scholarly journals Ion-Exchange and Adsorption Properties of Titania Gels Prepared from Titanous Chloride and Hydrogen Peroxide

2005 ◽  
Vol 23 (3) ◽  
pp. 215-224 ◽  
Author(s):  
Nahed Yacoub ◽  
Adham R. Ramadan ◽  
Jehane Ragai
Keyword(s):  
Hydrogen Peroxide ◽  
Ion Exchange ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Titanium Oxides ◽  
Oxidizing Agent ◽  
Ph Values ◽  
Cation Uptake ◽  
Infrared Studies

A study was carried out of the uptake of Cu2+, Ni2+, Co2+ and Ca2+ cations by hydrous titanium oxides prepared at different pH values using titanous chloride as the starting material and hydrogen peroxide as the oxidizing agent. Characterization of the oxides was carried out by nitrogen adsorption and infrared studies. The oxides were found to be amphoteric in nature and exhibited an isoelectric point of 6.6. An attempt was made to elucidate the mechanism of cation uptake which does not entail a simple ion-exchange mechanism.

scholarly journals Characterization of Hydrous Zirconia Gels: Adsorption and Related Studies

1989 ◽  
Vol 6 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Jehane Ragai
Keyword(s):  
Bound Water ◽  
Nitrogen Adsorption ◽  
Surface Characteristics ◽  
Hydrous Zirconia ◽  
Zirconyl Chloride ◽  
Ph Values ◽  
High Area ◽  
Infrared Studies ◽  
Coordinated Water

A series of zirconia gels has been prepared at different pH values by the addition of aqueous ammonia to aqueous solutions of zirconyl chloride. The gels were air dried at 110°C and their surface characteristics and structure studied with the aid of infrared spectroscopy, nitrogen adsorption and simultaneous DTA, TGA and DTG methods. Infrared studies suggest the formation of compounds of the type ZrO2 · xH2O · yNH3. Preparation pH values of 8.02 and 10.01 produced high area gels with considerable pore volumes, whereas pH values of 4.50 and 7.01 led to unpredictable areas with ill-defined textures reflecting the metastability of the systems. Differential thermal analysis curves revealed two distinctive endotherms allowing the separate identification of interstitial and cordinatively bound water. As the pH of precipitation increased, the amount of coordinated water decreased.

scholarly journals Porous Structure and Adsorption Properties of Synthetic Active Carbons

1995 ◽  
Vol 12 (4) ◽  
pp. 267-277 ◽  
Author(s):  
A.M. Puziy ◽  
R. Leboda ◽  
V.I. Bogillo ◽  
V.P. Shkilev ◽  
A. Lodyga
Keyword(s):  
Porous Structure ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Active Carbons ◽  
Regularization Technique ◽  
Synthetic Active Carbons ◽  
Nitrogen Adsorption Isotherms ◽  
Bimodal Porous Structure ◽  
Micropore Size

The porous structures of synthetic active carbons have been examined in detail on the basis of nitrogen adsorption isotherms at 77 K using the αS method, the Dubinin–Stoeckli approach and the regularization technique. Analysis of the porosity of synthetic active carbons shows that carbons obtained under identical conditions have dissimilar adsorption properties depending on the size of the granule. The application of the Dubinin–Stoeckli equation for the characterization of strongly heterogeneous carbons overestimates the maximum amount adsorbed in the micropores. In contrast to the Dubinin–Stoeckli equation, the regularization method gives a two-peak micropore size distribution and enables adsorbents with a bimodal porous structure to be estimated.

PURIFICATION AND PARTIAL CHARACTERIZATION OF THERMOACTINOMYCES VULGARIS AMYLASES

1967 ◽  
Vol 13 (9) ◽  
pp. 1157-1163 ◽  
Author(s):  
M. J. Kuo ◽  
P. A. Hartman
Keyword(s):  
Ion Exchange ◽  
Column Chromatography ◽  
Maximum Rate ◽  
Amylase Activity ◽  
Enzyme Preparations ◽  
Ph Values ◽  
Ion Exchange Column ◽  
Optimum Ph ◽  
Thermoactinomyces Vulgaris

An α-amylase from Thermoactinomyces vulgaris has been purified about 100-fold. Its optimum pH was between 5.9 and 7.0, and the maximum rate was achieved at 60 °C. In the absence of substrate, the enzymes were more stable at pH 5.9 than at higher or lower pH values; inactivation was rapid at pH 7.0. Temperatures of 70 °C or greater also caused rapid denaturation of the enzyme in the absence of substrate. Three major peaks of amylase activity were detected when purified enzyme preparations were passed through Sephadex G-75 columns. At least two of these amylases were interconvertible. Four or five T. vulgaris proteinases also were separated, using ion exchange column chromatography.

Characterization of Modified HZSM–5 with Gallium and its Reactivity in Direct Conversion of Methane to Liquid Hydrocarbons

2012 ◽  
Author(s):  
Nor Aishah Saidina Amin ◽  
Asmadi Ali
Keyword(s):  
Catalytic Activity ◽  
Ion Exchange ◽  
Zeolite Catalyst ◽  
Nitrogen Adsorption ◽  
Direct Conversion ◽  
Liquid Hydrocarbons ◽  
Exchange Method ◽  
Conversion Of Methane ◽  
Ion Exchange Method

Mangkin zeolit HZSM–5 diubahsuai secara kaedah pertukaran ion berasid bagi menghasilkan mangkin zeolit Ga–HZSM–5. Aktiviti bermangkin bagi HZSM–5 dan Ga–HZSM–5 dikaji pada suhu tindak balas 800°C dan halaju ruang jaman masa (GHSV) 7500 jam–1. Mangkin HZSM–5 dan Ga–HZSM–5 dicirikan secara XRD, NMR, Penjerapan Nitrogen dan TPD. Hasil pencirian menunjukkan aluminium keluar dari kerangka asal. HZSM–5 yang mengandungi galium adalah mangkin yang lebih baik daripada mangkin zeolit HZSM–5 bagi menghasilkan cecair hidrokarbon. Kata kunci: Ga-HZSM-5; metana; pertukaran ion berasid; cecair hidrokarbon The HZSM–5 zeolite catalyst was modified by an acidic ion exchange method to produce the Ga–HZSM–5 zeolite catalyst. The catalytic activity of HZSM–5 and Ga–HZSM–5 were studied at reaction temperature of 800°C and gas hourly space velocities (GHSV) of 7500 hr–1. HZSM–5 and Ga–HZSM–5 catalysts were characterized by XRD, NMR, Nitrogen Adsorption and TPD. The characterization results revealed that aluminium was removed from the parent framework. Gallium loaded HZSM–5 is a better catalyst than HZSM–5 zeolite catalyst to produce liquid hydrocarbons. Key words: Ga-HZSM-5; methane; acidic ion exchange; liquid hydrocarbons

Characterization of Specific N2-Adsorption Site Existing on CuZSM-5 Type Zeolite:  Effect of Ion-Exchange Level on Adsorption Properties

1999 ◽  
Vol 103 (12) ◽  
pp. 2155-2164 ◽  
Author(s):  
Yasushige Kuroda ◽  
Yuzo Yoshikawa ◽  
Shuichi Emura ◽  
Ryotaro Kumashiro ◽  
Mahiko Nagao
Keyword(s):  
Ion Exchange ◽  
Adsorption Properties ◽  
Adsorption Site ◽  
N2 Adsorption ◽  
Type Zeolite ◽  
Exchange Level

Chemische und biochemische Charakterisierung von α-Benzyl-α-brommalonitril (BBMD) als Oxidationsmittel / Chemical and Biochemical Characterization of α-Benzyl-α-bromo-malononitrile (BBMD) as Oxidizing Agent

1977 ◽  
Vol 32 (3-4) ◽  
pp. 150-157 ◽  
Author(s):  
J. Rieser ◽  
A. Höckendorf ◽  
G. Abou-Elenien ◽  
K. Wallenfels
Keyword(s):  
Biochemical Characterization ◽  
Reduction Process ◽  
Pyridine Nucleotides ◽  
Oxidizing Agent ◽  
Electron Wave ◽  
Ph Values ◽  
Reduction Potentials ◽  
Half Wave ◽  
Kinetic Investigations

Abstract The behaviour of α-benzyl-α-bromo-malononitrile (BBMD) as oxidizing agent was characterized. The dependence of the electrochemical reduction potentials of BBMD on the pH-values of the solutions was examined. BBMD is reduced in a two-electron wave with half-wave potentials between + 230 and + 312 mV vs. Ag/AgCl/Cl-. BBMD is able to oxidize different organic compounds with OH-, SH-, NH- and CH- groups as well as a series of biological reducing agents as ubihydroquinone, plastohydroquinone, dihydro-lipoic acid, FADH2, NADPH and NADH. In all these cases BBMD is reduced to benzylmalononitrile. Kinetic investigations of this reduction process using NADH as reducing agent and also NMR-investigations using deuterated NADH-models showed that BBMD is directly reduced to benzylmalononitrile without producing benzylidenemalononitrile as intermediate. The reduction of BBMD with reduced pyridine nucleotides as well as that of benzylidene­ malononitrile were accelerated by an enzyme which was concentrated from human erythrocytes, using 2-chloro-benzylidenemalononitrile (CS) as substrate.

CHARACTERIZATION OF A HYDROGEN PEROXIDE-BENZENE COMPLEX USING MATRIX ISOLATION INFRARED SPECTROSCOPY

2019 ◽  
Author(s):  
Jay Amicangelo ◽  
Lia Totleben ◽  
Jacob Oslosky ◽  
Yudhishtara Payagala ◽  
Catherine Kaiser ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Infrared Spectroscopy ◽  
Matrix Isolation
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