Evaluation of Kinetic Adsorption Models in Aquatic Environment, Models of Lagergren and Ho et al.
Vijay P. Singh
|Veröffentlicht in:||American Research Journal of Civil and Structural Engineering, 2018, n. 1, v. 2|
|Abstrakt:||Heavy metal pollution has become one of the most crucial environmental obstacle today. The treatment of heavy metals is of special concern due to their refractoriness and resistence in the environment. In recent years, different procedures for heavy metal removal from wastewater have been widely studied.This paper revises the common procedures that have been applied to treat heavy metal wastewater and considers these techniques.Presently kinetic adsorption equations are widely used in adsorption processes. The main objective of the present research is to evaluate the linear and non-linear equations of the Lagergren and Ho et al. models in the kinetics of nickel adsorption by activated carbon. For this purpose, powdered activated carbon, the raw material of which is wood, was purchased from the “Merck” company (Germany). The optimum PH of the adsorption was obtained to be 6. As well, the kinetics of adsorption showed that for the initial nickel concentration of 2.5, 5, 10, 50 and 125 mg/L, equilibrium time was 40, 75, 120, 150, 50 minutes respectively. The maximum removal efficiency of nickel in the initial concentration of 2.5 mg/L was obtained to be 89.6%. The fitting of the four linear kinetic models of Ho et al. (1995), and its non-linear model, as well as the linear model of kinetic data of adsorption at different concentrations showed that the non-linear model of Ho et al. (1995) better describes the kinetic data of nickel adsorption by activated carbon thanhis linear models. Comparison of the non-linear models of Ho et al. and Lagergren (1893) showed that in low concentrations the non-linear model of Ho et al., and in high concentrations non-linear model of Lagergren better describes the kinetic data of adsorption.First and second-order rate equations were pragmatic to etude adsorption kinetics.The most significant advantage of the offered model is its capability to predicate the balance time of adsorption, which is very essential to optimize the expense of the adsorption system design.The received consequences depict that the new model can analyze the experiential information very well.The equation is received clearly by changing the mass balance equation of a single step batch-type system into integrated first order rate equation. The proposed new formulation depends on maximum sorption (or removal) rather than equilibrium sorption, as given by Lagergren equation.The precise value of equilibrium sorption is not easy to describe in many cases, and it is exhibit that the modified formulation prepares better correlation with sorption data when the procedure is far from completion.A corrected formulation of the popular Lagergren pseudo first order rate equation is proposed.The equation is created clearly by changing the mass balance equation of a single step batch-type system into unified first order rate equation. The proposed new formulation depends on maximum sorption (or removal) rather than equilibrium sorption, as given by Lagergren equation. The precise value of equilibrium sorption is not simple to describe in many cases, and it is exhibited that the modified formulation provides better correlation with sorption data when the process is far from completion.|
|Copyright:||© Zahra Askari, Shayan Shamohammadi, Ali Hasantabar-Amiri, Kaveh Ostad-Ali-Askari, Saeid Eslamian, Vijay P. Singh|
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