Langmuir adsorption isotherm analysis on the addition of Myrmecodia Pendans extract as a corrosion inhibitor with a variety of corrosive media

Author(s):  
Atria Pradityana ◽  
Sulistijono ◽  
Subowo ◽  
Suhariyanto ◽  
Hari Subiyanto ◽  
...  
2021 ◽  
Vol 10 (4) ◽  
pp. 2655-2679

Artichoke extract (AE) was studied as the corrosion inhibitor for zinc in 1 M HCl utilizing chemical and electrochemical methods. The adsorption isotherm of Artichoke extract on Zn surface accords with Langmuir adsorption isotherm. The inhibition efficiency increases with increasing the extract's concentration and decreases with the rise in the medium's temperature. The inhibition efficiency reached a value of 93.2% at 300 ppm of extract. This extract may be forming a film and acts as a barrier, which minimizes the contact area between zinc surface and HCl solution. Artichoke extract acts as a mixed inhibitor in HCl solution. Thermodynamic parameters of activation and adsorption were determined and explained. The adsorption parameters also obeyed the Langmuir adsorption isotherm, and the sign of the free energy of adsorption showed a spontaneous process. The surface morphology of zinc metal was examined by employing various techniques. Also, the biological effect of the Artichoke extract was studied. Theoretical studies of quantum mechanics and molecular dynamics simulations studies were carried out on the Artichoke extract compounds, and the results agree with the experimental one. The efficiencies marked from all employed techniques were in perfect correspondence, demonstrating the validity of these procedures.


2019 ◽  
Vol 70 (2) ◽  
pp. 581-584 ◽  
Author(s):  
Liviu Mitu ◽  
Sweetlin Rajula Rubavathi ◽  
Muthupoongodi Subramani ◽  
T. Linda ◽  
S. Balakumar

The effect of Azadirachta indica leaf (AIL) extract on the corrosion of copper in 1M HNO3 was investigated by weight loss technique. The result showed that the corrosion rate decreased in the presence of plant extract and inhibition efficiency increased with increasing the concentration of extract. The decreased corrosion rate was due to adsorption of plant extract which was discussed on the basis of Langmuir adsorption isotherm.


1981 ◽  
Vol 77 (4) ◽  
pp. 475-487 ◽  
Author(s):  
S McLaughlin ◽  
J Brown

The Fick diffusion equation is combined with the Langmuir adsorption isotherm and the relevant equations from the Gouy-Chapman theory of the electrical diffuse double layer to demonstrate that the effective diffusion coefficient of calcium ions, both in the cytoplasm of the rod outer segment and within the aqueous space bounded by the disk membrane, should be reduced by a factor of 10-100 because these ions adsorb to phospholipids present in the disk membrane.


1965 ◽  
Vol s3-106 (76) ◽  
pp. 299-306
Author(s):  
D. J. GOLDSTEIN

If two histological sections, of thickness nµ and 2nµ, and having the same apparent intensity of staining, are at equilibrium with dyebaths of concentration B1 and B2 respectively, the affinity of the histological substrate for the dye is, under denned conditions, given by the expression ΔF° = - RT In I/B, where B is either (i) B2 if the thinner section is stained to saturation, or (ii) B1 if B1 = 3B2. The affinity tends to be greater when measured in a weaker dyebath, as implied in method (ii). Evidence is presented suggesting that the uptake of the basic dye Azure A by pancreatic basal chromidial substance, goblet cell mucin and intestinal epithelial cytoplasm follows a Langmuir adsorption isotherm to a first approximation, in that, at low dyebath concentrations, the uptake of dye is proportional to the concentration of dyebath with which the substrate is in equilibrium, while in strong dyebaths the uptake approaches a plateau. A deviation from the ideal Langmuir isotherm in dyebaths of moderate concentration, observed in epithelial cytoplasm and to a lesser extent in pancreatic basal chromidial substance, may have been due to interaction between neighbouring dye-binding sites, or to the presence in a single area of sites with different affinities for the dye.


1949 ◽  
Vol 27b (12) ◽  
pp. 879-889 ◽  
Author(s):  
R. Donovan ◽  
P. Larose

The amount of acid sorbed by wool from solutions of sulphuric acid of four different strengths (namely, 0.0505, 0.0339, 0.0182, and 0.0101 molar) and containing sodium sulphate in amounts varying up to 0.16 molar has been determined. It has been found that the presence of the salt has little effect on the quantity of acid sorbed within those limits. The results are analyzed in the light of the theory of Gilbert and Rideal but this theory fails to give a satisfactory explanation of the results obtained. It is possible, however, to explain the results of the authors' experiments on the basis of the recent application of the Donnan equilibrium by Peters and Speakman. The Langmuir adsorption isotherm equation has been applied to data on the absorption of hydrochloric acid and of sulphuric acid by wool. The data appear to fit the Langmuir equation and give, for the maximum combining capacity, values that agree well with those estimated in other ways.


2014 ◽  
Vol 511-512 ◽  
pp. 55-58
Author(s):  
Zhe Qin ◽  
Qian Wang ◽  
Zheng Liu

This paper regarded the sediments of Lake Baiyangdian as the object of study, researched and analyzed ammonia nitrogen adsorption characteristics of sediment samples. The results showed that: the sediments adsorption to ammonia nitrogen reached a state of equilibrium after 2.5h, The ammonia nitrogen adsorption rate was maximum in 0~10min. Sediment adsorption of ammonia nitrogen was higher as ammonia nitrogen liquid balance concentration increased. The adsorption isotherm curve of ammonia nitreogen can be fitted well by the Langmuir adsorption isotherm model. The total maximum adsorption quantity of ammonia nitrogen by the sediments of Lake Baiyangdian is between 54.12mg/kg to 240.12mg/kg.


2015 ◽  
Vol 39 (5) ◽  
pp. 3835-3844 ◽  
Author(s):  
Sachin Mane ◽  
Surendra Ponrathnam ◽  
Nayaku Chavan

Langmuir adsorption isotherm demonstrates monolayer drug loading with hyperhydrophilic three-dimensional crosslinked polymers. Furthermore, the pseudo order kinetics were also evaluated.


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