Quantitative Measurement of Functional Groups on Nanocarbon Allotropes Surface by Boehm Titration

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Hernández-Ortiz ◽  
J. D. Lozano-López ◽  
S. M. Durón ◽  
M. Galván-Valencia ◽  
Y. Estevez-Martínez ◽  
...  
Keyword(s):  
Functional Groups ◽  
Concentration Ratio ◽  
Quantitative Measurement ◽  
Carboxyl Group ◽  
Multiwalled Carbon ◽  
Derivative Method ◽  
Order Of Magnitude ◽  
Treated Carbon ◽  
Second Derivative Method ◽  
Vulcan Carbon

Various nanocarbons (NCs) were used to study their surface groups under standardized Bohem titration, including: multiwalled carbon nanotube (CNT), graphene (G), Vulcan carbon (VC), and nanodiamond (ND). Endpoint-measured titration using second derivative method to quantify carboxylic, lactonic, and phenolic groups created on treated carbon surfaces shows a high precision comparable to other recent reports and with errors of 1 order of magnitude lower. The results exhibit major concentration of carboxyl group increased after the NCs were oxidized compared to the amount of other functional groups like phenols and lactonic groups. It is important highlight, the concentration ratio of carboxyl group with VC:VC-O was showed at 1:77, exhibited a major result regarding other NCs which exhibited ratios of 1:4.5, 1:1.4, and 1:2.5 for ND:ND-O, CNT:CNT-O, and G:G-O, respectively. It is concluded that VC is a NC that competes and excels in its capacity of oxidation with respect to the popular NCs as CNT, graphene (G), and ND.

DETERMINATION OF THE SURFACE FUNCTIONALITY OF NANOCARBON ALLOTROPES BY BOEHM TITRATION

2019 ◽  
Vol 27 (08) ◽  
pp. 1950190
Author(s):  
M. HERNANDEZ-ORTIZ ◽  
H. A. DURÁN-MUÑOZ ◽  
J. D. LOZANO-LÓPEZ ◽  
S. M. DURÓN ◽  
M. GALVÁN-VALENCIA ◽  
...  
Keyword(s):  
Functional Groups ◽  
Titration Curve ◽  
Surface Functionality ◽  
Multi Walled Carbon Nanotube ◽  
Carboxylic Groups ◽  
Order Of Magnitude ◽  
Second Derivative Method ◽  
Vulcan Carbon ◽  
Titration Technique

Critical point (CP) in a titration curve to quantify carboxylic, lactonic, and phenolic groups on multi-walled carbon nanotube (CNT) and Vulcan carbon (VC). Titration technique used was Boehm type and tipping point measurement from titration curve was done by second derivative method. The calculation functional groups on nanocarbons (NCs) presents lowest uncertainty previously published. An order of [Formula: see text]meq/g is the precision of the values obtained, one order of magnitude below reported. Both NCs display a high quantity of carboxylic groups created after being treated with regard to the other functional groups generated, mainly for functionalized Vulcan carbon VC-F.

scholarly journals CVD Synthesis, Functionalization and CO2 Adsorption Attributes of Multiwalled Carbon Nanotubes

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 634 ◽  
Author(s):  
Shazia Shukrullah ◽  
Muhammad Yasin Naz ◽  
Norani M. Mohamed ◽  
Khalid A. Ibrahim ◽  
Nasser M. AbdEl-Salam ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Functional Groups ◽  
Co2 Adsorption ◽  
Breakthrough Curves ◽  
Multiwalled Carbon ◽  
Amine Functionalized ◽  
Co2 Adsorption Capacity

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.

Anisotropic Thermal Diffusivity of Aligned Multiwalled Carbon Nanotube Arrays

2002 ◽  
Author(s):  
Theodorian Borca-Tasciuc ◽  
Claudiu L. Hapenciuc ◽  
Bingqing Wei ◽  
Robert Vajtai ◽  
Pulickel M. Ajayan
Keyword(s):  
Carbon Nanotube ◽  
Thermal Diffusivity ◽  
Front Surface ◽  
Multiwalled Carbon Nanotube ◽  
Back Surface ◽  
Multiwalled Carbon ◽  
Conduction Model ◽  
Beam Incident ◽  
Order Of Magnitude ◽  
Photothermoelectric Technique

This work employs a photothermoelectric technique to measure the anisotropic thermal diffusivity of an aligned multiwalled carbon nanotube array. A modulated laser beam incident to the front surface of the sample creates a thermal wave which is detected by a fast responding thermocouple formed between the back surface of the sample and the tip of a sharp metallic probe. The anisotropic thermal diffusivity values are obtained by fitting the radial and frequency dependent thermal signals with an anisotropic heat conduction model. The room temperature thermal diffusivity measured perpendicular to the alignment direction is 0.246×10−5m2/s, an order of magnitude smaller than thermal diffusivity along the CNTs alignment direction 4.4×10−5m2/s. However, the thermal diffusivity of the aligned multiwalled CNT is two orders of magnitude smaller than expected for an individual multiwalled CNT.

Application of Boehm Titration for the Quantitative Measurement of Soot Oxygen Functional Groups

2020 ◽  
Vol 34 (6) ◽  
pp. 7363-7372 ◽  
Author(s):  
Hui Wu ◽  
Wei Lu ◽  
Yiwei Chen ◽  
Pu Zhang ◽  
Xiaobei Cheng
Keyword(s):  
Functional Groups ◽  
Quantitative Measurement ◽  
Oxygen Functional Groups ◽  
Boehm Titration

Different Spectrophotometric and Chromatographic Methods for Determination of Mepivacaine and Its Toxic Impurity

2017 ◽  
Vol 100 (5) ◽  
pp. 1392-1399 ◽  
Author(s):  
Nada S Abdelwahab ◽  
Nehal F Fared ◽  
Mohamed Elagawany ◽  
Esraa H Abdelmomen
Keyword(s):  
Particle Size ◽  
Stationary Phase ◽  
Second Derivative ◽  
Spectrophotometric Measurement ◽  
Spectrophotometric Methods ◽  
Derivative Method ◽  
Tlc Plates ◽  
Second Derivative Method ◽  
Developing System

Abstract Stability-indicating spectrophotometric, TLC-densitometric, and ultra-performance LC (UPLC) methods were developed for the determination of mepivacaine HCl (MEP) in the presence of its toxic impurity, 2,6-dimethylanaline (DMA). Different spectrophotometric methods were developed for the determination of MEP and DMA. In a dual-wavelength method combined with direct spectrophotometric measurement, the absorbancedifference between 221.4 and 240 nm was used for MEPmeasurements, whereas the absorbance at 283 nm was used for measuring DMA in the binary mixture. In the second-derivative method, amplitudes at 272.2 and 232.6 nm were recorded and used for the determination of MEP and DMA, respectively. The developed TLC-densitometric method depended on chromatographic separation using silica gel 60 F254 TLC plates as a stationary phase and methanol–water–acetic acid (9 + 1 + 0.1, v/v/v) as a developing system, with UV scanning at 230 nm. The developed UPLC method depended on separation using a C18 column (250 × 4.6 mm id, 5 μm particle size) as a stationary phase and acetonitrile–water (40 + 60, v/v; pH 4 with phosphoric acid) as a mobilephase at a flow rate of 0.4 mL/min, with UV detection at 215 nm. The chromatographic run time was approximately 1 min. The proposed methods were validated with respect to International Conference on Harmonization guidelines regarding precision, accuracy, ruggedness, robustness, and specificity.

Usefulness of a Curve Fitting Method in the Analysis of Overlapping Overtones and Combinations of CH Stretching Modes

2002 ◽  
Vol 10 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Yukiteru Katsumoto ◽  
Daisuke Adachi ◽  
Harumi Sato ◽  
Yukihiro Ozaki
Keyword(s):  
Curve Fitting ◽  
Second Derivative ◽  
Downward Shift ◽  
Fitting Method ◽  
Derivative Method ◽  
Structural Differences ◽  
Alcohol Mixtures ◽  
Curve Fitting Method ◽  
Second Derivative Method ◽  
Water Alcohol

This paper reports the usefulness of a curve fitting method in the analysis of NIR spectra. NIR spectra in the 7500–5500 cm−1 (1333–1818 nm) region were measured for water–methanol, water–ethanol and water–1-propanol mixtures with alcohol concentrations of 0–100 wt% at 25°C. The 6000–5600 cm−1 (1667–1786 nm) region, where the overtones and combinations of CH3 and CH2 stretching modes are expected to appear, shows significant band shifts with the increase in the alcohol content. To analyse the concentration-dependent spectral changes, a curve fitting method was utilised, and the results were compared with those obtained previously by a second derivative method. It was found that the first overtones of CH3 asymmetric and symmetric stretching modes of alcohols show a downward shift by about 15–30 cm−1 with the increase in the concentration of alcohols. The shifts are much larger for water–methanol mixtures than for water–ethanol and water–1-propanol mixtures. The first overtones and combinations of CH2 stretching modes of ethanol and 1-propanol also show a small downward shift. These shifts support our previous conclusion that there is an intermolecular “CH⃛O” interaction between the methyl group and water in the water–alcohol mixtures. The curve fitting method provided more feasible results for the band shifts than the second derivative method. It was revealed from the curve fitting method that the first overtone of the CH3 asymmetric stretching mode of water–methanol, water–ethanol and water–1-propanol mixtures shows different concentration-dependent plots. The first overtone of CH3 asymmetric stretching mode of water–methanol mixtures shifts more rapidly in the high methanol concentration range while that of water–1-propanol concentration shifts more markedly in the low 1-propanol concentration range. That of water–ethanol mixtures shows an intermediate trend. Based upon these differences structural differences among the three kinds of water–alcohol mixtures are discussed.

Spectral fingerprinting of structural defects in plasma-treated carbon nanotubes

2003 ◽  
Vol 18 (10) ◽  
pp. 2515-2521 ◽  
Author(s):  
Nirupama Chakrapani ◽  
Seamus Curran ◽  
Bingqing Wei ◽  
Pulickel M. Ajayan ◽  
Alvaro Carrillo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Plasma Etching ◽  
Photoelectron Spectroscopy ◽  
Morphological Changes ◽  
Structural Defects ◽  
Vibrational Modes ◽  
Multiwalled Carbon ◽  
Systematic Analysis ◽  
Treated Carbon ◽  
The Relationship

Controlled introduction of defects into aligned multiwalled carbon nanotubes (MWCNTs) was achieved by time-dependent plasma etching. The subsequent morphological changes in MWCNTs have been fingerprinted using Raman and x-ray photoelectron spectroscopy, by which induction of defects by functionalization was confirmed. We found that the introduction of defects along the nanotube body affects all Raman vibrational modes. A systematic analysis of the relationship between D, D′, D*, and G modes leads us to believe that no one peak can be used as an accurate standard for estimation of defects in nanotubes.

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