CONFORMATION OF LINEAR POLYMERIC CHAINS AT THE INTERFACE LAYER LIQUID / SOLID AND ADSORPTION ISOTHERM

2014 ◽  
pp. 95-118
Keyword(s):  
Adsorption Isotherm ◽  
Interface Layer ◽  
Polymeric Chains

High Quality HfO2 Film and Its Applications in Novel Poly-Si Devices

2002 ◽  
Vol 716 ◽  
Author(s):  
K.L. Ng ◽  
N. Zhan ◽  
M.C. Poon ◽  
C.W. Kok ◽  
M. Chan ◽  
...  
Keyword(s):  
Barrier Height ◽  
Nonvolatile Memory ◽  
Dielectric Material ◽  
Tunneling Current ◽  
Interface Layer ◽  
Si Substrate ◽  
Hfo2 Film ◽  
Effective Barrier Height ◽  
Effective Barrier ◽  
Nonvolatile Memory Devices

AbstractHfO2 as a dielectric material in MOS capacitor by direct sputtering of Hf in an O2 ambient onto a Si substrate was studied. The results showed that the interface layer formed between HfO2 and the Si substrate was affected by the RTA time in the 500°C annealing temperature. Since the interface layer is mainly composed of hafnium silicate, and has high interface trap density, the effective barrier height is therefore lowered with increased RTA time. The change in the effective barrier height will affect the FN tunneling current and the operation of the MOS devices when it is applied for nonvolatile memory devices.

Competitive adsorption of organic solvents using modified and unmodified calcium bentonite clay mineral

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Organic Solvents ◽  
Competitive Adsorption ◽  
Correlation Factor ◽  
Isotherm Model ◽  
Isotherm Models ◽  
High Concentration ◽  
Dual Purpose ◽  
Calcium Bentonite

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene > ethylbenzene > toluene > gasoline > dual purpose kerosene (DPK) > diesel > water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.

Gasoline Desulphurization by Reactive Adsorption on ZnO /Bentonite

2019 ◽  
Vol 70 (1) ◽  
pp. 50-53
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Vasile Matei
Keyword(s):  
Zinc Oxide ◽  
Adsorption Isotherm ◽  
Operating Temperature ◽  
Continuous System ◽  
Particle Sizes ◽  
Textural Characteristics ◽  
Reactive Adsorption ◽  
Atmospheric Distillation ◽  
Increased Pressure

Desulfurization of atmospheric distillation (DA) gasoline was performed by reactive adsorption on ZnO/ bentonite. The adsorbent was characterized by determining the distribution of particle sizes of zinc oxide powdered, adsorption isotherm and textural characteristics of granulated adsorbent. Adsorption experiments of atmospheric distillation gasoline were performed in continuous system at 280-320oC, 5-25 bar and volume hourly space velocities of 1-1.5 h-1. The adsorption on ZnO/ bentonite has been favored by increased pressure and operating temperature.

Desorption of Cationic Polyacrylamide from Bleached Kraft Pulp Fibers

1987 ◽  
Vol 19 (5-6) ◽  
pp. 939-951 ◽  
Author(s):  
Clifton F. Warren ◽  
R. Gehr
Keyword(s):  
Adsorption Isotherm ◽  
Total Nitrogen ◽  
Kraft Pulp ◽  
Detection System ◽  
Cationic Polyelectrolyte ◽  
Chemiluminescence Detection ◽  
Pulp Fibers ◽  
Paper Manufacturing ◽  
Bleached Kraft Pulp ◽  
Receiving Water

The adsorption and desorption behaviour of a cationic polyelectrolyte contacted with wood pulp fibers was determined by total nitrogen analysis using a pyrolysis/chemiluminescence detection system. Dialysed polymer generated an adsorption isotherm of higher affinity than did non-dialysed polymer. Capacity adsorption was maximized at pH 7, but decreased in the presence of alum depending on the dosage. Desorption of non-dialysed polymer was caused by changes in pH above or below 7.0 as well as by addition of alum. However for the alum doses typically encountered in paper manufacturing, significant desorption is unlikely. Nevertheless, the contaminants in non-dialysed polymers do hinder adsorption, and effluents from those processes using both alum and polymer may contain quantities of unadsorbed or desorbed polyelectrolytes which could be damaging to receiving water bodies.

Effects of Doping on the Electrochemical and Electrical Properties of Poly(2,5-di(2-thienyl)pyrrole)

1999 ◽  
Vol 64 (8) ◽  
pp. 1357-1368 ◽  
Author(s):  
Enric Brillas ◽  
José Carrasco ◽  
Ramon Oliver ◽  
Francesc Estrany ◽  
Víctor Ruiz
Keyword(s):  
Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Oxidation Potential ◽  
Ethanolic Solution ◽  
Pt Electrode ◽  
Reversible Process ◽  
Oxidation Potentials ◽  
Lower Productivity ◽  
Polymeric Chains ◽  
Linear Molecules

The electropolymerization of 2,5-di(2-(thienyl)pyrrole) (SNS) on a Pt electrode from ethanolic solution with LiClO4 or LiCl as electrolyte has been studied by cyclic voltammetry (CV) and chronoamperometry (CA). In both media, a quasi-reversible process has been indicated by CV, reversing the scan at low oxidation potentials. Under these conditions, reducible positive charges formed in both oxidized polymers are compensated by the entrance of anions from solution. Elemental analysis reveals that polymers generated at a low oxidation potential by CA contain a 21.03% (w/w) of ClO4- or a 9.56% (w/w) of Cl-. The poly(SNS) doped with Cl- presents higher proportion of reducible positive charges, higher polymerization charge and lower productivity. A much higher electrical conductivity, however, has been found for the poly(SNS) doped with ClO4-. Both polymers are soluble in DMSO, acetone and methanol. The dimer, trimer, tetramer and pentamer have been detected as soluble and neutral linear oligomers by mass spectrometry-fast atom bombardment. The analysis of polymers by infrared spectroscopy confirms the predominant formation of linear molecules with α-α linkages between monomeric units. A condensation mechanism involving one-electron oxidation of all electrogenerated linear and neutral polymeric chains is proposed to explain the SNS electropolymerization.

scholarly journals Tin Complexes of 4-(Benzylideneamino)benzenesulfonamide: Synthesis, Structure Elucidation and Their Efficiency as PVC Photostabilizers

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2434
Author(s):  
Hassan Ghani ◽  
Emad Yousif ◽  
Dina S. Ahmed ◽  
Benson M. Kariuki ◽  
Gamal A. El-Hiti
Keyword(s):  
Vinyl Chloride ◽  
Structure Elucidation ◽  
Poly Vinyl Chloride ◽  
Polymeric Chains ◽  
Process Decomposition ◽  
Stabilizing Effect ◽  
Surface Alteration ◽  
Tin Complexes ◽  
High Yields ◽  
Harsh Conditions

Poly(vinyl chloride) (PVC) suffers from photo-xidation and photodegradation when exposed to harsh conditions. Application of PVC thus relies on the development of ever more efficient photostabilizers. The current research reports the synthesis of new complexes of tin and their assessment as poly(vinyl chloride) photostabilizers. The three new complexes were obtained in high yields from reaction of 4-(benzylideneamino)benzenesulfonamide and tin chlorides. Their structures were elucidated using different tools. The complexes were mixed with poly(vinyl chloride) at a very low concentration and thin films were made from the blends. The effectiveness of the tin complexes as photostabilizers has been established using a variety of methods. The new tin complexes led to a decrease in weight loss, formation of small residues, molecular weight depression, and surface alteration of poly(vinyl chloride) after irradiation. The additives act by absorption of ultraviolet light, removal the active chlorine produced through a dehydrochlorination process, decomposition of peroxides, and coordination with the polymeric chains. The triphenyltin complex showed the greatest stabilizing effect against PVC photodegradation as a result of its high aromaticity.

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