Insight into the adsorption kinetics models for the removal of contaminants from aqueous solutions

On validity, physical meaning, mechanism insights and regression of adsorption kinetic models

Kinetic, equilibrium and thermodynamic phenomenological modeling of reactive dye adsorption onto polymeric adsorbent

This chapter is related to the main aspects of the kinetic adsorption models by heterogeneous mechanisms applied in the studies of mass transfer in chromatography. The kinetic adsorption models are implemented and described according to the adsorption mechanisms as in the next Figure 1. The illustrations as in Fig. 1 are a good way to show the steps in the determination of the final models that represent the mass transfer between the solid and liquid phase.

Removal of Reactive Red 195 from aqueous solutions by adsorption on the surface of TiO 2 nanoparticles

Magnetic nanosorbents efficiently capture substances, particularly basic dyes, and can be easily recovered using a magnetic field in water treatment. Adsorption is a cost-effective and highly efficient method for basic dye removal. This study compared eight nonlinear kinetic adsorption models using Microsoft Excel 2023, which provided a detailed analysis and statistical results comparable to advanced programs like MATLAB and OriginPro. The Fractal Like-Pseudo First Order (FL-PFO) model showed the best fit for the kinetic adsorption model, closely predicting experimental data at 33.09 mg g−1. This suggests that the diffusion rate of basic dye within the magnetic nanosorbent pores is a crucial factor. The statistical parameters confirmed the suitability of these kinetic adsorption models for describing the observed behavior. Overall, Microsoft Excel emerged as a reliable tool for predicting adsorption behavior using various kinetic models for basic dye removal, offering a wide range of functions for diverse applications, including environmental monitoring and modeling. Corrected Akaike’s information criterion was used to determine the optimal model. It found the lowest AICcorrected value of about −3.8479 for the FL-PFO kinetic model, while the Elovich kinetic adsorption model had the highest AICcorrected value of 29.6605. This indicates that the FL-PFO kinetic model effectively correlated the kinetic data. It can be concluded that Microsoft Excel’s accessibility, familiarity, and broad range of capabilities make it a valuable resource for many aspects of environmental engineering.

In this research, the adsorbents of ternary-component composites were developed to remove various types of toxic chemicals. The selected three components are clay, MgAl-layered double hydroxide (MgAl-LDH) and biochar because they are nontoxic and low cost and also possess high adsorption capacity and high surface area. The composites were synthesized by the combination of post-pyrolysis and co-precipitation methods, and characterized by XRD and SEM-EDS. The result shows that clay and LDH particles distributed and deposited on the biochar matrix, confirming the coexistence of three phases in micrometer and nanometer scales.
 
 Ni2+, CrO42- and 4-Nitrophenol were chosen as the representatives of chemical contaminant�species of cation, anion, and organic compounds, respectively, for the adsorption study. The kinetic adsorption models and the isotherm adsorption models were�used to explain the adsorption capacity and behavior of clay/MgAl-LDH/bagasse biochar composite (CLB) and clay/MgAl-LDH/rice straw biochar composite (CLR). The result of Ni2+ adsorption agreed with the pseudo-second-order kinetic model and the Langmuir isotherm model. The adsorption mechanism was proposed to be a cation exchange between Na+ and Ca2+ in the interlayer of clay and the adsorbate Ni2+. Meanwhile, the adsorption behavior of an anionic adsorbate CrO42- was also well fitted with the pseudo-second-order kinetic model and the Langmuir isotherm model. The proposed adsorption mechanism was the exchange of CrO42- with NO3- and CO32- in the interlayer of MgAl-LDH. The maximum adsorption capacities (Qmax) of CLB were 13.2 mg g-1 and 7.5 mg g-1 towards Ni2+ and CrO42-, respectively. Those of CLR were 12.7 mg g-1 and 6.1 mg g-1, respectively. The adsorption of 4-Nitrophenol could be explained by the pseudo-second-order kinetic model and the Freundlich isotherm model. The adsorption intensity (n) of CLB and CLR were 1.7 and 1.8, respectively, indicating favorable adsorption.
 
 In addition, this study explored the fixed bed adsorption technique by using the CLB and CLR for 4-nitrophenol removal. The adsorption performance was presented by the breakthrough curve corresponding to the ratio of the initial concentration, the residue concentration and the effluent volume of 4-nitrophenol. The cumulative adsorbed amounts of CLB and CLR were 0.88 mg g-1 and 0.37 mg g-1, respectively, obtained using 2 cm bed thickness, 0.3 mL min-1 and the initial concentration of 10 mg L-1. These ternary composite adsorbents were demonstrated as promising sorbents for the removal of various contaminant species.

Adsorption isotherm and kinetic models are essential in predicting the adsorption mechanisms, which helps in boron (B) recommendation at appropriate doses. This study is formulated with the objective of assessing different kinetic and adsorption models for the adsorption of B in different soil orders (Entisol, Alfisol, Inceptisol and Vertisol) in Oil Palm plantations in India. The B adsorption in soils followed the order: Vertisol > Alfisol > Inceptisol > Entisol. The results revealed that, the Langmuir adsorption model fitted well for alfisol (part1 R2 = 0.9912 & part2 R2 = 0.9678), entisol (R2 = 0.9862) and inceptisol (R2 = 0.9924), while the Freundlich model fitted well for vertisol (R2 = 0.9943). The soils under entisol and inceptisol showed linear isotherms whereas, the vertisol and alfisol had curvilinear isotherms and the split Langmuir isotherm was worked out. High bonding energy at the lower part of split isotherm represented stronger retention of B at lower B concentrations. The B equilibrium was attained in 24 h in alfisol and inceptisol, and 12 h in entisol, whereas in vertisol, the equilibrium was not completed until 72 h. From the correlation coefficients obtained from all models, the pseudo-second-order kinetic model explained the B sorption in a better way followed by elovich and power function kinetic models in different soil types. Desorption of B is higher in entisol in most of the added B concentrations. The study suggests a higher rate of B fertilizer application than the recommended in soils having high B adsorption capacity for optimum crop growth and yield.

Adsorption kinetic models: Physical meanings, applications, and solving methods

Facile Synthesis of NaOH-modified Fishbone Charcoal (FBC) with Remarkable Adsorption towards Methylene Blue

Adsorptive removal of pollutants from industrial wastewater using mesoporous kaolin and kaolin/TiO2 nanoadsorbents

Adsorption on activated carbons from end-of-life tyre pyrolysis for environmental applications. Part II. Adsorption from aqueous phase

Trends of natural and acid-engineered pumice onto phosphorus ions in aquatic environment: adsorbent preparation, characterization, and kinetic and equilibrium modeling

Equilibrium and kinetic models on the adsorption of Reactive Black 5 from aqueous solution using Eichhornia crassipes/chitosan composite

Study of adsorption isotherms and kinetic models for Methylene Blue adsorption on activated carbon developed from Egyptian rice hull (Part II)

Study of isotherm and kinetic models of lanthanum adsorption on activated carbon loaded with recently synthesized Schiff’s base