Accelerating ethylene polymerization using secondary metal ions in tetrahydrofuran

2019 ◽  
Vol 48 (48) ◽  
pp. 17887-17897 ◽  
Author(s):  
Dawei Xiao ◽  
Zhongzheng Cai ◽  
Loi H. Do
Keyword(s):  
Polyethylene Glycol ◽  
Metal Ions ◽  
Ethylene Polymerization ◽  
Metal Cations ◽  
Nickel Phosphine

A variety of metal cations are capable of enhancing the ethylene polymerization rates of nickel phosphine phosphonate-polyethylene glycol catalysts.

scholarly journals Isolation of humic acid from oxidized lignite and complexation with metal cations

2017 ◽  
Vol 71 (4) ◽  
pp. 319-327
Author(s):  
Benjamin Catovic ◽  
Minela Sisic ◽  
Majda Srabovic ◽  
Melita Huremovic
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Humic Acids ◽  
Metal Binding ◽  
Base Material ◽  
Metal Cations ◽  
Biological Properties ◽  
Metal Nitrate ◽  
Chemical Difference ◽  
The Difference

Lignite is brown coal, which in its composition contains humic acids. Humic acids are produced by coal combustion, which leads to the enrichment of coal humic acids. Lignite, from the opet pit mine Sikulje, lignite ore ?Kreka?, Bosnia and Herzegovina, was fragmented and sieved to the appropriate size and used as a base material. The isolation of humic acid was carried out from pre-oxidized and dried lignite after which it was refined. Identification thus obtained humic acids was carried out by FTIR spectroscopy and its characterization of UV analysis which is determined by optical density of isolated humic acid and its complexation with metal cations. Data obtained by FTIR spectroscopic analysis of isolated humic acids show no significant structural and chemical difference in relation to the spectrum obtained for standard humic acids (Sigma Aldrich). UV analysis showed that isolated and standard humic acid have E4/E6 ratio in an appropriate range of 3?5, which indicates the presence of a large number of aliphatic structure. Based on the degree of humification was found that the isolated humic acids belong to the type B standard while humic acids belong to type A. The most important property of the humic substances is the ability to interact with the metal ions forming soluble or insoluble complexes which possess different chemical and biological properties and stability. The nature of the complex between humic acid and metal cation derived from the heterogeneous, polyelectric and polydispersive character humic acids that occurs due to the presence of a large number of functional groups. Complexation of humic acid is carried out with different concentrations of metal nitrate solutions and at different pH values. Different amounts of humic acids were used for the complexation. The amount of the free metal ions was measured with the ICP-OES methode. The data were also statistically analyzed with ANOVA. The results showed that increasing the pH reduces the concentration of metal ions adsorbed on humic acid and by increasing the concentrations and amounts of metal humic acid that power increases. On the basis of the difference in absorbance between metals and humic acids can be said that there is an interaction between the metal and the ligand and is based on absorbance values obtained can be determine the next set of metal binding to humic acids Pb>Zn>Ni>Cu.

A novel thermodynamic approach for the complexation study of toxic metal cations by a landfill leachate

2018 ◽  
Vol 42 (10) ◽  
pp. 7640-7648 ◽  
Author(s):  
Salvatore Cataldo ◽  
Gabriele Lando ◽  
Demetrio Milea ◽  
Santino Orecchio ◽  
Alberto Pettignano ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Environmental Impact ◽  
Metal Ions ◽  
Landfill Leachate ◽  
Toxic Metal ◽  
Metal Cations ◽  
Thermodynamic Approach ◽  
Toxic Metal Ions ◽  
Solution Behaviour ◽  
Humic Fraction

The leachate humic fraction is a good sequestering agent towards toxic metal ions, influencing their aqueous solution behaviour and their environmental impact.

Interaction of Metal Cations with Functionalised Hydrocarbons in the Gas Phase: Further Experimental Evidence for Solvation of Metal Ions by the Hydrocarbon Chain

2016 ◽  
Vol 22 (2) ◽  
pp. 61-70 ◽  
Author(s):  
Nick A. van Huizen ◽  
Theo M. Luider ◽  
Karl J. Jobst ◽  
Johan K. Terlouw ◽  
John L. Holmes ◽  
...  
Keyword(s):  
Metal Ions ◽  
Experimental Evidence ◽  
Gas Phase ◽  
Metal Cations ◽  
Hydrocarbon Chain

scholarly journals STUDY ON THE ADSORPTION PROPERTIES OF NOVEL CALIX[6]ARENE POLYMERS FOR HEAVY METAL CATIONS

2012 ◽  
Vol 12 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Susy Yunita Prabawati ◽  
Jumina Jumina ◽  
Sri Juari Santosa ◽  
Mustofa Mustofa ◽  
Keisuke Ohto
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Adsorption Kinetics ◽  
Contact Time ◽  
Adsorption Process ◽  
Metal Cations ◽  
Kinetics Model ◽  
Batch Method ◽  
Heavy Metal Cations ◽  
Kinetics Of

A research has been conducted to investigate the capability of a series of novel calix[6]arenes-based polymers: poly-monoallyloxycalix[6]arene (2a), poly-monoallyloxypenta-estercalix[6]arene (2b) and poly-monoallyloxypenta-acidcalix[6]arene (2c) for trapping of heavy metal cations such as Cd(II), Cu(II) and Cr(III). The existence of active hydroxy group (-OH) and with a tunnel-like structure of the polymers, caused the polymers can be used as adsorbents for heavy metals. The adsorption process was carried out in batch method in the variation of acidity (pH), contact time and initial concentration of metal ions. The results showed that the amount of adsorbed metal increased with the increasing of the pH of metal solution. For these three polymers, the amount of metal ions Cd(II), Cu(II) and Cr(III) adsorbed was optimum at pH 7, 6 and 5 respectively. The optimum contact time for Cd(II) and Cu(II) was 120 min, while that for Cr(III) was 60 min. Study of the adsorption kinetics showed that the adsorption of Cd(II), Cu(II) and Cr(III) using polymer 2a followed kinetics model of Ho. For adsorbent 2b and 2c, the adsorption kinetics of Cd(II) and Cr(III) also followed kinetics model of Ho while for the Cu(II) followed Lagergren kinetic models. Isothermal studies showed that the adsorption of metal ions on all adsorbents tend to follow the Langmuir isotherm. The adsorption energies of the three adsorbents were higher than 23 kJ/mole and polymer 2c has the largest adsorption capacity for Cr(III).

scholarly journals Chitosan/zeolite composite membranes for the eliminating of trace metal ions in the evacuation permeability process

2019 ◽  
Vol 84 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Trang Truong ◽  
Kobayashi Takaomi ◽  
Ha Bui
Keyword(s):  
Mechanical Properties ◽  
Trace Metal ◽  
Metal Ions ◽  
Composite Membrane ◽  
Applied Pressure ◽  
Metal Cations ◽  
Composite Membranes ◽  
Adsorption Selectivity ◽  
Trace Metal Ions ◽  
Zeolite Composite

Chitosan was combined with zeolites into composite membranes reinforced with glutaraldehyde crosslinking. The zeolite loading in the composite membranes was varied in the range 10?50 %, and the resulting membrane loading was varied at around 50 wt. %. The zeolite-loaded membranes showed better mechanical properties. The elimination of trace metal cations, Cr, As, Cd and Pb, by the chitosan?zeolite composite membranes was examined through the evacuation permeation process (EPP). In the permeability at each applied pressure, the selectivity of the composite membranes to the Cr ion was shown in the order of Cr > As > Cd > Pb at pH 5.5. It was noticed that the composite membrane with 20 wt. % zeolite loading showed the highest performance in the adsorption selectivity to the Cr cations. These results reveal the potential ability of the composite membrane to purify wastewater by removal of trace metal ions.

scholarly journals Catalytic activation of ethylene C–H bonds on uniform d8 Ir(i) and Ni(ii) cations in zeolites: toward molecular level understanding of ethylene polymerization on heterogeneous catalysts

2019 ◽  
Vol 9 (23) ◽  
pp. 6570-6576 ◽  
Author(s):  
Nicholas R. Jaegers ◽  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Daniel W. Klas ◽  
Jian Zhi Hu ◽  
...  
Keyword(s):  
Metal Ions ◽  
Ethylene Polymerization ◽  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Catalytic Activation

The long-debated intermediates of ethylene polymerization are revealed using uniform d8 metal ions in zeolites.

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