WO2005028707A2

WO2005028707A2 - Methods for inhibiting microbiologically influenced corrosion of metals and alloys

Info

Publication number: WO2005028707A2
Application number: PCT/US2004/012147
Authority: WO
Inventors: Rengaswamy Srinivasan; Hassann M. Saffarian; Stuart A. Fogel; James C. Crookston
Original assignee: The Johns Hopkins University
Priority date: 2003-04-21
Filing date: 2004-04-20
Publication date: 2005-03-31
Also published as: WO2005028707A3

Abstract

Methods for inhibiting the microbiologically influenced corrosion of a metal are provided comprising treating the surface of the metal with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions; wherein the surface of the metal is in the presence of corrosive reagents such as chloride ions and acids and one or more microorganisms capable of colonizing on and/or embedding into the surface and preventing self-healing of the surface of the metal damaged by the corrosive reagents.

Description

METHODS FOR INHIBITING THE MICROBIOLOGICALLY INFLUENCED CORROSION OF METALS AND ALLOYS

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Application No.

60/464,182, filed April 21, 2003, the contents of which are incorporated herein by reference. STATEMENT OF GOVERNMENTAL INTEREST [0002] This invention was made with government support under U.S. Navy contract number N00024-03-D-6606. The government has certain rights in this invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0003] The present invention relates generally to methods for inhibiting microbiologically influenced corrosion.

2. Description of the Related Art

[0004] In general, highly alloyed metals such as, for example, stainless steel alloys and nickel based alloys, are ordinarily utilized in environments subjected to corrosion conditions due to their resistance to pitting and crevice corrosion. Corrosion typically occurs in an environment where the alloys are in contact with an aqueous medium such as, for example, seawater, well water, saltwater and tap water contaminated with various salts, particularly chlorides. Such environments are encountered in, for example, the off-shore industry (seawater, acid oil and gas), in heat exchangers and condensers (seawater), desalination plants (saltwater), flue-gas purification equipment (chlorides and acids), flue- gas condensing apparatus (strong acids), plants for the production of sulphuric acid or phosphoric acid, pipes and apparatus for oil and gas production (acid oil and gas), apparatus and pipes in cellulose bleaching plants and in chlorate production plants (chloride containing, oxidizing acids or solutions, respectively) and in tankers and petrol trucks (all kinds of chemicals). [0005] Stainless steel alloys will ordinarily contain chromium because of its ability to form a passivating film of chromium oxide on the surface of the steel thereby providing high corrosion resistance. The passivating oxide is highly inert and adheres to the surface of the metal so as to protect it from further chemical attack. Examples of other alloying elements, which also assist in improving the pitting corrosion resistance, are molybdenum and nickel.

[0006] Pitting corrosion is the first stage toward more serious forms of corrosion such as, for example, fatigue, stress corrosion cracking and hydrogen embrittlement in the alloy or metal. Thus, it is important to inhibit pitting corrosion at the earliest stage possible. One way to enhance the corrosion resistance of alloys and metals and, therefore, inhibit pitting corrosion is to dissolve corrosion inhibitors in the liquid that is in contact with the alloy or metal. Another way to enhance the corrosion resistance is by adding the corrosion inhibitors to a paint or polymer coating and then applying the paint or coating to the alloy or metal.

[0007] There is, however, another type of corrosion which differs substantially from ordinary chemical corrosion caused by, for example, acids or salts, and which affects even stainless steel and other, non-ferrous structural alloys having coatings of oxides (e.g., aluminum alloys). This type of corrosion is microbiologically influenced corrosion ("MIC") which is caused by certain types of bacteria. The bacteria induce pitting corrosion on the surface of the metal in corrosive chemical environments (e.g., acids and salts) even though the metals usually form oxide or passive oxide coatings. The standard technique for reducing MIC involve the use of biocides. However, there are problems associated with the use of biocides. For example, biocides have a limited shelf life, are toxic, eventually deteriorate in time and sometimes do not work effectively even if not deteriorated.

[0008] Accordingly, it would be desirable to have a method for inhibiting or at least mitigating MIC in corrosive environments. SUMMARY OF THE INVENTION [0008] A method for inhibiting the microbiologically influenced corrosion of a metal is provided herein. In accordance with the present invention, the method comprises treating the surface of the metal with a microbiologically influenced corrosion inhibitive effective amount of a source of rare earth metal ions; wherein the surface of the metal is in the presence of one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the surface and preventing self-healing of the surface of the metal.

[0009] In a second embodiment of the present invention, a method for inhibiting the microbiologically influenced corrosion of a metal is provided comprising: providing a metal in at least a portion of an aqueous environment with one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the metal surface and preventing self-healing of the surface; wherein the metal surface is treated with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions to modify the metal surface to inhibit the microbiologically influenced corrosion of the metal prior to the metal being in the aqueous environment.

[0010] In a third embodiment of the present invention, a method for inhibiting the microbiologically influenced corrosion of a metal is provided comprising: providing a metal vessel having an opening therein for storing an aqueous medium with one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the metal surface of the vessel and preventing self- healing of the surface; and, contacting the metal surface with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions to modify the metal surface to inhibit the microbiologically influenced corrosion of the metal. [0011] In a fourth embodiment of the present invention, a method for preventing the formation of colonies of microorganisms on the surface of a metal comprising: treating the metal surface with an effective amount of a source of rare earth metal ions to modify the metal surface to prevent the formation of colonies of the microorganism on the surface of the metal. [0012] In a fifth embodiment of the present invention, a method for deactivating and/or killing one or more microorganisms on a metal surface is provided comprising: treating the metal surface with an amount of a source of rare earth metal ions effective to deactivate and/or kill the microorganism on the surface of the metal. [0013] The methods of the present invention advantageously inhibits or prevents microbiological corrosion of metals influenced by microorganisms such as, for example, Ralstonia eutropha (R. eutropha).

[0014] The expression "rare earth group" or "rare earth element" or "rare earth metal ions" shall be used herein in its art recognized form, i.e., as referring to the lanthanide series of elements in the periodic table with atomic numbers ranging from cerium (58) to lutetium (71) inclusive. Lanthanum, yttrium and scandium, while not technically lanthanides because they do not have f-orbital electrons, are chemically very similar to the lanthanides and accordingly are also considered rare earth elements herein. The expression "rare earths" is used to refer to this particular group of rare earth elements both in chemical practice and hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS [0015] Various embodiments are described below with reference to the drawings wherein:

[0016] FIG. 1 is a diagram of a method of the present disclosure;

[0017] FIG. 2 is a graph showing the anodic polarization behavior of 17-4 PH stainless steel in two different solutions: (1) in 10 mM sodium chloride, and (2) in 10 mM sodium chloride and 100 μL of R eutropha; and,

[0018] FIG. 3 is a graph showing the anodic polarization behavior of 17-4 PH stainless steel in two different solutions: (3) in 10 mM sodium chloride and 10 mM cerium nitrate, and (4) in 10 mM sodium chloride, 10 mM cerium nitrate, and 100 μL of R eutropha. DETAILED DESCRIPTION OF PREFERRED EMBODLMENT(S [0019] The methods of this invention advantageously inhibit microbiologically influenced corrosion of a metal or alloy. It has been found that the microorganisms responsible for MIC colonize on the surface of metals and/or embed themselves in the pits and discontinuities in an oxide layer or passivation oxide layer on the surface of the metal. There they remain unreached by biocides, even with the use of brushes and scrubbing with detergents. Biocides eventually wear out and the bacterial population regrows. The only way to remove them is by abrading the surface of metal structure down to the bare metal, which is clearly not a feasible alternative in many circumstances. [0020] Metals to be protected from microbiologically influenced corrosion by the methods of the present invention include at least those which form an oxide layer or an inert oxide as a passivation layer which adheres to the metal and may protect the surface from further attack. Such metals for use in the method of the present disclosure include, but are not limited to, any commercially available stainless steel metal alloy known to one skilled in the art, iron, iron-based alloys, chromium, cmOmium-based metal alloys, nickel, nickel-based metal alloys, aluminum aluminum-based metal alloys, copper, copper-based metal alloys and the like. For listings of stainless steel metal alloys and their chemical composition, see, e.g., Metals Handbook, "Property and Selection: Irons, Steels and High- Performance Alloys", Vol. 1, ASM International, page 843 (1990), the contents of which are incorporated by reference herein. Examples of stainless steel alloys for use herein include, but are not limited to, 17-4 PH stainless steel, 304 stainless steel, 304L stainless steel, 316 stainless steel, 316L stainless steel, UNS S40900, UNS S41045, UNS 531603, UNS N08904, etc. Preferred alloys for use herein are the 17-4 PH and 316 stainless steel alloys. As previously stated, the metals advantageously form an inert oxide as an oxide layer or passivation layer on the surface of the metal. For example, stainless steel alloys typically include chromium as a component, which tends to form an inert chromium oxide surface film. Aluminum tends to form an inert aluminum oxide layer. Both chromium oxide and aluminum oxide insulate the metal beneath from electrochemical reactions. [0021] The metal may be in any shape or form. For example, such articles can be in the form of rebars, storage vessels, chambers, ducts or tubes, water cooling systems which recirculate water therein, composite materials, etc. The metal may also be immersed in (e.g., a boat) or exposed to fluids such as gases, e.g., natural gas, liquids, e.g., hydrocarbons such as, for example, gas crude oil, fuel oil, gasoline, etc., acids, bases, salt solutions, electrolytes, organic and inorganic solvents, oils, water, seawater and the like or the metal may have an aqueous medium contained therein such as, for example, a metal storage vessel having an opening therein containing chemicals such as acids, bases or an alkali medium, e.g., potassium hydroxide, sodium hydroxide and mixtures thereof. [0022] However, the oxide layer or passivating layer must be able to self heal or regenerate so as to prevent further propagation of corrosion. Generally, a portion of the oxide layer which does not restore itself will become the site of further corrosive attack, i.e., localized corrosion. It has been found that certain microorganisms, such as, for example, Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and the like, when colonized on and/or embedded into the oxide layer, modify the properties of the oxide layer so as to render the oxide unable to heal. Consequently, when corrosive reagents (e.g., chloride ions, sulfate ions, nitrate ions, acetate ions, phosphate ions, oxalate ions, thalate ions, borate ions and/or acids) come into contact with the metal surface, the metal corrodes relatively more easily.

[0023] Accordingly, the methods of the present invention utilize a source of rare earth metal ions (e.g., Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), particularly cerium, from salts such as cerium sulfate, cerium nitrate, or cerium chloride such that when the source of rare earth metal ions are in contact with the surface of the metal, these ions advantageously inhibit or prevent MIC by at least three different mechanisms: (1) embedding itself into the oxide layer to slow down or mitigate MIC; (2) preventing bacteria from forming colonies on the oxide layer and/or metal surface; and (3) directly interacting with the microorganism, i.e., bacteria, and deactivating and/or killing the microorganism. A colony is a population of cells which grow as a cluster or assemblage on a solid surface sufficient to become visible to the naked eye or under a microscope.

[0024] To carry out the methods of this invention, at least a portion of a surface of the foregoing metals will be advantageously treated with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions e.g. at least one salt of at least one rare earth element salt selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof for a sufficient period of time such that at least a portion of one or more of the rare earth metal ions inhibit or prevents MIC and increases the corrosion resistance of the metal. The salts will typically be dissolvable in an aqueous medium e.g., water. Accordingly, in the case where a metal vessel for storing an aqueous medium is to be treated by the methods of the present invention, the source of rare earth metal ions can be added directly to the aqueous medium (which is also the case for a water cooling system which recirculates an aqueous medium) or the metal surface of the vessel to be in contact with the aqueous medium can be treated prior to the aqueous medium being stored therein, e.g., by applying a coating on the metal surface as discussed further hereinbelow. Alternatively, depending on the particular application, an aqueous solution can be employed herein and will contain at least a salt of at least one element of the rare earth element group. [0025] Concentration of the rare earth element salt(s) can vary widely according to the metal being treated. Generally, a concentration of the rare earth element salt will range in an amount effective to advantageously inhibit the microbiologically influenced corrosion of the metal by the microorganism such that the corrosion resistance of the metal will be significantly improved. The concentration of the rare earth element salt will ordinarily range from about 0.1 mM to about 300 mM. The aqueous solution is advantageously kept at ambient temperature to allow for minimum evaporation of water and to avoid unnecessary heating of the structure that is being treated or its environment. [0026] The metal to be treated will be contacted with the rare earth element salt(s) or aqueous solution by techniques known in the art such that at least a portion of a surface of the metal or alloy is in contact with the salt. Suitable techniques include, but are not limited to, immersion, dispersing, spraying and the like. The use of an aqueous solution advantageously allows full access to the surface area of any piece of metal in need of corrosion protection. However, it will be understood that other methods may be used, such as, for example, sputtering, plasma spraying and the like, such that the rare earth elements are deposited on the metal surface. Those skilled in the art will be able to determine the operative processing conditions for each of the deposition procedures. The preferred technique for use herein is immersing at least a portion of the alloy in need of corrosion protection in a bath of the aqueous solution.

[0027] Once the metal is contacted with the rare earth element salt(s) the metal or alloy may then be subjected to processing steps to implant the rare earth element salt(s) into at least a portion of the oxide layer on the surface of the metal, e.g., electrochemical processing steps. For example, referring now to Figure 1, metal 30 will act as an anode after being immersed in the aqueous solution 24. The vessel 32 which contains the aqueous solution 24 may be used as the cathode. Suitable vessels for use herein as a cathode are known in the art and include, for example, a stainless steel vessel. The anode may be connected through a switch 34 to a rectifier 36 while the vessel 32 may be directly connected to the rectifier 36. The rectifier 36, rectifies the voltage from a voltage source 38, to provide a direct current source to the aqueous solution. Preferably, the rectifier provides a pulsed DC signal to drive the deposition process.

[0028] The current will flow through the aqueous solution at an effective level and for a time period sufficient to implant the rare earth element(s) into at least a portion of the oxide layer on the surface of the metal. For example, in the case of a stainless steel chromium alloy, by flowing the current through the aqueous solution with the stainless steel alloy immersed therein, the current will advantageously dissolve at least a portion of the oxide layer formed on the surface of the alloy. However, the chromium present in the oxide layer on the surface of the alloy is insoluble and will precipitate back onto the surface of the alloy. At this point, the rare earth element(s) will replace and implant in the voids remaining in the oxide layer on the surface of the alloy, in amounts comparable to the amount of chromium in the oxide layer, to provide the rare earth element oxide- containing coating on the surface of the alloy and increasing the corrosion protection of the resulting alloy. Thus, for this to occur a voltage differential between the anode comprising the alloy and the cathode in the solution is established by flowing a current not exceeding a current density of 10 μA/cm² through the solution. Generally, the current will flow through the solution such that the current density will range from about 0.1 μA/cm² to about 2.5 μA/cm², preferably from about 0.25 μA/cm² to about 2.0 μA/cm² and most preferably from about 0.5 μA/cm² to about 1.0 μA/cm². The time period sufficient to provide the increased corrosion protection of alloy can range from about 10 minutes to about 120 minutes and preferably from about 50 minutes to about 60 minutes. During the course of the anodization process, it is important to ensure the electrochemical potential of the anode (i.e., the alloy) remains within the potential range that is commonly known in the art as the "passivation potential".

[0029] If desired, a corrosion inhibiting surface active agent may be added to the aqueous solution following the step of electrochemistry to further increase the corrosion resistance of the alloys. Suitable corrosion inhibiting surface active agents include, but are not limited to, corrosion inhibiting surfactants, e.g., sodium lauryl sulfate. The solution will ordinarily contain from about 0.01 to about 0.05 weight percent of the surfactant. [0030] In another embodiment of the present invention, the metals which are in the presence of corrosive reagents and at least one microorganism capable of colonizing on and/or embedding into the oxide layer and or metal surface and preventing self-healing thereof causing microbiologically influenced corrosion may be coated using a coating such as paint or a sealant containing a microbiologically influenced corrosion inhibiting effective amount of the foregoing source of rare earth metal ions. The coatings may include inorganic and organic compositions. Representative, non-limiting inorganic compositions for use as the coating include alkali metal silicates, phosphates, borates, molydates and vanadates. Representative, non-limiting organic coatings include polymers such as polyfluoroethylene, polyurethane polyglycol, silicon, non-tar epoxy resins, tar epoxy resins, pure epoxy resins and the like. The rare earth metal ions can be incorporated into the coating by techniques well known in the art, e.g., complexation of the ions with the coating. Generally, the effective amount of the rare earth metal ions will ordinarily range from about 0.1 mM to about 300 mM. Additional coating materials will be known to those skilled in the art.

[0031] The following non-limiting examples are illustrative of the methods of the present invention.

[0032] Test results are provided below which illustrate the effectiveness of the methods of the present invention in mitigating microbiologically influenced corrosion. The following test solutions were employed: Test Solution 1 lO mM NaCl 2 10 mM NaCl + 100 μL R. eutropha 3 10 mM NaCl + 10 mM cerium (III) nitrate 4 10 mM NaCl + 100 μL R. eutropha + 10 mM cerium (III) nitrate [0033] NaCl was included as a corrosive ion source. R. eutropha was the microbial agent capable of embedding itself in the passivation layer of the metal. Cerium nitrate was the source of rare earth metal ions. Test solutions 1 and 2 were formed without cerium nitrate and were presented for purposes of comparison. Test solutions 3 and 4 included cerium nitrate. Test solution 4 included both corrosive ions (NaCl), a microbial agent capable of forming colonies on the metal surface and/or embedding itself in an oxide layer and modifying its self healing properties (R. eutropha), and the rare earth metal ions (cerium) to demonstrate the effectiveness of the invention in mitigating microbiologically influenced corrosion.

[0034] All experiments were conducted in a glass cell which was closed but not sealed from the atmosphere. An electrode was fabricated from 17-4 PH stainless steel alloy, which was machined into the form of a 3 mm diameter rod. 17-4 PH stainless steel was a precipitation hardened ferrous alloy containing 17% chromium and 4% nickel. The cylindrical peripheral surface of the rod was insulated with epoxy so as to leave a circular cross-sectional circular disc shaped area (about 0.07 cm ) exposed to the test solution. The disc area was polished with from 120 to 1200 grit abrasive before exposing to the test solution, the polishing being repeated between each experiment. The experiments were conducted using the four test solutions as described above.

[0035] In each test a freshly polished electrode was immersed in the test solution for 16 to 18 hours. The open circuit potential (Eoc) was monitored over the last one hour of immersion and found to be stable within 1 or 2 millivolts. A silver/silver chloride/NaCl reference electrode was used in potential measurement. The Eoc of test solution 1 was determined to be -0.18 volts (V). The E₀c of test solution 2 was determined to be -0.26 V. The Eoc of the tests solutions 3 and 4 with cerium ions was shifted towards relatively more positive values at about -0.125 V. [0036] Next, using a platinum coil as a counter electrode, the 17-4 PH alloy electrode as the working electrode, and a CH Instruments Analyzer Model 630 potentiostat, the potential of the 17-4 PH electrode was varied from E₀c to more positive values until the total charge due to pitting was 7.3 millicoulombs (mC). At that charge limit, the electrode potential was reverse scanned back toward Eoc- The scan rate in both directions was 0.167 mV/second (10 mV/min).

[0037] Polarization experiments were used in estimating the pitting susceptibility of alloys, and their ability to repassivate, or repair themselves from pitting corrosion. As the electrode was polarized to more positive from Eoc a sudden increase in the current indicates breakdown of the oxide (passivation ) layer and occurrence of pitting corrosion. The decrease in current during the reverse scan indicates repassivation of the oxide layer. [0038] Referring now to FIG. 2, the results obtained for test solutions land 2 are shown, the arrows indicating the direction of the potential scan. In the presence of the bacterial agent R. eutropha, the Eoc was more negative than in its absence, which illustrates that the bacteria was degrading the passivating ability of the oxide layer on the alloy. The forward scan of the electrical potential was taken to the breakdown potential E at which the current showed a sudden increase, and indicated pitting corrosion. E_b was higher (about 0.32V) for test solution 2 in the presence of the bacteria than E_b for test solution 1 without bacteria (about 0.23V). By limiting the total charge to 7.3 mC, the total amount of metal oxidized was limited to the same value whether in the absence or presence of bacteria. Thus, when the reverse scan was started, the alloy had oxidized to the same extent in both test solutions 1 and 2. During the reverse scan, the current due to metal oxidation rate diminished in recognizable steps until it reached a fraction of a microampere at the repassivation potential Ere ass- However, during the reverse scan, at potentials between E and Erepas_s a net charge of 127 mC had passed for test solution 2, with the bacteria, before the surface fully repassivated. Whereas for test solution 1, without the bacteria, the net charge was only 39.5 mC. In other words, about three times more metal was corroded in the presence of the bacteria than in its absence. In other words, the alloy was able to repassivate more easily in the absence of the bacteria. These results indicate the ability of the bacteria to disable the oxide layer from repairing itself against pitting corrosion attack. [0039] Referring now to FIG. 3, similar tests were performed for test solutions 3 and 4, with the rare earth ion source, cerium (III) nitrate and/or bacteria. These results indicate that in the presence of the cerium salt, even when the electrodes were polarized up to 1.0 V (i.e., about 0.7 V higher than Eb for test solution 2 in FIG. 2) , the metal oxidation currents were three orders of magnitude lower than those of test solutions 1 and 2, i.e., oxidation currents for test solutions 3 and 4 were on the order of 10^"7 amperes as opposed to 10^"4 amperes for test solutions 1 and 2. These results show that the addition of lOmM cerium (LTI) nitrate to the corrosive environment prevents the bacteria from attacking the oxide layer.

[0040] While the above description contains many specifics, these specifics should not be construed as limitations of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other embodiments within the scope and spirit of the invention as defined by the claims appended hereto.

Claims

WHAT IS CLAIMED IS: 1. A method for inhibiting the microbiologically influenced corrosion of a metal comprising: treating the surface of the metal with a microbiologically influenced corrosion inhibitive effective amount of a source of rare earth metal ions; wherein the surface of the metal is in the presence of one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the surface and preventing self-healing of the surface of the metal.

2. The method of claim 1 wherein the microorganism is selected from the group consisting oϊRalstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

3. The method of claim 1 wherein the surface of the metal possesses an oxide layer.

4. The method of claim 1 wherein the metal is a stainless steel alloy.

5. The method of claim 3 wherein the stainless steel alloy is selected from the group consisting of 17-4 PH stainless steel, 304 stainless steel, 304L stainless steel, 316 stainless steel, 316L stainless steel, UNS S40900, UNS S41045, UNS 531603 and UNS N08904.

6. The method of claim 1 wherein the metal is selected from the group consisting of iron, iron-based alloys, chromium, chromium-based alloys, aluminum, aluminum-based alloys, nickel, and nickel-based alloys.

7. The method of claim 1 wherein the source of rare earth metal ions is at least one salt of at least one element of the rare earth group selected from the group consisting of yttrium, gadolimum, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof.

8. The method of claim 7 wherein the salt is selected from the group consisting of a nitrate, sulfate and chloride.

9. The method of claim 1 wherein the source of rare earth metal ion is a cerium salt.

10. The method of claim 9 wherein the cerium salt is selected from the group consisting of a cerium nitrate, cerium sulfate and cerium chloride.

11. The method of claim 1 wherein the corrosive reagents are selected from the group consisting of chloride ions, sulfate ions, nitrate ions, acetate ions, phosphate ions, oxalate ions, thalate ions, borate ions, acids and combinations thereof.

12. The method of claim 1 wherein the microbiologically influenced corrosion inhibiting effective amount is a concentration of about 0.1 mM to about 300 mM.

13. The method of claim 1 wherein the step of treating the metal surface comprises contacting the metal with a coating containing the microbiologically influenced corrosion inhibiting effective amount of the source of rare earth metal ions.

14. The method of claim 13 wherein the coating is an inorganic or organic composition.

15. The method of claim 1 wherein the step of treating the metal surface comprises contacting at least a portion of the metal surface with an aqueous solution containing the microbiologically influenced corrosion inhibiting effective amount of the source of rare earth metal ions.

16. A method for inhibiting the microbiologically influenced corrosion of a metal comprising: providing a metal in an aqueous environment with one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the metal surface and preventing self-healing of the surface; wherein the metal surface is treated with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions to modify the metal surface to inhibit the microbiologically influenced corrosion of the metal prior to the metal being in the aqueous environment.

17. The method of claim 16 wherein the microorganism is selected from the group consisting of Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

18. The method of claim 16 wherein the metal is selected from the group consisting of iron, iron-based alloys, chromium, chromium-based alloys, aluminum, aluminum-based alloys, nickel, and nickel-based alloys.

19. The method of claim 16 wherein the source of rare earth metal ions is at least one salt of at least one element of the rare earth group selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof.

20. The method of claim 19 wherein the salt is selected from the group consisting of a nitrate, sulfate and chloride.

21. The method of claim 16 wherein the treated metal surface comprises a coating thereon, the coating containing a microbiologically influenced corrosion inhibiting effective amount of the source of rare earth metal ions.

22. The method of claim 21 wherein the coating is an inorganic or organic composition.

23. The method of claim 22 wherein the source of rare earth metal ions is a cerium salt selected from the group consisting of a cerium nitrate, cerium sulfate and cerium chloride.

24. The method of claim 23 wherein the microorganism is selected from the group consisting of Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

25. The method of claim 16 wherein the corrosive reagents are selected from the group consisting of chloride ions, sulfate ions, nitrate ions, acetate ions, phosphate ions, oxalate ions, thalate ions, borate ions acids and combinations thereof.

26. The method of claim 16 wherein the microbiologically influenced corrosion inhibiting effective amount is a concentration of about 0.1 mM to about 300 mM.

27. A method for inhibiting the microbiologically influenced corrosion of a metal comprising: providing a metal vessel having an opening therein for storing an aqueous medium, wherein the surface of the metal vessel to be in contact with the aqueous medium is in the presence of one or more corrosive reagents and one or more microorganisms capable of colonizing on and/or embedding into the metal surface of the vessel and preventing self- healing of the surface; and, contacting the metal surface with a microbiologically influenced corrosion inhibiting effective amount of a source of rare earth metal ions to modify the metal surface to inhibit the microbiologically influenced corrosion of the metal..

28. The method of claim 27 wherein the microorganism is selected from the group consisting of Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

29. The method of claim 27 wherein the metal is selected from the group consisting of iron, iron-based alloys, chromium, chromium-based alloys, aluminum, aluminum-based alloys, nickel, and nickel-based alloys.

30. The method of claim 27 wherein the source of rare earth metal ions is at least one salt of at least one element of the rare earth group selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof.

31. The method of claim 30 wherein the salt is selected from the group consisting of a nitrate, sulfate and chloride.

32. The method of claim 27 wherein the step of contacting the metal surface comprises applying a coating containing the microbiologically influenced corrosion inhibiting effective amount of the source of rare earth metal ions onto the metal surface to be in contact with the aqueous medium.

33. The method of claim 32 wherein the coating is an inorganic or organic composition.

34. The method of claim 27 wherein the step of contacting the metal surface comprises adding the microbiologically influenced corrosion inhibiting effective amount of the source of rare earth metal ions to the aqueous medium in the vessel.

35. The method of claim 27 wherein the microbiologically influenced corrosion inhibiting effective amount is a concentration of about 0.1 mM to about 300 mM

36. A method for preventing the formation of colonies of one or more microorganisms on the surface of a metal comprising: treating the metal surface with an effective amount of a source of rare earth metal ions to modify the metal surface to prevent the formation of colonies of one or more microorganisms on the surface of the metal.

37. The method of claim 36 wherein the microorganism is selected from the group consisting of Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

38. The method of claim 36 wherein the source of rare earth metal ions is at least one salt of at least one element of the rare earth group selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof.

39. The method of claim 38 wherein the source of rare earth metal ion is a cerium salt selected from the group consisting of a cerium nitrate, cerium sulfate and cerium chloride.

40. The method of claim 37 wherein the effective amount is a concentration of about 0.1 mM to about 300 mM.

41. A method for deactivating and/or killing one or more microorganisms on a metal surface comprising: treating the metal surface with an amount of a source of rare earth metal ions effective to deactivate and/or kill the microorganism on the surface of the metal.

42. The method of claim 41 wherein the microorganism is selected from the group consisting of Ralstonia eutropha, Shewanella, Desulfovibrio desulfucans and combinations thereof.

43. The method of claim 42 wherein the source of rare earth metal ions is at least one salt of at least one element of the rare earth group selected from the group consisting of yttrium, gadolinium, cerium, europium, terbium, samarium, neodymium, praseodymium, lanthanum, holmium, ytterbium, dysprosium, erbium and combinations thereof.

44. The method of claim 43 wherein the source of rare earth metal ion is a cerium salt selected from the group consisting of a cerium nitrate, cerium sulfate and cerium chloride.

45. The method of claim 41 wherein the effective amount is a concentration of about 0.1 mM to about 300 mM.