Adsorption of textile dyes on raw Tunisian clay: Equilibrium, kinetics and thermodynamics

Natural clay from Nabeul region (north of Tunisia) was investigated for the removal of two anionic textile dyes (RR120 and BB150) from aqueous solution. The raw clay was characterized by means of XRD, IR spectroscopic, chemical analysis, cation exchange capacity and BET surface area analysis.Adsorption studies were carried out under various parameters such as pH, contact time, initial dye concentration and temperature. The adsorption kinetic data was tested by pseudo-first order, pseudo second-order and intra-particle diffusion kinetic models. The equilibrium data were analyzed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The thermodynamic parameters (DH°, DS° and DG°) of the adsorption were also evaluated. The adsorption process was found spontaneous and endothermic in nature. The kinetics of adsorption were best described by pseudo-second order kinetic model. The Langmuir adsorption model totally agrees with the experimental data.Â

Actions with finite orbits on local dendrites

It is shown that the restriction of the action of any group with finite orbit on the minimal sets of local dendrites is equicontinuous. Consequently, we obtain that the action of any amenable group and Thompson group restricted to any minimal sets of dendrite is equicontinuous. We further provide a class of non-amenable groups whose action on the minimal sets of local dendrites is equicontinuous. Moreover, we extend some of our results to dendron. We further give a characterization of the set of invariant probability measures and its extreme points