Adsorption studies of Ce(III) and Zr(IV) from aqueous solution using clay and humic acid—clay materials

Delonix regia seed pod-an efficient biosorptive candidate toward the removal of Rhodamine B from simulated wastewater: characterization, kinetics, and equilibrium approach

This study focused on the comparative analysis of biosorption performance of Delonix regia seed pod toward the removal of Rhodamine B (RB) from simulated solution using native (DRSP) and chemically treated form (ADRSP). The surface morphology, structural analysis, textural properties, and thermal analysis of DRSP and ADRSP were examined using scanning electron microscopy (SEM), BET analysis, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), respectively. FTIR analysis concluded that surface functional groups like hydroxyl -OH stretching, C-N stretching, and C = C stretching of the aromatic ring were largely responsible for the attachment of RB. The chemical treatment enhanced the surface morphology of D. regia seed in terms of heterogeneity, distinct depth cavities, and irregular pores responsible for RB biosorption. The biosorption of RB was investigated using parametric analyses such as solution pH, biosorbent dosage, contact time, initial RB concentration, and operating temperature. The obtained equilibrium data were fitted with different isotherm and kinetic models. Langmuir isotherm model and pseudo-second-order kinetic were well suitable for the biosorption of RB using DRSP and ADRSP. The maximum monolayer biosorption capacities (mg/g) of DRSP and ADRSP were predicted to be 39.37 and 60.61, respectively. Using thermodynamic principles, the removal of RB was found to be thermodynamically feasible, endothermic, and spontaneous process. The results of the present study proved that DRSP and ADRSP can be identified as promising biosorbents for the removal of RB.

Adsorption and Separation of Crystal Violet, Cerium(III) and Lead(II) by Means of a Multi-Step Strategy Based on K10-Montmorillonite

A multi-step procedure, based on the employment of K10-Montmorillonite, is proposed for the selective removal of metal ions and dyes from a multicomponent solution. The objective is twofold: decontaminate the effluents and separate and recover the valuable byproducts present in wastewaters. Three common contaminants, i.e., crystal violet dye (CV), Ce(III) and Pb(II) were chosen as “model” pollutants. The main factors affecting the pollutants’ sorption were investigated. The experimental data were correlated with adsorption isotherms and kinetic models to obtain a deeper insight into the adsorption processes. The affinity of the clay toward the pollutants is favored by an increasing pH and follows the order CV > Pb(II) > Ce(III). Whereas Ce(III) metal ions do not adsorb onto clay under strongly acidic conditions, both Pb(II) and CV can adsorb under all the investigated pH conditions. The analysis of isotherms and kinetic profiles revealed that CV adsorbs onto clay through a mechanism consisting of two parallel processes, namely cation exchange on the external mineral surface and in the interlayer and surface complexation at the edge sites, while metal ion uptake is due solely to cation exchange processes involving mineral surfaces. The time required for the complete removal of pollutants follows the order CV > Ce(III) >> Pb(II). The possibility to modulate the adsorption features by changing experimental conditions was successfully employed to propose the best strategy for the progressive removal of different components from aqueous solutions.

Modification of perlite to prepare low cost zeolite as adsorbent material for removal of 144Ce and 152+154Eu from aqueous solution

The expanded perlite and base activated perlite (Zeolite-NaA) results from treating perlite has a SiO2:Al2O3 ratio ~2 were used as an adsorbents for the removal of 144Ce and 152+154Eu. The two adsorbents were fully characterized. The factors affecting the sorption of radionuclides onto expanded and modified perlite including contact time, pH, ion concentration were investigated. The modification process of expanded perlite enhanced the removal of 152+154Eu from 17.0 to 97.0 %, while for 144Ce from 22.0 to 91.0 %. Both 144Ce and 152+154Eu obey Langmiur isotherm model in case of using modified perlite (Zeolite-NaA) and expanded perlite.