![]() ![]() For analysis of the equilibrium experimental data the General Langmuir isotherm was applied, in the case of kinetic data various equations and models including first-, second-, mixed-order, their fractal analogus, and multi-exponential equations, and diffusion models were used. An increase in the adsorption rate and amount was observed with increasing temperature. The adsorption kinetics were measured at 278, 288, 298, 308, 318 and 328 K. ![]() High sorption capacities were obtained, reaching even about 11, 5 and 6 mmol/g for 2-, 3- and 4-nitrophenol, respectively. The adsorption equilibrium measurements were carried out at 278, 298 and 318 K. The structural and surface characteristics of the applied adsorbent were estimated by nitrogen adsorption/desorption and potentiometric titration. ![]() The temperature dependences of adsorption equilibrium and kinetics were measured and analyzed for 2-, 3-, 4-nitrophenol removed from aqueous solutions by activated carbon. This was due to the mathematical simplicity of the linearised form of the PSO and the errors generally associated with the linearisation of kinetic models. It was observed that 10% of the studies had PFO as best-fit when linear modelling was used but 15% was best-fit with non-linear modelling. PSO is superior to PFO because it captures both the amount of active sites and the concentration of adsorbate as rate-limiting factors. However, 15% of the studies for mesoporous adsorbent had Pseudo-second-order (PFO) model as best-fit and 6% for microporous adsorbents. The Pseudo-second-order (PSO) model was best suited for all cases. The mesoporous range is the superior pore size for MB adsorption kinetics. Microporous pore size leads to a drop in kinetic constant because the diffusion of MB through very small pores is restricted and gradual due to the adsorbate size. However, MB uptake was significantly slower for micropores. It was observed from the study that the kinetic constant increased as the pore size progressed from the macroporous to the mesoporous range. The paper employed a novel methodology where empirical findings across studies were summarised, analysed juxtaposed to derive observations. The aim of this study was to investigate the effect of pore size on the adsorption kinetics of methylene blue (MB). The kinetics/rapidity is an important aspect of its uptake which is affected by the adsorbent pore properties. The experimental data showed that the greatest adsorbed amounts of lysozyme were obtained at the lowest tested frequencies (0.1 – 1.0 Hz), results that are in line with the corresponding dielectric features of the protein.ĭue to the negative environmental effect of methylene blue (MB), researchers have been investigating several aspects of its adsorption. In these experiments, the applied signal was defined by a sinusoidal wave with an amplitude of 100 mV and superimposed to +800 mV (applied as a working potential) and varying the frequency in the 0.1 – 10000 Hz range. ![]() To verify the validity of these observations, the adsorption behavior of lysozyme onto optically transparent carbon electrodes was also investigated under the influence of an applied alternating potential. The basic experiment, that can be performed in less than 5 min and with a single sample, not only allowed confirming the susceptibility of the selected protein towards the electric signal but also identified that this protein would respond more efficiently to signals with lower frequencies. Specifically, the polarization behavior of a layer of adsorbed lysozyme was investigated using a triangular‐wave signal with frequencies varying from 0.5 Hz to 2 Hz. As a simple and fast way to guide protein adsorption experiments, this report describes the application of dielectric spectroscopy. ![]()
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