BASIC PHYSICAL AND CHEMICAL-PROPERTIES OF REILLEX(TM)-HPQ ANION-EXCHANGE RESIN AND ITS SORPTION BEHAVIOR OF HALIDES IN AQUEOUS NITRIC-ACID SOLUTION

The Reillex(TM)-HPQ anion exchange resin has a good potential toward t he pretreatment of liquid nuclear wastes. In this work, a short proced ure was devised to convert 99.997% of the resin from its chloride form to the nitrate form as a foundation of all quantitative measurements. It is determined that the resin can be dried to a constant mass at 60 degrees C in 28 hours and the electrostatic effect during weighings c an hence be eliminated. The weight ratio between resins dried at 110 d egrees C and 60 degrees C is 0.927+/-0.005 (one standard deviation). T he resin has an apparent pK(a) of 3.36+/-0.05. The sorption capacity f rom primarily the weakly basic ionogenic sites (RNH(+)) is 1.08+/-0.04 meq/g for resins dried at 60 degrees C. In highly basic solutions, th e resin became unstable and started to release a substantial amount of methanol. In nitric acid solutions, the selectivity sequence of halid e ions versus nitrate and pertechnetate ions is: TcO4- > I- > NO3- > B r- > Cl- > F-. The HPQ resin showed no sorption of fluoride ions. Alth ough the sorption of chloride ions is also low the data can be modelle d well by an equation similar to the Freundlich isotherm at a pH range between 2.0 and 3.0. Both bromide and iodide ions showed moderate sor ptions when [HNO3] less than or equal to 1.00 (M) under bar and the so rption data can be fitted well to an equation closely related to the T emkin isotherm.