Falix Lawrence

Destruction of soluble organics generated during the dissolution of sintered uranium carbide by mediated electrochemical oxidation process

Abstract The destruction of soluble carbonaceous compounds formed during the dissolution of sintered uranium mono carbide pellets in 11.5 M nitric acid at 65 °C has been investigated by employing mediated electrochemical oxidation (MEO) method, in which process 0.05 and 0.01 M Ag(II) and 0.1 and 0.06 M Ce(IV) were used as the regenerable catalysts. The current density and temperature of the process for maximum destruction efficiency were optimized to be 25 mA/cm2 and 75 °C respectively. The electro-oxidation behaviour of the mediator ions Ag(II) and Ce(IV) with respect to their concentration in the removal of organics and the dependence of temperature on the stabilities of the two electrochemical catalysts were compared. The effect of fission product elements in a synthetic dissolver solution on the performance of Ag(II) mediator in oxidizing the carbon content was discussed. The destruction efficiency of MEO process in eliminating the soluble organics was ascertained to be better than that of direct electrochemical oxidation method as well as prolonged oxidation of the organics with concentrated nitric acid.

Organo-modified layered silicate nanocomposites of EPDM–chlorobutyl rubber blends for enhanced performance in γ radiation and hydrocarbon environment:

In this work, blends of ethylene propylene diene monomer rubber and chlorobutyl rubber were reinforced with organo-modified layered silicate (nanoclay) to enhance their performance in radiation as well as hydrocarbons environments. The mechanical properties of the nanocomposites increased (up to 57%) and solvent transport coefficients decreased (by 30%) with increasing nanoclay content. The enhancement in properties was attributed to the dispersion of nanoclay platelets in the ethylene propylene diene monomer–chlorobutyl rubber blends and the chemical interaction between nanoclay and the polymer which were confirmed by morphological and spectroscopic analysis, respectively. The effect of nanofiller content on the mechanical properties, solvent uptake and thermal degradation of blends exposed to gamma radiation was investigated by irradiating the nanocomposites with gamma rays for cumulative doses of 0.5, 1 and 2 MGy. The ethylene propylene diene monomer–chlorobutyl rubber nanocomposites with 5 phr nanoclay had the best retention of mechanical properties and solvent sorption coefficients on exposure to radiation. Depending on the dose of cumulative radiation exposure, chain scission and/or crosslinking occurred in the nanocomposites, resulting in varying degrees of changes in properties.