Studies of cation exchange for the isolation and concentration of trace level components of complex aqueous mixtures

摘要

Trace level organic bases are concentrated from aqueous solu- tion by cation exchange on a column of sulfonated macroreticular XAD-4 resin. Washing of the column with organic solvents removes neutrals and acids. Ammonia gas is introduced into the column prior to elution of the basic organics with either methanol or ether containing ammonia. After solvent evaporation, the concentrated sample is analyzed by gas chromatography. Recoveries of over 85% are found with at least one of the eluents for over 50 bases tested at levels \u3c 1 ppm. Improved recoveries and reproducibility are seen over a simple ether extraction procedure. Samples of river water, shale oil process water, and supernatant from an agricultural chemical disposal pit are analyzed;Porous, bifunctional chelating resins are prepared by base-catalyzed polymerization of a phenol and iminodiacetic acid (IDA) with an aldehyde. Porosity is introduced by the inclusion of a base-insoluble solid \u22template\u22 in the reaction mixture prior to polymer- ization and curing, which is later dissolved. These resins are used to concentrate trace levels of cesium-137 and strontium-90 from simulated nuclear waste. Various phenols, aldehydes, and templates are tested. Several of the polymers made porous by CaCO(,3) show improved affinities and capacities for the ions of interest versus nonporous resins of similar structure;Several experimental parameters are examined to determine their effect on resin affinity. Reaction temperature is found to have a significant effect on resin affinity. Attempts to determine the structure of these resins are made using various analytical techniques, most notably photoacoustic spectroscopy. The affinity of these resins for other metals is examined, and they are found to sorb Cu(\u272+), Fe(\u272+), and Pb(\u272+) effectively;Preliminary studies of functionalized poly(styrene-divinylbenzene)s, coated exchangers, and liquid ion exchangers;as possible approaches to nuclear waste decontamination are performed; (\u271)DOE Report IS-T-1120. This work was performed under Contract W-7405-eng-82 with the Department of Energy.