Efficiency of Ag(0)@chitosan gel beads in catalytic reduction of nitroaromatic compounds by sodium borohydride

2019 ◽  
Vol 137 ◽  
pp. 576-582 ◽  
Author(s):  
Idris Sargin
Keyword(s):  
Sodium Borohydride ◽  
Catalytic Reduction ◽  
Nitroaromatic Compounds ◽  
Gel Beads ◽  
Chitosan Gel

scholarly journals Equilibrium modeling of mono and binary sorption of Cu(II) and Zn(II) onto chitosan gel beads

2016 ◽  
Vol 37 (4) ◽  
pp. 485-501 ◽  
Author(s):  
Józef Nastaj ◽  
Małgorzata Tuligłowicz ◽  
Konrad Witkiewicz
Keyword(s):  
Metal Ion ◽  
Ph Value ◽  
Experimental Studies ◽  
Process Conditions ◽  
Optimal Process ◽  
Sorption Data ◽  
Gel Beads ◽  
Two Component ◽  
Equilibrium Data ◽  
Chitosan Gel

Abstract The objective of the work are in-depth experimental studies of Cu(II) and Zn(II) ion removal on chitosan gel beads from both one- and two-component water solutions at the temperature of 303 K. The optimal process conditions such as: pH value, dose of sorbent and contact time were determined. Based on the optimal process conditions, equilibrium and kinetic studies were carried out. The maximum sorption capacities equaled: 191.25 mg/g and 142.88 mg/g for Cu(II) and Zn(II) ions respectively, when the sorbent dose was 10 g/L and the pH of a solution was 5.0 for both heavy metal ions. One-component sorption equilibrium data were successfully presented for six of the most useful three-parameter equilibrium models: Langmuir-Freundlich, Redlich-Peterson, Sips, Koble-Corrigan, Hill and Toth. Extended forms of Langmuir-Freundlich, Koble-Corrigan and Sips models were also well fitted to the two-component equilibrium data obtained for different ratios of concentrations of Cu(II) and Zn(II) ions (1:1, 1:2, 2:1). Experimental sorption data were described by two kinetic models of the pseudo-first and pseudo-second order. Furthermore, an attempt to explain the mechanisms of the divalent metal ion sorption process on chitosan gel beads was undertaken.

Flavan derivatives. XXIII. Preparation and synthetic applications of Flav-3-enes

1968 ◽  
Vol 21 (9) ◽  
pp. 2247 ◽  
Author(s):  
JW Clark-Lewis ◽  
RW Jemison
Keyword(s):  
Sodium Borohydride ◽  
Acidic Medium ◽  
Catalytic Reduction ◽  
Heterocyclic Ring ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Lower Field ◽  
Field Characteristic ◽  
Lithium Aluminium ◽  
New Synthesis

2'-Hydroxychalcones and α-alkoxy-2'-hydroxychalcones are converted by sodium borohydride in isopropanol into flav-3-enes and 3-alkoxyflav-3-enes in the convenient new synthesis which makes these flavenes readily available. Catalytic reduction of the flavenes gives the corresponding flavans or 3-alkoxyflavans in high yield, and the latter are obtained mainly in the 2,s-cis-form. The flavenes immediately give flavs lium cations in the cold when treated with acids in air, and oxidation of 5,7,3',4'-tetramethoxyflav-3-ene with benzoquinone in an acidic medium gave the flavylium salt, isolated as the ferrichloride. Reduction of 5,7,3',4'-tetramethoxy-flavylium chloride with lithium aluminium hydride gave 5,7,3',4'-tetramethoxy-flav-2-ene identical with the flavene obtained from (-)-epicatechin tetramethyl ether, and confirms an earlier investigation by Gramshaw, Johnson, and King. In its N.M.R. spectrum the heterocyclic-ring protons of this flav-2-ene give an ABX multiplet which is easily distinguished from the ABX multiplet at much lower field characteristic of flav-3-enes.

Catalytic Reduction of Nitrobenzene Using Silver Nanoparticles Embedded Calcium Alginate Film

2019 ◽  
Vol 19 (11) ◽  
pp. 7487-7492 ◽  
Author(s):  
Supriya ◽  
Jayanta Kumar Basu ◽  
Sonali Sengupta
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Sodium Borohydride ◽  
Calcium Alginate ◽  
Catalytic Reduction ◽  
Average Particle Size ◽  
Catalyst Loading ◽  
Average Particle ◽  
Transmission Electron

Synthesis of silver nanoparticles embedded on calcium alginate film and the catalytic property of this film in the reduction of nitrobenzene with sodium borohydride are demonstrated in this work. Natural polymer alginate acts as effective reducing and stabilizing agent in synthesis of silver nanoparticles. Effect of different parameters on the preparation of silver nanoparticles, such as, temperature, concentration of silver precursor and heating time was investigated. As-prepared silver nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectrometry, and atomic absorption spectrometry. Transmission electron microscopy analysis con-firms the formation of silver nanoparticles with particles size range of 3–19 nm and average particle size was found to be 10±4 nm. Effect of concentration of nitrobenzene and sodium borohydride, catalyst loading and temperature on the catalytic reduction of nitrobenzene was studied. Reusability of catalyst was examined in this reduction reaction and the catalyst shows good activity up to 10th run.

Synthesis of Modified Chitosan Gel Beads and Adsorption Performance of Cu(II)

2020 ◽  
Vol 231 (6) ◽  
Author(s):  
Shan Liu ◽  
Xuanni Li ◽  
Tao Li ◽  
Lei Liao ◽  
Lei Cao ◽  
...  
Keyword(s):  
Modified Chitosan ◽  
Adsorption Performance ◽  
Gel Beads ◽  
Chitosan Gel

Green synthesis of gold nanoparticles reduced and stabilized by squaric acid and supported on cellulose fibers for the catalytic reduction of 4-nitrophenol in water

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91185-91191 ◽  
Author(s):  
Md. Tariqul Islam ◽  
Julio E. Padilla ◽  
Noemi Dominguez ◽  
Daisy C. Alvarado ◽  
Md Shah Alam ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
Sodium Borohydride ◽  
Catalytic Reduction ◽  
Cellulose Fibers ◽  
Squaric Acid

Gold nanoparticles reduced and stabilized by sodium squarate in water that attach to cellulose fibers and catalyse the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride.

Preparation of porous chitosan gel beads for copper(II) ion adsorption

2007 ◽  
Vol 147 (1-2) ◽  
pp. 67-73 ◽  
Author(s):  
F ZHAO ◽  
B YU ◽  
Z YUE ◽  
T WANG ◽  
X WEN ◽  
...  
Keyword(s):  
Ion Adsorption ◽  
Gel Beads ◽  
Porous Chitosan ◽  
Chitosan Gel
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