A method for separating and recovering carbon dioxide from ambient air includes continuously bringing ambient air into contact with a basic aqueous solution; electrodialysis of the solution using bipolar and anion-selective ion exchange membranes as well as recycling the depleted solution; separating CO.sub.2 from the enriched solution and recycling the solution depleted of CO.sub.2. The absorption is performed in an absorber, open basin, or a combination thereof. Separation is achieved by thermal desorption of CO.sub.2 by steam stripping to obtain a carbon dioxide/steam mixture; and/or by chemical reaction of the (hydrogen-) carbonate ions, in which the CO.sub.2 contained is converted into a water-insoluble salt or a gas and simultaneously removed from the solution. The pH of either obtained solution is measured before the recycling or before the separation, and is adjusted to a predetermined value. pH is measured and adjusted based on how absorption and separation are performed.

The present invention relates to a chemically modified anion exchange membrane and a method of preparing the same and, more particularly, an anion exchange membrane in which sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane are substituted with anion conductive groups such as ammonium group, phosphonium group, imidazolium group, pyridinium group and sulfonium group, and a method of preparing an anion exchange membrane by chemically modifying sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane.

The present invention relates to a chemically modified anion exchange membrane and a method of preparing the same and, more particularly, an anion exchange membrane in which sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane are substituted with anion conductive groups such as ammonium group, phosphonium group, imidazolium group, pyridinium group and sulfonium group, and a method of preparing an anion exchange membrane by chemically modifying sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane.

A single piece-type bipolar film roll with a mesh cloth support and a manufacturing method therefor. The single piece-type bipolar film roll is supported by a high-strength ultra-high molecular weight polyethylene mesh cloth, one side of the single piece-type bipolar film roll is a cation exchange layer containing a benzenesulfonic acid group, the other side of the single piece-type bipolar roll is an anion exchange layer containing a benzyl dimethyl butyl ammonium quaternary amino group, and the middle is a water dissociation catalyst layer containing a benzyl methyl butyl amine tertiary amino group, and the three layers form the single piece-type bipolar film roll. By providing a wider protective film and a narrower spacing film, a dipping and absorbing film roll is polymerized to prepare a composite base film roll which is then subjected to continuous sulfonation to prepare a single-sided sulfonated composite positive film roll, and then the unreacted blank side is sequentially subjected to three-step chemical reactions such as complete chloromethylation, complete tertiary amination and incomplete methylation, so as to prepare a single piece-type bipolar film roll having a compact structure, a clear middle interface, a high mechanical strength and a stable quaternary amino group, and the product qualification rate is high; and the single piece-type bipolar film roll is suitable for a bipolar film electrodialysis engineering application of an organic material-containing system.

The present disclosure is directed to ion-exchange systems and devices that can monitor key parameters related to the performance of the ion-exchange device. Specifically, the ion-exchange systems and devices disclosed herein can provide real time voltage drop across groups of membrane pairs using diagnostic spacer borders between the pairs. In addition, the ion-exchange systems and devices disclosed herein can monitor the compression force applied by the compression plates holding the ion-exchange systems and devices together.

A pure water production system includes a reverse osmosis membrane device; an electric deionized water production device that is disposed downstream of the reverse osmosis membrane device; and a control device that controls a processing condition of the reverse osmosis membrane device. The control device controls a processing condition of the reverse osmosis membrane device such that a removal rate of a specific substance of the electric deionized water production device is equal to or lower than a threshold value, and concentration of the specific substance in the treated water of the electric deionized water production device is equal to or lower than a prescribed value and specific resistance of the treated water of the electric deionized water production device is equal to or higher than a prescribed value.

A method of providing water suitable for irrigation use includes feeding pre-treated water to an electrodialysis apparatus, treating the pre-treated water in the electrodialysis apparatus by selectively removing either one or both of monovalent anionic and monovalent cationic species from the pre-treated water while retaining either one or both of multivalent anionic and multivalent cationic species to produce a treated water stream having a lower ratio of monovalent ions to multivalent ions than the pre-treated water, and directing the treated water into an irrigation water distribution system.

A method of providing water suitable for irrigation use includes feeding pre-treated water to an electrodialysis apparatus, treating the pre-treated water in the electrodialysis apparatus by selectively removing either one or both of monovalent anionic and monovalent cationic species from the pre-treated water while retaining either one or both of multivalent anionic and multivalent cationic species to produce a treated water stream having a lower ratio of monovalent ions to multivalent ions than the pre-treated water, and directing the treated water into an irrigation water distribution system.

The present invention relates to a method for producing lithium phosphate, comprising: passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent, passing the distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution, and putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate.

The present invention relates to a method for producing lithium phosphate, comprising: passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent, passing the distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution, and putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate.