Abstract:
Process for preparing fine-particle, water-insoluble polymers of aziridines by polymerizing aziridines, preferably ethylenimine, in the presence of crosslinkers which contain at least two functional groups, and in at least one ether, and also modified, water-insoluble polymers of aziridines which can be obtained by reacting fine-particle, water-insoluble, crosslinked polymers of aziridines, in aqueous medium, with carbon disulfide or formaldehyde and a nucleophilic agent from the group consisting of alkali metal cyanides, primary amines, secondary amines, alkali metal sulfites and alkali metal phosphites, and use of the modified and non-modified fine-particle, water-insoluble polymers for immobilizing active compounds, as absorbents for aldehydes, ketones and acids, and also for removing heavy metal ions from wastewaters.
Abstract:
A method for removing, separating, and concentrating certain selected ions from a source solution that may contain larger concentrations of other ions comprises bringing the source solution in contact with a composition comprising an ion-binding ligand covalently bonded to a membrane having hydrophilic surface properties. The ligand portion of the composition has affinity for and forms a complex with the selected ions, thereby removing them from the source solution. The selected ions are then removed from the composition through contact with a much smaller volume of a receiving solution in which the selected ions are either soluble or which has greater affinity for the selected ions than does the ligand portion of the composition, thereby quantitatively stripping the complexed ions from the ligand and recovering them in concentrated form in the receiving solution. The concentrated ions thus removed may be further separated and recovered by known methods. The process is useful in the removal of selected ions, including noble metals and other transition metals from a variety of source solutions such as are encountered in semiconductor, nuclear waste cleanup, metals refining, environmental cleanup, providing ultra high purity fluids, electric power, and other industrial enterprises. The invention is also drawn to the ligand-membrane compositions.
Abstract:
The invention comprises a process for air separation using oxygen-selective sorbents with enhanced selectivity, loading capacities and oxygen uptake rates have a transition element complex in solid form supported on a high surface substrate. The transition element complex is substantially uniformly spaced, and includes a transition element ion accessible to an oxygen-containing gas stream during use in the separation of oxygen from an oxygen-containing gas mixture such as air.
Abstract:
A process for the separation of pentavalent arsenic from an aqueous solution using an N-alkyl pyridinium-containing adsorption medium is disclosed. An oxidizing medium and process for the oxidation of trivalent arsenic to pentavalent arsenic with removal of the pentavalent arsenic so formed is also disclosed.
Abstract:
Recovery of gold from alkaline cyanide leach solutions using ion exchange adsorbents, comprising (a) contacting the cyanide leach solution containing the gold with an extraction reagent comprised of a solid adsorbent carrying an organic base functionality of a compound having a pK.sub.a between about 9-14, such as a guanidyl functionality, to adsorb gold and eluting the adsorbed gold from the solid adsorbent with an aqueous alkaline eluant solution having a pH above about 12 and containing an alkali metal salt of an aromatic or aliphatic carboxylic acid having from about 4-14 carbon atoms, the eluant solution having incorprated therein from about 0.001 moles to about 0.2 moles per liter of an alkali metal cyanide salt. The solid adsorbent containing the aurocyanide complex may be contacted with a concentrated aqueous solution of a zinc tetracyanide salt whereby the aurocyanide complex is displaced with a zinc tetracyanide complex before treatment with the eluant solution.
Abstract:
A method for the recovery of a metal from an organic complex thereof, said method comprising treating the complex with a weakly acid aqueous solution of an alkali metal or alkaline earth metal chloride having a chloride content of at least 4 molar whereby said complex is decomposed and metal ions are transferred to the aqueous solution.
Abstract:
It concerns a monomer, a polymer obtained from the monomer and a process for obtaining the said polymer. The monomer consists of a polyether containing at least 3 ether units and pyrrole or thiophene units bonded to the ends of the chains of this polyether via, for each of these heterocycic compounds, either their carbon atoms in the 3,3'-positions of their heterocycles or, as regards more particularly the pyrrole groups, via their respective nitrogen atoms, the 2- and 2'-positions of these heterocycles being, however, free of all substitutions or, at the very most, substituted by easily removable groups (protective groups, for example). Application to the purification and recovery of metal ions such as radioactive silver.
Abstract:
The present invention is concerned with improved chelating resins. More particularly, the present invention is concerned with macroporous, aminoalkylphosphonic or iminodiacetic acid chelating resins having improved stability and capacity in the removal of cations (e.g. calcium, magnesium, barium and strontium) from brines and in the removal of metals (e.g. nickel, copper and zinc) from waste streams.
Abstract:
A method for the making and use of a porous, preferably dimensionally stable, hydrophobic polymer for the extraction of metal ions from an aqueous solution, with the polymer being in the form of a regenerative granulate or powder having an average particle diameter of from 0.1 to 10 mm and pores of from 0.1 to 50 .mu.m, which is obtained by the dissolving of a polymer, with heating, at a temperature above the upper critical demixing temperature Tc in a complexing agent containing hydrophobic liquid, followed by lowering of the temperature, resulting in a porous polymer filled with the hydrophobic liquid, and the mechanical diminution of the solidified mass is disclosed. Favorable results have been attained using polypropylene as the hydrophobic polymer, bis(2,4,4-trimethylpentyl)thio acid as the complexing agent, and with a mixture of dibenzyl toluene and/or polypropylene glycol ether being part of the hydrophobic liquid.
Abstract:
A composition comprising a crosslinked, highly porous body derived from a water-soluble hydrogel polymer, said porous body being characterized in that it has an open-celled three-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 300 m.sup.2 /g, a compression strength of equal to or less than about 10 percent yield at 300 psi, and an average pore diameter of less than about 500 Angstroms, wherein said hydrogel polymer is selected from the group consisting of alginates, gums, starch, dextrins, agar, gelatins, casein, collagen, polyvinyl alcohol, polyethylenimine, acrylate polymers, starch/acrylate copolymers, and mixtures and copolymers thereof; and a metal extractant.The composition may be used in removing and/or recovering metal ions from aqueous streams.A process of recovering metal ions from an aqueous metal ion solution including the steps of impregnating a metal extractant within the porous body described above, contacting the aqueous ion solution with the impregnated porous body in order to remove the metal ions therefrom, and separating the ions from the impregnated porous body.