scholarly journals Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media

2021 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Antun Barišić ◽  
Johannes Lützenkirchen ◽  
Nikol Bebić ◽  
Qinzhi Li ◽  
Khalil Hanna ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Media ◽  
Colloid Chemistry ◽  
Acid Base ◽  
Batch Type ◽  
Proton Charge ◽  
Salt Level ◽  
Isoelectric Points ◽  
Before And After ◽  
Inert Surfaces

We studied the charging of inert surfaces (polytetrafluoroethylene, i.e., PTFE; graphite; graphene; and hydrophobic silica) using classical colloid chemistry approaches. Potentiometric titrations showed that these surfaces acquired less charge from proton-related reactions than oxide minerals. The data from batch-type titrations for PTFE powder did not show an effect of ionic strength, which was also in contrast with results for classical colloids. In agreement with classical colloids, the electrokinetic results for inert surfaces showed the typical salt level dependence. In some cases, the point of zero net proton charge as determined from mass and tentatively from acid–base titration differed from isoelectric points, which has also been previously observed, for example by Chibowski and co-workers for ice electrolyte interfaces. Finally, we found no evidence for surface contaminations of our PTFE particles before and after immersion in aqueous solutions. Only in the presence of NaCl-containing solutions did cryo-XPS detect oxygen from water. We believe that our low isoelectric points for PTFE were not due to impurities. Moreover, the measured buffering at pH 3 could not be explained by sub-micromolar concentrations of contaminants. The most comprehensive explanation for the various sets of data is that hydroxide ion accumulation occurred at the interfaces between inert surfaces and aqueous solutions.

Sorption of Bisphenol A in Aqueous Solutions on Irradiated and as-Grown Multiwalled Carbon Nanotubes

2018 ◽  
Vol 69 (5) ◽  
pp. 1233-1239
Author(s):  
Raluca Madalina Senin ◽  
Ion Ion ◽  
Ovidiu Oprea ◽  
Rusandica Stoica ◽  
Rodica Ganea ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Bisphenol A ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Adsorption Process ◽  
Sorption Process ◽  
Multiwalled Carbon ◽  
Before And After ◽  
Kinetic Sorption

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.

THE SOLUBLE PROTEINS OF THE MUSCLE TISSUE OF THE HADDOCK

1931 ◽  
Vol 6 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J. F. LOGAN
Keyword(s):  
Sodium Chloride ◽  
Aqueous Solutions ◽  
Muscle Tissue ◽  
Soluble Protein ◽  
Potassium Phosphate ◽  
Extraction Methods ◽  
Water Soluble ◽  
Tabular Form ◽  
Water Soluble Protein ◽  
Isoelectric Points

As a contribution to the chemistry of muscle tissue, the solubility of the protein of haddock muscle in aqueous solutions of sodium chloride and neutral potassium phosphate, respectively, was determined. The results are expressed in tabular form and graphically in the form of solubility curves. A water-soluble protein and also a salt-soluble protein were isolated from dialyzed haddock muscle by extraction methods. These proteins were obtained in a comparatively pure condition by precipitation from solution in the region of their isoelectric points.

scholarly journals Speed Limits for Acid–Base Chemistry in Aqueous Solutions

2012 ◽  
Vol 66 (4) ◽  
pp. 182-186 ◽  
Author(s):  
Mateusz L. Donten ◽  
Joost VandeVondele ◽  
Peter Hamm
Keyword(s):  
Aqueous Solutions ◽  
Acid Base ◽  
Speed Limits

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

2016 ◽  
Vol 75 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Lucas Meili ◽  
Társila Santos da Silva ◽  
Daniely Carlos Henrique ◽  
João Inácio Soletti ◽  
Sandra Helena Vieira de Carvalho ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Experimental Design ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Fiber Diameter ◽  
Aqueous Media ◽  
Process Efficiency ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.

Temperature dependence of the acid–base and Ca2+-complexation equilibria of d-gluconate in hyperalkaline aqueous solutions

Polyhedron ◽  
2019 ◽  
Vol 158 ◽  
pp. 117-124 ◽  
Author(s):  
Ákos Buckó ◽  
Bence Kutus ◽  
Gábor Peintler ◽  
István Pálinkó ◽  
Pál Sipos
Keyword(s):  
Aqueous Solutions ◽  
Temperature Dependence ◽  
Acid Base ◽  
Complexation Equilibria

scholarly journals Acid-Base Transport and Control in Locust Hindgut: Artefacts Caused by Short-Circuit Current

1991 ◽  
Vol 155 (1) ◽  
pp. 455-467
Author(s):  
R. BRENT THOMSON ◽  
N. AUDSLEY ◽  
JOHN E. PHILLIPS
Keyword(s):  
Cyclic Amp ◽  
Acid Secretion ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Salt Bridges ◽  
Electrical Parameters ◽  
Acid Base ◽  
Before And After ◽  
And Control ◽  
Stimulation Of

The commonly used method of passing short-circuit current (Isc) across insect epithelia through Ag-AgCl electrodes, without the use of salt bridges, leads to significant OH− production at the cathode (lumen side) when high currents are applied. The alkalization of the lumen previously reported when cyclic AMP was added to short-circuited locust hindgut is a result of this phenomenon rather than cyclic-AMP-mediated stimulation of acid-base transport in the hindgut. When salt bridges are used to pass short-circuit current across locust hindgut, acid secretion (JH) into the lumen equals alkaline movement (JOH) to the haemocoel side, and JH is similar under both open- and short-circuit conditions. JH is similar (1.5 μequiv cm−2 h−1) in recta and ilea. Addition of cyclic AMP inhibits JH across the rectum by 42–66%, but has no effect on the ileum when salt bridges are used. Electrical parameters (Isc, Vt, Rt) reflecting hindgut Cl− transport (JCL) before and after stimulation with cyclic AMP are the same whether or not salt bridges are used. We found no evidence of any coupling between JCl and JH/JOH.

scholarly journals Recyclable glucose-derived palladium(0) nanoparticles as in situ-formed catalysts for cross-coupling reactions in aqueous media

RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16115-16121 ◽  
Author(s):  
Jason E. Camp ◽  
Jay J. Dunsford ◽  
Oliver S. G. Dacosta ◽  
Rebecca K. Blundell ◽  
James Adams ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Media ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions

Renewable sugar-derived palladium(0) nanoparticles (PdNPs) are effective as in situ formed catalysts for cross-coupling reactions in aqueous solutions.

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