Bio sorption of an anionic textile dye from aqueous solution by natural non-absorbent as solution to reduce toxic dye pollutant from wastewater Modelling and kinetic study

Na-bentonite was prepared and tested as an adsorbent for a dye (Reactive Blue2) removal from aqueous solution. The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, initial dye concentration, pH of the initial dye solution, temperature and time contact effects upon dye adsorption on Na–bentonite having a structural formula of (Si7.86 Al0.14)(Al2.98 Fe0.39 Mg0.65) Ca0.06 Na0.44 k0.12 O22, were thoroughly examined. The amounts adsorbed at equilibrium were measured. The Langmuir and Freundlich and Dubinin– Radushkevich (D–R) isotherm models were tested for their applicability. The equilibrium data satisfied Freundlich and D-R models since the correlation coefficients R was found to be around unity in these cases. Amount of dye removal by Na– bentonite was found to be around 37.6 mmol/100g at 20°C which close the anionic exchange capacity of the clay used in this study. The experimental data were analyzed using the pseudo-first-order, the pseudo-second-order and the intraparticle diffusion adsorption kinetic models. According to this model, the rate constants were evaluated for initial dye concentrations. The experimental data fit well with the pseudo-second-order kinetic model and very well interpreted with the intra-particle diffusion system.