaluated. Results The impact of nanoparticles NPs (ZnO, SiO2, and Fe3O4) on callus growth of Salvadora persica and the production of its active constituent benzyl isothiocyanate was examined, regarding some oxidative stress markers, antioxidant enzymes, and genetic variabilities. An encouraging impact of 0.5 mg/l ZnO NPs on benzyl isothiocyanate production was shown reaching up to 0.905 mg/g callus fresh weight in comparison to 0.539 mg/g in control callus. This was associated with decreasing hydrogen peroxide content and increasing superoxide dismutase and peroxidase activities. The deposition of the NPs on cellular organelles was detected using a transmission microscope. Fifteen Inter-Simple Sequence Repeats (ISSR) primers detected an overall, 79.1% polymorphism among different treatments. A reduction in genomic DNA template stability (GTS) was made and was more pronounced in higher doses of different NPs. Conclusion This study is a stepping stone in developing a productive protocol for in vitro production of benzyl isothiocyanate from Salvadora persica using NPs as a valuable anticancer compound.

Experimental Evaluation of Compressor Blade Fouling

2016 ◽  
Author(s):  
Rainer Kurz ◽  
Grant Musgrove ◽  
Klaus Brun
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
Blade Surface ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Compressor Blades ◽  
Performance Deterioration ◽  
Quantitative Results ◽  
The Impact ◽  
Dust Retention

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on performance, as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions of the blade surface. Quantitative results both indicate the amount of dust as well as the distribution of dust on the airfoil, for a dry airfoil, as well as airfoils that were wet from ingested water, as well as different types of oil. The retention patterns are correlated with the boundary layer shear stress. The tests show the higher dust retention from wet surfaces compared to dry surfaces. They also provide information about the behavior of the particles after they impact on the blade surface, showing that for a certain amount of wet film thickness, the shear forces actually wash the dust downstream, and off the airfoil. Further, the effect of particle agglomeration of particles to form larger clusters was observed, which would explain the disproportional impact of very small particles on boundary layer losses.

Study on Grinding Force in Two-Dimensional Ultrasonic Grinding Nano-Ceramics

2010 ◽  
Vol 42 ◽  
pp. 204-208 ◽  
Author(s):  
Xiang Dong Li ◽  
Quan Cai Wang
Keyword(s):  
Mathematical Model ◽  
Ultrasonic Vibration ◽  
Contact Time ◽  
Reaction Force ◽  
Grinding Force ◽  
Two Dimensional ◽  
Indentation Fracture ◽  
Ultrasonic Grinding ◽  
The Impact ◽  
Ultrasonic Vibration Assisted Grinding

In this paper, the characteristic of grinding force in two-dimensional ultrasonic vibration assisted grinding nano-ceramic was studied by experiment based on indentation fracture mechanics, and mathematical model of grinding force was established. The study shows that grinding force mainly result from the impact of the grains on the workpiece in ultrasonic grinding, and the pulse power is much larger than normal grinding force. The ultrasonic vibration frequency is so high and the contact time of grains with the workpiece is so short that the pulse force will be balanced by reaction force from workpiece. In grinding workpiece was loaded by the periodical stress field, which accelerates the fatigue fracture.

scholarly journals Drops bouncing off macro-textured superhydrophobic surfaces

2017 ◽  
Vol 824 ◽  
pp. 866-885 ◽  
Author(s):  
Ali Mazloomi Moqaddam ◽  
Shyam S. Chikatamarla ◽  
Iliya V. Karlin
Keyword(s):  
Contact Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Nonlinear Behaviour ◽  
Textured Surfaces ◽  
Texture Density ◽  
Wide Range ◽  
Quantitative Manner ◽  
The Impact

Recent experiments with droplets impacting macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. Here we present a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantifies the roles played by various external and internal forces. For the first time, accurate three-dimensional simulations involving realistic macro-textured surfaces are performed. After demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analysing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyse the role played by the texture density. Moreover, we report a nonlinear behaviour of the contact time with the increase of the Weber number for imperfectly coated textures, and study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers.

Sign in / Sign up

Export Citation Format

Share Document