Determination of multi-valent metal contamination and system for removal of multi-valent metal contaminants from water

Abstract

A test for determining the presence of multi-valent metal contaminants, such as arsenic, mercury and chromium, when present in certain valence states and a system for removal of these contaminants from water. Multi-valent metal salts, for example, Cr +6 , which are highly toxic, can be detected and potentially removed from water through a redox reaction by reaction with iron or cobalt salts to obtain a reductive elimination of the Cr +6 by conversion to Cr +3 . The determination may be in the form of a test, such that a tableted composition can be introduced into water for reduction of a metal salt, such as Cr +6 to Cr +3 in order to provide a visual indication thereof, The system for the conversion of Cr +6 or other reducible metal salts to other lower valence states having less toxicity would rely upon introduction of a metal salt in the form of a reducing agent which would be introduced into the water allowing for a reduction/oxidation action to take place. This would be followed by removal of the flocculated/precipitated reduced contaminant metal salt and by re-reduction of the oxidized reducing agent.

Having thus described the invention, what I desire to claim and secure by Letters Patent is:  
     
         1 . A method of making a determination for a presence of a harmful water-soluble multi-valent, and ionically reducible metal contaminant in water, said method comprising: 
 a) introducing into a sample of the water to be tested a composite comprising a water-soluble, multi-valent, metal-containing reducing agent which will reduce the metal contaminant to a lower valence state;    b) allowing for a change in said water to provide indication of the presence of the potentially harmful metal contaminant based on said change.    
     
     
         2 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said metal contaminant is a contaminant which comprises a metal selected from the group consisting of arsenic, chromium and mercury and salts thereof.  
     
     
         3 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said reducing agent is a free metal or metal salt selected from the class consisting of iron and iron salts and cobalt and cobalt salts.  
     
     
         4 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, titanium, and ytterbium.  
     
     
         5 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said composition comprises a member selected from the class consisting of sequestering agents, flocculating agents and precipitating agents.  
     
     
         6 . The method for determining a presence of a metal contaminant in water of  claim 5  further characterized in that said composition also comprises a dispersing agent.  
     
     
         7 . The method for determining a presence of a metal contaminant in water of  claim 6  further characterized in that said composition is present in the form of a water-soluble tablet capable of being introduced into a sample of water to be tested.  
     
     
         8 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said change is a visual change in the water.  
     
     
         9 . The method for determining a presence of a metal contaminant in water of  claim 1  further characterized in that said change is a presence of suspended solid matter in the water.  
     
     
         10 . A method for testing for the presence of a potentially harmful multi-valent metal containing contaminant capable of being reduced, said method comprising: 
 a) introducing into a sample of the water to be tested a composition which will reduce the metal contaminant to a lower or reduced valence state and concomitantly change the visual appearance of the water containing medium based on a potential presence of the metal contaminant of water.    
     
     
         11 . The method of testing for the presence of a potentially harmful metal constituent in water of  claim 10  further characterized in that said method comprises also introducing into the sample of water to be tested a member selected from the class consisting of sequestering agents and flocculating agents.  
     
     
         12 . The method of testing for the presence of a potentially harmful metal constituent in water of  claim 10  further characterized in that said method introducing into the sample of water to be tested a sequestering agent to enable efficient interaction of the constituents in the water and complete reduction of the metal contaminant.  
     
     
         13 . The method of testing for the presence of a potentially harmful metal constituent in water of  claim 10  further characterized in that said method comprises detecting for the presence of any one of arsenic, chromium and mercury or salts thereof.  
     
     
         14 . The method of testing for the presence of a potentially harmful metal constituent in water of  claim 10  further characterized in that said method comprises adding to said sample of water a metal-containing reducing agent selected from the class consisting of iron and cobalt.  
     
     
         15 . The method of testing for the presence of a potentially harmful metal constituent in water of  claim 10  further characterized in that said method comprises introducing into the sample of water a metal-containing reducing agent selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.  
     
     
         16 . A composition making a determination of the presence of a potentially harmful water-soluble, multi-valent and ionically reducible metal contaminant in water, said composition comprising: 
 a) a water-soluble multi-valent, metal-containing reducing agent introducible into the water to be tested and which will reduce the metal contaminant to a lower valence state; and    b) another ingredient which will allow for stabilization of any reaction products, and present indication of these products by a rapid visible change in the water thereby identifying presence of the potentially harmful metal contaminants.    
     
     
         17 . The composition for determining a presence of a metal contaminant in water of  claim 16  further characterized in that said reducing agent is one which will readily reduce the valence state of a metal-containing contaminant selected from the group consisting of arsenic, chromium and mercury or salts thereof.  
     
     
         18 . The composition for determining a presence of a metal contaminant in water of  claim 16  further characterized in that said reducing agent is one which will readily reduce the valence state of the contaminant and is a free metal or metal salt selected from the class consisting of iron and iron salts and cobalt and cobalt salts.  
     
     
         19 . The composition for determining a presence of a metal contaminant in water of  claim 16  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.  
     
     
         20 . The composition for determining a presence of a metal contaminant in water of  claim 16  further characterized in that another ingredient comprises a member selected from the class consisting of sequestering agents, precipitating agents and flocculating agents.  
     
     
         21 . The composition for determining a presence of a metal contaminant in water of  claim 20  further characterized in that said composition also comprises a dispersing agent.  
     
     
         22 . The composition for determining a presence of a metal contaminant in water of  claim 21  further characterized in that said composition is present in the form of a water-soluble tablet capable of being introduced into a sample of water to be tested.  
     
     
         23 . The method for determining a presence of a metal contaminant in water of  claim 16  further characterized in that said change is a visual change in the water.  
     
     
         24 . The method for determining a presence of a metal contaminant in water of  claim 16  further characterized in that said change is a presence of suspended solid matter in the water.  
     
     
         25 . A tableted composition for detecting the presence of a potentially harmful metal contaminant in water by visual determination when the tableted composition is introduced into the water, said tableted composition comprising: 
 a) a reductant capable of reducing the metal contaminant to a reduced state; and    b) a component selected from the class consisting of a sequestering agent and a stabilizing agent.    
     
     
         26 . The tableted composition of  claim 25  further characterized in that said composition comprises a dispersing agent for obtaining rapid mixing and dispersal of the reducing agent throughout the sample of water to be tested.  
     
     
         27 . The tableted composition of  claim 25  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of ferrous and cobalt metals and metal salts.  
     
     
         28 . The tableted composition of  claim 25  further characterized in that said dispersing agent is sodium bicarbonate.  
     
     
         29 . The tableted composition of  claim 25  further characterized in that said sequestering agent is a dicarboxylic or tricarboxylic acid.  
     
     
         30 . The tableted composition of  claim 25  further characterized in that said visual determination arises by observation of a suspension of solid matter in water.  
     
     
         31 . The tableted composition of  claim 25  further characterized in that said metal contaminant is a contaminant which comprises a metal selected from the group consisting of arsenic, chromium and mercury or salts thereof.  
     
     
         32 . The tableted composition of  claim 25  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.  
     
     
         33 . A method for eliminating from a body of water a potentially harmful multi-valent water-soluble metal contaminant capable of being reduced to a lower valence state, said method comprising: 
 a) introducing into said body of water a composition comprising a water-soluble, multi-valent, metal-containing reducing agent capable of reducing the metal contaminant to a lower valence state;    b) also introducing into said body of water a flocculating and precipitating ingredient which enables consolidation of the reduced metal contaminant in the body of water; and    c) removing the reduced metal contaminant from the body of water.    
     
     
         34 . The method for eliminating from a body of water the potentially harmful multi-valent water-soluble contaminant of  claim 33  further characterized in that said method causes precipitation of reduced contaminants in the water and permits removal of the reduced constituents from the body of water.  
     
     
         35 . The method for eliminating from a body of water the potentially harmful multi-valent water-soluble contaminant of  claim 33  further characterized in that said metal contaminant is a contaminant which comprises a metal select d from the group consisting of arsenic, chromium and mercury or salts thereof.  
     
     
         36 . The method for eliminating from a body of water the potentially harmful multi-valent water-soluble contaminant of  claim 33  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.  
     
     
         37 . The method for eliminating from a body of water the potentially harmful multi-valent water-soluble contaminant of  claim 33  further characterized in that said composition comprises a member selected from the class consisting of sequestering agents and flocculating and precipitating agents.  
     
     
         38 . The method for eliminating from a body of water the potentially harmful multi-valent, water-soluble contaminant of  claim 33  further characterized in that said composition also comprises a dispersant.  
     
     
         39 . A reaction system for eliminating from water multi-valent, water-soluble metal contaminants which are reducible in the presence of a selected reducing agent, said system comprising: 
 a) a reaction volume containing a body of water to be treated for elimination of said harmful metal constituent;    b) means for introducing into said reaction volume a water-soluble, multi-valent metal reducing agent able to react with and effectively reduce the metal contaminant to a reduced valence state and simultaneously oxidize the reducing agent to a higher oxidized valence state;    c) means allowing for introduction into the body of water an ingredient which permits separation of solid constituents formed through reaction of the metal contaminant with the reducing agent; and    d) means for discharging and removing any separated solid constituents from the body of water.    
     
     
         40 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said metal contaminant is a contaminant which comprises a metal selected from the group consisting of arsenic, chromium and mercury or salts thereof.  
     
     
         41 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said reaction volume is contained in a reaction chamber.  
     
     
         42 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 41  further characterized in that said chamber comprises a window through which to view an indication of the presence of the potentially harmful metal contaminant based on a visual change in a reaction medium therein.  
     
     
         43 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said reducing agent is a finely divided free metal or metal salt selected from the class consisting of iron and iron salts and cobalt and cobalt salts.  
     
     
         44 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said reducing agent is a metal or metal salt selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.  
     
     
         45 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said ingredient comprises a member selected from the class consisting of sequestering agents, precipitating agents and flocculating agents.  
     
     
         46 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 45  further characterized in that said ingredient also comprises a dispersing agent.  
     
     
         47 . A reaction system for eliminating water-soluble, multi-valent metal contaminants from water which are reducible in the presence of a selected reducing agent, said system comprising: 
 a) a reaction volume containing a body of water to be treated for elimination of said harmful metal constituent;    b) means for introducing into said reaction volume a water-soluble, multi-valent metal reducing agent able to react with and effectively reduce the metal contaminant to the reduced valence state and simultaneously oxidize the reducing agent to a higher oxidized valence state;    c) introducing through said means for introducing a member selected from the class consisting of sequestering agents and flocculating and precipitating agents to collect any precipitated constituents in the body of water; and    d) a dispersing agent to enable fairly rapid dispersal of the reducing agent in the body of water.    
     
     
         48 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said system comprises a reactor detecting for presence of arsenic, chromium and mercury or salts thereof.  
     
     
         49 . The reaction system for liminating multi-valent metal contaminants from water of  claim 39  further characterized in that said metal-containing reducing agent is a member selected from the class consisting of iron and cobalt.  
     
     
         50 . The reaction system for eliminating multi-valent metal contaminants from water of  claim 39  further characterized in that said metal-containing reducing agent is a member selected from the class consisting of cerium, cobalt, europium, iron, manganese, nickel, platinum, praseodymium, rhenium, rhodium, samarium, terbium, tin, titanium, and ytterbium.