An investigation of the formation of molecular complexes of O-(3,5-dinitrobenzoyl)-O-acetylcellulose with n- and π-donors

1988 ◽  
Vol 53 (3) ◽  
pp. 581-587
Author(s):  
Gabriel Čík ◽  
František Šeršeň ◽  
Anton Blažej ◽  
Viktor Hayden ◽  
Bohuslava Havlínová
Keyword(s):  
Aromatic Amines ◽  
Heterocyclic Compounds ◽  
Molar Mass ◽  
Specific Resistance ◽  
Molecular Complexes ◽  
Langmuir Adsorption Isotherm ◽  
Electric Resistance ◽  
Langmuir Adsorption ◽  
Condensed Hydrocarbons ◽  
Formation Of Complexes

Soluble O-(3,5-dinitrobenzoyl)-O-acetylcellulose was synthesized, and the formation of molecular complexes with n- and π-donors was investigated. The formation of complexes obeys the Langmuir adsorption isotherm adjusted for macromolecules. The formation of molecular complexes with low-molar mass compounds of the type of heterocyclic compounds, aromatic amines and condensed hydrocarbons was confirmed by electric resistance measurements. The largest decrease in the specific resistance by 2-3 orders of magnitude was observed with indole and phenothiazine, while the specific resistance of the other types of donors decreased by 1-2 orders of magnitude. A decrease in the activation energy took place with all types of complexes.

scholarly journals Diffusion of calcium ions in retinal rods. A theoretical calculation.

1981 ◽  
Vol 77 (4) ◽  
pp. 475-487 ◽  
Author(s):  
S McLaughlin ◽  
J Brown
Keyword(s):  
Diffusion Coefficient ◽  
Adsorption Isotherm ◽  
Calcium Ions ◽  
Outer Segment ◽  
Effective Diffusion ◽  
Langmuir Adsorption Isotherm ◽  
Diffuse Double Layer ◽  
Langmuir Adsorption ◽  
Retinal Rods ◽  
Disk Membrane

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.

A further note on the measurement of the affinity of a dye (Azure A) for histological substrates

1965 ◽  
Vol s3-106 (76) ◽  
pp. 299-306
Author(s):  
D. J. GOLDSTEIN
Keyword(s):  
Adsorption Isotherm ◽  
Goblet Cell ◽  
Binding Sites ◽  
Langmuir Isotherm ◽  
Langmuir Adsorption Isotherm ◽  
Intestinal Epithelial ◽  
Langmuir Adsorption ◽  
Azure A ◽  
First Approximation ◽  
The Ideal

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.

THE SORPTION OF ACIDS BY WOOL

1949 ◽  
Vol 27b (12) ◽  
pp. 879-889 ◽  
Author(s):  
R. Donovan ◽  
P. Larose
Keyword(s):  
Hydrochloric Acid ◽  
Adsorption Isotherm ◽  
Sulphuric Acid ◽  
Sodium Sulphate ◽  
Langmuir Adsorption Isotherm ◽  
Langmuir Equation ◽  
Recent Application ◽  
Satisfactory Explanation ◽  
Isotherm Equation ◽  
Langmuir Adsorption

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.

Adsorption Characteristic Research of Sediments of Lake Baiyangdian

2014 ◽  
Vol 511-512 ◽  
pp. 55-58
Author(s):  
Zhe Qin ◽  
Qian Wang ◽  
Zheng Liu
Keyword(s):  
Adsorption Isotherm ◽  
Nitrogen Adsorption ◽  
Ammonia Nitrogen ◽  
Langmuir Adsorption Isotherm ◽  
Adsorption Characteristic ◽  
Langmuir Adsorption ◽  
Lake Baiyangdian ◽  
Object Of Study ◽  
Total Maximum ◽  
Adsorption Quantity

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.

Removal of VOCs Using Sludge-Based Adsorbents

2012 ◽  
Vol 599 ◽  
pp. 305-308 ◽  
Author(s):  
Ping Fang ◽  
Chao Ping Cen ◽  
Hong Tao Zhang ◽  
Zi Jun Tang ◽  
Ding Sheng Chen ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Physical Adsorption ◽  
Low Cost ◽  
Fixed Bed ◽  
Cost Effective ◽  
Langmuir Adsorption Isotherm ◽  
Fixed Bed Reactor ◽  
Dynamic Adsorption ◽  
Langmuir Adsorption ◽  
Isotherm Equations

Efficient and cost-effective sludge-based adsorbents were developed and the adsorption of VOCs on the sludge-based adsorbents was studied in a fixed bed reactor. The results indicate that the adsorption of VOCs on sludge-based adsorbents is typical physical adsorption, the dynamic adsorption capacity of VOCs on adsorbents sharply increases as the VOCs concentration is increased at first, then increasing gradually, at last retains stable with the change of VOCs concentration. The dynamic adsorption capacity of sludge-based adsorbents for VOCs is O-Xylene > Butylcetate > Toluene > Ethylacetate > Benzene > Propanone > n-Hexane, the maximum dynamic adsorption capacity is 0.247, 0.225, 0.192, 0.186, 0.180, 0.176, 0.133g/g, respectively. Meanwhile the adsorption of VOCs on sludge-based adsorbents corresponds to the Langmuir adsorption isotherm equations. The sludge-based adsorbent is a low-cost alternative to activated carbon for VOCs treatment, and this technology is a promising method for the VOCs removal.

STUDIES ON THE ADSORPTION OF BORON ON HUMIC ACIDS

1990 ◽  
Vol 70 (3) ◽  
pp. 305-311 ◽  
Author(s):  
BAOHUA GU ◽  
L. E. LOWE
Keyword(s):  
Boric Acid ◽  
Humic Acids ◽  
Organic Matter Content ◽  
Langmuir Adsorption Isotherm ◽  
Matter Content ◽  
Langmuir Equation ◽  
Langmuir Adsorption ◽  
Ph Values ◽  
Ph Range

The adsorption of B, in the form of boric acid, was studied on three precipitated humic acids (HA), representing three distinct soil types. B adsorption by HA was strongly pH-dependent, being low and relatively constant in the pH range 3.0–6.5, increasing markedly up to a peak at near pH 9.5, and then decreasing at still higher pH values. Adsorption isotherms for pH values near 6.7 and 8.8 conformed well to the Langmuir equation. The adsorption maxima (b values), as calculated with the Langmuir equation, ranged from 73 to 207 mmol kg−1 HA at a pH near 8.8, and from 10 to 42 mmol kg−1 at a pH near 6.7. The considerable variation in B adsorption by these HA samples was attributed to "Fe + Al" contents present as contaminants in the HA. The role of HA in B adsorption is expected to be minor in most acid and near neutral soils, but may be of greater significance in soils of high pH and above average organic matter content. Key words: Boron adsorption, boric acid, humic acid, Langmuir adsorption isotherm.

Hyperhydrophilic three-dimensional crosslinked beads as an effective drug carrier in acidic medium: adsorption isotherm and kinetics appraisal

2015 ◽  
Vol 39 (5) ◽  
pp. 3835-3844 ◽  
Author(s):  
Sachin Mane ◽  
Surendra Ponrathnam ◽  
Nayaku Chavan
Keyword(s):  
Adsorption Isotherm ◽  
Acidic Medium ◽  
Drug Carrier ◽  
Drug Loading ◽  
Three Dimensional ◽  
Langmuir Adsorption Isotherm ◽  
Effective Drug ◽  
Crosslinked Polymers ◽  
Langmuir Adsorption

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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