The positive effect of water on acetaldehyde oxidation depended on the reaction temperature and MnO2 structure

AbstractConditions of polyaniline (PANI) nanotubes preparation were analyzed. Aniline was oxidized with ammonium peroxydisulfate in 0.4 M acetic acid. There are two subsequent oxidation steps and the products were collected after each of them. At pH > 3, neutral aniline molecules are oxidized to non-conducting aniline oligomers. These produce templates for the subsequent growth of PANI nanotubes, which takes place preferably at pH 2–3. At pH < 2, granular morphology of the conducting PANI is obtained. High final acidity of the medium should be avoided in the preparation of nanotubes, e.g., by reducing the amount of sulfuric acid which is a by-product. Reduction of the peroxydisulfate-to-aniline mole ratio was tested for this purpose in the present study. Lowering of the reaction temperature from 20°C to −4°C had a positive effect on the formation of nanotubes.

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Positive Effect of Water in Asymmetric Direct Aldol Reactions with Primary Amine Organocatalyst: Experimental and Computational Studies

Chemistry - An Asian Journal ◽

10.1002/asia.201500078 ◽

2015 ◽

Vol 10 (10) ◽

pp. 2112-2116 ◽

Cited By ~ 19

Author(s):

Shin A. Moteki ◽

Hiroki Maruyama ◽

Keiji Nakayama ◽

Hai-Bei Li ◽

Galina Petrova ◽

...

Keyword(s):

Primary Amine ◽

Aldol Reactions ◽

Computational Studies ◽

Effect Of Water ◽

Positive Effect

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Positive Effect of Water Vapor on CO Oxidation at Low Temperature over Pd/CeO2–TiO2 Catalyst

Catalysis Letters ◽

10.1007/s10562-008-9630-2 ◽

2008 ◽

Vol 126 (3-4) ◽

pp. 353-360 ◽

Cited By ~ 17

Author(s):

Feixue Liang ◽

Huaqing Zhu ◽

Zhangfeng Qin ◽

Hui Wang ◽

Guofu Wang ◽

...

Keyword(s):

Water Vapor ◽

Low Temperature ◽

Co Oxidation ◽

Tio2 Catalyst ◽

Effect Of Water ◽

Positive Effect

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Water absorption behavior of cellulosic fibres polymer composites: A review on its effects and remedies

Journal of Industrial Textiles ◽

10.1177/1528083720974424 ◽

2020 ◽

pp. 152808372097442

Author(s):

Parul Sahu ◽

MK Gupta

Keyword(s):

Water Absorption ◽

Polymer Composites ◽

Environmental Conditions ◽

Mechanical Performance ◽

Absorption Capacity ◽

Effect Of Water ◽

Negative Effect ◽

Cellulosic Fibres ◽

Kinetics Of ◽

Positive Effect

Recently, researchers and scientists are trying to overcome the environmental burden by using biocomposites in engineering applications as far as possible. The main source of biocomposites is cellulosic fibres which is a class of natural fibres. Instead of many advantages of cellulosic fibres, they and their polymer composites suffer from some limitations as well. The environmental conditions are one of the most important issues to degradation behavior of the cellulosic fibres polymer composites (CFPCs). Among the environmental conditions, water absorption is an important ground to degradation in the mechanical performance of the CFPCs, which resists them to be used in outdoor applications. Several studies have been presented on water absorption characteristics of cellulosic fibres and its polymer-based biocomposites. Further, the consequence of water uptake on the mechanical performance of biocomposites was also reported in many studies. In most of the cases, a negative effect of water absorption was observed, whereas in a few cases a positive effect was also seen. In the present study, mechanics and kinetics of water absorption for CFPCs are discussed. Further, a detailed literature review on water absorption of cellulosic fibres and their different types of polymer-based biocomposites has also been carried out. Furthermore, studies reported on the effect of water absorption on the mechanical properties were also systematically presented. Moreover, all the possible remedies to lower the water absorption capacity were also discussed in the present review paper.

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Preparation of Amino-Modified PAN Fibers with Triethylenetetramine as Aminating Reagents and Their Application inCO2Adsorption

Journal of Nanomaterials ◽

10.1155/2014/940908 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7

Author(s):

Wenbo Zhao ◽

Biao Liu ◽

Jian Chen

Keyword(s):

Porous Materials ◽

Adsorption Capacity ◽

Surface Area ◽

Reaction Temperature ◽

Weight Increase ◽

Alkali Content ◽

Effect Of Water ◽

Pan Fiber ◽

Water Amount ◽

Pan Fibers

Amino-modified polyacrylonitrile (AMPAN) fiber was synthesized by the reaction of polyacrylonitrile (PAN) fiber and triethylenetetramine (TETA) in the presence of water. The effect of water amount, reaction temperature, and time on the weight increase degree and alkali content of the AMPAN fiber was investigated in detail. The characterization results indicated that TETA could be grafted onto the surface of PAN fiber by this method. However, the highest adsorption capacity of the AMPAN fibers was only 0.09 g/g even at 15 bar and 50°C, which was much lower than the porous materials. The reason for this result may be related to its low surface area.

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Efficient Removal of Cr (VI) with Biochar and Optimized Parameters by Response Surface Methodology

Processes ◽

10.3390/pr9050889 ◽

2021 ◽

Vol 9 (5) ◽

pp. 889

Author(s):

Hao Peng ◽

Jing Guo ◽

Hongzhi Qiu ◽

Caiqiong Wang ◽

Chenyu Zhang ◽

...

Keyword(s):

Response Surface Methodology ◽

Reaction Time ◽

Response Surface ◽

Reaction Temperature ◽

Reduction Process ◽

Order Model ◽

Reaction Conditions ◽

Efficient Reduction ◽

Experimental Parameters ◽

Positive Effect

A highly efficient reduction process of Cr (VI) with biochar was conducted in this paper. The results showed that nearly 100% Cr (VI) was reduced at selected reaction conditions: Dosage of biochar at m (C)/m(Cr) = 3.0, reaction temperature of 90 °C, reaction time of60 min, and concentration of H2SO4 of 20 g/L. The reduction kinetics analysis demonstrated that the reduction of Cr (VI) fitted well with the pseudo-first-order model and the apparent activation energy was calculated to be 40.24 kJ/mol. Response surface methodology confirmed that all of the experimental parameters had a positive effect on the reduction of Cr (VI). The influence of each parameter on the reduction process followed the order: Dosage of biochar>concentration of H2SO4>reaction temperature >reaction time. This paper provides a versatile strategy for the treatment of wastewater containing Cr (VI) and shows a bright tomorrow for wastewater treatment.

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Efficient Removal of Cr (VI) with Biochar and Parameters Optimized by Response Surface Methodology

10.20944/preprints202103.0193.v1 ◽

2021 ◽

Author(s):

Hao Peng ◽

Jing Guo

Keyword(s):

Response Surface Methodology ◽

Reaction Time ◽

Response Surface ◽

Reaction Temperature ◽

Reduction Process ◽

Order Model ◽

Reaction Conditions ◽

Efficient Reduction ◽

Experimental Parameters ◽

Positive Effect

A highly efficient reduction process of Cr (VI) with biochar was conducted in this paper. The results showed that nearly 100% Cr (VI) was reduced at selected reaction conditions: the dosage of biochar at m (C)/m(Cr) = 3.0, reaction temperature of 90 ℃, reaction time at 60 min and concentration of H2SO4 of 20 g/L, respectively. The reduction kinetics analysis demonstrated that the reduction of Cr (VI) fitted well with the pseudo-first-order model and the apparent activation energy was calculated to 40.24 kJ/mol. Response surface methodology confirmed that all the experimental parameters had positive effect on the reduction of Cr (VI). The influence of each parameter on the reduction process followed the order: dosage of biochar> Concentration of H2SO4 > Reaction Temperature > Reaction Time. This paper provided a versatile strategy for treatment of wastewater containing Cr (VI) and showed a bright tomorrow for wastewater treatment.

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Effect of Water Cooling on Grain Structures and General Mechanical Properties of 2219-T6 Friction Stir Welded Joint

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.2986 ◽

2012 ◽

Vol 706-709 ◽

pp. 2986-2991

Author(s):

Hui Jie Liu ◽

H.J. Zhang ◽

L. Yu

Keyword(s):

Mechanical Properties ◽

Mechanical Analysis ◽

Water Cooling ◽

Temperature Level ◽

Friction Stir ◽

Effect Of Water ◽

Grain Structures ◽

Joint Properties ◽

External Water ◽

Positive Effect

Regarding the friction stir welding (FSW) of heat–treatable aluminum alloys, although the thermal flow does not cause any material fusion, it can still deteriorate the local mechanical properties of the joints due to coarsening or dissolution of the strengthening precipitates. Therefore, it is of significance and possible to improve the joint properties by controlling the temperature level. For this purpose, a 2219-T6 aluminum alloy was underwater friction stir welded in the present study, and the temperature histories, grain structures and the general mechanical properties of the joints were investigated in order to illuminate the effect of water cooling. The results reveal that the water cooling action can effectively control the temperature level in the joint. The recrystallized grains in the weld nugget zone (WNZ) are significantly refined under the water cooling effect. The mechanical analysis indicates that the tensile strength of the joint can be improved by 6% through the external water cooling action. Additionally, the underwater joint also exhibits superior bend and impact properties to the normal joint, indicating the positive effect of water cooling on the general mechanical properties of the joints.

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Non-Catalytic Dissolution of Biochar Obtained by Hydrothermal Carbonization of Sawdust in Hydrogen Donor Solvent

Energies ◽

10.3390/en14185890 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5890

Author(s):

Alla Krylova ◽

Kristina Krysanova ◽

Mayya Kulikova ◽

Albert Kulikov

Keyword(s):

Reaction Temperature ◽

Raw Materials ◽

Hydrothermal Carbonization ◽

Hydrogen Donor ◽

Hexane Fraction ◽

Thermal Dissolution ◽

Donor Solvent ◽

Liquid Products ◽

Different Temperatures ◽

Positive Effect

The production of fuel hydrocarbons from CO2-neutral raw materials is a promising task at present. The thermal dissolution of biochar obtained by the method of hydrothermal carbonization of sawdust was studied. The dissolution of biochar in tetralin (hydrogen donor solvent) was studied at different temperatures (350–450 °C) and with two types of dilution of the mixture with tetralin: 1/3 and 1/4. The process proceeded without a catalyst. It was found that the samples subjected to thermal dissolution at temperatures of 425–450 °C had the highest conversion and yield of liquid products. The reaction temperature also had a significant effect on the composition of liquid products. It was found that an increase in the reaction temperature led to a significant increase in benzenes, both in the direct and in the hexane fraction. A benzene yield of more than 50% was observed for both fractions at a temperature of 450 °C. It was also suggested that the possible positive effect of abietates on the homogenization of the reaction mixture contributed to high conversion in the process. The biochar/tetralin ratio effects the yield and composition of the liquid products as well. An increase in the tetralin concentration in the mixture during thermal dissolution led to an increase in the conversion and yield of hydrocarbon fractions for fuel purposes. This is undoubtedly due to the large amount of elemental hydrogen involved in the hydrogenation of the reaction mixture.

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The positive effect of water on photo-induced step transfer-addition & radical-termination (START) polymerization

RSC Advances ◽

10.1039/c7ra01925d ◽

2017 ◽

Vol 7 (29) ◽

pp. 17988-17996 ◽

Cited By ~ 4

Author(s):

Tianchi Xu ◽

Lifen Zhang ◽

Zhenping Cheng ◽

Xiulin Zhu

Keyword(s):

Effect Of Water ◽

Function Loss ◽

Positive Effect

In photo-induced Step Transfer-Addition & Radical-Termination (START) polymerization, the addition of water greatly enhanced the overall polymerization efficiency and inhibited the function loss (C–I).

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