Liquid-phases adsorption equilibrium of phenol onto two naturally available soils namely Kalathur soil (Kr) and Adhanur soil (Ar) were studied. The experimental data were analyzed using fourteen Isotherm models, ranging from single-parametric model to multi-parametric models (up to 5 parameters) of the system. Results show that in general the accuracy of models to fit experimental data improves with the degree of freedom. To understand the mechanism involved with different types of sorbate-sorbent system as well as to find out the best fitting Isotherm model, the correlation coefficients, and average percentage error and student t-test were carried out. Temkin Isotherm model, Langmuir-Freundlich Isotherm model and Fritz-Schlunder model as well as Baudu model were found to be the best fit models amongst the two-parametric models, three parametric models and four parametric Isotherms modeling, respectively. This study brings out the need of simultaneous solution of multi-parametric equations (using relevant softwares, MATLAB, in present case) than solution of their linearized forms, which is mostly followed by contemporary investigators.

Adsorption plays an important role in water and wastewater treatment. The analysis and design of processes that involve adsorption rely on the availability of Isotherms that describe these adsorption processes. Adsorption Isotherms are usually estimated empirically from measurements of the adsorption process variables. Unfortunately, these measurements are usually contaminated with errors that degrade the accuracy of estimated Isotherms. Therefore, these errors need to be filtered for improved Isotherm estimation accuracy. Multiscale wavelet based filtering has been shown to be a powerful filtering tool. In this work, multiscale filtering is utilized to improve the estimation accuracy of the Freundlich adsorption Isotherm in the presence of measurement noise in the data by developing a multiscale algorithm for the estimation of Freundlich Isotherm parameters. The idea behind the algorithm is to use multiscale filtering to filter the data at different scales, use the filtered data from all scales to construct multiple Isotherms and then select among all scales the Isotherm that best represents the data based on a cross validation mean squares error criterion. The developed multiscale Isotherm estimation algorithm is shown to outperform the conventional time-domain estimation method through a simulated example.

Introduction: The effects of pH and temperature on the equilibrium of bovine serum albumin (BSA) adsorption onto hydroxyapatite (HA) were investigated.Aim: Adsorption equilibrium using Isotherms experiment was carried out at fixed pH and temperature.Materials and Methods: The amount of protein BSA onto HA measured with UV-Vis spectroscopy at l=280 nm.Results: The Langmuir Isotherm constants corresponding to adsorption capacity, qm, 0 was 3.3478 mg/g at 22oC and pH=7.2.Conclusion: Higher values of the adsorption of BSA onto HA at pH 7.2, could be due to the change of pore structure of HA or denaturation by conformational change of BSA.

Estimation of absolute adsorption in shale gas reservoirs is one of the key parameters. Experimental studies can only measure the excess adsorption Isothermal directly. Also, in most experimental studies, excess adsorption up to a pressure of 15 MPa is measured. As a result, Langmuir and supercritical Dubinin–Radushkevich (SDR) adsorption models are used to convert the excess to absolute adsorption at measured pressures and above. Using hybrid grand canonical Monte Carlo/molecular dynamics (GCMC/MD) simulations, we simulate methane fluid in kerogen with 4 nm pore size at three temperatures of 303. 15, 333. 15, and 363. 15 K up to a pressure of 50 MPa. Then the accuracy of adsorption models to estimate the absolute adsorption is investigated. The molecular simulation results show that the adsorbed density is a function of pressure and temperature and is always less than the liquid methane density. The Langmuir and SDR adsorption models show low accuracy of both models in estimating the absolute adsorption at all temperatures. Finally, using the adsorbed volume obtained from molecular simulation to estimate the absolute adsorption at all temperatures and pressures has an error of less than 10%, and the use of this method is recommended.

In this work, we consider each normal alkane as a hypothetical mixture of methyl and methylene groups, in which the interaction potential of each pair is assumed to be the average effective pair potential. Then, the LIR equation of state (EOS) is extended for such a hypothetical mixture. Also, three basic compounds, namely, propane, n-butane and cyclohexane, are used to obtain the contribution of each carbonic group in the EOS parameters. Using the calculated EOS parameters along with the modified EOS, the density of n-alkanes and their mixtures at different pressures and temperatures are calculated. The average percentage error in density is found to be less than 1.5% for both the pure normal alkanes and their binary mixtures.

The optimization of adsorption-based operations requires an accurate model to represent the separation process. In the present study, single-component adsorption data of L-lysine on its imprinted polymer were fitted to Freundlich, Langmuir-type and Jovanovic-type models. L-Lysine imprinted polymer (LLIP) was prepared by free radical solution polymerization. The best estimate of the parameters of these models by regression analysis was obtained. The statistical analysis of results showed that the experimental data fit the Jovanovic-Freundlich mode, better than other models in terms off value. The best prediction of retention capacity equal to 0.186 mmol lysine per g of LLIP, which is the nearest value to the experimental data, was obtained by applying the Jovanovic model.

The adsorption of polymeric systems onto reservoir rock through altering the wettability of rock surface improves oil recovery and reduces the unwanted water production. In this study, the adsorption behavior of dilute polymeric systems based on sulfonated polyacrylamide on the glass particles surfaces (representative of sandstone reservoirs) was investigated and the effect of this phenomenon on changing their surface properties was examined. Results show that crosslinked polymeric samples have lower adsorption on glassy surface comparing with uncrosslinked sulfonated polyacrylamide solution. Furthermore, the contact angle tests results showed that crosslinked samples change the surface property of glass particle less than sulfonated polyacrylamide solution. In addition the Langmuir Isotherm model fitted the Isotherm data better than the Freundlich model for these dilute polymeric systems. Furthermore, study of the thermodynamic of adsorption showed that their adsorption behavior on glassy surfaces is a spontaneous and exothermic process.