scholarly journals Thermodynamics, Kinetics and Dilational Visco‑Elasticity of Adsorbed CnEOm Layers at the Aqueous Solution/Air Interface

2021 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Valentin B. Fainerman ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Francesca Ravera ◽  
Libero Liggieri ◽  
...  
Keyword(s):  
Surface Area ◽  
Adsorption Kinetics ◽  
Profile Analysis ◽  
Alkyl Ether ◽  
Adsorption Model ◽  
Adsorption Parameters ◽  
Apparent Diffusion Coefficients ◽  
Model Based ◽  
Equilibrium Surface Tension ◽  
Air Interface

The adsorption behaviour of linear poly(oxyethylene) alkyl ether (CnEOm) is best described by a reorientation model. Based on a complete set of experimental data, including the adsorption kinetics, the equilibrium surface tension isotherm and the surface dilational visco-elasticity, the thermodynamic and kinetic adsorption parameters for some CnEOm at the water/air interface were determined. For the study, six CnEOm surfactants were selected (n = 10, 12 and 14 and m = 4, 5 and 8) and were studied by bubble profile analysis and maximum bubble pressure tensiometry. A refined theoretical model based on a reorientation-adsorption model combined with a diffusion-controlled adsorption kinetics and exchange of matter allowed us to calculate the surface layer composition by adsorbing molecules in different orientations. It turns out that at larger surface coverage, the adsorption rate decreases, i.e., the apparent diffusion coefficients are smaller. This deceleration can be explained by the transition of molecules adsorbed in a state of larger molar surface area into a state with smaller molar surface area.

scholarly journals A Multistate Adsorption Model for the Adsorption of C14EO4 and C14EO8 at the Solution/Air Interface

2021 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Valentin B. Fainerman ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Francesca Ravera ◽  
Libero Liggieri ◽  
...  
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Profile Analysis ◽  
Alkyl Ether ◽  
Adsorption Model ◽  
Data Description ◽  
Classical Version ◽  
Air Interface ◽  
Complete Set ◽  
Adsorption Layers

The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (CnEOm) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously surfactants that can adsorb in more than two possible conformations. The experimental data for C14EO4 and C14EO8 (dynamic and equilibrium surface tensions and surface dilational visco-elasticity as measured by bubble profile analysis tensiometry) are used to verify if a reorientation model with more than two possible adsorption states can better describe the complete set data of CnEOm adsorption layers at the water/air interface. The proposed refined theoretical model allows s different states of the adsorbing molecules at the interface. The comparison between the model and experiment demonstrates that, for C14EO4, the assumption of s = 5 adsorption states provides a much better agreement than for s = 2, while for C14EO8, a number of s = 10 adsorption states allows an optimum data description.

scholarly journals Interfacial properties of chitosan lactate at the liquid/air interface

2021 ◽  
Vol 12 (4) ◽  
pp. 374-381
Author(s):  
G. I. Kovtun ◽  
Keyword(s):  
Surface Tension ◽  
Surface Layer ◽  
Surface Coverage ◽  
Interfacial Properties ◽  
Adsorption Model ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension ◽  
Air Interface ◽  
Exchange Processes ◽  
Chitosan Lactate

The interfacial properties (dynamic and equilibrium surface tension, viscosity and elasticity moduli) of chitosan lactate have been studied at the liquid/air interface by the oscillating drop shape method. Isotherms of dynamic surface tension of chitosan lactate are similar to dependences for other polyelectrolyte solutions, in particular for proteins. Chitosan is a weak cationic polyelectrolyte which can change its conformation from a linear rod to a chaotic and compacted coil. Therefore, the experimental dependence of the equilibrium surface tension on concentration of chitosan lactate was analyzed with the adsorption model proposed earlier for proteins. This model accounts the possibility of polyelectrolyte molecules existence in surface layer in n states with different molar surface varying from the maximum value at very low surface coverage by polyelectrolyte molecules to a minimum value at high surface coverage. Good agreement between the calculated and experimental values of surface tension was observed. The dependences of the elasticity and viscosity moduli of chitosan lactate solutions on the drop oscillations frequency are conditioned by the influence of exchange processes both between the surface layer and the bulk solution and in the surface layer itself. An increase of the solution concentration intensifies the exchange processes, and an increase of the oscillation frequency suppresses them. It is shown that the dependence of the surface viscoelasticity modulus of chitosan lactate is extreme in nature with a pronounced maximum. The reason for such behavior is the possibility of changing the molar surface area of the polyelectrolyte at the interface dependent on the amount of adsorption and its structural properties. Attempt of theoretical description of the viscoelasticity modulus within the framework of model accounting mono- or bilayer adsorption did not lead to a satisfactory result, possibly due to barrier adsorption mechanism of chitosan. But bilayer model provide qualitative description of extreme behavior of surface viscoelasticity on concentration. The values of the surface viscoelasticity modulus of chitosan lactate occupy an intermediate position in comparison with the data available in the literature for globular and flexible-chain proteins, that is consistent with their molecular structure. In addition, the work shows the applicability of the adsorption model, developed earlier for proteins in the framework of a nonideal two-dimensional solution theory, for describing the surface properties of other polyelectrolytes. This makes it possible to obtain qualitative and quantitative information about the processes occurring in the systems under study.

Removal of Heavy Metal Ions from Aqueous Solution by Manganese Dioxide-Coated Polypropylene Granules: An Implication of Rainwater Runoff Treatment

2007 ◽  
Vol 544-545 ◽  
pp. 131-134
Author(s):  
Sardor Abdukakharovich Mavlyankariev ◽  
Dong Seok Rhee
Keyword(s):  
Metal Ions ◽  
Manganese Dioxide ◽  
Surface Area ◽  
Mercury Porosimetry ◽  
Surface Characteristics ◽  
Metal Species ◽  
Adsorption Model ◽  
Rainwater Runoff ◽  
Flow Through ◽  
Fast Removal

Modified polypropylene granules (MDPG) were coated by manganese dioxide and their surface and adsorptive characteristics were studied. Surface characteristics of the adsorbent were investigated by B.E.T. surface area and mercury porosimetry. Coating has significantly increased the surface area of granules from 0.12 m 2 /g B.E.T. N 2 to 15.42 m 2 /g. Gas pycnometry measurements resulted in low density of 0.13 g/cm 3 for uncoated granules, the fact ascribed to 0.65 porosity measured. Coating increased micro pore volume of raw granules by a factor of 58. Adsorption experiments were conducted in column flow-through reactors at pH 6.0 and 10 g/L sorbent dosage for mixture of four metal species, each having 5 mg/L initial concentration. More than 60 % of Pb and Cu was removed within first 20 min, whereas just over 29 and 13 % for Cd and Zn respectively. Furthermore, more than 99, 84, 40, 16 % of Pb, Cu, Cd, and Zn was removed within 1 h. Adsorption efficiencies for 5 ppm of initial metal concentration at pH 5.0 and 10 g/L sorbent/solute ratio resulted in 4.9, 3.9 mg of Pb and Cu sorbed per gram of sorbent. And these ratios for separate metal ions were substantially higher than those for the mixture of the four metal ions. For 5 g/L of sorbent under the same parameters, removal efficiencies of Cd and Zn were respectively 0.98, 0.75 mg/g, correlating well with Freundlich adsorption model. Adsorption kinetics showed relatively fast removal rates within first 5 h of sorption. Desorption resulted in eluting 57, 70, 76, 78 % of the initial feeding concentrations for Pb, Cu, Cd, Zn, respectively.

scholarly journals A Comparative Study on The Adsorption Behavior of Congo Red on to ZnAl and ZnCr Layered Double Hydroxides

2020 ◽  
Vol 9 (2) ◽  
pp. 108-116
Author(s):  
Tarmizi Taher ◽  
◽  
Nyanyu Ummu Hani ◽  
Neza Rahayu Palapa ◽  
Risfidian Mohadi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Surface Area ◽  
Adsorption Kinetics ◽  
Layered Double Hydroxides ◽  
Congo Red ◽  
Adsorption Process ◽  
Bet Surface Area ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Double Hydroxides

In this work, two synthetic layered double hydroxides (LDH) consists of Zn2+ as M2+ cation with different M3+ cation, i.e., Al3+ and Cr3+ were used as an adsorbent for Congo Red removal aqueous solution. Both Zn-Al and Zn-Cr LDH were characterized by X-ray diffraction, FT-IR, and BET surface area analyzer. The effect of contact time, initial dye concentration, and temperature were evaluated in a batch technique in order to investigate the characteristic of Congo Red adsorption onto both adsorbents. The experimental data were assessed according to the parameter of adsorption kinetics, isotherm, and thermodynamics. The results of LDH characterization showed that Zn-Al LDH has a higher interlayer distance than Zn-Cr LDH, although Zn-Cr LDH has a higher surface area. The FT-IR analysis indicated the interlayer space of both Zn-Cr and Zn-Al LDH was dominated by CO32- as the interlayer anion species. The adsorption kinetics study of Congo Red on both LDH revealed that the adsorption process followed the pseudo-second-order model. For the adsorption isotherm, the experimental data fit well with the Freundlich model rather than the Langmuir model. The thermodynamic study indicated that the adsorption process that occurred on both adsorbents was spontaneous with exothermic nature.

scholarly journals STUDI ADSORPSI ZAT WARNA NAPHTHOL YELLOW S PADA LIMBAH CAIR MENGGUNAKAN KARBON AKTIF DARI AMPAS TEBU

Jurnal Kimia ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 104
Author(s):  
W. P. Utoo1 ◽  
E. Santoso ◽  
G. Yuhaneka ◽  
A. I. Triantini ◽  
M. R. Fatqi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Contact Time ◽  
Adsorption Process ◽  
Activation Process ◽  
Adsorption Model ◽  
High Adsorption ◽  
Prolonged Contact ◽  
Test Result

The aim of this research is to get activated carbon from sugarcane bagasse with high adsorption capacity to Naphthol Yellow S and to know factors influencing the adsorption capacity. Activated carbon is prepared by incomplete combustion of sugracane bagasse. The resulting carbon is activated with H2SO4 with concentration variation of 0.5; 1.0; 1.5 and 2.0 M and is continued by calcination at 400 °C. The measurement of the surface area of ??activated carbon by the methylene blue method indicates that the activation process successfully extends the surface area of carbon from 31.87 m2/g before activation to 66-72 m2/g after activation. Activated carbon with concentration of 2.0 M H2SO4 showed the highest surface area of ??71.85 m2/g, however, the best adsorption was shown by activated carbon with a concentration of 0.5 M H2SO4 with the adsorption capacity of 83.93%. The adsorption test showed that the best amount of adsorbent was 0.2 g with contact time for 30 minutes. Prolonged contact time can decrease the amount of Naphthol Yellow S adsorbed. The best adsorption test result was shown by sample with activator concentration of 0,5 M, mass of 0,2 g and contact time of 30 min with adsorption capacity 95,81% or amount of dye adsorbed equal to 143,72 mg/g. The adsorption study also showed that the entire Naphthol Yellow S adsorption process followed the Langmuir isothemal adsorption model. Qualitative testing of real batik waste indicates that activated carbon can reduce the dyes waste containing Naphthol Yellow Sexhibited by the color of batik waste which is more faded.  

scholarly journals Effect of Sodium Periodate on the Adsorption Capacity of Silica-Lignin from Rice Husk on Chromium(VI)

2019 ◽  
Vol 22 (6) ◽  
pp. 242-249 ◽  
Author(s):  
Yati B. Yuliyati ◽  
Solihudin Solihudin ◽  
Atiek Rostika Noviyanti
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Sodium Periodate ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Adsorption Model ◽  
Chromium Vi ◽  
Reactive Groups ◽  
Isotherm Adsorption

Reactive groups such as silanol, hydroxyl, and carbonyl groups in silica-lignin composites play a role in binding to chromium(VI) ions. The activation of functional groups in silica-lignin can be increased by the addition of an activator such as sodium periodate, which can also oxidize the lignin monomer (guaiasil) to ortho-quinone. This study aimed to obtain silica-lignin composites from rice husks activated by sodium periodate with a high surface area. Composite absorption was tested on chromium(VI) adsorption. Silica-lignin isolation was carried out by using the sol-gel method at concentrations of sodium hydroxide 5, 10, 15, and 20% (b/b). Silica-lignin activated with sodium periodate 10% (b/b) had the smallest particle size of about 8μm, with a surface area of 14.0888 m2.g-1 and followed Halsey isotherm adsorption model, with an adsorption capacity of 0.3054 mg.g-1.

scholarly journals Adsorption kinetics and isothermal adsorption model of crystal violet on modified red mud

2020 ◽  
Vol 508 ◽  
pp. 012151
Author(s):  
Wei Li ◽  
Shuwen Luo ◽  
Hongfei Ma ◽  
Fanghua Yi ◽  
Zheng Li ◽  
...  
Keyword(s):  
Adsorption Kinetics ◽  
Crystal Violet ◽  
Red Mud ◽  
Adsorption Model ◽  
Isothermal Adsorption

scholarly journals Adsorption kinetics of surfactant molecules at a liquid–air interface

1988 ◽  
Vol 89 (5) ◽  
pp. 3386-3387 ◽  
Author(s):  
Th. Rasing ◽  
T. Stehlin ◽  
Y. R. Shen ◽  
M. W. Kim ◽  
P. Valint
Keyword(s):  
Adsorption Kinetics ◽  
Air Interface ◽  
Kinetics Of

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.

Sign in / Sign up

Export Citation Format

Share Document