Adsorption performance of Zr-pillared montmorillonite for the removal of organic pollutants from aqueous phase

This study examined the effectiveness of Zr-pillared Na-rich montmorillonite (PILC) in removing humic acid (HA) and tannic acid (TA) from aqueous solutions by adsorption. Batch experiments were conducted to evaluate the pH effects, the kinetics, temperature effects and sorption isotherm on the HA and TA adsorption onto PILC. The research demonstrated that the PILC could sufficiently remove HA and TA from aqueous solutions. The most effective pH range was found to be 3.0 to 4.0 for both HA and TA. The kinetic studies showed that all equilibrium time of 6 h was needed for the adsorption or HA and TA oil PILC and adsorption rates could be described by a first-order Lagergren equation. The adsorption of HA and TA was found to increase with ionic strength due to the compression of diffuse double layer. The equilibrium isotherm data for both HA and TA fitted Langmuir isotherm model and based on Langmuir constants, the PILC had a greater adsorption capacity for HA than for TA. The isosteric heats of the adsorption process were determined at various surface coverages or the adsorbent. The thermodynamic parameters such as change in free energy (DeltaG(0)), enthalpy (DeltaII(0)), and entropy (DeltaS(0)) were derived to predict the nature of adsorption. Sheindrof-Rebhun-Sheintucth isotherm model was used to study the competition interaction for the adsorption of single component from mixture by PILC. About 91.4 and 94.8% or HA and TA call be recovered from the spent adsorbent by controlling the pH at 11.0.