The Adsorption of Bilirubin from Aqueous Solution onto Solid Cholestyramine and Polyvinylpyrrolidone

1982 ◽  
Vol 5 (6) ◽  
pp. 373-378 ◽  
Author(s):  
D.S. Henning ◽  
G.R. Brown ◽  
L.E. St-Pierre
Keyword(s):  
Aqueous Solution ◽  
Visible Spectrum ◽  
Specific Interactions

Shifts in the visible spectrum of aqueous bilirubin (BR) resulting from the addition of soluble polyvinylpyrrolidone (PVP) suggest specific interactions. Hence, isotherms were determined for the adsorption of BR from aqueous solution onto solid, cross-linked PVP and onto cholestyramine (CA) (used as a reference adsorbent) at 0, 10, 20 and 25°C. Although adsorption onto PVP reaches equilibrium values more rapidly than for CA, the latter adsorbent has a larger capacity. Furthermore the isotherms for PVP are independent of temperature while those for CA show an increase in BR adsorbed with an increase in temperature.

Optimization of the electrochemical pre-concentration of trivalent lanthanum from aqueous media

2016 ◽  
Vol 104 (10) ◽  
Author(s):  
Jamie L. Doyle ◽  
Sue B. Clark
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Processing Time ◽  
Aqueous Media ◽  
Basic Mechanism ◽  
Specific Interactions ◽  
Film Electrode ◽  
Optimal Conditions ◽  
Applied Potential ◽  
Mercury Film Electrode

AbstractElectrochemical pre-concentration has been shown to effectively increase sample sensitivity and decrease processing time; however, the basic mechanism and optimal conditions of the technique remain unknown, specifically for lanthanides. To gain a better understanding of the mechanism of action, the aqueous solution conditions required to maximize the electrochemical pre-concentration of lanthanum (La) were studied. Parameters investigated included pH, applied potential, and ionic strength. To further optimize and elucidate the mechanism of lanthanide pre-concentration, specific interactions of lanthanum with the mercury film electrode were studied. Three possible mechanisms were proposed based on preliminary observations, including ligand bridging, hydroxide formation, and amalgamation.

scholarly journals One-step Green Preparation of Nano-silver Aqueous Solution, Characterization, and Its Antibacterial Potential for Cut Carnation Flowers

2021 ◽  
Author(s):  
Zhenpei Pang ◽  
Hongmei Li ◽  
Guidong Lin ◽  
Yunhao Sun ◽  
Hongjun Zhou ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ph Value ◽  
Visible Spectrum ◽  
Inhibitory Effect ◽  
Ion Source ◽  
Cut Flowers ◽  
Environmental Friendliness ◽  
Nano Silver ◽  
Strong Inhibitory Effect ◽  
One Step

Abstract The green synthesis of nano-silver (NS) has gained increasing attention owing to its cost-effectiveness and environmental friendliness. Herein, we have described a novel one-step green preparation method of stable NS aqueous solution using Tollens reagent as the silver ion source, D-fructose as the reduction agent, and polyvinyl pyrrolidone (PVP) as the stabilizing and capping agent. The optimum preparation parameters were 40 mL 10 g L−1 PVP, 100 mL 0.116 mol L−1 D-fructose, and 200 mL 0.001 mol L−1 Tollens at a reaction temperature of 25 °C for 2 h. The prepared NS solution had a pH value of 7.10, with approximately spherical NS particles in the range of 13.95–87.36 nm. The resulting NS solution was stable under normal temperature, boiling water bath, and acidic environment; however, it did not exhibit stability under an alkaline environment. The NS solution had a remarkable absorption peak at 410 nm in its ultraviolet visible spectrum. Moreover, it exerted strong inhibitory effect on the growth of the bacteria isolated from the vase water of cut carnation ‘Prince’ flowers. These findings indicate that the obtained NS aqueous solution is potentially a practical and effective antibacterial agent for preserving cut carnations and other cut flowers.

Antimicrobial screening of silver nanoparticles synthesized by marine cyanobacterium Phormidium formosum

2020 ◽  
Author(s):  
Reham G. Elkomy .
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Chemical Properties ◽  
Visible Spectrum ◽  
Antimicrobial Effect ◽  
Inhibition Zone ◽  
Aqueous System ◽  
Human Pathogens ◽  
Trans Form ◽  
Transmission Electron

Background and Objectives: Nanoparticles are widely used in various fields such as electronics, cosmetics, water purifica- tion, biomedical and biotechnology. Biosynthesis of nanoparticles using biological agents have gained much attention in the area of nanotechnology in the last few decades because of cost effective, non-toxic, and eco-friendly. Algae have been used to reduce metal ions and subsequently for the biosynthesis of nanoparticles. Materials and Methods: Silver nanoparticles (AgNPs) have been biosynthesized by Phormidium formosum isolated from Mediterranean Sea coast Egypt in an aqueous system. An aqueous solution of silver ions was treated with alive biomass of P. formousm for the formation of AgNPs. The physio-chemical properties of synthesized silver nanoparticles were studied using analytical techniques such as UV-Vis spectrophotometer, transmission electron microscopy (TEM), and Fourier Trans- form Infrared Spectroscopy (FTIR).  The antimicrobial effect of synthesized silver nanoparticles was also tested on several microorganisms by measuring the inhibition zone. Results: These nanoparticles showed an absorption peak at λmax 437 nm in the UV-visible spectrum, corresponding to the Surface Plasmon Resonance of AgNPs. The transmission electron micrographs of nanoparticles in an aqueous solution showed production of silver nanoparticles synthesized by P. formosum. The obtained AgNPs are spherical in shape with a size ranging from 1.83 nm to 26.15nm. The Fourier transmittance infrared spectrum (FTIR) confirms the presence of bio component in alive biomass of P. formosum which was responsible for the nanoparticles synthesis. The antimicrobial test revealed that AgNPs synthesized by P. formosum is capable to inhibit the growth of microorganisms. Conclusion: The results confirmed that AgNPs can act as a powerful antimicrobial agent against fish and human pathogens.

Visible spectrum of dinitrogen trioxide in aqueous solution

1996 ◽  
pp. 2055 ◽  
Author(s):  
Anne M. M. Doherty ◽  
Neil Haine ◽  
Eleanor Jones ◽  
Geoffrey Stedman
Keyword(s):  
Aqueous Solution ◽  
Visible Spectrum

scholarly journals Identifying the chloroperoxyl radical in acidified sodium chlorite solution

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252079
Author(s):  
Hiroyuki Kawata ◽  
Masahiro Kohno ◽  
Kohei Nukina ◽  
Isanori Horiuchi ◽  
Hisataka Goda ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Linear Relationship ◽  
Chlorine Dioxide ◽  
Signal Intensity ◽  
Visible Spectrum ◽  
Active Species ◽  
Sodium Chlorite ◽  
Maximum Absorbance ◽  
Linear Relationships ◽  
Spin Resonance

The present study identified the active radical species in acidic sodium chlorite and investigated the feasibility of quantifying these species with the diethylphenylenediamine (DPD) method. Electron spin resonance (ESR) spectroscopy was used to identify the active species generated in solutions containing sodium chlorite (NaClO2). The ESR signal was directly observed in an acidified sodium chlorite (ASC) aqueous solution at room temperature. This ESR signal was very long-lived, indicating that the radical was thermodynamically stable. The ESR parameters of this signal did not coincide with previously reported values of the chlorine radical (Cl●) or chlorine dioxide radical (O = Cl●-O and O = Cl-O●). We refer to this signal as being from the chloroperoxyl radical (Cl-O-O●). Quantum chemical calculations revealed that the optimal structure of the chloroperoxyl radical is much more thermodynamically stable than that of the chlorine dioxide radical. The UV-visible spectrum of the chloroperoxyl radical showed maximum absorbance at 354 nm. This absorbance had a linear relationship with the chloroperoxyl radical ESR signal intensity. Quantifying the free chlorine concentration by the DPD method also revealed a linear relationship with the maximum absorbance at 354 nm, which in turn showed a linear relationship with the chloroperoxyl radical ESR signal intensity. These linear relationships suggest that the DPD method can quantify chloroperoxyl radicals, which this study considers to be the active species in ASC aqueous solution.

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

TEM observation of iron oxide pillars in montmorillonite

1990 ◽  
Vol 48 (4) ◽  
pp. 882-883
Author(s):  
H. Mori ◽  
Y. Murata ◽  
H. Yoneyama ◽  
H. Fujita
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Fine Particles ◽  
Aqueous Suspension ◽  
Volume Ratio ◽  
Exchange Capacity ◽  
Nano Composites ◽  
Pillared Montmorillonite ◽  
Topographic Features ◽  
Transmission Electron

Recently, a new sort of nano-composites has been prepared by incorporating such fine particles as metal oxide microcrystallites and organic polymers into the interlayer space of montmorillonite. Owing to their extremely large specific surface area, the nano-composites are finding wide application[1∼3]. However, the topographic features of the microstructures have not been elucidated as yet In the present work, the microstructures of iron oxide-pillared montmorillonite have been investigated by high-resolution transmission electron microscopy.Iron oxide-pillared montmorillonite was prepared through the procedure essentially the same as that reported by Yamanaka et al. Firstly, 0.125 M aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate, [Fe3(OCOCH3)7 OH.2H2O]NO3, was prepared and then the solution was mixed with an aqueous suspension of 1 wt% clay by continuously stirring at 308 K. The final volume ratio of the latter aqueous solution to the former was 0.4. The clay used was sodium montmorillonite (Kunimine Industrial Co.), having a cation exchange capacity of 100 mequiv/100g. The montmorillonite in the mixed suspension was then centrifuged, followed by washing with deionized water. The washed samples were spread on glass plates, air dried, and then annealed at 673 K for 72 ks in air. The resultant film products were approximately 20 μm in thickness and brown in color.

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