Nanoporous chelating fibers

Abstract

A composite includes substrate fibers, and an organosilica coating including a structure-directing template, on the substrate fibers. The composite may be formed by coating substrate fibers with an organosilica sol containing a structure-directing template, and curing the organosilica sol to form an organosilica coating. A nanoporous chelating fiber includes a substrate fiber and a nanoporous chelating coating, on the substrate fiber. Nanoporous chelating fibers may be formed by removing the structure-directing template from a composite to form a nanoporous chelating coating on the substrate fibers. Contaminants may be removed from a fluid by contacting nanoporous chelating fibers with a fluid containing at least one contaminant.

1 . A nanoporous chelating fiber, comprising: 
 a substrate fiber; and    a nanoporous chelating coating, on the substrate fiber.    
   
   
       2 . The nanoporous chelating fiber of  claim 1 , wherein the nanoporous chelating coating comprises an organosilica comprising a plurality of chelating groups.  
   
   
       3 . The nanoporous chelating fiber of  claim 2 , wherein the plurality of chelating groups comprises at least one chelating group selected from the group consisting of a thiol, an alcohol, a primary amine, a secondary amine, an ammonium group, and a calix[n]arene.  
   
   
       4 . The nanoporous chelating fiber of  claim 2 , wherein the plurality of chelating groups comprises thiol groups.  
   
   
       5 . The nanoporous chelating fiber of  claim 1 , wherein the substrate fiber comprises a material selected from the group consisting of glass, mineral, ceramic, metal, natural fiber and polymer.  
   
   
       6 . The nanoporous chelating fiber of  claim 1 , wherein the substrate fiber is present with a plurality of substrate fibers in a form selected from the group consisting of papers, fabrics, felts and mats.  
   
   
       7 . A composite, comprising: 
 substrate fibers; and    an organosilica coating comprising a structure-directing template, on the substrate fibers.    
   
   
       8 . The composite of  claim 7 , wherein the structure-directing template comprises a member selected from the group consisting of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, CH 3 (CH 2 ) 15 (OCH 2 CH 2 ) 10 OH, (EO) 20 (PO) 70 (EO) 20 , (EO) 105 (PO) 70 (EO) 105 , dibenzoyl-/-tartaric acid and a cyclodextrin.  
   
   
       9 . The composite of  claim 7 , wherein the organosilica coating further comprises a plurality of chelating groups.  
   
   
       10 . The composite of  claim 9 , wherein the plurality of chelating groups comprises at least one chelating group selected from the group consisting of a thiol, an alcohol, a primary amine, a secondary amine, an ammonium group, and a calix[n]arene.  
   
   
       11 . A method of forming a composite, comprising: 
 coating substrate fibers with an organosilica sol comprising a structure-directing template; and    curing the organosilica sol to form an organosilica coating.    
   
   
       12 . The method of  claim 11 , wherein the organosilica sol is formed by combining ingredients comprising an organotrialkoxysilane comprising a chelating group, a tetraalkoxysilane, a structure-directing template, an acid catalyst, water, and a volatile solvent.  
   
   
       13 . The method of  claim 12 , wherein the combining comprises: 
 forming a homogeneous monomer mixture comprising the organotrialkoxysilane, the tetraalkoxysilane, the acid catalyst, water, and the volatile solvent; and    adding the structure-directing template to the homogeneous monomer mixture.    
   
   
       14 . The method of  claim 12 , wherein the organotrialkoxysilane comprises a compound having the structure of formula (I): 
       R(CH 2 ) n Si(OR 5 ) 3   (I) wherein —R is the chelating group, n is an integer from 0 to 20, and —R 5  is a C1-C8 hydrocarbon group.    
   
   
       15 . The method of  claim 12 , wherein the chelating group is selected from the group consisting of a thiol, an alcohol, a primary amine, a secondary amine, an ammonium group, and a calix[n]arene.  
   
   
       16 . The method of  claim 12 , wherein the chelating group is a thiol.  
   
   
       17 . The method of  claim 11 , wherein the structure-directing template comprises a member selected from the group consisting of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, CH 3 (CH 2 ) 15 (OCH 2 CH 2 ) 10 OH, (EO) 20 (PO) 70 (EO) 20 , (EO) 105 (PO) 70 (EO) 105 , dibenzoyl-/-tartaric acid and a cyclodextrin.  
   
   
       18 . A method of forming nanoporous chelating fibers, comprising: 
 removing the structure-directing template from the composite of  claim 7  to form a nanoporous chelating coating on the substrate fibers.    
   
   
       19 . The method of  claim 18 , wherein the removing the structure-directing template comprises contacting the organosilica coating with a mixture comprising an acid and a volatile solvent.  
   
   
       20 . A method of removing a contaminant from a fluid, comprising: 
 contacting the nanoporous chelating fiber of  claim 1  with a fluid comprising at least one contaminant.