Abstract:
Methods and apparatus for separating aqueous solution of alkali aluminate into alkali hydroxide and aluminate hydroxide are disclosed. These methods are enabled by the use of alkali ion conductive membranes in electrolytic cells that are chemically stable and alkali ion selective. The alkali ion conductive membrane includes a chemically stable ionic-selective cation membrane.
Abstract:
Systems and methods for using carbon dioxide to remove an alkali catalyst and to recover free carboxylic acids after a transesterification reaction are disclosed. Generally, the methods include first providing a mixture resulting from the transesterification of an ester, wherein the mixture includes substances selected from the alkali catalyst, an alcohol, and a transesterification reaction product such as biodiesel. Second, the methods generally include adding carbon dioxide to the mixture. In some cases, adding the carbon dioxide to the mixture causes the alkali catalyst to convert into an alkali carbonate and/or an alkali bicarbonate. In other cases, adding the carbon dioxide to the mixture causes the carboxylic acid alkali salt to convert into a free carboxylic acid. In either case, the alkali carbonate, the alkali bicarbonate, and/or the free carboxylic acid can be separated from the mixture in any suitable manner.
Abstract:
A method for producing and recovering a carboxylic acid in an electrolysis cell. The electrolysis cell is a multi-compartment electrolysis cell. The multi-compartment electrolysis cell includes an anodic compartment, a cathodic compartment, and a solid alkali ion transporting membrane (such as a NaSICON membrane). An anolyte is added to the anodic compartment. The anolyte comprises an alkali salt of a carboxylic acid, a first solvent, and a second solvent. The alkali salt of the carboxylic acid is partitioned into the first solvent. The anolyte is then electrolyzed to produce a carboxylic acid, wherein the produced carboxylic acid is partitioned into the second solvent. The second solvent may then be separated from the first solvent and the produced carboxylic acid may be recovered from the second solvent. The first solvent may be water and the second solvent may be an organic solvent.
Abstract:
Systems and methods for using carbon dioxide to remove an alkali catalyst and to recover free carboxylic acids after a transesterification reaction are disclosed. Generally, the methods include first providing a mixture resulting from the transesterification of an ester, wherein the mixture includes substances selected from the alkali catalyst, an alcohol, and a transesterification reaction product such as biodiesel. Second, the methods generally include adding carbon dioxide to the mixture. In some cases, adding the carbon dioxide to the mixture causes the alkali catalyst to convert into an alkali carbonate and/or an alkali bicarbonate. In other cases, adding the carbon dioxide to the mixture causes the carboxylic acid alkali salt to convert into a free carboxylic acid. In either case, the alkali carbonate, the alkali bicarbonate, and/or the free carboxylic acid can be separated from the mixture in any suitable manner.