Abstract:
A process and system for removing ammonia from an aqueous ammonia solution. A first aqueous solution and the ammonia solution are flowed respectively through a first and a second separation chamber of a bipolar membrane electrodialysis (“BPMED”) stack. The first separation chamber is bounded on an anodic side by a cation exchange membrane and the second separation chamber is bounded on a cathodic side by the cation exchange membrane and on an anodic side by a bipolar membrane. The bipolar membrane has an anion-permeable layer and a cation-permeable layer respectively oriented to face the stack's anode and cathode. While the solutions are flowing through the stack a voltage is applied across the stack that causes the bipolar membrane to dissociate water into protons and hydroxide ions. The protons migrate into the second separation chamber and react there with ammonia to form ammonium ions that migrate to the first separation chamber.
Abstract:
A process for preparing an acrylamide-based crosslinking monomer comprising reacting in the presence of a catalyst an isocyanate compound containing at least two isocyanate groups with one of acrylic acid or methacrylic acid. These acrylamide-based crosslinking monomers are used in the preparation of coating compositions, adhesive compositions curable by applying thermal or radiation energy, and in the preparation of cation or anion exchange membranes.
Abstract:
A monovalent ion permselective ion exchange membrane comprising a base layer consisting of an ion exchange membrane, and a monovalent ion permselective layer affixed to the surface of the base layer. The monovalent ion permselective layer is formed by coating and polymerizing a polymerizable solution onto the base ion exchange membrane layer. The polymerizable solution comprises: (i) of an ionic monomer having one or more ethylenic groups selected from (meth)acryloxy groups, (meth)acryl-amido groups, and vinylbenzyl groups, (ii) a hydrophobic crosslinking monomer having two or more ethylenic groups selected from (meth)acryloxy groups, (meth)acrylamido groups, and vinylbenzyl groups, (iii) a free radical initiator, in (iv) a solvent medium. The monovalent ion permselective ion exchange membranes include monovalent cation permselective ion exchange membranes and monovalent anion permselective ion exchange membranes. Also disclosed are processes for preparing the monovalent ion permselective ion exchange membranes.
Abstract:
A method for making a resilient ion exchange membrane comprising polymerizing a composition containing at least an ionic surfactant monomer having an ethylenic group and a long hydrophobic alkyl group filling the pores of and covering the surfaces of a porous substrate. The hydrophobic long alkyl group in the ionic surfactant monomer provides ion exchange membranes with improved mechanical properties, and good chemical stability.
Abstract:
Methods, systems, and techniques for desalinating monovalent anion species from wastewater. A system includes an electrodialysis stack that performs the desalination. The stack has a cathode, an anode, and at least one electrodialysis cell. The at least one electrodialysis cell includes a product chamber, a metal cation concentrating chamber adjacent to a cathodic side of the product chamber, and a transfer solution chamber adjacent to an anodic side of the product chamber. The product chamber and the metal cation concentrating chamber are each bounded by and share a cation exchange membrane, the product chamber and the transfer solution chamber are each bounded by and share a monovalent anion exchange membrane, and the transfer solution chamber is bounded on an anodic side by one of an anion exchange membrane and a monovalent anion exchange membrane. The wastewater may be generated by a flue gas desulfurization process.
Abstract:
Processes, systems, and techniques for multivalent ion desalination of a feed water use an apparatus that has a cathode, an anode, and an electrodialysis cell located between the cathode and anode. The cell has a product chamber through which the feed water flows, a multivalent cation concentrating chamber on a cathodic side of the product chamber through which the concentrated multivalent cation solution flows, and a multivalent anion concentrating chamber on an anodic side of the product chamber through which the concentrated multivalent anion solution flows. The product chamber and the multivalent cation concentrating chamber are each bounded by and share a cation exchange membrane, and the product chamber and the multivalent anion concentrating chamber are each bounded by and share an anion exchange membrane. A monovalent ion species is added to at least one of the concentrated multivalent cation solution and the concentrated multivalent anion solution.
Abstract:
A resilient anion exchange membrane including a homogeneous cross-linked ion-transferring polymer substantially filling pores and substantially covering surfaces of a porous substrate, wherein the resilient anion exchange membrane is prepared by polymerizing a composition including a quaternary ammonium cationic surfactant monomer, a crosslinking monomer including two or more ethylenic groups, a free radical initiator, and a solvent.
Abstract:
A multivalent ion separating desalination system and associated process employs at least one multivalent ion separator subsystem to split sparingly soluble multivalent ion species from saltwater into highly soluble salts comprising multivalent cations and monovalent anions and salts comprising monovalent cations and multivalent anions.