scholarly journals Impact of As-Prepared and Purifıed Multi-Walled Carbon Nanotubeson the Liquid-Phase Aerobic Oxidatıon of Hydrocarbons

2021 ◽  
Vol 15 (4) ◽  
pp. 479-485
Author(s):  
Eldar Zeynalov ◽  
◽  
Asgar Huseynov ◽  
Elchin Huseynov ◽  
Nazilya Salmanova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Aerobic Oxidation ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Oxidation Of Hydrocarbons ◽  
Multi Walled Carbon Nanotubes ◽  
Approaches To Study ◽  
Oxidation Chain ◽  
Walled Carbon Nanotubes

The article presents simple kinetic approaches to study the effect of multi-walled carbon nanotubes (MWCNTs) additives on the aerobic oxidation of hydrocarbons and to propose real acceptable mechanisms of the process. The aerobic liquid phase low-temperature oxidation of ethylbenzene conducted in the presence of multi-walled carbon nanotubes has been used as a model pattern. Kinetic analysis established the catalytic action associated with the presence of the iron compounds in inner channels of MWCNTs. These compounds are identified as ferric carbides provoking decomposition of the ethylbenzene hydroperoxide and thereby suppressing the competitive route of alky-peroxide radicals addition to the nanocarbon cage. Thus the reaction finally proceeds in the autocatalytic mode.Contradictory conclusions on the effect of CNTs on the oxidation chain processes existing in the literature are associated with the lack of control over nature and content of metal impurities in channels of nanotubes.

Multi-walled Carbon Nanotubes Reinforced into Hollow Fiber by Chitosan Sol-gel for Solid/Liquid Phase Microextraction of NSAIDs from Urine Prior to HPLC-DAD Analysis

2019 ◽  
Vol 20 (5) ◽  
pp. 390-400 ◽  
Author(s):  
Nabil N. AL-Hashimi ◽  
Amjad H. El-Sheikh ◽  
Rania F. Qawariq ◽  
Majed H. Shtaiwi ◽  
Rowan AlEjielat
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Hollow Fiber ◽  
Sol Gel ◽  
Liquid Phase Microextraction ◽  
Extraction Device ◽  
Multi Walled Carbon Nanotubes ◽  
Solid Liquid ◽  
Walled Carbon Nanotubes

Background: The efficient analytical method for the analysis of nonsteroidal antiinflammatory drugs (NSAIDs) in a biological fluid is important for determining the toxicological aspects of such long-term used therapies. Methods: In the present work, multi-walled carbon nanotubes reinforced into a hollow fiber by chitosan sol-gel assisted-solid/ liquid phase microextraction (MWCNTs-HF-CA-SPME) method followed by the high-performance liquid chromatography-diode array detection (HPLC–DAD) was developed for the determination of three NSAIDs, ketoprofen, diclofenac, and ibuprofen in human urine samples. MWCNTs with various dimensions were characterized by various analytical techniques. The extraction device was prepared by immobilizing the MWCNTs in the pores of 2.5 cm microtube via chitosan sol-gel assisted technology while the lumen of the microtube was filled with few microliters of 1-octanol with two ends sealed. The extraction device was operated by direct immersion in the sample solution. Results: The main factors influencing the extraction efficiency of the selected NSAIDs have been examined. The method showed good linearity R2 ≥ 0.997 with RSDs from 1.1 to 12.3%. The limits of detection (LODs) were 2.633, 2.035 and 2.386 µg L-1, for ketoprofen, diclofenac, and ibuprofen, respectively. The developed method demonstrated a satisfactory result for the determination of selected drugs in patient urine samples and comparable results against reference methods. Conclusion: The method is simple, sensitive and can be considered as an alternative for clinical laboratory analysis of selected drugs.

scholarly journals Multi-walled carbon nanotube-based composite materials as catalyst support for water–gas shift and hydroformylation reactions

RSC Advances ◽  
2019 ◽  
Vol 9 (47) ◽  
pp. 27732-27742 ◽  
Author(s):  
Patrick Wolf ◽  
Morten Logemann ◽  
Markus Schörner ◽  
Laura Keller ◽  
Marco Haumann ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Liquid ◽  
Liquid Phase ◽  
Catalyst Support ◽  
Water Gas Shift ◽  
Supported Ionic Liquid ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Water Gas

Multi-walled carbon nanotubes (MWCNT) show promising behavior in supported ionic liquid phase (SILP) catalyzed hydroformylation and water–gas shift reactions.

scholarly journals Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi‐Walled Carbon Nanotubes in Liquid Phase

2019 ◽  
Vol 25 (53) ◽  
pp. 12288-12293 ◽  
Author(s):  
Tom Wirtanen ◽  
Santeri Aikonen ◽  
Mikko Muuronen ◽  
Michele Melchionna ◽  
Marianna Kemell ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Conversion of guaiacol as lignin model component using acid-treated, multi-walled carbon nanotubes supported Ru–MnO bimetallic catalysts

2020 ◽  
Vol 98 (2) ◽  
pp. 57-65 ◽  
Author(s):  
Wei Long ◽  
Pingle Liu ◽  
Wei Xiong ◽  
Fang Hao ◽  
He’an Luo
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Bimetallic Catalysts ◽  
Catalytic Performance ◽  
Particle Dispersion ◽  
Reaction Conditions ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Lignin Model ◽  
Walled Carbon Nanotubes

Acid-treated, multi-walled carbon nanotube (AMWCNT) supported Ru and MnO bimetallic catalysts were prepared for liquid phase hydrodeoxygenation of guaiacol. The physicochemical properties of the prepared catalysts were characterized by FTIR, XRD, NH3-TPD, CO2-TPD, TEM, and XPS. MnO species were loaded on the inner surface of carbon nanotubes and were helpful for Ru particle dispersion. The 6%Ru-8%MnO/AMWCNTs with smaller Ru particle size, better dispersion, and more basic sites gave the best catalytic performance of 99.38% conversion of guaiacol and 85.84% selectivity to cyclohexanol. The effects of reaction conditions on liquid phase guaiacol hydrodeoxygenation were discussed and a possible reaction path was proposed.

Functionalized Multi Walled Carbon Nanotubes-Reinforced Hollow Fiber Solid/Liquid Phase Microextraction and HPLC-DAD for Determination of Phenazopyridine in Urine

2019 ◽  
Vol 15 (5) ◽  
pp. 447-455 ◽  
Author(s):  
Nabil N. Al-Hashimi ◽  
Anas I. Awwad ◽  
Aqeel N. Al-Hashimi ◽  
Iman A. Mansi ◽  
Rand O. Shahin ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Hollow Fiber ◽  
Limit Of Detection ◽  
Liquid Phase Microextraction ◽  
Multi Walled Carbon Nanotubes ◽  
Good Repeatability ◽  
Solid Liquid ◽  
Walled Carbon Nanotubes

Introduction: A sensitive analytical method based on functionalized multi walled carbon nanotubes reinforced hollow fiber solid/liquid phase microextraction (F-MWCNTs-HF-SLPME) forwarded with HPLC-DAD for analyzing phenazopyridine from urine is presented. Materials and Methods: The extraction of phenazopyridine is performed using specially designed FMWCNTs- HF-SLPME device constructed as follows: the functionalized multi walled carbon nanotubes (F-MWCNTs) were immobilized into the pores of 2.5 cm hollow fiber micro-tube using capillary forces and ultrasonication, then, the lumen of the micro-tube was filled with 1-octanol with two ends sealed. Subsequently, the device was placed into 10-mL of urine sample containing the analyte with agitation. After ending extraction, the device was removed, rinsed, sonicated in 250 µL of organic solvent and analyzed directly by the separation system. Results and Conclusion: Different parameters affecting the performance of the developed method were optimized. The method showed good linearity with (R2) 0.999 and good repeatability with (RSDs) from 3.7 to 0.9% at analyte concentration ranged from 0.01 to 10 µg L-1 of spiked urine samples. The limit of detection/ quantitation, LODs/LOQs was 0.02/0.09 µg L-1. In comparison with reference methods, the developed method is considered as a promising microextraction technique for determination of trace phenazopyridine in human urine using a common HPLC without further cleanup procedures.

scholarly journals Carbon nanotubes catalysis in liquid-phase aerobic oxidation of hydrocarbons: Influence of nanotube impurities

2019 ◽  
Vol 127 ◽  
pp. 245-251 ◽  
Author(s):  
Eldar Zeynalov ◽  
Norman S. Allen ◽  
Nazilya Salmanova ◽  
Vladimir Vishnyakov
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Aerobic Oxidation ◽  
Oxidation Of Hydrocarbons

Multi-walled Carbon Nanotubes Penetrate into Plant Cells and Affect the Growth of Onobrychis arenaria Seedlings

Acta Naturae ◽  
2011 ◽  
Vol 3 (1) ◽  
pp. 99-106 ◽  
Author(s):  
E A Smirnova ◽  
A A Gusev ◽  
O N Zaitseva ◽  
E M Lazareva ◽  
G E Onishchenko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Plant Cells ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes
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