Determination and correlation of solubility of thiamine nitrate in water+ethanol mixtures and aqueous solution with different pH values from 278.15K to 303.15K

2015 ◽  
Vol 400 ◽  
pp. 53-61 ◽  
Author(s):  
Haisheng Wang ◽  
Yujia Qin ◽  
Dandan Han ◽  
Xiaona Li ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ph Values

scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

Effects of Surface Properties and Solvent PH Values on the Adsorption/Desorption Abilities of Mesoporous SBA-15 to Methylene Blue Molecules

2012 ◽  
Vol 518-523 ◽  
pp. 352-355
Author(s):  
Hui Liu ◽  
Hong Liang Li ◽  
Meng Xue Wang ◽  
Jing Jing Sang ◽  
Xiu Song Zhao
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Properties ◽  
Weak Base ◽  
Adsorption Ability ◽  
Ph Values ◽  
Model Molecule ◽  
Adsorption Desorption

Methylene blue (MB) was used as model molecule to investigate the effects of surface properties and solvent pH values on the adsorption and desorption (or release) behaviors of mesoporous SBA-15 materials. It was found that the treatment of SBA-15 with a pH 7.8 aqueous solution can enhance the adsorption rate and capacity in comparison with the pristine SBA-15. The effect of pH values on MB releasing from the weak base treated SBA-15 and the pristine one have been studied and been compared in pH values range from 0.5 to 7.0. Both of them showed a maximum releasing rate at about pH 2 and all of the treated SBA-15 samples showed a higher releasing quantity than the pristine ones. The influence mechanisms of base treatment on the adsorption ability and that of pH values on the releasing properties of SBA-15 samples have been analyzed and been discussed based on the composition, the morphology, the surface area and pore size distribution and adsorption/desorption measurements.

scholarly journals Succinic acid in aqueous solution: connecting microscopic surface composition and macroscopic surface tension

2014 ◽  
Vol 16 (39) ◽  
pp. 21486-21495 ◽  
Author(s):  
Josephina Werner ◽  
Jan Julin ◽  
Maryam Dalirian ◽  
Nønne L. Prisle ◽  
Gunnar Öhrwall ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Succinic Acid ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Md Simulations ◽  
Vapor Interface ◽  
X Ray ◽  
Ph Values ◽  
Microscopic Surface

The water–vapor interface of aqueous solutions of succinic acid, where pH values and bulk concentrations were varied, has been studied using surface sensitive X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations.

Proteolysis of αs1-casein by chymosin: influence of pH and urea

1977 ◽  
Vol 44 (3) ◽  
pp. 533-540 ◽  
Author(s):  
D. M. Mulvihill ◽  
P. F. Fox
Keyword(s):  
Aqueous Solution ◽  
The State ◽  
Ph Values ◽  
Influence Of Ph ◽  
Hydrolysis Of

SummaryThe specificity of chymosin on αs1-casein was shown to be dependent on the reaction pH and on the state of aggregation of the substrate. In aqueous solution αs1-casein was optimally hydrolysed to αs1-I at pH 5·8; if the casein was solubilized in the isoelectric region by the use of 5 M-urea, optimum proteolysis occurred at pH 2·8. Hydrolysis of αs1-I to yield αs1-II, αs1-III and αs1-IV occurred at pH values > 5·8 in the presence or absence of urea. In the isoelectric region αs1-II, αs1-III and αs1-IV were not formed in the absence of urea where the substrate was aggregated: instead a peptide αs1-V was produced; at the same pH and using urea as a solubilizing agent αs1-II, αs1-III and αs1-IV were formed together with a further peptide αs1-VI.

Removal of Phosphate Ions from Aqueous Solution Using Anthracite

2012 ◽  
Vol 60 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Mohammad Arifur Rahman ◽  
Tamanna Azam ◽  
A. M. Shafiqul Alam
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Flow Rate ◽  
Cost Effective ◽  
Phosphate Concentration ◽  
Phosphate Solution ◽  
Adsorption Study ◽  
Adsorption Column ◽  
Ph Values ◽  
Phosphate Ions

Anthracite was used as an adsorbent to remove excess phosphate from wastewater. Anthracite used in the present study is environmentally friendly and of cost effective. The adsorption study was carried out using different particle size of adsorbents, different concentration of phosphate solution ranging from 25.0 mg/L to 100.0 mg/L, different pH values ranging from 0.5 to 11.5 along with different adsorbent amount from 1.0 g to 5.0 g. Flow rate was also varied in the range of 0.6 mL/min to 1.8 mL/min. Adsorption column methods show the optimum removal of phosphate under the following conditions: initial phosphate concentration 25 mg/L, initial volume 25.0 mL, flow rate 1.0 mL/min adsorbent amount 2.0 g, particle size, < 90?m. This removal method may provide a solution to the removal phosphate from wastewater in Bangladesh as well as other countries of the world.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11490 Dhaka Univ. J. Sci. 60(2): 181-184, 2012 (July)

Ultrasonic Formation of Copper/Iron Graphene Oxide for Ketorolac Delivery

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940072
Author(s):  
D. Radziuk ◽  
L. Mikhnavets ◽  
L. Tabulina ◽  
V. Labunov ◽  
M. Vorokhta ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Decay Constant ◽  
Decay Curve ◽  
Ambient Conditions ◽  
Iron Compounds ◽  
Ph Values ◽  
Curve Fit ◽  
Modified Graphene Oxide ◽  
Modified Graphene

New accessible sonochemical methods were developed for the functionalization of synthesized graphene oxide (GO) with copper/iron compounds and drug intercalation into their structure in aqueous solution at ambient conditions by using ultrasound (20[Formula: see text]kHz) treatment. The sonochemical formation mechanism of a new nanomaterial was revealed through the structural analysis of three types of nanocomposites: (i) copper@graphene oxide, (ii) copper/iron@graphene oxide and (iii) iron@graphene oxide. Unique copper/iron-modified graphene oxide nanocomposites can be used as nanocarriers for the anti-inflammatory drug (ketorolac) delivery in aqueous solution due to the reduced submicron size and enlarged surface area. Disintegration of the ultrasonically intercalated ketorolac followed the exponential decay curve fit at higher pH values of the aqueous solution with a higher decay constant observed in copper/iron-modified graphene oxide nanocomposites.

scholarly journals Photoinduced Transformation of Carbon Monoxide in Aqueous Solution

1988 ◽  
Vol 43 (5) ◽  
pp. 430-434
Author(s):  
Hyoung Ryun Park ◽  
Nikola Getoff
Keyword(s):  
Aqueous Solution ◽  
Carbon Monoxide ◽  
Product Formation ◽  
Quantum Yields ◽  
Ph Values ◽  
Probable Reaction Mechanism ◽  
Probable Reaction ◽  
Photoinduced Transformation ◽  
Vacuum Uv Radiation ◽  
Vacuum Uv

Abstract The photoinduced conversion of CO in aqueous solution under the influence of vacuum-uv radiation at λ = 185 nm has been investigated at pH values ranging from 2 to 13. Formaldehyde, glyoxal, carboxylic acids and small amounts of glycol were determined as final products. Initial quantum yields for product formation have been determined. A probable reaction mechanism is presented.

Conductometric Pulse Radiolysis Study on the Reaction of the Solvated Electron with 5-Bromouracil in Aqueous Solutions at Different pH Values

1974 ◽  
Vol 29 (1-2) ◽  
pp. 86-88b ◽  
Author(s):  
Burkhard O. Wagner ◽  
Herbert Klever ◽  
Dietrich Schulte-Frohlinde
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Rate Constant ◽  
Pulse Radiolysis ◽  
Solvated Electron ◽  
Ph Values

To study the reaction of the solvated electron with 5-bromouracil an aqueous solution has been examined by conductometric pulse radiolysis at pH values between 4.68 and 8.74. Alcohol was added to scavenge the hydrogen atom and the hydroxyl radical. G(Br—) = (2.64 ± 0.08)/100 eV was found to be independent of the pH. The mobility of the bromouracil mono-anion was measured to be (2.7 ± 0.2) 10-4 cm2 V-1 s-1 at 20°C, and the rate constant of reaction (3b) was determined to be k(H+ BrUr-) = (2.3 ± 0.2) 1010 I mole-1 s-1*.

The Adsorption Mechanism of Sodium Lignosulfonate on Al2O3 Particle in the Aqueous Solution

2012 ◽  
Vol 550-553 ◽  
pp. 1120-1123
Author(s):  
Rong Li ◽  
Dong Jie Yang ◽  
Wen Yuan Guo ◽  
Xue Qing Qiu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Driving Force ◽  
Adsorption Mechanism ◽  
Hydrophobic Interactions ◽  
Adsorption Properties ◽  
Sodium Lignosulfonate ◽  
Ph Values ◽  
Electrostatic And Hydrophobic Interactions ◽  
Monolayer Coverage

The adsorption properties of sodium lignosulfonate (SL) on Al2O3 particles under different pH values have been investigated. Results show that at low pHs, SL adsorbs on the Al2O3 particles in the form of aggregate as dosage of SL increases; at high pHs, the adsorption is approximately monolayer coverage. With pH values ranging from 3 to 11, the adsorption results are found to be not significantly affected by the addition of urea, ruling out the hydrogen bond as the controlling factor. The paper demonstrates that the main driving force of adsorption is considered as the synergistic effect of electrostatic and hydrophobic interactions when pH pHIEP with additives of Na2SO4 and NaCl.

Adsorptive Removal of Ni(II) Ions from Aqueous Solution by Polyacrylic Acid/Attapulgite Composite Hydrogels

2017 ◽  
Vol 727 ◽  
pp. 859-865 ◽  
Author(s):  
Yi Wei Zheng ◽  
Wen Wen Tao ◽  
Gui Fang Zhang ◽  
Chao Lv ◽  
Yi Ping Zhao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Polyacrylic Acid ◽  
Swelling Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorptive Removal ◽  
Composite Hydrogels ◽  
Ph Values ◽  
Ft Ir

Polyacrylic acid/attapulgite (PAA/ATP) composite hydrogels used for removal of heavy metal ions from aqueous solution was synthesized via radical polymerization with acrylic acid (AA) and attapulgite (ATP) modified by hydrochloric acid as adsorbent. Chemical composition of the modified ATP was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) and the morphology of the PAA/ATP hydrogels was characterized by scanning electron microscope (SEM), respectively. The swelling ratio, pH-sensitivity and adsorption performance of Ni (II) ions of the composite hydrogels were studied. The results showed the swelling ratio of the PAA/ATP composite hydrogels was higher than that of PAA hydrogels and the composite hydrogels displayed sensitivity to pH values with a sharp increase of swelling ratio when the pH values increased from 4 to 6. Comparing with PAA hydrogels, the composite hydrogels obtained a larger adsorption capacity of Ni (II) ions, the average adsorption capacity could reach 72.8 mg/g and adsorption ratio could reach 84%.

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