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Calculation of Metal Ion Uptake in Environmental Systems
Published in Jiaping Paul Chen, Decontamination of Heavy Metals, 2012
The Langmuir adsorption model assumes that there are a fixed number of definite localized adsorption sites on a homogeneous surface, that each site can hold one adsorbate molecule (monolayer adsorption), and that there is no interaction between adsorbed molecules on neighboring sites. Adsorption occurs according to the following reaction: S+X=SXb=[SX][S][X]
Removal of chromium from water using manganese (II, III) oxides coated sand: adsorption and transformation of Cr(VI) and Cr(III)
Published in Environmental Technology, 2023
Lisha Wu, Amid P. Khodadoust, Snover Punia
The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) adsorption isotherm equations were employed in this study to evaluate the adsorption of chromium species onto the MCS sorbent. The Langmuir adsorption model is an empirical model that assumes the adsorbent surface consists of identical and equivalent adsorption sites that only allow monolayer adsorption [41]. The non-linear form of Langmuir can be represented by the following equation: where Ce is the equilibrium concentration of chromium in solution (mg/L), qe is the equilibrium amount of chromium adsorbed per unit mass of the MCS sorbent (mg/kg), qmax is the maximum adsorption (adsorption capacity) of the MCS sorbent (mg/kg), and KL is Langmuir constant related to the binding energy or affinity parameter of the adsorption system. These parameters can be determined by obtaining the slope and intercept from the linear plot Ce/qe verse Ce.
Removal of vanadium from aquatic environment using phosphoric acid modified rice straw
Published in Bioremediation Journal, 2020
Wen-yan He, Wei Liao, Jin-yan Yang, Paramsothy Jeyakumar, Christopher Anderson
To understand the extent and driving force of the adsorption process, experiment data were analyzed by the Langmuir and Freundlich adsorption isotherm models. The Langmuir adsorption model presumes that the adsorbent surface is homogeneous, all sites are equivalent, and each site can hold at most one molecule and no interactions between adsorbate molecules on adjacent sites (Langmuir 1918) [Eq. (2) – (3)]. The Freundlich adsorption model assumes that the adsorbent surface is heterogeneous and interaction between adsorbate molecules is possible (Freundlich 1932) [Eq. (4)]. where qm is the Langmuir maximum adsorption capacity (mg g−1); RL is the Langmuir constant, and the RL value between 0 to 1 indicates favorable adsorption; b is equation constant; KF is Freundlich constant (L g−1); n is heterogeneity coefficient.
A combination method based on chitosan adsorption and duckweed (Lemna gibba L.) phytoremediation for boron (B) removal from drinking water
Published in International Journal of Phytoremediation, 2018
The Langmuir adsorption model is a very common isotherm model for monolayer adsorption and it is used to assess adsorption capacity. Langmuir model for adsorption on a homogeneous surface with a finite number of identical sorption is as follows (Oladipo and Gazi 2016):where qe is the quantity of B adsorbed per unit weight of sorbent (peat-chitosan and dried Lemna-chitosan beads) and Ce is the unadsorbed B concentration remaining in the effluent. qm corresponds to the maximum quantity of B adsorbed per unit dry weight of sorbent (peat-chitosan and dried Lemna-chitosan beads) to form a complete monolayer on the surface and KL is a constant associated with the affinity of the binding site.