Adsorbent for Water Adsorption and Desorption

Abstract

The present invention relates to an adsorbent obtained by using porous hybrid inorganic-organic materials that have high surface area, and have pore with the size of molecules or nanometers. More specifically, the present invention relates to a water adsorbent showing facile adsorption-desorption even below 100° C., having high adsorption capacity, and having high desorption capacity when it is heated up to the temperature below 100° C. The adsorbent of the present invention can be applied to a humidifier, dehumidifier, cooler and heater. The present invention also relates to a technology to control humidity using the adsorbent.

1 . A water adsorbent comprising a hybrid inorganic-organic material that:
 a) is synthesized from a reaction between metal precursors and ligands selected from organic compounds; and   b) has a surface area larger than 1000 m 2 /g; and   c) has a pore volume larger than 1.0 mL/g; and   d) has a pore dimension of 0.5 nm-2 nm.   
   
   
       2 . The water adsorbent according to  claim 1 , wherein the hybrid inorganic-organic material has a ratio of (adsorption capacity at 100° C.)/(adsorption capacity at room temperature) less than 0.2. 
   
   
       3 . The water adsorbent according to  claim 1 , wherein the average particle size is less than 500 nm. 
   
   
       4 . The water adsorbent according to  claim 1 , wherein the metal precursors are one or more of metals selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mg, Ca, Sr, Ba, Sc, Y, Al, Ga, In, TI, Si, Ge, Sn, Pb, As, Sb, or Bi; or metal compounds containing one or more components selected from. Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Mg, Ca, Sr, Ba, Sc, Y, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, or Bi. 
   
   
       5 . The water adsorbent according to  claim 1 , wherein the organic compounds are the molecules or molecular mixtures containing one or more of the functional groups selected from carboxylic acid, carboxylate, amino (—NH 2 ), imino, amide (—CONH 2 ), sulfonic acid (SO 3 H), sulfonate (—SO 3   − ), methanedithionic acid (—CS 2 H), methanedithionate (—CS 2   − ), pyridine or pyrazine. 
   
   
       6 . The water adsorbent according to  claim 5 , wherein the organic compounds containing carboxylic functional groups are selected from benzenedicarboxylic acids, naphthalenedicarboxylic acids, benzenetricarboxylic acids, naphthalenetricarboxylic acids, pyridinedicarboxylic acids, bipyridyldicarboxylic acids, formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, hexanedionic acids, heptanedionic acids and cyclohexyldicarboxylic acids. 
   
   
       7 . The water adsorbent according to  claim 6 , wherein the porous hybrid inorganic-organic material is one selected from chromium terephthalate, iron terephthalate or vanadium terephthalate. 
   
   
       8 . The water adsorbent according to  claim 7 , wherein the porous hybrid inorganic-organic material is chromium terephthalate. 
   
   
       9 . The water adsorbent according to  claim 8 , wherein the porous hybrid inorganic-organic material is a cubic chromium terephthalate that has pores. 
   
   
       10 . The water adsorbent according to  claim 1 , wherein the hybrid inorganic-organic material is synthesized by the steps of;
 (a) preparing reaction mixtures by mixing (i) metal precursors, (ii) organic compounds that can be used as ligands, and (iii) solvent; and   (b) heating to a temperature of 100° c. or higher by microwave irradiation, with the frequency of microwave of 0.3-300 GHz, on the reaction mixtures of step (a).   
   
   
       11 . The water adsorbent according to  claim 10 , wherein the heating temperature for the porous hybrid inorganic-organic material is 100-250° C. 
   
   
       12 . The water adsorbent according to  claim 10 , wherein the reaction mixtures are treated additionally by ultrasonic treatment for 1 min or longer or by agitation for 5 min or longer between Step (a) and Step (b). 
   
   
       13 . The water adsorbent according to  claim 1 , wherein the porous hybrid inorganic-organic material is in the states of thick films, thin films or membranes. 
   
   
       14 . The water adsorbent according to  claim 13 , wherein the porous hybrid inorganic-organic material in thick films, thin films or membranes are prepared by microwave heating after dipping alumina, silicon, glass, indium tin oxide (ITO), indium zinc oxide (IZO) or heat resistant polymers in the reaction mixtures; or after dipping the surface treated alumina, silicon, glass, indium tin oxide (ITO), indium zinc oxide (IZO) or heat resistant polymers in the reaction mixtures.