scholarly journals EFFECT OF ELECTROLYTES ON ELECTROSURFACE PROPERTIES OF MICROCRYSTALLINE CELLU-LOSE PARTICLES

2021 ◽  
pp. 55-60
Author(s):  
Aleksandr Valentinovich Lorentsson ◽  
Nadezhda Leonidovna Koroleva ◽  
Yuriy Mitrofanovich Chernoberezhskii
Keyword(s):  
Isoelectric Point ◽  
Specific Adsorption ◽  
Point Of Zero Charge ◽  
Ph Values ◽  
Zero Charge ◽  
Anions And Cations ◽  
Acidic Region ◽  
Charge Point ◽  
Positively Charged ◽  
Specific Adsorption Of Ions

The electrical surface properties (specific surface charge of particles - σ0, point of zero charge – pHPZC, electrokinetic potential - ζ and position of isoelectric point - pHIEP) of dispersions of microcrystalline cellulose (MCC) in aqueous solutions of H2SO4, NaOH, Na2SO4 and TiOSO4 were investigated. Significant effects of specific adsorption of anions and cations on pHPZC and pHIEP have been demonstrated. The isoelectric point of the MCC particles in the H2SO4 solution is at pH 2.0, while the zero charge point in 5·10-4 M solution Na2SO4 at pH 5.6. An explanation of the observed effects is given. Possible schemes of the structure of the electrical double layer at different pH values, taking into account specific adsorption of ions in the Stern layer, are given. The introduction of TiOSO4 (10-5 mol/dm3) shifts the position of IEP to a less acidic region (pHIEP 4.5) due to the specific adsorption of positively charged TiOSO4 hydrolysis products particles.

scholarly journals Adsorption studies of Mo and Vonto ferrihydrite

2008 ◽  
Vol 72 (1) ◽  
pp. 385-388 ◽  
Author(s):  
L. Brinza ◽  
L. G. Benning ◽  
P. J. Statham
Keyword(s):  
Binary System ◽  
Binding Sites ◽  
Point Of Zero Charge ◽  
High Uptake ◽  
Adsorption Efficiency ◽  
Adsorption Studies ◽  
Ph Values ◽  
Zero Charge ◽  
Kinetics Of

AbstractIn this paper, the kinetics of Mo and V (100 μM) uptake on ferrihydrite (FHY) were evaluated in batch, mono-sorbate systems at pH between 4 and 9, and in bi-sorbate systems in the presence of P (100 μM) at pH 7. In the Mo and V single-sorbate experiments, 100% adsorption was observed at pH values below 6 and 8, respectively. Above the point of zero charge (PZC = 7.97) of FHY, the adsorption efficiency for Mo dropped dramatically (20% at pH 8) while V showed high uptake efficiencies even at pH 9 (60% efficiency). The results from the bi-sorbate experiments (Mo-P and V-P) showed that at pH 7, P out-competed (97%) Mo for binding sites on FHY, while in the V-P binary system only ∼44% of the binding sites are occupied by P with the remaining sites being occupied by V.

Influence of Pulp pH on Flotation of Fluorite and Calcite

2012 ◽  
Vol 616-618 ◽  
pp. 614-618
Author(s):  
Wen Juan Zhao ◽  
Dian Wen Liu ◽  
Hong Shuai Li ◽  
Qi Cheng Feng ◽  
Guo Yin Xu ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Fatty Acid ◽  
Significant Role ◽  
Ph Value ◽  
Froth Flotation ◽  
Point Of Zero Charge ◽  
Zeta Potentials ◽  
Ph Values ◽  
Zero Charge ◽  
Optimum Ph

Pulp pH value plays a significant role in the froth flotation. Especially in the flotation of fluorite, the performance of flotation will be affected greatly by pulp pH. MO, a new kind of modified fatty acid was used as collector, and H2SO4 and Na2CO3 were used to regulate pulp pH in the experiment. The mechanism of influence of pulp pH on flotation of fluorite and calcite was investigated by such parameters as fluorite recovery, zeta potentials and the infrared spectroscopy about minerals at different pulp pH values. As is shown in the results, the point of zero charge(PZC) of fluorite is pH=9.5 and the PZC of calcite is pH=8.5. The optimum pulp pH of the flotation of fluorite and calcite is determined as 9.5~10 and 8~9 respectively. pH value should be controlled above 9 to depress calcite. Finally, 9.5~10 was determined as the optimum pH to float the fluorite from the calcium-containing fluorite ores.

Point of Zero Charge, Isoelectric Point and Aggregation of Phyllosilicate Minerals

2010 ◽  
Vol 49 (4) ◽  
pp. 405-410 ◽  
Author(s):  
M. Alvarez-Silva ◽  
M. Mirnezami ◽  
A. Uribe-Salas ◽  
J.A. Finch
Keyword(s):  
Isoelectric Point ◽  
Point Of Zero Charge ◽  
Zero Charge

scholarly journals Removal of estrone in water and wastewater by photocatalysis: a systematic review

2019 ◽  
Vol 14 (1) ◽  
pp. 18-32
Author(s):  
Leadina Sánchez-Barbosa ◽  
Paul Steven Villagran-Sánchez ◽  
Sabino Alexander Armenise-Gil
Keyword(s):  
Systematic Review ◽  
Isoelectric Point ◽  
Removal Rate ◽  
Pure Water ◽  
Endocrine Disrupting Compounds ◽  
Normal Function ◽  
Experimental Conditions ◽  
Ultra Pure Water ◽  
Zero Charge ◽  
Charge Point

Introduction. Estrone (E1) is a type of natural hormone estrogen which is produced mainly by the ovaries, adipose tissue, fibroblasts skin, placenta, and brain. E1 is part of the so called endocrine disrupting compounds (EDC), a type of organic contaminants present at trace levels in the water that can interfere with the normal function of the endocrine systems in humans and wildlife. Objective. To describe the experimental conditions that have given the best results in the degradation or photocatalytic removal of estrone referenced in the scientific literature using photocatalysis. Materials and methods used a systematic review, directed by search criteria, inclusion and exclusion, to extract information concerning the experimental conditions. Results. The results show that a) a higher removal rate is achieved with a higher load of the catalyst or with a modified catalyst; b) the use of radiation at 254 nm is convenient in matrices containing mixtures of compounds; c) the ideal pH will be lower than the isoelectric point or the zero charge point of the catalyst; d) the removal rate is faster in ultra-pure water than in synthetic or real wastewater. The study was limited to the identification of investigations in which the degradation was performed using TiO2 as a catalyst and the articles fulfilled the inclusion and exclusion criteria. Conclusions. The main contribution of this research is the identification of the best conditions for the degradation of the pollutant in different conditions and matrices, which is the basis for the work of the research group. The removal of estrone is greater when the catalyst load is increased or by the use of a modified one; or when the pH is lower than the isoelectric point or the zero charge point of the catalyst; higher in ultra-pure water than in wastewater.

scholarly journals Influence of organic cations sorption on the point of zero charge of natural zeolite

2009 ◽  
Vol 63 (4) ◽  
pp. 325-330 ◽  
Author(s):  
Milan Kragovic ◽  
Aleksandra Dakovic ◽  
Sonja Milicevic ◽  
Zivko Sekulic ◽  
Slobodan Milonjic
Keyword(s):  
Ion Exchange ◽  
Natural Zeolite ◽  
Point Of Zero Charge ◽  
Organic Cations ◽  
Ammonium Ions ◽  
Inorganic Cations ◽  
Ph Values ◽  
Zero Charge ◽  
Basic Characteristics

In this paper, the results of the surface modification of natural zeolite with different amounts (2, 5 and 10 mmol M+/100g) of octadecyldimethylbenzyl ammonium ions (ODMBA) are presented. The obtained organozeolites were denoted as OZ-2, OZ-5 and OZ-10. The degree of ion exchange was followed by determination of amounts of inorganic cations released from zeolite. Results confirmed that reaction between ODMBA and starting zeolite has occurred via ion exchange mechanism. The obtained value for point of zero charge, pHpzc, of natural zeolite was 6.8?0.1, while for OZ-2, OZ-5 and OZ-10 pHpzc was 7.0?0.1. Below the pHpzc, the surfaces of materials are positive while at pH values higher than pHpzc their surfaces are negative. Compared to the pHpzc of natural zeolite, no significant differences in pHpzc was observed for all three organozeolites indicating that obtained products have similar functional groups with similar acid and basic characteristics as starting zeolite. The pHpzc was not dependent on the amount of ODMBA ions at the zeolitic surface and the value of pHpzc for all investigated sorbents is the same for all three electrolyte concentrations indicating that the pHpzc of each material is independent of the ionic strength of KNO3.

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