scholarly journals Screw-Dislocation-Driven Hierarchical Superstructures of Ag-Ag2O-AgO Nanoparticles

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1084
Author(s):  
Hua Yang ◽  
Jing Ru Zhang ◽  
Wentao Cao ◽  
Jin Zhen ◽  
Ji Hong Wu
Keyword(s):  
Screw Dislocation ◽  
Uv Irradiation ◽  
Growth Mechanism ◽  
Irradiation Time ◽  
Structural Evolution ◽  
Physiochemical Properties ◽  
Promising Strategy ◽  
Photochemical Method ◽  
Step Density ◽  
Average Size

Constructing multi-dimensional hierarchical superstructures has been, for a longtime, regarded as a promising strategy for modifying the physiochemical properties of nanomaterials. Guided by this rule, this work reports the synthesis of hierarchical superstructures of Ag-Ag2O-AgO nanoparticles (HSANs) using a convenient and surfactant-less photochemical method under 254 nm UV-irradiation. The formation of the HSANs superstructures is dominated by screw-dislocation-driven growth mechanism at low supersaturation condition. The structural evolution of the HSANs superstructures has been systematically investigated. The average size of the HSANs superstructures increased with prolonged 254 nm UV-irradiation. The step density on the superstructure surfaces also increased along with the 254 nm UV-irradiation time.

scholarly journals Green Synthesis and Characterization of Pullulan Mediated Silver Nanoparticles through Ultraviolet Irradiation

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2382 ◽  
Author(s):  
Muhammad Jamshed Khan ◽  
Suriya Kumari ◽  
Kamyar Shameli ◽  
Jinap Selamat ◽  
Awis Qurni Sazili
Keyword(s):  
Silver Nanoparticles ◽  
Uv Irradiation ◽  
Irradiation Time ◽  
Edible Films ◽  
Crystallographic Structure ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Vis Spectroscopy ◽  
Face Centered ◽  
Average Lattice

Nanoparticles (NPs) are, frequently, being utilized in multi-dimensional enterprises. Silver nanoparticles (AgNPs) have attracted researchers in the last decade due to their exceptional efficacy at very low volume and stability at higher temperatures. Due to certain limitations of the chemical method of synthesis, AgNPs can be obtained by physical methods including sun rays, microwaves and ultraviolet (UV) radiation. In the current study, the synthesis of pullulan mediated silver nanoparticles (P-AgNPs) was achieved through ultraviolet (UV) irradiation, with a wavelength of 365 nm, for 96 h. P-AgNPs were formed after 24 h of UV-irradiation time and expressed spectra maxima as 415 nm, after 96 h, in UV-vis spectroscopy. The crystallographic structure was “face centered cubic (fcc)” as confirmed by powder X-ray diffraction (PXRD). Furthermore, high resolution transmission electron microscopy (HRTEM) proved that P-AgNPs were covered with a thin layer of pullulan, with a mean crystalline size of 6.02 ± 2.37. The average lattice fringe spacing of nanoparticles was confirmed as 0.235 nm with quasi-spherical characteristics, by selected area electron diffraction (SAED) analysis. These green synthesized P-AgNPs can be utilized efficiently, as an active food and meat preservative, when incorporated into the edible films.

scholarly journals Comparison of Various Advanced Oxidation Processes for the Degradation of Bisphenol A

2017 ◽  
pp. 147
Author(s):  
Naser Jamshidi ◽  
Farzad Nezhad Bahadori ◽  
Ladan Talebiazar ◽  
Ali Akbar Azimi
Keyword(s):  
Bisphenol A ◽  
Uv Irradiation ◽  
Advanced Oxidation Processes ◽  
Irradiation Time ◽  
Advanced Oxidation ◽  
Chemical Oxidation ◽  
Photochemical Oxidation ◽  
Input Concentration ◽  
Oxidation Processes ◽  
Ph Range

Today, advanced oxidation processes (AOPs) is considered as a key and effective method for environment preservation from pollutions. In this study , advanced photochemical oxidation processes using O3/H2O2 and O3/H2O2/UV systems were investigated batch photolytic reactor in lab-scale for the degradation of bisphenol A (BPA). In ozone generator source, air, as of the initial instrument feed, changes to ozone after electrical action and reaction. The UV irradiation source was a medium-pressure mercury lamp 300 W that was immerse in the wastewater solution with in 1.5 liter volume reactor. The reaction was influenced by the pH, the input concentration of H2O2, the input concentration of BPA, ozone dosage, chemical oxidation demand (COD) and UV irradiation time. Results showed that at initial bisphenol A concentration of 100 mg/l will completely degrade after 60 minutes by using O3/H2O2 in the pH range from 9.8 to 10 and by adding UV, it will happen in less than 36 minutes in the pH range of 3 to 10. The O3/H2O2/UV process reduced COD to 75 percents.

Effect of solution chemistry and operating conditions on the nanofiltration of acid dyes by a nanocomposite membrane

2011 ◽  
Vol 64 (12) ◽  
pp. 2404-2409 ◽  
Author(s):  
A. Akbari ◽  
M. Homayoonfal ◽  
V. Jabbari
Keyword(s):  
Uv Irradiation ◽  
Separation Efficiency ◽  
Irradiation Time ◽  
Membrane Surface ◽  
Operating Conditions ◽  
Solution Chemistry ◽  
Polymerization Process ◽  
Inversion Method ◽  
Sem Images ◽  
Polysulfone Membrane

A composite nanofiltration membrane was developed by a poly(acrylic acid) in situ ultraviolet (UV) graft polymerization process using an ultrafiltration polysulfone membrane as a porous support, by a phase inversion method. SEM images showed that the PSf membranes had numerous finger-like pores. Atomic force microscopy (AFM) showed that the roughness of the surface was reduced by an increase in UV irradiation times. The rejections of sodium chloride and sodium sulfate were moderate and declined with the increase of concentration. We observed that by increasing UV irradiation time and nanofiltration pressure applied, retention of dyes was enhanced and in the most irradiated membrane (M-4 membrane) at 4 bars, color removal with a high rejection of about 99.80% was achieved. It was found that the separation efficiency of dyes in the mixture of salt and dyes decreased with the salt concentration due to a decrease in the Donnan effect. It was also found that by varying the pH, the membrane surface and the dyes' charges are changed, which meant that the membrane surface and dyes had different interactions at various pHs.

scholarly journals One-step Oxidation of Total Organic Carbon, Total Nitrogen, and Total Phosphorous using Wet Chemical Oxidation

2020 ◽  
Vol 42 (12) ◽  
pp. 603-609
Author(s):  
Jeong-Hwan Choi ◽  
Dong-Hun Shin ◽  
Hye-Bin Kim ◽  
Jong-Gook Kim ◽  
Kitae Baek
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Total Nitrogen ◽  
Uv Irradiation ◽  
Oxidation Process ◽  
Irradiation Time ◽  
Suitable Condition ◽  
Chemical Oxidation ◽  
Total Phosphorous ◽  
Wet Chemical

Objective:This study proposed the simultaneous multi-oxidation of total organic carbon, total nitrogen, and total phosphorous using modified wet chemical oxidation method.Methods:The multi oxidation process was based on the dual radical system with sulfate and hydroxyl radicals. The sodium persulfate (Na2S2O8) and sodium hydroxide (NaOH) were activated at 40℃ and UV irradiation with 254 nm to generate the sulfate radical and hydroxyl radical. The organic matters were oxidized by the dual radicals, and TOC, TN, and TP values were compared with the control group.Results and Discussion:The dual radical system oxidized organic carbon to carbon dioxide effectively, and the TOC values were similar to the value obtained from the high-temperature combustion technique. However, the residual persulfate after oxidation process interfered the absorbance for TN and inhibit the complexation in TP measurement. The residual persulfate was effectively converted to sulfate by longer heating and UV irradiation, and the interferences were more sensitive to reaction temperature than UV irradiation time. As a result, a higher temperature condition was more effective and enhanced the applicability of multi-oxidation.Conclusions:The multi oxidation of TOC, TN, and TP was demonstrated by wet chemical oxidation, and the proposed method is expected to secure the sample and reduce the analytic time. However, the more suitable condition to enhance the accuracy of TOC, TN, and TP in the multi-oxidation system should be studied further.

scholarly journals Influence of solution pH on degradation of atrazine during UV and UV/H2O2 oxidation: kinetics, mechanism, and degradation pathways

RSC Advances ◽  
2019 ◽  
Vol 9 (61) ◽  
pp. 35847-35861 ◽  
Author(s):  
Yucan Liu ◽  
Kai Zhu ◽  
Miaomiao Su ◽  
Huayu Zhu ◽  
Jianbo Lu ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Oxidation Kinetics ◽  
Irradiation Time ◽  
Degradation Mechanism ◽  
Degradation Pathways ◽  
Solution Ph ◽  
H2o2 Oxidation ◽  
Ph Conditions

The kinetics, degradation mechanism and degradation pathways of atrazine (ATZ) during sole-UV and UV/H2O2 processes under various pH conditions were investigated; the effects of UV irradiation time and H2O2 dose were also evaluated.

scholarly journals The growth mechanism of titania/hydroxyapatite and its application in the photodegradation of methyl orange dye under UV irradiation

2018 ◽  
Vol 11 ◽  
pp. 112-117 ◽  
Author(s):  
Wei Liu ◽  
Gongming Qian ◽  
Lulu Liu ◽  
Xianyuan Fan ◽  
Xianyan Cai ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Uv Irradiation ◽  
Growth Mechanism ◽  
Methyl Orange Dye

Synthesis, characterization, and application of polyanisidines as efficient photostabilizers for poly(vinyl chloride) films

2019 ◽  
Vol 52 (6) ◽  
pp. 537-547
Author(s):  
Magdy W. Sabaa ◽  
Mohamed A Sanad ◽  
Mahmoud A Abd El-Ghaffar ◽  
Nourelhoda A Abdelwahab ◽  
Soha MA Sayed ◽  
...  
Keyword(s):  
Vinyl Chloride ◽  
Uv Irradiation ◽  
Oxidation Process ◽  
Irradiation Time ◽  
Chemical Oxidation ◽  
Polymeric Chain ◽  
Conductivity Measurements ◽  
Uv Absorber ◽  
Poly Vinyl Chloride ◽  
Pvc Film

Conducting polymers have great attention due to their electrical activity in π-electrons conjugation over backbone of the polymeric chain. These properties make them attractive for enormous applications. On that account, we prepared polyanisidines (PAs) derivatives ( ortho, meta, and para) by chemical oxidation process using ammonium peroxydisulfate as an initiator. The prepared PAs were characterized using various techniques. Moreover, conductivity measurements of PA derivatives showed that the ortho-derivative gave the highest value. The prepared PAs were investigated as photostabilizers for poly(vinyl chloride) (PVC) films. Different PVC films were prepared in the absence and the presence of PA derivatives and they were exposed to ultraviolet (UV) irradiation for 30 days. The gel weight % for irradiated PVC films was followed as a function of irradiation time. The results revealed that the blank PVC film (free PA derivatives) was completely degraded reaching 100% gel content. PVC films contain PA derivatives showed higher photostability than PVC blank film. A comparison between the investigated PA derivatives as UV stabilizers and Chimassorb commercial UV absorber was also investigated. PA derivatives showed better efficiency as UV stabilizers than the commercial one till 288 h of UV irradiation.

Preparation and Characterization of CdSe Nanoparticles Synthesized Using the Ultrasonic Irradiation

2007 ◽  
Vol 124-126 ◽  
pp. 1229-1232 ◽  
Author(s):  
Myoung Seok Sung ◽  
Yoon Bok Lee ◽  
Yong Jin Kim ◽  
Yang Do Kim
Keyword(s):  
Ultrasonic Irradiation ◽  
Photoelectron Spectroscopy ◽  
Irradiation Time ◽  
Xrd Analysis ◽  
Cdse Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Emission ◽  
Transmission Electron ◽  
Average Size

Cadmium selenide(CdSe) nanoparticles were prepared in the aqueous solution containing isopropyl alcohol by the ultrasonic irradiation at room temperature. The cadmium chloride (CdCl2) and sodium selenosulfate (Na2SeSO3) were used as the cadmium and selenium source, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-Vis absorption spectra and PL spectra were used to characterize the CdSe nanoparticles. XRD analysis revealed the formation of cubic structure CdSe. TEM images showed aggregated CdSe nanoparticles with the size of nanometer scale. Average size of CdSe nanoparticles were about 3.9, 5.0 and 5.1nm with sonication time of 6, 30 and 40 minutes, respectively. The surface emission became less intensive and shifted to red with increasing irradiation time. This paper presents the effects of ultrasonic on the formation of CdSe nanoparticles and its characteristics.

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