摘要:
Cross-linked polymeric gels or films are prepared by dissolving in a suitable solvent a linear polymer or polymers at least one of which is predominantly (at least 80%) made from monomers containing pendant amidocarbonyl or oxycarbonyl groups. For the cross-linking reaction are present either hydroxyl groups, present as either pendant groups from the polymer, or as low molecular weight polyols; or amino groups, present as either pendant groups from the polymer, or as low molecular weight diamines or polyamines. Either no catalyst is present or a strongly acidic catalyst (which may also be a pendant group on a polymer) is used. The solvent is removed by coagulation and/or drying and the dry material is heat-cured, thus cross-linking and insolubilizing the polymer or polymers.
摘要:
A process for the treatment of an aqueous stream containing an acid or base and typically a precipitatable material such as a metal ion comprises:(a) subjecting the aqueous stream to (i) a treatment to produce a relatively pure stream of water and a concentrated aqueous stream, and (ii) water splitting to produce a stream of base, a stream of acid and a dilute aqueous stream of a concentration lower than the concentrated aqueous stream, the treatments (i) and (ii) being effected in either order,(b) recycling at least part of the pure water stream produced in (a)(i) to an earlier stream either in the production leading to said aqueous stream or to step (i) or (ii),(c) recycling at least part of the acid and/or base streams produced in (a)(ii) to an earlier stream either in the production leading to said aqueous stream or to an earlier step in the process, and(d) recycling at least part of the lower concentration stream produced in (a)(ii) to either (a)(i) or to another step in the process, whereby, when present, only the precipitatable material is removed from the aqueous stream, thereby obviating toxic waste disposal problems.
摘要:
Interpolymer fixed-charge membranes of macroscopic homogeneity are prepared by providing a solution containing a matrix polymer, a polyelectrolyte and a crosslinking agent, evaporating the solvent until substantially the desired pore size and other physical properties are obtained in a film cast from the solution, the thereafter chemically crosslinking the film to insolubilize the membrane.
摘要:
Water insoluble polymers are treated to place on their exposed surfaces the pendant alkyl imidocarbonyl (amide) groups to impart a high degree of hydrophilicity to that surface. Nitrile-containing polymers or copolymers in the form of insoluble films, filters or membranes are treated to convert a substantial fraction of the surface nitrile groups into the corresponding amide by the use of hydrogen peroxide or concentrated acids. The surface is rendered hydrophilic and resistant to fouling to the extent that even proteins are not denatured thereupon. The surface may also be converted to substituted amides by subsequent reactions to impart to it other functionalities or to serve as the basis for coupling reactions. Other polymers capable of surface treatment to produce pendant amidocarbonyl groups include ones containing pendant esters which on cleavage of the oxygen-carbon bond give pendant alcohol groups. These are converted by cyanoethylation to form the pendant nitrile groups which can be converted to the amide. Other polymers which on hydrolysis give pendant carboxylic acids can be treated with ammonia to also produce pendant amide groups.
摘要:
Water insoluble polymers are treated to place on their exposed surfaces the pendant alkyl imidocarbonyl (amide) groups to impart a high degree of hydrophilicity to that surface. Nitrile-containing polymers or copolymers in the form of insoluble films, filters or membranes are treated to convert a substantial fraction of the surface nitrile groups into the corresponding amide by the use of hydrogen peroxide or concentrated acids. The surface is rendered hydrophilic and resistant to fouling to the extent that even proteins are not denatured thereupon. The surface may also be converted to substituted amides by subsequent reactions to impart to it other functionalities or to serve as the basis for coupling reactions. Other polymers capable of surface treatment to produce pendant amidocarbonyl groups include ones containing pendant esters which on cleavage of the oxygen-carbon bond give pendant alcohol groups. These are converted by cyanoethylation to form the pendant nitrile groups which can be converted to the amide. Other polymers which on hydrolysis give pendant carboxylic acids can be treated with ammonia to also produce pendant amide groups.
摘要:
Cross-linked polymeric gels or films are prepared by dissolving in a suitable solvent a linear polymer or polymers containing pendant amidocarbonyl or oxycarbonyl groups, hydroxyl groups present as either pendant groups from the polymer or as a low molecular weight polyol, and a strongly acidic catalyst (which may also be a pendant group on a polymer). The solvent is removed by coagulation and/or drying and the dry material is heat-cured, thus cross-linking and insolubilizing the polymer or polymers.
摘要:
Pressure-driven affinity sorption membranes are prepared from a membrane filter composed of an insoluble matrix polymer or an interpolymer composite and used for separation and purification by passing therethrough solutions containing mixtures, one or more of which forms a specific complex with the ligand on the pore surface of the membrane, washing out the uncoupled solutes, then employing an appropriate displacing or eluting agent to recover the desired component in a pure and concentrated state, all under pressure-driven conditions.
摘要:
A membrane is produced by dissolving, in a water-miscible solvent, a water insoluble copolymer of acrylontrile with at least one monomer selected from the group consisting of an aminostyrene, a vinyl pyridine and an N-hydroxy-containing-substituent-acrylamide, casting said solution to form a thin layer of solution, contacting said solution with water thereby to coagulate the copolymer into a film, and washing away from the copolymer film the solution of solvent and water. The amine or hydroxy group of the copolymer is then activated and coupled with a ligand such as glucose isomerase, chymotrypsin or Protein A. The coupled membranes can then be used for biological separations and reactions.
摘要:
An aliphatic organic acid fraction is separated from the kraft black liquor by subjecting the liquor to ultrafiltration, treating the resulting permeate by electrodialysis, acidifying the resultant deionate to about pH 4-5, separating the lignin solids which precipitate following this acidification, raising the pH of the separated solution to about 7-8 and finally subjecting the neutralized solution to electrodialytic water-splitting.
摘要:
A process for the treatment of an aqueous stream containing an acid or base and typically a precipitatable material such as a metal ion comprises:(a) subjecting the aqueous stream to (i) a treatment to produce a relatively pure stream of water and a concentrated aqueous stream, and (ii) water splitting to produce a stream of base, a stream of acid and a dilute aqueous stream of a concentration lower than the concentrated aqueous stream, the treatments (i) and (ii) being effected in either order,(b) recycling at least part of the pure water stream produced in (a) (i) to an earlier stream either in the production leading to said aqueous stream or to step (i) or (ii),(c) recycling at least part of the acid and/or base streams produced in (a) (ii) to an earlier stream either in the production leading to said aqueous stream or to an earlier step in the process, and(d) recycling at least part of the lower concentration stream produced in (a) (ii) to either (a) (i) or to another step in the process, whereby, when present, only the precipitatable material is removed from the aqueous stream, thereby obviating toxic waste disposal problems.