Uranium- and iron-containing waste simulated effluent has been treated sequentially with a novel resin, viz., polyacrylamide hydroxamic acid (PAAHA). The motivation is to investigate the competitive interactions with transition metals during the removal of radiologically and chemically toxic uranium. The sequential sorption results indicate that the resin is more Fe selective compared to U and it retains more iron. X-ray absorption fine structure measurements, which comprise of both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) techniques, have been carried out on the PAAHA resin at the Fe K-edge and U L3-edge to probe the change in the local coordination environment on sequential sorption of uranium and iron. EXAFS measurements conclude that the U-O distances and coordination are modified when the treatment sequences of U and Fe are interchanged, whereas the Fe local structure remains intact. The results obtained from EXAFS measurements have been verified by detail analysis of XANES data.

Local Structure Investigations of Sequential Sorption of U and Fe on Polyacrylamide Hydroxamic Acid Resins.

Availability of analytical instruments for a methodical detection of known and unknown effluents imposes a serious hindrance in qualification and quantification. Several analytical instruments such as Elemental analyzer, ICP-MS, ICP-AES, EDXRF, ion chromatography, Electro-analytical instruments which are not only expensive but also time consuming, required maintenance, damaged essential parts replacement which are of serious concern. Move over for field study and instant detection installation of these instruments are not convenient to each and every place. Therefore, technique such as pre-concentration of metal ions especially for lean stream elaborated and justified. Chelation/sequestration is the key of immobilization technique which is simple, user friendly, most effective, least expensive, time efficient; easy to carry (10g - 20g vial) to experimental field/site has been demonstrated.

Pre-concentration technique for reduction in "Analytical instrument requirement and analysis"

An investigation of morphology w.r.t. Fourier transform infrared spectroscopy (FT-IR), energy dispersive X- ray fluorescence (EDXRF), scanning electron microscope (SEM), Mossbauer spectra (MS), X- ray diffraction (XRD) study based on resin column experiment has been performed for ascertaining breakthrough point in a resin loaded column for metal ions present in front stage generated nuclear effluent. Effect of chelation (FT-IR study) of different elements such as Cu(II), Sr(II), Gd(III), U(VI) on polyhydroxamate resin leads to prominent colouration (green for Cu), upper layer deposition (Sr), or loosely bound Gd or strongly bound U or Fe (Mossbauer and XRD studies) onto resin has been investigated during passing of Rad-effluents. In this regard, metal ions were analysed by inductively coupled plasma mass spectroscopy (ICP-AES) and confirmed by EDXRF. A vertical glass column chromatography with resin bed diameter 38 mm and height 350 mm produced the “S” shape break through curve. The high capacity of resin was attributed to corrugate and symmetrically folded tunnelled structure derived from SEM.

Morphological and chromatographical characterization of RAD-effluent trammelled resin

Hydroxamic acid moiety has enormous selectivity towards uranium or uranyl ions. The fresh and metal ions loaded Polyacrylamidehydroxamic acid (PHA) matrix were characterized by FT-IR, XRD, and Mossbauer spectroscopy techniques. XRD, Mossbauer spectroscopy, and coloration of different metal ions have been confirmed the removal of uranium and other ions with high selectivity and immobilization factor of PHA resin for nuclear effluent treatment. (Inductively coupled plasma - atomic emission spectrophotometer) ICP-AES and Stripping voltameter data analysis also justifies the same fact.

Characterization and performance of nuclear plant floor washed effluent treated resin

The Jekyll and Hyde nature of iron and uranium loaded “IN-HOUSE’ resin viz., Polyacrylamide hydroxamic acid (PAAHA) has been characterized by FT-IR, SEM, Mossbauer spectroscopy, EDXRF and magnetization measurements techniques. Among all Mossbauer spectra and magnetization properties indicates supportive documents of characteristic special acquaintance nature of iron w.r.t accumulated U within the matrix even after loading of Fe in vast.

Supratik Roy Chowdhury

Papers

SEM, magnetization and Mössbauer spectroscopic characterization of Fe-U sequestration