Media for the removal of heavy metals and volatile byproducts from drinking water

Abstract

Water purification media contain an activated carbon having at least one of specific a particle size, surface area, and porosity; and a microcrystalline and/or amorphous titanosilicate at least partially coating the activated carbon. Methods of making the media of microcrystalline and/or amorphous titanosilicate coated activated carbon involve contacting activated carbon with titanosilicate precursors. Methods of purifying water involve contacting water containing both heavy metals and volatile byproducts with the media.

1 . A water purification composition comprising:
 an activated carbon having at least one of a particle size distribution from about 50 μm to about 500 μm, a surface area of about 300 m 2 /g or more and about 1,600 m 2 /g or less, and a porosity of at least about 0.25 cc/g in pores having a diameter of at least about 10 Å and at most about 500 Å; and a microcrystalline and/or amorphous titanosilicate at least partially coating the activated carbon.   
   
   
       2 . The water purification composition of  claim 1 , wherein the activated carbon has at least two of a particle size distribution from about 60 μm to about 300 μm, a surface area of about 500 m 2 /g or more and about 1,400 m 2 /g or less, and a porosity of at least about 0.4 cc/g in pores having a diameter of at least about 10 Å and at most about 500 Å. 
   
   
       3 . The water purification composition of  claim 1  comprising from about 0.1% to about 15% by weight of microcrystalline and/or amorphous titanosilicate coated on the activated carbon. 
   
   
       4 . The water purification composition of  claim 1 , wherein the activated carbon has less than 50% microporosity and from 50% to about 100% mesoporosity and/or macroporosity. 
   
   
       5 . The water purification composition of  claim 1 , with the proviso that the water purification composition does not comprise more than about 5% by weight of crystalline titanosilicate. 
   
   
       6 . The water purification composition of  claim 1 , further comprising at least one of ferric hydroxide, alumina, magnesia, bauxite, and zeolites. 
   
   
       7 . The water purification composition of  claim 1  comprising from about 0.01 g/in 3  to about 1 g/in 3  of microcrystalline and/or amorphous titanosilicate on the activated carbon. 
   
   
       8 . The water purification composition of  claim 1  consisting essentially of the activated carbon and the microcrystalline and/or amorphous titanosilicate at least partially coating the activated carbon. 
   
   
       9 . An end of tap filter comprising the water purification composition of  claim 1 . 
   
   
       10 . A fixed-bed column comprising the water purification composition of  claim 1 . 
   
   
       11 . A method of making a water purification composition comprising:
 contacting activated carbon, a titanium compound, a silicon compound, and optionally a hydroxide compound to form a mixture, the activated carbon having at least one of a particle size distribution from about 50 μm to about 500 μm, a surface area of about 300 m 2 /g or more and about 1,600 m 2 /g or less, and a porosity of at least about 0.25 cc/g in pores having a diameter of at least about 10 Å and at most about 500 Å; and   drying the mixture to provide a microcrystalline and/or amorphous titanosilicate coated activated carbon capable of purifying water.   
   
   
       12 . The method of  claim 11 , wherein the activated carbon, the titanium compound, and the silicon compound are contacted under a pH from about 6 to about 12. 
   
   
       13 . The method of  claim 11 , wherein the mixture is dried at a temperature from about 30° C. to about 150° C. for a time from about 1 minute to about 50 hours. 
   
   
       14 . The method of  claim 11 , wherein at least one of the activated carbon, the titanium compound, and the silicon compound are in water when contacted. 
   
   
       15 . A method of purifying water comprising:
 contacting water comprising a first amount of a heavy metal and a first amount of a volatile byproduct with a composition comprising an activated carbon having at least one of a particle size distribution from about 50 μm to about 500 μm, a surface area of about 300 m 2 /g or more and about 1,600 m 2 /g or less, and a porosity of at least about 0.25 cc/g in pores having a diameter of at least about 10 Å and at most about 500 Å; and a microcrystalline and/or amorphous titanosilicate at least partially coating the activated carbon; and   recovering water comprising a second amount of the heavy metal and a second amount of the volatile byproduct, wherein the second amount of the heavy metal is less than the first amount of the heavy metal and the second amount of the volatile byproduct is less than the first amount of the volatile byproduct.   
   
   
       16 . The method of  claim 15 , wherein the water recovered has a lead content of about 15 ppb or less and a total trihalomethane content of about 100 ppb or less. 
   
   
       17 . The method of  claim 15 , wherein the composition is in granule form, the average granule size by weight is from about 60 μm to about 300 μm. 
   
   
       18 . The method of  claim 15 , wherein the heavy metal comprises at least one selected from the group consisting of lead, cadmium, zinc, copper, chromium, arsenic, cobalt, and mercury; and the volatile byproduct comprises at least one selected from the group consisting of trihalomethane, bromate, chlorite, haloacetic acids, chloramines, benzene, halobenzenes, acrylamide, carbontetrachloride, bromodichloromethane, chlorodibromomethane, dichloroethylene, dichloromethane, halopropanes, dioxin, alkylbenzenes, PCBs, toluene, xylenes, vinyl chloride, and styrene. 
   
   
       19 . The method of  claim 15 , wherein the composition is comprised in an end of tap filter. 
   
   
       20 . The method of  claim 19 , wherein the composition removes at least about 75% of the heavy metal and at least about 75% of the volatile byproduct in 800 gallons of water passed therethrough.