The influence of negatively charged silica nanoparticles on the surface properties of anionic surfactants: electrostatic repulsion or the effect of ionic strength?

2020 ◽  
Vol 22 (4) ◽  
pp. 2238-2248 ◽  
Author(s):  
Milad Eftekhari ◽  
Karin Schwarzenberger ◽  
Aliyar Javadi ◽  
Kerstin Eckert
Keyword(s):  
Ionic Strength ◽  
Silica Nanoparticles ◽  
Surface Properties ◽  
Surface Activity ◽  
Aqueous Phase ◽  
Anionic Surfactants ◽  
Electrostatic Repulsion ◽  
Charged Nanoparticles

The presence of negatively charged nanoparticles affects the surface activity of anionic surfactants in an aqueous phase. This effect is mainly caused by the change in ionic strength of the system resulted from the addition of nanoparticles.

Extraction of hafnium(IV) with organophosphorus reagents from solutions of mineral acids mixtures

1979 ◽  
Vol 44 (12) ◽  
pp. 3656-3664
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola ◽  
Rostislav Kolouch
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Synergic Effect ◽  
Salting Out ◽  
Initial Concentration ◽  
Mixed Complexes ◽  
Synergic Extraction ◽  
Mineral Acids

Extraction of hafnium(IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids for constant ionic strength, I = 2, 4, 6, or 8, and for cHf 4 . 10-4 mol l-1. The organic phase was constituted by solutions of some acidic or neutral organophosphorus reagents or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. A pronounced synergic extraction of hafnium proceeds only on applying organophosphorus reagents from an aqueous phase whose acidity is not lower than 3M-(HClO4 + HNO3) or 5M-(HClO4 + HCl). The synergic effect was not affected markedly by a variation of the initial concentration of hafnium in the range 1 . 10-8 -4 .10-4 mol l-1, it lowered with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H+ ions. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.

Extraction of hafnium by means of some substituted 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-ones

1981 ◽  
Vol 46 (8) ◽  
pp. 1901-1905 ◽  
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Dissociation Constants ◽  
Parent Substance ◽  
Benzoyl Group ◽  
Extraction Constants ◽  
Extraction Parameters ◽  
Substituted 1

Distribution between aqueous phase and benzene or chloroform was studied for 1-phenyl-3-methyl-4-benzoylpyrazol-5-ones with 2-chloro, 4-methoxy, 3-nitro, and 4-nitro substitution in the benzoyl group (ionic strength of the aqueous phase 0.1) and for hafnium in their presence (ionic strength 2.0). The distribution and dissociation constants of the reagents and the extraction constants of their hafnium complexes were determined. Hafnium was found to be extracted as the HfA4 species. The extraction parameters of the derivatives in question do not differ substantially from those of the parent substance.

scholarly journals Influence of intracrystalline ionic strength in MFI zeolites on aqueous phase dehydration of methylcyclohexanols

2021 ◽  
Author(s):  
Lara Milaković ◽  
Peter Hintermeier ◽  
Yue Liu ◽  
Eszter Barath ◽  
Johannes Lercher
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Mfi Zeolites

EUROPIUM OXALATE ION ASSOCIATION IN WATER

1966 ◽  
Vol 44 (24) ◽  
pp. 3057-3062 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Sodium Acetate ◽  
Ion Association ◽  
Sodium Oxalate ◽  
Aqueous Sodium ◽  
Oxalate Ion

The partitioning of radiotracer 152/151Eu between aqueous sodium oxalate (Na2L) solutions and toluene solutions of thenoyltrifluoroacetone (HTTA) has been studied as a function of the oxalate concentration. The pH of the aqueous phase was controlled by means of sodium acetate – acetic acid mixtures and the ionic strength (I) by NaCl or NaClO4.At low ionic strengths (~0.05) and [L] ~10−4 M EuL+ formed, but at I = 0.95 and [L] ~10−3 M EuL2− also formed. Stability constants for the 1:1 and 1:2 (metal:ligand) complexes are reported.The magnitudes of the stepwise stability constant ratios are discussed.

scholarly journals Comparative study on microbial enhanced oil recovery using mannosylerithritol lipids and surfactin

2016 ◽  
Vol 4 (2) ◽  
pp. 69 ◽  
Author(s):  
Cristiano José de Andrade ◽  
Gláucia Maria Pastore
Keyword(s):  
Ionic Strength ◽  
Enhanced Oil Recovery ◽  
Surface Activity ◽  
Oil Recovery ◽  
Extreme Conditions ◽  
Microbial Enhanced Oil Recovery ◽  
Oil Displacement ◽  
Recovery Processes ◽  
Emulsification Index ◽  
Good Surface

Worldwide oil production has been declining. Microbial enhanced oil recovery is one of the most important tertiary recovery processes. The aim of this work was to evaluate the surface activity properties of surfactin and mannosylerithritol lipids-B. In our previous studies, surfactin and mannosylerithritol lipids were produced using cassava wastewater as substrate and then purified by ultrafiltration. Thus, this work extends our previous studies. Experiments of surface activity under extreme conditions (temperature, ionic strength and pH), oil displacement, removal of oil from sand and emulsification index were carried out. Central composite rotational design was performed under extreme conditions of temperature, pH and ionic strength. The results indicated that ionic strength significantly affected the surface activity of surfactin. On the other hand, ionic strength, but also temperature and pH significantly affected the tenso activity of mannosylerithritol lipids-B. Regarding oil displacement test, mannosylerithritol lipids-B showed higher clear zone than surfactin. Contrary, in the experiments of removal of crude oil from sand, minimal differences were observed between surfactin and mannosylerithritol lipids-B. Therefore, both surfactin and mannosylerithritol lipids-B showed good surface activity under extreme conditions. In addition, it seems that mannosylerithritol lipids-B is subtly better than surfactin for microbial enhanced oil recovery.

scholarly journals Bridging interactions of proteins with silica nanoparticles: The influence of pH, ionic strength and protein concentration

Soft Matter ◽  
2014 ◽  
Vol 10 (5) ◽  
pp. 718-728 ◽  
Author(s):  
Bhuvnesh Bharti ◽  
Jens Meissner ◽  
Sabine H. L. Klapp ◽  
Gerhard H. Findenegg
Keyword(s):  
Ionic Strength ◽  
Silica Nanoparticles ◽  
Protein Concentration ◽  
Influence Of Ph

scholarly journals Dynamic Surface Properties of Mixed Dispersions of Silica Nanoparticles and Lysozyme

2019 ◽  
Vol 123 (22) ◽  
pp. 4803-4812 ◽  
Author(s):  
Olga Yu. Milyaeva ◽  
Richard A. Campbell ◽  
Georgi Gochev ◽  
Giuseppe Loglio ◽  
Shi-Yow Lin ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Surface Properties ◽  
Dynamic Surface
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