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Identification Of Receptors In Vitro
Published in William C. Eckelman, Lelio G. Colombetti, Receptor-Binding Radiotracers, 2019
This expression is equivalent to the Langmuir adsorption isotherm, derived for the formally equivalent situation of the binding of a gas to a surface.5 It is also analogous to the expression derived for a different case, the velocity of an enzyme-catalyzed reaction based on the reaction E + S⇋ES →E + P. This reaction gives the MichaelisMenten equation:6
Pharmacokinetic-Pharmacodynamic Relationships of Cardiovascular Drugs
Published in Hartmut Derendorf, Günther Hochhaus, Handbook of Pharmacokinetic/Pharmacodynamic Correlation, 2019
Similar equations and models have been used to describe a variety of biochemical processes (e.g., protein binding, enzyme kinetics) since they all reflect reversible binding of a ligand to a receptor. The classic Michaelis-Menten equation, which relates the rate of a chemical reaction to the concentration of substrate, the maximum velocity (Vmax) and the Michaelis constant (Km), is in the form of Equation 7. The equation is also analogous to the Langmuir adsorption isotherm, which is used to describe the adsorption of gases to solid surfaces.5 Similarly, the association of oxygen and hemoglobin was described by Hill6 in 1910 using the equation:
Polymer Adsorption: Fundamentals
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
The adsorption of polymers at the liquid/liquid interface is somewhat different from that at the solid/liquid interface as the polymer can penetrate both phases. χ determines the adsorption behavior of polymers at liquid/liquid interfaces. The presence of the polymer at the interface between the two immiscible liquids lowers the surface tension. Determination of the adsorption isotherm (see Section IX.B) is more straightforward compared to particulate dispersions as surface tension measurements, interpreted using the Gibbs equation, can be used to give accurate adsorbed amounts.
Optimization of Swiss blue dye removal by cotton boll activated carbon: response surface methodological approach
Published in Toxin Reviews, 2022
Rekha Rani, Summaiya Tasmeem, Anju Malik, Vinod Kumar Garg, Lakhvinder Singh, Sanju Bala Dhull
The mechanism of adsorption is commonly investigated through graphical representation known as adsorption isotherm. Isotherms illustrate the dispersal of dye among solid and liquid stage at certain temperature (Aljeboree et al.2017). The adsorption equilibrium of dye on AC was assessed in adsorption experiments. Different models have been applied in literature to express preliminary adsorption data in the isotherm. Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D–R) are the generally applied models (Pathania et al.2017, Hasan et al.2019, Shakya et al.2019, Kıvanç and Yönten 2020). Equilibrium sorption isotherms prove to be incredibly important for efficiency determination of an adsorbent. In the present investigation, four types of isotherms, viz. Langmuir, Freundlich, Temkin, and D–R were applied to the adsorption data. Thermodynamic parameter – Gibbs free energy change (ΔG0ads) was also computed and used for describing the results.
High surface area microporous activated carbon from Pisum sativum peels for hexavalent chromium removal from aquatic environment
Published in Toxin Reviews, 2022
Taher Sahlabji, Mohamed A. El-Nemr, Ahmed El Nemr, Safaa Ragab, Majed M. Alghamdi, Adel A. El-Zahhar, Abubakr M. Idris, Tarek O. Said
Langmuir, Freundlich, and Tempkin adsorption isotherm models were applied to the experimental results and illustrated in supplementary Figure S2(a, b and c) in a Supplemental file. Moreover, the models parameters were determined from the linear regression and the results are displayed in Table 2. The results in Table 2 reveal a significant fit for the adsorption of Cr(VI) on AC with the Langmuir, Freundlich, and Tempkin models with correlation coefficients R2 > 0.99. This finding reflects applicability of the three isotherm model’s for the adsorption of Cr(VI) on AC, which might indicate that chemical and physical adsorption could participated in the process, in which the presence of oxygen atoms in AC could play an important role in this concern.
Eriochrme black-T removal from aqueous environment by surfactant modified clay: equilibrium, kinetic, isotherm, and thermodynamic studies
Published in Toxin Reviews, 2019
Ghader Zeydouni, Mahsa Kianizadeh, Yusef Omidi Khaniabadi, Heshmatollah Nourmoradi, Shirin Esmaeili, Mohammad Javad Mohammadi, Rajab Rashidi
In order to understanding how a molecules interact with adsorbents and how the molecules distribute between the phases of solid and liquid, when a uptake process reaches equilibrium state. Thus, it is necessary to optimize the selective adsorbent for removal of pollutants from the environment (Babaei et al. 2016, Khurana et al. 2018). The experimental data of EBT adsorption were used to determine of the isotherms. Therefore, two isotherms include Langmuir and Freundlich models were employed for this purpose. The Langmuir isotherm approximates the greatest monolayer adsorption on the uniform surface of the adsorbent (Liu et al. 2015). The linearized form of Langmuir isotherm is presented by the following equation: Ce (mg/L) and qe (mg/g) are the initial EBT concentration and the HDTMA-modified MC uptake capacity in the equilibrium time, respectively. Qm (maximum sorption amount, mg/g) and b (the rate constant of Langmuir, L/mg) were acquired from the slope and intercept of linear plotting of Ce/qe versus Ce, respectively (Yang et al. 2004). The maximum adsorption capacity of EBT removal by HDTMA-modified MC was found to be 321.5 mg/g. Figure 7 (left) shows the liner plot of Langmuir isotherm. The Langmuir isotherm can be depicted with a dimensionless constant separation factor, RL, also called the equilibrium parameter that used to describe the characteristics of Langmuir adsorption isotherm. RL was obtained from the following equation: