scholarly journals Interpretation of the adsorption of metals on quartz crystal based-macromolecule via advanced modeling of equilibrium isotherms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fatma Aouaini ◽  
Mohamed Ben Yahia ◽  
Haifa I. Alrebdi ◽  
Miysoon A. Alothman
Keyword(s):  
Double Layer ◽  
Quartz Crystal ◽  
Equilibrium Concentration ◽  
Configurational Entropy ◽  
Physical Models ◽  
Lateral Interactions ◽  
Free Enthalpy ◽  
Adsorption Model ◽  
High Concentration ◽  
Chromium Compound

AbstractIn this article, new insights about the metals-porphyrin complexes are proved by analyzing the zinc, nickel and chromium adsorption process over the well-known porphyrin macromolecule. The use of the quartz crystal microbalance (QCM) apparatus allows the control of the complexation systems’ experimental adsorption data operating at four temperatures. The experimental results and the physical models reveal that the zinc and nickel complexation processes are to be examined using the mono layer adsorption model. While, the double layer model describes the interaction between the chromium compound and the porphyrin. Actually, the three metals are shown to be adsorbed by a multi-docking process in the physicochemical description. The endothermic character of the investigated processes is shown through the appropriate data of the principal parameter adsorbent sites’ density. Hence, several porphyrin sites are exclusively stimulated at high temperature. The parameters of van del Waals, depicting the influences of the lateral interactions, explain the nickel isotherms down trend. The chemical bonds are shown to be carried out between the zinc and the porphyrin through the calculated adsorption energies. Considering the thermodynamic study, and referring to the configurational entropy and the free enthalpy, it is to be noted that the disorder peak of the three mechanisms is reached when the equilibrium concentration is equal to the energetic parameters’ values for each system. The nickel enthalpy revealed for high concentration that the adsorbates’ lateral interactions disapproved the nickel chloride adsorption. The free enthalpy trends, that observed two stability states of the chromium compound, confirmed the chromium double layer mechanism.

NUMERICAL MODELING OF RADIATION EXPOSURE ON A QUARTZ CRYSTAL STRUCTURE DEFECTS AND SIGNAL ANALYSIS THERMOLUMINESCENT

2020 ◽  
Vol 6 (4) ◽  
pp. 158-178
Author(s):  
Vladimir S. Sheinkman ◽  
Yuliya Yu. Erina ◽  
Oleg A. Simonov
Keyword(s):  
Crystal Structure ◽  
Radiation Exposure ◽  
Electron Concentration ◽  
Numerical Experiments ◽  
Quartz Crystal ◽  
Equilibrium Concentration ◽  
Band Model ◽  
Structure Defects ◽  
Crystal Structure Defects ◽  
Intense Radiation

Developing thermoluminescent (TL) dating methods for quartz-containing deposits has required a series of numerical experiments within the framework of the band model to study the rate of electron accumulation in quartz crystal structure defects under radioactive radiation. The crystal model contained two different types of electron traps and one emission center. A system of differential equations was solved numerically, relating the rates of change in the electron concentration in defects of the crystal structure and the electron concentration in the conduction band and holes in the valence band. The results have shown that the intense radiation exposure alters the dynamic equilibrium concentration of electrons in the traps, which significantly modifies the TL signal. In accordance with this, the sensitivity marker material to the radioactive dose, required for absolute dating and received by its intense radiation exposure, cannot be determined correctly. In addition, the numerical experiments have confirmed the possibility of dating the samples by the position of the TL signal’s maximum on the time axis, as well as the possibility of obtaining the dating by the TL signal’s amplitude.

Phase diversity in an adsorption model of an additive binary gas mixture for all sets of lateral interactions

2018 ◽  
Vol 20 (15) ◽  
pp. 10359-10368 ◽  
Author(s):  
V. F. Fefelov ◽  
A. V. Myshlyavtsev ◽  
M. D. Myshlyavtseva
Keyword(s):  
Phase Behavior ◽  
Square Lattice ◽  
Complete Analysis ◽  
Gas Mixture ◽  
Lateral Interactions ◽  
Adsorption Model ◽  
Adsorbed Molecules ◽  
Phase Diversity ◽  
Binary Gas Mixture ◽  
Different Types

Complete analysis of phase behavior of an adsorption model of a binary gas mixture on a square lattice was carried out for all possible sets of lateral interactions between nearest adsorbed molecules of the same type and no interaction between adsorbed molecules of different types.

scholarly journals In situ NMR and electrochemical quartz crystal microbalance techniques reveal the structure of the electrical double layer in supercapacitors

2015 ◽  
Vol 14 (8) ◽  
pp. 812-819 ◽  
Author(s):  
John M. Griffin ◽  
Alexander C. Forse ◽  
Wan-Yu Tsai ◽  
Pierre-Louis Taberna ◽  
Patrice Simon ◽  
...  
Keyword(s):  
Double Layer ◽  
Quartz Crystal Microbalance ◽  
Electrical Double Layer ◽  
Quartz Crystal ◽  
Electrochemical Quartz Crystal Microbalance ◽  
In Situ Nmr

Adsorption of toluene from the mixed water−toluene system on medicinal activated carbon

2014 ◽  
Vol 92 (5) ◽  
pp. 392-396
Author(s):  
Igor Winkler ◽  
Volodymyr Diychuk
Keyword(s):  
Experimental Investigation ◽  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Surface Adsorption ◽  
Equilibrium Concentration ◽  
Coal Surface ◽  
Adsorption Model ◽  
Insufficient Amount ◽  
Mixed Water ◽  
Kinetics Of

An experimental investigation of adsorption of toluene from the aqueous phase on medicinal activated carbon revealed that the process runs by the mechanism of preactivated adsorption. Kinetics of the initial stages of adsorption can be adequately represented by the empirical Elovich adsorption model. An insufficient amount of the adsorbent can cause an unexpected jump in the toluene equilibrium concentration in water caused by transferring this substance from the toluene phase into water through the process of additional adsorption on the coal surface. Adsorption constants and “imaginary” adsorption values have been determined for a series of toluene contents.

On the Adsorption Capability of Powder Activated Carbon for Phenol

2014 ◽  
Vol 709 ◽  
pp. 422-425
Author(s):  
Shao Fen Zhong ◽  
Jian Wen Mo ◽  
Yang Ping Li
Keyword(s):  
Activated Carbon ◽  
High Performance ◽  
Solid Phase ◽  
Pure Water ◽  
Equilibrium Concentration ◽  
Impact Factors ◽  
Raw Water ◽  
Adsorption Model ◽  
Powder Activated Carbon ◽  
Adsorption Capability

Using solid phase extraction and high performance liquid chromatography (HPLC), this paper studies the adsorption capability of activated carbon to phenol. The phenol wastewater is simulated with raw water and pure water, respectively. In detail, we examine impact factors including adsorption time, activated carbon dosage, equilibrium concentration of phenol. Using the adsorption principles from the aspect of kinetics, our study shows that adsorption of powder activated carbon to phenol conforms to the Fran Delhi Freundrich adsorption model.

A novel double-layer nanotube structure fabricated in high concentration H3PO4 and fluoride-containing mixed electrolyte without annealing

2019 ◽  
Vol 716 ◽  
pp. 167-170 ◽  
Author(s):  
Lizhen Wu ◽  
Dawei Xu ◽  
Zhen Liu ◽  
Shaoyu Zhang ◽  
Yang Du ◽  
...  
Keyword(s):  
Double Layer ◽  
High Concentration ◽  
Mixed Electrolyte

Quartz Crystal Microbalance Coated with 18-Crown-6 Ether Film for 2,4,6-Trinitrotolurene (TNT) Vapor Detection

2017 ◽  
Vol 748 ◽  
pp. 358-362
Author(s):  
Pavaris Phuvanatai ◽  
Toempong Phetchakul
Keyword(s):  
Steady State ◽  
Frequency Shift ◽  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Film Surface ◽  
Vapor Concentration ◽  
High Concentration ◽  
Vapor Detection ◽  
Steady State Condition ◽  
Shift Response

The 2, 4, 6-trinitrotoluene (TNT) vapor detection by quartz crystal microbalance (QCM) coated with 18-crown-6 ether film is introduced. The film acts as selective or sensitive layer for detecting TNT molecule. The frequency shift response is depend on the amount of mass of molecule adhere on the coated film surface. In this study, the concentrations of TNT vapor which is related to responses are studied. It shows that the TNT vapor concentration is related to the time for steady state condition and the frequency shift response. The high concentration vapor will increase the frequency shift response but increase the steady state time.

Semiempirische Rechnungen zur Bestimmung der Konformation des 4,5-Dihydro-1,3-dioxepins und seines 2-Methyl-Derivats

1994 ◽  
Vol 49 (6) ◽  
pp. 714-718 ◽  
Author(s):  
Josef Esser ◽  
Jörg Fleischhauer ◽  
Herbert Frauenrath ◽  
Christoph Jansen ◽  
Bernd Kramer ◽  
...  
Keyword(s):  
Equilibrium Concentration ◽  
Chair Conformation ◽  
Experimental Results ◽  
Semiempirical Methods ◽  
Equatorial Position ◽  
Vibration Frequencies ◽  
Local Minima ◽  
Free Enthalpy ◽  
Methyl Derivative

Abstract Semiempirical Calculations for the Determination of the Conformation of 4,5-dihydro-1,3-dioxepine and its 2-methyl derivative The possible conformations of the title compounds have been studied with the semiempirical methods MNDO and AM1. In the local minima, the vibration frequencies have been calculated to get the free enthalpy of each conformer and its equilibrium concentration. The energy minimized structures and the calculated thermodynamical values are compared with experimental results. From our investigations we conclude that the chair conformation is preferred. In the case of the methyl derivative, the substituent favours the equatorial position.

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