scholarly journals Influence of rGO, n-Al2O3 and n-SiO2 Nanomaterials on the Microstructure of OPC Paste Immersed in 0.5 M HNO3 Solution

◽  
2016 ◽  
Author(s):  
M. Murugan ◽  
◽  
Manu Santhanam ◽  
Keyword(s):  
Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1736
Author(s):  
Karol Sidor ◽  
Tomasz Berniak ◽  
Piotr Łątka ◽  
Anna Rokicińska ◽  
Marek Michalik ◽  
...  

The polycondensation of resorcinol and formaldehyde in a water–ethanol mixture using the adapted Stöber method was used to obtain resol resins. An optimization of synthesis conditions and the use of an appropriate stabilizer (e.g., poly(vinyl alcohol)) resulted in spherical grains. The resins were carbonized in the temperature range of 600–1050 °C and then chemically activated in an aqueous HNO3 solution, gaseous ammonia, or by an oxidation–reduction cycle (soaking in a HNO3 solution followed by treatment with NH3). The obtained carbons were characterized by XRD, the low-temperature adsorption of nitrogen, SEM, TGA, and XPS in order to determine degree of graphitization, porosity, shape and size of particles, and surface composition, respectively. Finally, the materials were tested in phenol adsorption. The pseudo-second order model perfectly described the adsorption kinetics. A clear correlation between the micropore volume and the adsorption capacity was found. The content of graphite domains also had a positive effect on the adsorption properties. On the other hand, the presence of heteroatoms, especially oxygen groups, resulted in the clogging of the pores and a decrease in the amount of adsorbed phenol.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2123
Author(s):  
Maria Râpă ◽  
Maria Stefan ◽  
Paula Popa ◽  
Dana Toloman ◽  
Cristian Leostean ◽  
...  

The electrospun nanosystems containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and 1 wt% Fe doped ZnO nanoparticles (NPs) (with the content of dopant in the range of 0–1 wt% Fe) deposited onto polylactic acid (PLA) film were prepared for food packaging application. They were investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), antimicrobial analysis, and X-ray photoelectron spectrometry (XPS) techniques. Migration studies conducted in acetic acid 3% (wt/wt) and ethanol 10% (v/v) food simulants as well as by the use of treated ashes with 3% HNO3 solution reveal that the migration of Zn and Fe falls into the specific limits imposed by the legislation in force. Results indicated that the PLA/PHBV/ZnO:Fex electrospun nanosystems exhibit excellent antibacterial activity against the Pseudomonas aeruginosa (ATCC-27853) due to the generation of a larger amount of perhydroxyl (˙OOH) radicals as assessed using electron paramagnetic resonance (EPR) spectroscopy coupled with a spin trapping method.


2010 ◽  
Vol 7 (3) ◽  
pp. 278-283
Author(s):  
F. Ahmadia ◽  
A. Khanmohammadi ◽  
A. Malekpour

A cloud point extraction method was presented for preconcentration of copper in various samples. After complexation with 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (ADPP) or N-Benzoyl-N-phenylhydroxylamine (BPA)  in water, analyte ions are quantitatively extracted to the phase rich in Triton X-114 after centrifugation. 2.0 mol L-1 HNO3 solution in methanol was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for ADPP, Triton X-114, HNO3 and parameters such as bath temperature, centrifuge rate and time were optimized. Detection limits (3SDb/m) of 1.3 and 1.9 ng mL-1 for ADPP and BPA along with enrichment factors of 30 and 38 for ADPP and BPA were achieved. The high efficiency of cloud point extraction to carry out the determination of analyte in complex matrices was demonstrated. The proposed method was applied to the analysis of biological, industrial, natural and wastewater, soil and blood samples.   Keywords: 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (ADPP), N-Benzoyl-N-phenylhydroxylamine (BPA) ,   Cloud Point Extraction, Triton X-114, Flame Atomic Absorption Spectrometry.


2011 ◽  
Vol 493-494 ◽  
pp. 426-429 ◽  
Author(s):  
Junichi Tazaki ◽  
Masaru Murata ◽  
Y. Nakanishi ◽  
M. Ochi ◽  
Y. Hirose ◽  
...  

In our previous clinical study, autogenous demineralized dentin matrices (DDM) prepared from the functional vital teeth (#38, #41) of thirty-five-year-old female were grafted on the bone defect, using newly developed mill, and then received to the host without troubles. In this study, we implanted the human tooth dentin adjusted previously and the dental implants into the regions of missing tooth simultaneously. Fifty-seven-year-old female presented with missing teeth (#35-#37, #45-#47). First, a non-functional vital tooth (#18) were extracted and cryopreserved immediately. 11 months after extraction, the tooth was crushed by newly developed auto-crash mill using ZrO2 vessel and ZrO2 blade for 1 minute. The crushed granules were demineralized completely in 2% HNO3 solution, rinsed in cold distilled water and lyophilized (granule size: 0.5-2.0mm). The bacteria-free of the DDM were confirmed by the bacteriological examination before use. Drilling of the prospective implant beds were then performed according to the manufacture’s protocol and a screw-type rough surface implants (Nobel Biocare® Mk III) were placed. The adjusted DDM granules were implanted into the bone defect (#45). There are no postoperative complications at 3 years after implantation. This case indicates that the preserved autogenous DDM can be used as collagenous biomaterials with osteoinductive potency.


2013 ◽  
Vol 284 ◽  
pp. 894-899 ◽  
Author(s):  
Nacéra Megouda ◽  
Toufik Hadjersi ◽  
Sabine Szunerits ◽  
Rabah Boukherroub

2013 ◽  
Vol 285 ◽  
pp. 795-804 ◽  
Author(s):  
Banu Poobalan ◽  
Jeong Hyun Moon ◽  
Sang-Cheol Kim ◽  
Sung-Jae Joo ◽  
Wook Bahng ◽  
...  

2006 ◽  
Vol 510-511 ◽  
pp. 574-577
Author(s):  
Jae Myung Kim ◽  
Hyung Sun Kim

We present the preliminary results of our research on the behavior of lead free glasses in the acid etching process, which is used for the formation of barrier ribs in plasma display panel. The glasses (BaO-B2O3-ZnO system) were etched in HNO3 solution (0.1-1.0% HNO3) at 50°C. The structure and surface of the etched bulk glass were investigated by using inductively coupled plasma and X-ray photoelectron spectroscopy. As a result, Ba (3-35ppm/min) and Zn (2- 27ppm/min) ions as major components were leached in the solution. A decrease of the bridge oxygen and a relative increase of non bridge oxygen in the etched glass were found by X-ray photoelectron spectroscopy.


Sign in / Sign up

Export Citation Format

Share Document