Abstract: A layered double hydroxide (LDH) includes at least one intermediate layer, and MII surrounded by OH−, with replacement of the bivalent metal ions by MIII producing an excess of positive charge, balanced by anions An− in the intermediate layer, wherein MII dennotes a divalent metal ion or 2 LI, MIII dennotes a trivalent metal ion. The LDH can be used in mixtures and preparations such as auxiliary materials, additives, seeds, seedlings, or propagation materials. Also it is possible to use the LDH in a method of nitrate removal in purification of water.

Abstract: Minerals that reversibly fix ions, in particular NO3—, i.e. that can exchange one anion for another anion can be used as fertilizers and soil conditioners, as well as for the purification and treatment of water, particularly for the elimination of nitrate. The minerals used are preferably natural or synthetic mixed value metal-metal-hydroxyl salts, e.g. layered double hydroxides (LDHs) that contain exchangeable fixed anions in the intermediary layers. A method for producing anion-exchanging minerals, particularly suitable LDHs, and their use as fertilizers and soil conditioners and for the purification and treatment of water.