PC-88A – impregnated polymeric beads: Preparation, characterization and application for extraction of Pu(IV) from nitric acid medium

Chain Entanglement of 2-Ethylhexyl Hydrogen-2-Ethylhexylphosphonate into Methacrylate-Grafted Nonwoven Fabrics for Applications in Separation and Recovery of Dy (III) and Nd (III) from Aqueous Solution

A nonwoven fabric adsorbent loaded with 2-ethylhexyl hydrogen-2-ethylhexylphosphonate (EHEP) was developed for the separation and recovery of dysprosium (Dy) and neodymium (Nd) from an aqueous solution. The adsorbent was prepared by the radiation-induced graft polymerization of a methacrylate monomer with a long alkyl chain onto a nonwoven fabric and the subsequent loading of EHEP by hydrophobic interaction and chain entanglement between the alkyl chains. The adsorbent was evaluated by batch and column tests with a Dy (III) and Nd (III) aqueous solution. In the batch tests, the adsorbent showed high Dy (III) adsorptivity close to 25.0 mg/g but low Nd (III) adsorptivity below 1.0 mg/g, indicating that the adsorbent had high selective adsorption. In particular, the octadecyl methacrylate (OMA)-adsorbent showed adsorption stability in repeated tests. In the column tests, the OMA-adsorbent was also stable and showed high Dy (III) adsorptivity and high selectivity in repeated adsorption-elution circle tests. This result suggested that the OMA-adsorbent may be a promising adsorbent for the separation and recovery of Dy (III) and Nd (III) ions.

Solvent impregnated resins for the treatment of aqueous solutions containing different compounds: a review

In this review paper, a complete study and analysis of the research articles dealing with the removal of various organic and inorganic pollutants using solvent impregnated resins (SIR) is carried out. The method of impregnation, characterizations of prepared resin, and regeneration techniques of different SIRs for batch and continuous fixed bed columns are presented. The effects of different operating parameters (e.g., loading of solvent on the resin, dosage of adsorbent, initial solute concentration, pH, temperature, time, ionic strength) on the separation efficiency of SIR in the batch mode are discussed. Thermodynamic parameters (change in Gibbs free energy, enthalpy, and entropy) are tabulated from the data available in the literature, and if not given, then their values are calculated and presented. The influence of parameters (flow rate, bed height, pH, concentration of the solution, etc.) on the fixed bed column performance is analyzed. Design aspects of the column are also discussed, and the dimensions of fixed bed columns for industrial applications are proposed.

Encapsulated polymeric beads impregnating unexplored amide, N,N′-bis(2-ethyl hexyl) α-hydroxy acetamide (BEHGA) – preparation, sorption and kinetic studies for tri-, tetra- and hexavalent radionuclides

Removal of actinides (trivalent, tetravalent and hexavalent) from nitric acid medium was studied using solid-liquid extraction technique employing polymeric encapsulated beads (PEBs) using an indigenously synthesized, unexplored novel monoamide, N,N′-bis(2-ethyl hexyl) α-hydroxy acetamide (BEHGA). The PEBs were synthesized by phase inversion technique. The structure and morphology of the synthesized PEBs were evaluated by employing various characterization techniques like FT-IR, TGA and SEM. The well characterized PEBs were studied for its Am(III), Pu(IV) and U(VI) sorption behavior from nitric acid medium. Kinetics studies showed that the sorption is fast with equilibrium being reached within 60 min of equilibration. The sorption mechanism follows pseudo-second-order mechanism with intraparticle diffusion playing an important role. Langmuir isotherm model was found to best describe the sorption isotherm. The maximum Am(III) sorption capacity of the PEBs was found to be 8.45 mg/g (experimental) and 8.43 mg/g (Langmuir). Back extraction was possible using 0.5 M HNO3. Stability of the PEBs was found to be quite good with no significant structural deformation or leaching out of the extractant in 4.0 M HNO3 solution for at least up to 8 days.

Removal of americium from aqueous nitrate solutions by sorption onto PC88A-impregnated macroporous polymeric beads

The removal of Am (III) ions from aqueous solutions was studied by solid-liquid extraction using indigenously synthesized Extractant Impregnated Macroporous Polymeric Beads (EIMPBs). These beads were prepared by an in situ phase inversion method using polyethersulfone (PES) as base polymer and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) as an extractant. The synthesized EIMPBs were characterized by FTIR, TGA and SEM techniques. The batch equilibration study using these beads for the uptake of Am (III) was carried out as a function of parameters, like pH, equilibration time, Am (III) concentration, etc. The blank polymeric beads, without PC88A, have shown negligible sorption of Am (III) under the experimental conditions. The experimental data on the sorption behavior of Am (III) on the polymeric beads fitted well in the pseudo-second-order kinetics model. The synthesized polymeric beads exhibited very good sorption capacity for Am (III) at pH 3. The reusability of the beads was also ascertained by repetitive sorption/desorption of Am (III) up to 10 cycles of operation, without any significant change in their sorption characteristics.