Electrostatic repulsion as a mechanism in fouling of ultrafiltration membranes

2008 ◽  
Vol 58 (10) ◽  
pp. 1955-1961 ◽  
Author(s):  
Elizabeth Arkhangelsky ◽  
Inna Levitsky ◽  
Vitaly Gitis
Keyword(s):  
Ionic Strength ◽  
Zeta Potential ◽  
Organic Compounds ◽  
Organic Molecule ◽  
Size Exclusion ◽  
Electrostatic Repulsion ◽  
Hydrophobic Properties ◽  
Ultrafiltration Membranes ◽  
Water Parameters ◽  
Electrostatic Mechanism

Studies of electrostatic repulsion in ultrafiltration membranes are limited to applications of different organic compounds carrying a set of unique characteristics, or to changes of general water parameters such as ionic strength and pH. The proposed method of deliberate alteration of surface charge of organic molecule by succinylation or by guanidination provides an opportunity to selectively investigate the electrostatic mechanism without changing size or hydrophobic properties of investigated molecule. The approach was successfully implemented on BSA protein, and new inside into the mechanism of electrostatic mechanism was obtained. The electrostatic repulsion becomes important when zeta potential of the protein exceeded 20 mV, when before the threshold the interactions were mainly governed by size exclusion.

Adsorption of Organic Compounds on Refined Latvian Clay

2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka
Keyword(s):  
Methyl Orange ◽  
Zeta Potential ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Organic Compounds ◽  
Clay Mineral ◽  
Rhodamine B ◽  
Ph Value ◽  
Ftir Spectra ◽  
Ph Values

Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.

The influence of ionic strength and organic compounds on nanoparticle TiO2 (n-TiO2) aggregation

Chemosphere ◽  
2016 ◽  
Vol 154 ◽  
pp. 187-193 ◽  
Author(s):  
Jaewoong Lee ◽  
Shannon L. Bartelt-Hunt ◽  
Yusong Li ◽  
Erica Jeanne Gilrein
Keyword(s):  
Ionic Strength ◽  
Organic Compounds

Stacking-dependent tetracolour luminescence and mechanofluorochromic properties of an isoquinoline derivative with aggregation-induced emission

2022 ◽  
Author(s):  
Yating Chen ◽  
Bo Wang ◽  
yunxiang Lei ◽  
Yun-Bing Zhou ◽  
Yang Guo ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Molecule ◽  
Aggregation Induced Emission ◽  
Crystalline Structures ◽  
Isoquinoline Derivative

Although nearly one-third of organic compounds have polymorphism, more than three polymorphs with definite crystalline structures in an organic molecule are very rare. Herein, an aggregation-induced-emission-active isoquinoline derivative containing ethyl...

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.

scholarly journals Testing the capabilities of the Mars Organic Molecule Analyser (MOMA) chromatographic columns for the separation of organic compounds on Mars

2020 ◽  
Vol 186 ◽  
pp. 104903
Author(s):  
Melissa Guzman ◽  
Cyril Szopa ◽  
Caroline Freissinet ◽  
Arnaud Buch ◽  
Fabien Stalport ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Molecule ◽  
Chromatographic Columns

scholarly journals The Effect of the Ionic Strength of Process Water on the Interaction of Talc and CMC: Implications of Recirculated Water on Floatable Gangue Depression

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 231 ◽  
Author(s):  
Malibongwe Manono ◽  
Kirsten Corin ◽  
Jenny Wiese
Keyword(s):  
Ionic Strength ◽  
Zeta Potential ◽  
Saline Water ◽  
Process Water ◽  
Gangue Mineral ◽  
Mineral Surface ◽  
Base Interaction ◽  
Long Run ◽  
Complex Process ◽  
Closed Water

Previous studies speculate that hydroxo species present in flotation pulps at pH > 9, particularly those of polyvalent cations, selectively adsorb onto gangue minerals. Such species supposedly enhance the depressive action of carboxymethyl cellulose (CMC) onto gangue via an acid-base interaction between the positively charged mineral surface and the negatively charged CMC molecule. Thus, the hydrophilicity of gangue minerals is enhanced, preventing the dilution of the concentrate. However, as there is little evidence to support these claims for complex process waters of increasing ionic strength, it is important to investigate. Adsorption data and mineral surface charge analyses provide a fundamental understanding of how electrolytes and their ionic strengths affect gangue mineral-depressant adsorption. It is strongly anticipated that decoupling these effects will allow process operators to tailor their process water quality needs towards best flotation operating regimes and, in the long run, effect closed water circuits. Thus, using talc as a proxy for naturally floatable gangue common in sulfidic Cu–Ni–PGM ores, this work investigates the influence of the ionic strength of process water on the adsorption of CMC onto talc for a perspective on how saline water in sulfidic ores would affect the behavior and therefore management of floatable gangue. In the presence of CMC, the microflotation results showed that the rate of talc recovery decreased with increasing ionic strength of process water. Increases in ionic strength resulted in an increase in the adsorption of CMC onto talc. Talc particles proved to have been more coagulated at higher ionic strength since the settling time decreased with increasing ionic strength. Furthermore, the zeta potential of talc particles became less negative at higher ionic strengths of process water. It is thus proposed that increases in the ionic strength of process water increased the zeta potential of talc particles, enhancing the adsorption of CMC onto talc. This in turn created a more coagulated nature on talc particles, increasing their hydrophilicity and thereby retarding floatability.

scholarly journals Cetylpyridinium chloride produces increased zeta-potential on Salmonella Typhimurium cells, a mechanism of the pathogen’s inactivation

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yagmur Yegin ◽  
Jun K. Oh ◽  
Mustafa Akbulut ◽  
Thomas Taylor
Keyword(s):  
Zeta Potential ◽  
Salmonella Typhimurium ◽  
Membrane Lipids ◽  
Cetylpyridinium Chloride ◽  
Membrane Integrity ◽  
Electrostatic Repulsion ◽  
Phase Interaction ◽  
Human Pathogens ◽  
Two Phase ◽  
Oppositely Charged

Abstract Cetylpyridinium chloride (CPC) is a quaternary ammonium sanitizer approved for fresh poultry animal carcass sanitization from microbial human pathogens, such as Salmonella enterica. Nonetheless, the interactions of CPC with Salmonella cells, and the mechanism of the sanitizer’s neutralization by lecithin remains largely unknown. This study aimed to investigate the interaction of CPC with lecithin and Salmonella Typhimurium to determine the interactions of the sanitizer and neutralizer impacting the bacterium’s survival. Application of 0.8% CPC is proposed to produce loss of microbial membrane integrity with loss of electrostatic repulsion between individual cells, resulting in the eventual emulsification of membrane lipids with cytoplasmic contents leakage. Our findings point to a two-phase interaction between CPC and lecithin impacting S. Typhimurium survival. The first consists of electrostatic attraction and charge neutralization between oppositely charged components of pathogen cell and CPC. The second involves formation of aggregates between sanitizer and pathogen, or between sanitizer, pathogen membrane lipids, and lecithin.

Assimilable organic carbon and biodegradable organic carbon removal by nanofiltration: full and bench-scale evaluation

2001 ◽  
Vol 1 (4) ◽  
pp. 35-42 ◽  
Author(s):  
I.C. Escobar ◽  
A.A. Randall ◽  
S.K. Hong
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Organic Carbon ◽  
Effective Means ◽  
High Hardness ◽  
Full Scale ◽  
Significant Fraction ◽  
Size Exclusion ◽  
Small Molecular Weight ◽  
Bench Scale

The main objective of this research was to evaluate the effectiveness of nanofiltration (NF) at full and bench scale for controlling AOC and BDOC, which are the main indicators of biological stability of the finished potable water. One of the major observations from full-scale operation was that nanofiltration was a very effective means to reduce BDOC, but conversely, did not reject a significant fraction of AOC. The high BDOC rejection by nanofiltration (NF) membranes at full scale can be explained by size exclusion, since a significant fraction of BDOC consists of compounds, such as humic and fulvic acids, which are larger than the pores of NF membranes (molecular-weight cutoff ≈200 daltons). The insignificant AOC rejection observed in full-scale systems was probably due to the low pH, high hardness, and high ionic strength (TDS) of the raw water. Bench scale tests using simulated waters clearly demonstrated that AOC removal by NF membranes decreases markedly with decreasing pH, and increasing hardness and ionic strength, implying that electrostatic repulsion plays a significant role in AOC removal mechanisms. These solution environments repress the electrostatic interaction between charged organic compounds and membranes, allowing passage of small molecular weight compounds and thus reducing AOC rejection.

scholarly journals Influence of surface modification by sulfuric acid on coking coal's adsorption of coking wastewater

2017 ◽  
Vol 76 (3) ◽  
pp. 555-566 ◽  
Author(s):  
Lihui Gao ◽  
Hong Wen ◽  
Quanzhi Tian ◽  
Yongtian Wang ◽  
Guosheng Li
Keyword(s):  
Sulfuric Acid ◽  
Zeta Potential ◽  
Surface Area ◽  
Pore Volume ◽  
Ash Content ◽  
Raw Material ◽  
Acid Activation ◽  
Coking Wastewater ◽  
Hydrophobic Properties ◽  
Coking Coal

Coking coal, the raw material of a coke plant, was applied to the adsorption of coking wastewater. In this study, coking coal was directly treated with sulfuric acid to improve its surface properties and adsorption ability. Acid treatment was carried out at various concentrations, by varying from 0.001 to 1 mol/L. The samples were characterized by ash content analysis, scanning electron microscope (SEM), N2 adsorption-desorption analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), wettability analysis, and zeta potential analysis. These results demonstrated that H+ could react with inorganic minerals, which resulted in a significant variation of the chemical composition and the structure of coal surface. Furthermore, both the ash content and the surface content of O = C-O, C = O and C-O groups declined gradually as the concentration of sulfuric acid increased, while the surface area and pore volume of micropore, the lipophilic and hydrophobic properties, and zeta potential magnitude increased, resulting in enhanced hydrophobic and Van der Waals' forces between the fine coal and organic pollutants. Characterization modification showed a better performance in adsorption, the removal rate enhanced from 23% to 42% after treated by 1 mol/L sulfuric acid. It was concluded that the acid activation modified the lipophilic and hydrophobic properties, the surface charge properties, surface area and pore volume, the content of oxygen functional groups, all of which could be potentially useful in wastewater adsorption.

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