Composite material for treating photographic effluents

Abstract

The present invention relates to a composite material with an improved structure in which is dispersed an active organic compound, and a method for treating effluents, in particular a method for treating photographic effluents. The present invention relates to a composite material that takes the form of a structured gel comprising an aluminosilicate polymer matrix in the form of fibers in which at least two distinct fibers are interconnected by at least two covalent bonds to form an irreversible chemical gel and, dispersed in the matrix, an active organic compound. The choice of the degree of cross-linking of the matrix makes it possible to control the diffusion of a hydrophilic active organic compound. The invention further concerns a method for preparing such a composite material.

What is claimed is:  
     
         1 . A composite material in the form of a structured gel comprising an aluminosilicate polymer matrix in the form of an imogolite gel made up of fibers in which at least two distinct fibers are interconnected by at least two covalent bonds to form an irreversible chemical gel and, dispersed in the matrix, an active organic compound.  
     
     
         2 . The material according to  claim 1 , wherein said covalent bonds are O-M or O-M′ bonds where M and M′ are respectively a quadrivalent atom and a trivalent atom selected from among the transition metals and the elements of groups III and IV of the periodic table of the elements.  
     
     
         3 . The material according to  claim 2 , wherein M is selected from silicon, titanium or zirconium, and M′ is selected from aluminum or boron.  
     
     
         4 . The material according to  claim 1 , wherein the active organic compound is hydrophilic.  
     
     
         5 . The material according to  claim 1 , wherein the active organic compound is a bacterial growth control agent.  
     
     
         6 . The material according to  claim 5 , wherein the bacterial growth control agent is selected from among thiazole, azole, sulfamide and organoarsenide derivatives, benzoic acid, sorbic acid, benzalkonium quaternary ammonium salts and nitroalcohols.  
     
     
         7 . The material according to  claim 6  wherein the active compound is a mixture of bacterial growth control agents comprising at least one hydrophilic control agent and at least one hydrophobic control agent, said control agents being selected from among the isothiazolones.  
     
     
         8 . A method for preparing the composite material in the form of a structured gel of  claim 1 , comprising the hydrolysis in basic medium of at least one structuring agent in the presence of an active organic compound and an aqueous solution of an aluminosilicate polymer in the form of an imogolite made up of fibers comprising on their surface active hydroxyl groups, said structuring agent containing at least two leaving groups that react with said active hydroxyl groups to form at least two covalent bonds between at least two distinct imogolite fibers to yield an irreversible chemical gel.  
     
     
         9 . The method according to  claim 8  wherein the structuring agent is selected from among compounds of formula A or A′ wherein: 
 A has the formula (CH 3 ) n M(R) 4-n  wherein M is a quadrivalent atom selected from among the transition metals and elements of groups III and IV of the periodic table of the elements, and R is hydrogen, a halogen, a methoxy group, an ethoxy group, an isopropoxy group, a carboxyl or acetoxy group, and n is 0, 1 or 2, and wherein the different groups R can be either identical or different.  
 A′ has the formula (CH 3 ) n M′(R) 3-n  where M′ is a trivalent atom selected from among the transition metals and elements of groups III and IV of the periodic table of the elements, R being as defined above, and n is 0 or 1, and wherein the different groups R can be either identical or different.  
 
     
     
         10 . The method according to  claim 9 , wherein M is selected from silicon, titanium or zirconium.  
     
     
         11 . The method according to  claim 9 , wherein of M′ is selected from aluminum or boron.  
     
     
         12 . The method according to  claim 10 , wherein compound A is tetramethoxysilane.  
     
     
         13 . The method according to  claim 8 , wherein the concentration of structuring agent is less than 10% by weight relative to the [Al+Si] content of the imogolite.  
     
     
         14 . A method for treating a medium by an active organic compound that involves placing said medium in contact with the composite material of  claim 1 .  
     
     
         15 . The method according to  claim 14  for the treatment of an aqueous solution liable to harbor micro-organisms that involves placing said aqueous solution in contact with the composite material  claim 1 .  
     
     
         16 . The method according to  claim 15  for the treatment of a photographic bath.  
     
     
         17 . A device for delivering a controlled quantity of an active organic compound consisting of a support that is permeable to said active organic compound in which is placed the composite material of  claim 1.