scholarly journals Organic-inorganic membranes for filtration of corn distillery

2016 ◽  
pp. 153-165 ◽  
Author(s):  
Valeriy Myronchuk ◽  
Yuliya Dzyazko ◽  
Yurii Zmievskii ◽  
Anatoliy Ukrainets ◽  
Alexander Bildukevich ◽  
...  
Keyword(s):  
Active Layer ◽  
Colloidal Particles ◽  
Deionized Water ◽  
Point Of View ◽  
Inorganic Membranes ◽  
Secondary Porosity ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Freundlich Equation ◽  
Zirconium Hydrophosphate

Organic-inorganic membranes were obtained by modification of polymer microfiltration membrane with inorganic ion-exchangers, which form secondary porosity inside macroporous substrate (zirconium hydrophosphate) or simultaneously in the macroporous substrate and active layer, depending of the particle size (from ?50 nm up to several microns). Precipitation of the inorganic constituent is considered from the point of view of Ostwald-Freundlich equation. Such processes as pressing test in deionized water and filtration of corn distillery at 1-6 bar were investigated. Theoretical model allowing to establish fouling mechanism, was applied. It was found that the particles both in the substrate and active layer prevent fouling of the membrane with organics and provide rejection of colloidal particles.

scholarly journals MEMBRANES MODIFIED BY NANOCOMPOSITES OF HYDRATED ZIRCONIUM DIOXIDE AND OXIDIZED GRAPHENE

2020 ◽  
Vol 86 (4) ◽  
pp. 91-107
Author(s):  
Liudmyla Rozhdestvenskaya ◽  
Kateryna Kudelko ◽  
Volodymyr Ogenko ◽  
Alexandr Bildyukevich ◽  
Tatiana Plisko ◽  
...  
Keyword(s):  
Active Layer ◽  
Ion Exchanger ◽  
Protein Solutions ◽  
Inorganic Membranes ◽  
Organic Substances ◽  
Permeate Flux ◽  
Inorganic Ion ◽  
Hydrated Zirconium Dioxide ◽  
Hydrated Zirconium ◽  
Na Ions

Organo-inorganic membranes were obtained by impregnating ultrafiltration membranes with a composite modifier - zirconium (IV) hydroxide, containing oxidized graphene (0.5 wt.%). The modifier was precipitated in the active layer of the membrane, thus forming a "secondary active layer". The layer thickness calculated according to the Kozeny-Carman equation is 0.66-1.38 μm. A thinner layer is formed in the membrane with smaller pore size. The diffusion coefficients of Li+ and Na+ ions were found. The effect of the modifier on the retention ability relative to hardness ions (10-14%) and to protein compounds (95-98%) during filtration is determined. Mathematical modeling of the dependence of the permeate flux via time showed that the presence of ion exchanger particles in the polymer active layer prevents the accumulation of organic substances in the pores. Therefore, only the outer surface of the membrane is contaminated, and the precipitate can be easily removed mechanically. It was shown that insertion of a carbon component into pores of the membranes, in addition to the inorganic ion-exchangers, is advisable only in the case of a finely porous active layer. In particular, the performance of the initial polymer membrane (20 dm3/m3.h)) and the selectivity to the calibration substance with a molecular weight of 40 kDa (99%) serve as expediency criteria. In comparison with a membrane modified only with inorganic ion exchanger, selectivity is increased, the rate of filtration of protein solutions is higher, and resistance to contamination by organic substances is achieved. The results are discussed from the view of the hydrophobic-hydrophilic properties of oxidized graphene.

scholarly journals Sorption of U(VI) compounds on inorganic composites containing partially unzipped multiwalled carbon nanotubes

2021 ◽  
Vol 12 (1) ◽  
pp. 18-31
Author(s):  
O. V. Perlova ◽  
◽  
I. S. Ivanova ◽  
Yu. S. Dzyazko ◽  
M. O. Danilov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ion Exchange ◽  
Zirconium Dioxide ◽  
Solution Ph ◽  
Multiwalled Carbon ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Component Solution ◽  
Pseudo Second Order ◽  
Zirconium Hydrophosphate

Unlike ion-exchange resins, inorganic sorbents possess high selectivity towards heavy metal ions and stability against ionizing radiation. However, sorption on these materials is rather slow. Moreover, sorption capacity strongly depends on the solution pH. In order to improve sorption properties of inorganic ion-exchangers, composites containing advanced carbon materials are obtained. Regularities of sorption of U(VI) compounds from low-concentrated aqueous solutions (up to 0.1 mmol dm–3 of uranium) on hydrated zirconium dioxide and zirconium hydrophosphate are considered. The sorbents were modified with partially unzipped multiwalled carbon nanotubes (PUMWCNTs). Sorption isotherms were obtained and analyzed. They obey Dubinin-Radushkevich model indicating sorption sites, a size of which is comparable with that of ions being sorbed. As found, the sorption mechanism is ion exchange. The effect of the solution pH on the sorption rate of U(VI) ions and capacity of inorganic ion-exchangers and their composites has been considered. Carbon additions increase sorption capacity of zirconium dioxide and zirconium hydrophosphate, when the initial pH of one-component solution is 3–4 and 5–7 respectively. Under these conditions, U(VI)-containing cations are removed from the solution practically completely. The rate of sorption obeys the model of chemical reaction of pseudo-second order, when uranium is removed from one-component solution. PUMWCNTs slow down sorption on zirconium dioxide and accelerate it on zirconium hydrophosphate. The dependence of the pseudo second order equation constants on the pH of U(VI) solutions was analyzed. The reaction of the first order occurs, when the solution contains also Ca2+ and Mg2+ ions. Regeneration was carried out using HNO3 and NaHCO3 solutions: the rate-determining stage of desorption is particle diffusion. It has been shown that one-component ZHP can be regenerated with a NaHCO3 solution practically completely. The most suitable solution for U(VI) desorption from ZHP-PUMWCNTs composite is a 1 M HNO3 solution.

scholarly journals Modeling and theoretical description of magnetic hybrid materials—bridging from meso- to macro-scales

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Andreas M. Menzel ◽  
Hartmut Löwen
Keyword(s):  
Colloidal Particles ◽  
Colloidal Particle ◽  
Theoretical Description ◽  
Point Of View ◽  
Material Behavior ◽  
Theoretical Point ◽  
Mechanical Stiffness ◽  
Theoretical Approaches ◽  
Theoretical Predictions ◽  
Particle Level

Abstract Magnetic gels and elastomers consist of magnetic or magnetizable colloidal particles embedded in an elastic polymeric matrix. Outstanding properties of these materials comprise reversible changes in their mechanical stiffness or magnetostrictive distortions under the influence of external magnetic fields. To understand such types of overall material behavior from a theoretical point of view, it is essential to characterize the substances starting from the discrete colloidal particle level. It turns out that the macroscopic material response depends sensitively on the mesoscopic particle arrangement. We have utilized and developed several theoretical approaches to this end, allowing us both to reproduce experimental observations and to make theoretical predictions. Our hope is that both these paths help to further stimulate the interest in these fascinating materials.

Instrumental neutron activation analysis of lanthanides and coexisting elements in monazite samples and group separation using synthesized inorganic ion exchangers

2020 ◽  
Vol 108 (11) ◽  
pp. 901-912
Author(s):  
Mohamed A. Ghamry ◽  
Fatma H. El-Sweify ◽  
Alaa El-Din A. Abdel-Fattah ◽  
Shorouk M. Aly ◽  
Mohamed F. El-Shahat
Keyword(s):  
Neutron Activation Analysis ◽  
Instrumental Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Group Separation ◽  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Lanthanide Elements ◽  
Instrumental Neutron Activation

AbstractSamples of Egyptian monazite ore obtained from black sand of Abu-Khashaba, Rashied (Rosetta) area on the Mediterranean Sea coast were analyzed for some lanthanides and coexisting elements using instrumental neutron activation analysis (INAA). The analyses were carried out qualitatively and quantitatively for the elements Ce, Nd, Eu, Gd, Tb, Yb and Sc, La as well as the accompanying elements Co, Cr, Fe, Hf, Nb, Zn, Zr in addition to the actinides Th and U; whereas after relatively longer decay time the following lanthanide elements were analyzed: Ce, Nd, Eu, Gd, Tb, Yb and Sc, beside the accompanying elements Co, Cr, Fe, Hf, Nb, Zn, Zr and Th. Two certified reference materials (CRM) were used in this study. For sorption studies, radioactive isotopes 141Ce, 160Tb, 169Yb, 95Zr, 181Hf, and 95Nb were prepared by neutron irradiation to trace the adsorption behaviors of their corresponding elements under certain conditions. Furthermore, radiochemical separation of the analyzed elements in the irradiated monazite samples in sulfuric acid solutions was carried out. Ion exchange technique was applied under static and dynamic conditions and the employed inorganic ion exchangers were locally synthesized and characterized using FT-IR and scanning electron microscopy (SEM) tools. Good group separation of the analyzed lanthanide elements from the accompanying elements was achieved.

Inorganic ion exchangers—IX

1974 ◽  
Vol 36 (10) ◽  
pp. 2377-2383 ◽  
Author(s):  
Sten Ahrland ◽  
Nils-Olof Björk ◽  
Robert Blessing ◽  
Richard Herman
Keyword(s):  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion

Amine cobalt(II) hexacyanoferrate(II) compounds as inorganic ion exchangers

1968 ◽  
Vol 40 (7) ◽  
pp. 1135-1136 ◽  
Author(s):  
Richard B. Hahn ◽  
Henry C. Klein
Keyword(s):  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion
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