scholarly journals Influence of excitation wavelength, solution pH, incubation time, absolute configuration (S and R) and constitutional isomerism (ortho-, meta- and para-) on the adsorption on the surface of Ag nanoparticles of N-benzylamino(boronphenyl)methylphosphonic acid analogues

2021 ◽  
pp. 150341
Author(s):  
Edyta Proniewicz ◽  
John R. Lombardi
Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 428
Author(s):  
Masaku Kgatle ◽  
Keneiloe Sikhwivhilu ◽  
Gebhu Ndlovu ◽  
Nosipho Moloto

The release of azo dye contaminants from textile industries into the environment is an issue of major concern. Nanoscale zerovalent iron (nZVI) has been extensively studied in the degradation of azo dye pollutants such as methyl orange (MO). In this study, iron was coupled with copper and silver to make trimetallic Fe/Cu/Ag nanoparticles, in order to enhance the degradation of MO and increase reactivity of the catalyst by delaying the rate of oxidation of iron. The synthesis of the trimetallic nanoparticles (Fe/Cu/Ag) was carried out using the sodium borohydride reduction method. The characterization of the particles was performed using XRD, XPS, EDX, and TEM. The analyses confirmed the successful synthesis of the nanoparticles; the TEM images also showed the desired structures and geometry of the nanoscale zerovalent iron particles. The assessment of the nanoparticles in the degradation of methyl orange showed a notable degradation within few minutes into the reaction. The effect of parameters such as nanoparticle dosage, initial MO concentration, and the solution pH on the degradation of MO using the nanoparticles was investigated. Methyl orange degradation efficiency reached 100% within 1 min into the reaction at a low pH, with lower initial MO concentration and higher nanoparticle dosage. The degradation rate of MO using the nanoparticles followed pseudo first-order kinetics and was greatly influenced by the studied parameters. Additionally, LC-MS technique confirmed the degradation of MO within 1 min and that the degradation occurs through the splitting of the azo bond. The Fe/Cu/Ag trimetallic nanoparticles have proven to be an appropriate and efficient alternative for the treatment of dye wastewater.


Molekul ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. 48 ◽  
Author(s):  
Teguh Endah Saraswati ◽  
Yudha Pratama Putra ◽  
Mohammad Rifqi Ihsan ◽  
Isnaeni Isnaeni ◽  
Yuliati Herbani

Ag nanoparticles were synthesized by laser ablation using an Ag plate in distilled water. This method was performed using a laser with a wavelength of 532 nm and energy of 30 mJ for 60 min. Ag nanoparticles successfully formed, confirmed by the selected area electron diffraction (SAED) which revealed four principal crystal planes of (111), (200), (220) and (311). The size distribution of Ag nanoparticles ranged from 5 to 40 nm, as estimated from electron imaging observed by transmission electron microscope (TEM). Ascorbic acid was used as the analyte to test the characteristics of surface-enhanced Raman scattering (SERS) of colloidal Ag nanoparticles. The concentration of ascorbic acid (1.0, 0.5 and 0.25 wt%) and incubation time (0 and 6 h) were varied to determine the limit of detection and the effect of incubation time. The Raman scattering spectroscopy results showed that the colloidal Ag nanoparticle substrate improved the signals for detection of ascorbic acid.


Author(s):  
Long Hoang Nguyen ◽  
Thanh Ha Nguyen ◽  
Tuan Anh Dao ◽  
Ke Huu Nguyen ◽  
Hung Vu Tuan Le

This study investigated the effect of changing the density of Ag nanoparticles on the ZnO/Ag nanorod structure on the SERS substrate signal amplification ability. First, ZnO nanorods were fabricated by the sol - gel method combining with the chemical bath deposition method. Next, the Ag nanoparticles were decorated on ZnO nanorods by the DC magnetron sputtering method. The density and size of the modified Ag nanoparticles on the ZnO nanorods were changed by adjusting the sputtering times to 5, 10, 15 and 20s respectively. The optical properties of the material are characterized by UV - Vis and PL measurements. The surface morphology of ZnO nanorods and Ag nanoparticles were investigated by scanning electron microscope (SEM). X-ray diffraction measurement (XRD) is used to examine the crystal structures of materials. The composition and distribution of the chemical elements inside the material were investigated by Energy-dispersive X-ray spectroscopy (EDX). The ability of SERS substrates to amplify Raman signals was evaluated by measuring the R6G solution and investigating application for abamectin with a laser excitation wavelength of 532 nm. The results showed that SERS ZnO/Ag substrates with sputtering time of 15s gave the best ability to amplify SERS with the detection of R6G solution at 10􀀀9 M and abamectin at 50 ppm.


Author(s):  
Bhavani Prasad Vinjamuri ◽  
Katarina Papachrisanthou ◽  
Rahul V. Haware ◽  
Mahavir B. Chougule

Author(s):  
C.N. Sun

The present study demonstrates the ultrastructure of the gingival epithelium of the pig tail monkey (Macaca nemestrina). Specimens were taken from lingual and facial gingival surfaces and fixed in Dalton's chrome osmium solution (pH 7.6) for 1 hr, dehydrated, and then embedded in Epon 812.Tonofibrils are variable in number and structure according to the different region or location of the gingival epithelial cells, the main orientation of which is parallel to the long axis of the cells. The cytoplasm of the basal epithelial cells contains a great number of tonofilaments and numerous mitochondria. The basement membrane is 300 to 400 A thick. In the cells of stratum spinosum, the tonofibrils are densely packed and increased in number (fig. 1 and 3). They seem to take on a somewhat concentric arrangement around the nucleus. The filaments may occur scattered as thin fibrils in the cytoplasm or they may be arranged in bundles of different thickness. The filaments have a diameter about 50 A. In the stratum granulosum, the cells gradually become flatted, the tonofibrils are usually thin, and the individual tonofilaments are clearly distinguishable (fig. 2). The mitochondria and endoplasmic reticulum are seldom seen in these superficial cell layers.


Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
A Debbab ◽  
R Bara ◽  
A Pretsch ◽  
R Edrada Ebel ◽  
V Wray ◽  
...  

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