scholarly journals Preparation of Graphite Oxide Containing Different Oxygen-Containing Functional Groups and the Study of Ammonia Gas Sensitivity

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3745 ◽  
Author(s):  
Liming Luo ◽  
Tongjiang Peng ◽  
Mingliang Yuan ◽  
Hongjuan Sun ◽  
Shichan Dai ◽  
...  
Keyword(s):  
Moisture Content ◽  
Functional Groups ◽  
Reaction Temperature ◽  
Graphite Oxide ◽  
Photoelectron Spectroscopy ◽  
Raw Material ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Gas Sensitivity ◽  
X Ray

A series of graphite oxide samples were prepared using the modified Hummers method. Flake graphite was used as the raw material and the reaction temperature of the aqueous solution was changed (0 °C, 30 °C, 50 °C, 60 °C, 70 °C, 80 °C, and 100 °C). X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectral analysis, X-ray photoelectron spectroscopy, and contact angle tests were performed to characterize the structure, chemical bonding, type, and content of oxygen-containing functional groups of the graphite oxide samples. The results showed that the type and content of each oxygen-containing functional group could be controlled by changing the reaction temperature with the addition of water. As the temperature of the system increased, the degree of oxidation of the graphite oxide samples first increased and then decreased. Too high a temperature (100 °C) of the system led to the formation of epoxy groups by the decomposition of some hydroxyl groups in the samples, causing the reduction of oxygen-containing functional groups between the graphite layers, poor hydrophilic properties, and low moisture content. When the system temperature was 50 °C, the interlayer spacing of the graphite oxide samples was at its highest, the graphite was completely oxidized (C/O = 1.85), and the oxygen-containing functional groups were mainly composed of hydroxyl groups (accounting for approximately 28.88% of the total oxygen-containing functional groups). The high content of hydroxyl and carboxyl groups had good hydrophilic ability and showed the highest moisture content. The sample at 50 °C had better sensitivity to ammonia because of its high hydroxyl group and carboxyl group content, with the sample showing an excellent profile when the ammonia concentration was 20–60 ppm.

scholarly journals The The Effect of Concentration of Citric Acid Solution on Extraction of Pectin from Watermelon Albedo

KOVALEN ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 194-201
Author(s):  
Tifa Paramitha ◽  
Tika Paramitha
Keyword(s):  
Citric Acid ◽  
Moisture Content ◽  
Acid Solution ◽  
Functional Groups ◽  
Acid Content ◽  
Galacturonic Acid ◽  
Raw Material ◽  
Hydroxyl Group ◽  
Main Process ◽  
Citric Acid Solution

Watermelon albedo or the white flesh of watermelon rind contains pectin with high enough content. In this study was conducted the extraction of pectin from watermelon albedo by the liquid-solid extraction method. The citric acid solution was used as a solvent with concentrations varied by 4%, 7%, and 10%. The research steps include the pretreatment of raw material, the extraction, the posttreatment of extraction, and the analysis of pectin. The pretreatment aimed to reduce water content and reduce the size of raw material. The extraction process was the main process in which pectin dissolution occurred in the citric acid solvent. Furthermore, the posttreatment of extraction aimed to obtain pectin solid with the addition of ethanol. The final step was the analysis, including pectin yield, moisture content, methoxyl content, galacturonic acid content, and pectin functional group. Based on research obtained, an increase in the concentration of citric acid increased pectin yield, methoxyl content, and galacturonic acid content. The moisture content of pectin decreased with the increasing concentration of citric acid. Pectin yield, moisture content, methoxyl content, galacturonic acid content resulted from 10% concentration of citric acid solvent are 8.356%, 19.748%, 7.029%, and 69.048%, respectively. Based on FTIR analysis, the functional groups contained in pectin are hydroxyl group, methyl group, carbonyl group, and ether group. This functional groups are main constituents of pectin structure.

scholarly journals Study on Adsorption Properties of Modified Corn Cob Activated Carbon for Mercury Ion

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Physical Adsorption ◽  
Raw Material ◽  
Order Kinetic ◽  
Mercury Ions ◽  
Corn Cob ◽  
Adsorption Time ◽  
X Ray

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.

scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Graphene Nanosheets ◽  
Electrochemical Exfoliation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mb Adsorption

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

Thermally Induced Superlow Friction of DLC Films in Ambient Air

2018 ◽  
Vol 37 (8) ◽  
pp. 725-731 ◽  
Author(s):  
Qunfeng Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ambient Air ◽  
Friction Model ◽  
Repulsive Force ◽  
Hydroxyl Group ◽  
Thermally Induced ◽  
X Ray ◽  
Thermally Activated ◽  
Charged Interface ◽  
Positively Charged

AbstractThermally induced superlow friction (0.008) of diamond-like carbon (DLC) films was achieved in ambient air in the present work. Raman and XPS (X-ray Photoelectron Spectroscopy) measurements and analyses show that superlow friction of the annealed DLC films is involved in the transformation of sp3 to sp2 hybridized carbon during annealing and the tribochemical reactions during sliding. The thermally activated graphitization and oxidation of the annealed DLC films in ambient air is beneficial to form the positively charged interface and achieve the stable superlow friction. A friction model was developed and applied to explain superlow friction, which is attributed to Van de Waals force between graphite layers and the repulsive force between hydroxyl group of graphite oxide and hydrogen terminated DLC films surface.

Physical and Thermal Properties of Chitosan

2014 ◽  
Vol 979 ◽  
pp. 315-318 ◽  
Author(s):  
W. Siriprom ◽  
K. Chantarasunthon ◽  
K. Teanchai
Keyword(s):  
Physical Properties ◽  
Thermo Gravimetric Analysis ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Biodegradable Films ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Good Agreement

This work aims at characterizing the thermal and physical properties of chitosan. The samples were evaluated for potentiality to use as raw material for biodegradable films raw material. Their thermal and physical properties have been also discussed in detail which Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), Energy Dispersive X-Ray Fluorescence (EDXRF) and X-Ray Diffraction (XRD), respectively. The result of the XRD pattern indicated the sample has amorphous-crystalline structure and FTIR results confirmed the formation of intermolecular hydrogen bonding between the amino and hydroxyl groups of the sample. In good agreement between the EDXRF and TGA results, noticed that the removal of moisture and volatile material.

scholarly journals Polyarylene Ether Nitrile and Barium Titanate Nanocomposite Plasticized by Carboxylated Zinc Phthalocyanine Buffer

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 418 ◽  
Author(s):  
Shuning Liu ◽  
Chenchen Liu ◽  
Changyu Liu ◽  
Ling Tu ◽  
Yong You ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Barium Titanate ◽  
Photoelectron Spectroscopy ◽  
Energy Dispersive Spectrometer ◽  
Composite Films ◽  
Zinc Phthalocyanine ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Polyarylene Ether Nitrile ◽  
High Dielectric

Barium titanate (BT) and polyarylene ether nitrile (PEN) nanocomposites with enhanced dielectric properties were obtained by using carboxylatedzinc phthalocyanine (ZnPc-COOH) buffer as the plasticizer. Carboxylated zinc phthalocyanine, prepared through hydrolyzing ZnPc in NaOH solution, reacted with the hydroxyl groups on the peripheral of hydrogen peroxide treated BT (BT-OH) yielding core-shell structured BT@ZnPc. Thermogravimetric analysis (TGA), transmission electron microscopy (TEM), TEM energy dispersive spectrometer mapping, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) demonstrated successful preparation of BT@ZnPc. The fabricated BT@ZnPc was incorporated into the PEN matrix through the solution casting method. Rheological measurements demonstrated that the ZnPc-COOH buffer can improve the compatibility between BT and PEN effectively. With the existence of the ZnPc-COOH buffer, the prepared BT@ZnPc/PEN nanocomposites exhibit a high dielectric constant of 5.94 and low dielectric loss (0.016 at 1000 Hz). BT@ZnPc/PEN dielectric composite films can be easily prepared, presenting great application prospects in the field of organic film capacitors.

scholarly journals X-Ray Photoelectron Spectroscopy Study of Silane Coupling Agents/Basalt Fiber Interface

2011 ◽  
Vol 236-238 ◽  
pp. 1467-1471 ◽  
Author(s):  
Ya Lan Liu ◽  
Shi Jie Shen ◽  
Li Zhang ◽  
Ling Min Shao
Keyword(s):  
Coupling Agent ◽  
Photoelectron Spectroscopy ◽  
Silane Coupling Agent ◽  
Basalt Fiber ◽  
Fiber Surface ◽  
Chemical Compositions ◽  
Hydroxyl Groups ◽  
Silane Coupling Agents ◽  
X Ray ◽  
Silane Coupling

In this paper, two types of fiber surface treatment methods, namely heat treatment and chemical coupling, were used to improve the basalt fiber surface properties. The basalt fiber surface was heated under 250Celsius degree for 30minites, and then was treated by silane coupling agent ethanol solution with different concentrations. X-ray photoelectron spectroscopy (XPS) was utilized to study the surface chemical compositions of basalt fiber after treatments. The XPS analysis indicated that chemical bonds between basalt fiber and KH-550 have occurred, and silanols were adsorbed to the surface of basalt fibers by an ether linkage between the silanols and the hydroxyl groups of the fibers. When the concentration of KH-550 is 0.8wt%, the optimal bonding condition is formed between basalt fiber and silane coupling agent.

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