Removal agent composition for removing iron sediments of organic cultural relics in ocean effluent

Abstract

The invention discloses a removal agent composition for removing iron sediments in marine effluent organic matter cultural relics. The removal agent composition comprises ascorbic acid and disodium ethylene diamine tetraacetate. The removing agent composition can be used for efficiently removing iron sediments in marine effluent wood cultural relics, marine effluent bamboo cultural relics, marine effluent leather cultural relics, marine effluent lacquerware and marine effluent plant fiber woven cultural relics, and the raw materials are safe, low in cost and easy to obtain.

Description

Technical Field

[0001] The present invention belongs to the field of cultural relics protection and relates to a remover composition for removing iron deposits from organic cultural relics unearthed from the sea. Background Art

[0002] During the burial process of marine organic cultural relics such as the hull of a sunken wooden ship or wooden cultural relics in the sea, various types of iron deposits will be formed due to the action of the marine environment, including iron sulfide compounds such as FeS and FeS2, iron oxide compounds such as Fe2O3, Fe3O4, FeOOH, and iron-containing salts such as FeCO3. After being salvaged from the water, the iron sulfide compounds are extremely easy to oxidize in the presence of moisture and oxygen, generating sulfuric acid, which promotes the degradation of cellulose in the material. At the same time, iron oxides such as Fe2O3 and FeOOH, and iron-containing salts such as FeNa2(SO4)2·12H2O are generated. The redox between Fe 2+ / Fe 3+ will catalyze the Fenton reaction, resulting in the degradation of the organic components in the material and the reduction of the material strength. When the temperature and relative humidity in the environment change, the iron compounds will continuously dissolve / precipitate, causing damage to the microscopic structure of the material. The presence of iron deposits seriously affects the appearance, dehydration, reinforcement work, and long-term stable preservation of organic cultural relics such as wooden hulls. Therefore, after the excavation of marine organic cultural relics unearthed from the sea, it is necessary to first remove the iron deposits in the material structure as much as possible to reduce their adverse effects and provide basic conditions for the long-term stable preservation of the cultural relics.

[0003] However, the iron-containing compounds have extremely low solubility in water, making it difficult for the iron deposits in the material structure to dissolve in water. In recent years, studies have used complexing reagents, mixtures of complexing reagents and reducing agents, and mixed solutions of complexing reagents and oxidizing agents to remove iron deposits from marine organic cultural relics unearthed from the sea. By forming stable water-soluble metal complexes with Fe 3+ or Fe 2+ to remove the iron deposits therein and prevent Fe 3+ or Fe 2+Precipitate again or attach to the surface of the material in the structure of cultural relic materials. Commonly used complexing reagents include disodium ethylenediaminetetraacetate, diethylenetriaminepentaacetic acid, and ethylenediamine-bis(2-hydroxy-4-tolyl)acetic acid. The reducing agent used in combination with the complexing agent is mainly sodium dithionite (Na2S2O4), and the oxidizing agent used in combination with the complexing agent is mainly hydrogen peroxide (H2O2). However, there are some problems with the use of these materials. Among them, the efficiency of disodium ethylenediaminetetraacetate in removing iron sulfide compounds is low, the removal time is long, and the amount of iron removed per unit time is low. Diethylenetriaminepentaacetic acid and ethylenediamine-bis(2-hydroxy-4-tolyl)acetic acid are expensive and cannot be actually used for removing iron deposits in organic matter cultural relics from the sea in large quantities, such as wooden shipwrecks salvaged from the sea. The addition of sodium dithionite, although it improves the iron removal efficiency to a certain extent, the decomposition of sodium dithionite will produce sulfur, and the further oxidation of sulfur will generate sulfuric acid, which is not conducive to the preservation of the material. The decomposition of the oxidizing agent hydrogen peroxide will produce free radicals, resulting in the degradation of organic matter materials.

[0004] Therefore, a remover for iron deposits in organic matter cultural relics salvaged from the sea is needed, whose components can form soluble complexes with the insoluble iron deposits in the cultural relic materials to effectively remove the iron deposits, and will not have an adverse impact on the main body of the cultural relic materials during the process of removing the iron deposits. The selected materials should be inexpensive, easily available, and economically practical.

[0005] In view of the above problems, the present invention provides a remover composition for removing iron deposits in organic matter cultural relics salvaged from the sea, which improves the removal efficiency of iron deposits in cultural relic materials; moreover, the raw materials are safe, harmless, inexpensive, and easily available. Summary of the Invention

[0006] The purpose of the present invention is to provide a remover composition for removing iron deposits in organic matter cultural relics salvaged from the sea, which has a high removal efficiency of iron deposits in organic matter cultural relics salvaged from the sea. This purpose is achieved through the following technical solutions:

[0007] A remover composition for removing iron deposits in organic matter cultural relics salvaged from the sea, comprising ascorbic acid (ASA, i.e., vitamin C (VC)) and disodium ethylenediaminetetraacetate (EDTA-2Na); wherein the molar ratio of disodium ethylenediaminetetraacetate to ascorbic acid is 50:1 - 10:1.

[0008] When prepared into a solution for use, control the concentration of disodium ethylenediaminetetraacetate to be 10 mmol / L - 50 mmol / L and the concentration of ascorbic acid to be 1 mmol / L - 5 mmol / L, based on the total volume of the solution.

[0009] The disodium ethylenediaminetetraacetate is a complexing agent, and ascorbic acid is a reducing agent.

[0010] The remover composition of the present invention can be used to remove iron deposits in various kinds of organic cultural relics unearthed from the sea, such as for wooden cultural relics unearthed from the sea, such as the hull of a wooden sunken ship unearthed from the sea, wooden components attached to a wooden sunken ship unearthed from the sea, and other wooden cultural relics unearthed from the sea. It can also be used for bamboo cultural relics unearthed from the sea, leather cultural relics unearthed from the sea, lacquerware unearthed from the sea, plant fiber woven cultural relics unearthed from the sea, etc.

[0011] Furthermore, the present invention provides a method for removing iron deposits in organic cultural relics unearthed from the sea, which is characterized in that: using the remover composition according to the present invention, and this method comprises the following steps:

[0012] (1) Dissolve disodium ethylenediaminetetraacetate and ascorbic acid in deionized water to prepare a remover solution with a certain concentration;

[0013] (2) Immerse the organic cultural relics to be treated in the remover solution prepared in step (1);

[0014] Or, spray the organic cultural relics to be treated with the remover solution prepared in step (1) or apply a dressing soaked with the remover solution prepared in step (1) to the organic cultural relics to be treated;

[0015] (3) Take a certain amount of the soaking solution at regular intervals and measure the iron concentration therein. When the iron concentration in the solution no longer increases, then replace the remover solution and continue soaking;

[0016] Or, take a certain amount of the sprayed effluent or the leachate from the applied dressing at regular intervals and measure the iron concentration therein. When the iron concentration in the solution no longer increases, then replace the remover solution and continue spraying or applying;

[0017] (4) Repeat step (3) until the iron concentration in the solution is not more than 10 mmol / L.

[0018] (5) Take out the cultural relics from the soaking solution and rinse the surface of the cultural relics with deionized water;

[0019] Or, in the case of spraying or applying, directly rinse the surface of the cultural relics with deionized water.

[0020] In step (1), the concentration of disodium ethylenediaminetetraacetate is 10 mmol / L to 50 mmol / L, and the concentration range of ascorbic acid is 1 mmol / L to 5 mmol / L, based on the total volume of this solution.

[0021] In step (3), the concentration of disodium ethylenediaminetetraacetate / ascorbic acid solution in the stripping agent solution used may be the same as or different from that in step (1). In this step, optionally, before replacing the stripping agent solution and continuing to soak, the cultural relic is soaked in deionized water to dissolve the iron that has complexed with the stripping agent but remains in the capillary structure of the material; or, before replacing the stripping agent solution and continuing to spray or apply, it is rinsed with deionized water to dissolve the iron that has complexed with the stripping agent but remains in the capillary structure of the material.

[0022] In the method of the present invention, the removal of iron deposits in relatively small organic cultural relics can be carried out by soaking, spraying or applying. For large organic cultural relics that are not convenient for soaking, such as the hull of a wooden sunken ship, it is preferably carried out by spraying or applying to remove iron deposits.

[0023] For organic cultural relics unearthed from archaeology, their chemical components have been severely degraded during the burial process. When removing iron deposits during the protection process, further degradation of the remaining organic components should be prevented as much as possible. Therefore, the materials selected for the stripping agent cannot be strongly acidic or strongly alkaline, and when formulated into a solution for use, the pH should be controlled within the range of 4-8. The concentration of the solution used should be moderate. Too high a concentration will cause waste, especially for huge wooden ships, which will greatly increase the cost of cultural relic protection; too low a concentration will lead to too long a treatment time, which is not conducive to the preservation of cultural relics.

[0024] Ascorbic acid is a weak acid and also a reducing chelating agent. It can reduce different types of iron compounds under acidic conditions to form more water-soluble Fe 2+ . Ascorbic acid makes the Fe on the surface of the iron deposit 3+ transform into Fe 2+ through a reduction reaction, and then is released into the solution in the form of Fe 2+ by ion exchange. For example, if the deposits contained in the unearthed organic cultural relics are mainly iron oxides, ascorbic acid can effectively reduce the iron oxides therein. In the stripping agent composition of the present invention, ascorbic acid and EDTA-2Na act synergistically, thus significantly improving the efficiency of EDTA-2Na in removing iron deposits from cultural relic materials; moreover, its component ascorbic acid is safe, harmless, low in price and easy to obtain, providing an effective solution for removing iron deposits from organic cultural relics unearthed from the sea, which is of great significance for the protection of organic cultural relics unearthed from the sea. Specific implementation examples

[0025] The present invention will be further explained in detail below with reference to specific examples, but the present invention is not limited thereto. The samples and reagents used in the examples of the present invention are all commercially available. The chemical reagents used are all of analytical grade. The experimental wooden block samples used in the examples and comparative examples all come from the Song Dynasty ship Nanhai No. 1.

[0026] Example 1

[0027] Take EDTA-2Na (0.336 g, 0.001 mol) and ascorbic acid (0.018 g, 0.0001 mol) respectively, add them into 100 ml of deionized water to prepare a solution with a pH of about 4.2. Immerse a marine water-exposed wood sample block of 1 cm × 1 cm × 1 cm in the solution.

[0028] Take samples of the scavenger solution on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day and 365th day respectively, and test the iron concentration in it. The test results are shown in Table 1.

[0029] Table 1. Variation of iron concentration in the solution used in Example 1 with time

[0030] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 14.7 80 103 138 168 191.8 198.6 252.5

[0031] Example 2

[0032] Take EDTA-2Na (1.008 g, 0.003 mol) and ascorbic acid (0.054 g, 0.0003 mol) respectively, add them into 100 ml of deionized water to prepare a solution with a pH of about 4.2. Immerse a wood sample block of 1 cm × 1 cm × 1 cm in the solution. Take samples of the scavenger solution on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day and 365th day respectively, and test the iron concentration in it. The test results are shown in Table 2.

[0033] Table 2. Variation of iron concentration in the solution used in Example 2 with time

[0034] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 65.2 156.7 212.5 289.9 343.3 398.5 426.2 513.4

[0035] Example 3

[0036] Take EDTA-2Na (1.68 g, 0.005 mol) and ascorbic acid (0.092 g, 0.0005 mol) respectively, add them into 100 ml of deionized water to prepare a solution with a pH of about 4.2. Immerse a wood sample block of 1 cm × 1 cm × 1 cm in the solution. Take samples of the scavenger solution on the 15th day, 39th day, 54th day, 94th day and 110th day respectively, and test the iron concentration in it. The test results are shown in Table 3.

[0037] Table 3. Variation of iron concentration in the solution used in Example 3 with time

[0038] Sampling time (days) 15 39 54 94 110 [Fe] (mmol / L) 146.2 232.2 246.1 278.9 342.5

[0039] Example 4

[0040] Weigh out EDTA-2Na (1.68 g, 0.005 mol) and ascorbic acid (0.018 g, 0.0001 mol) separately, add them to 100 ml of deionized water to prepare a solution with a pH of approximately 4.5. Immerse a 1 cm × 1 cm × 1 cm wood sample block into the said solution. Take samples of the removing agent solution on the 15th day, 39th day, 54th day, 94th day, and 110th day respectively, and test the iron concentration therein. The test results are shown in Table 4.

[0041] Table 4. Variation of iron concentration in the solution used in Example 4 with time

[0042] Sampling time (days) 15 39 54 94 110 [Fe] (mmol / L) 112.3 180.7 194.6 223.4 268.8

[0043] Example 5

[0044] Weigh out EDTA-2Na (1.008 g, 0.003 mol) and ascorbic acid (0.018 g, 0.0001 mol) separately, add them to 100 ml of deionized water to prepare a solution with a pH of approximately 4.4. Immerse a 1 cm × 1 cm × 1 cm wood sample block into the said solution. Take samples of the removing agent solution on the 15th day, 39th day, 54th day, 94th day, and 110th day respectively, and test the iron concentration therein. The test results are shown in Table 5.

[0045] Table 5. Variation of iron concentration in the solution used in Example 5 with time

[0046] Sampling time (days) 15 39 54 94 110 [Fe] (mmol / L) 33.2 78.8 112.6 135.4 140.9

[0047] Comparative Example 1

[0048] Repeat Example 1, except that a 0.01 mol / L EDTA-2Na solution with a volume of 100 mL is used to soak the sample to remove iron deposits. Take samples of the removing agent solution on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day, and 365th day respectively, and test the iron concentration therein. The test results are shown in Table 6.

[0049] Table 6. Variation of iron concentration in the solution used in Comparative Example 1 with time

[0050] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 35.8 42.9 47.6 50.1 51.6 54.5 55.5 62.92

[0051] Comparative Example 2

[0052] Repeat Example 1, except that a 0.001 mol / L ascorbic acid solution with a volume of 100 mL is used to soak the sample to remove iron deposits. Take samples of the removing agent solution on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day, and 365th day respectively, and test the iron concentration therein. The test results are shown in Table 7.

[0053] Table 7. Variation of iron concentration in the solution used in Comparative Example 2 with time

[0054] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 0.3 0.3 0.7 5.2 8.4 9.2 16.9 51.1

[0055] Comparative Example 3

[0056] Repeat Example 1, except that a 100 mL sodium oxalate solution with a concentration of 0.01 mol / L is used to soak the sample to remove iron deposits. Samples of the removing agent solution are taken on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day and 365th day respectively, and the iron concentration in them is tested. The test results are shown in Table 8.

[0057] Table 8. Variation of iron concentration in the solution used in Comparative Example 3 with time

[0058] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 8.8 7.4 6.9 5.4 6.3 7.1 7.1 4.4

[0059] Comparative Example 4

[0060] Repeat Example 1, except that a 100 mL ammonium citrate solution with a concentration of 0.01 mol / L is used to soak the sample to remove iron deposits. Samples of the removing agent solution are taken on the 30th day, 71st day, 120th day, 173rd day, 200th day, 270th day, 300th day and 365th day respectively, and the iron concentration in them is tested. The test results are shown in Table 9.

[0061] Table 9. Variation of iron concentration in the solution in Comparative Example 3 with time

[0062] Sampling time (days) 30 71 120 173 200 270 300 365 [Fe] (mmol / L) 8.8 7.4 6.9 5.4 6.3 7.1 7.1 4.4

[0063] Comparative Example 5

[0064] Repeat Example 1, except that a 100 mL solution of diethylenetriaminepentaacetic acid + 0.1 mol / L H2O2 with a concentration of 0.01 mol / L is used to soak the sample to remove iron deposits. Samples of the removing agent solution are taken on the 15th day, 32nd day, 54th day, 70th day, 107th day, 124th day and 202nd day respectively, and the iron concentration in them is tested. The test results are shown in Table 10.

[0065] Table 10. Variation of iron concentration in the solution used in Comparative Example 5 with time

[0066] Sampling time (days) 15 32 54 70 107 124 202 [Fe] (mmol / L) 40.3 40.2 43.5 45.9 46.3 48.89 54.5

[0067] Comparative Example 6

[0068] Repeat Example 1, except that the sample was immersed in a solution of 100 mL of diethylenetriaminepentaacetic acid at a concentration of 0.01 mol / L + 0.001 mol / L ascorbic acid to remove iron deposits. Samples of the stripping agent solution were taken on the 15th, 32nd, 54th, 70th, 107th, 124th, and 202nd days, and the iron concentration in them was measured. The test results are shown in Table 11.

[0069] Table 11. Variation of iron concentration in the solution used in Comparative Example 6 with time

[0070] Sampling time (days) 15 32 54 70 107 124 202 [Fe] (mmol / L) 39.6 42.5 44.8 45.1 45.2 46.3 51.0

[0071] It can be seen from the test results that under the conditions of the same solution volume and molar concentration, and the same or similar stripping time, the amount of iron removed by the EDTA-2Na / VC solution (Example 1) is much higher than that of the EDTA-2Na solution and VC solution used alone, and also much higher than that of the sodium oxalate solution, ammonium citrate solution, diethylenetriaminepentaacetic acid + H2O2 solution, and diethylenetriaminepentaacetic acid + VC solution. This shows that the EDTA-2Na / VC solution has a much better effect on removing iron from wood than other solutions.

[0072] It can be seen that in the stripping agent composition of the present invention, the complexing agent EDTA-2Na and ascorbic acid combine to produce a synergistic effect, significantly improving the stripping efficiency of iron deposits, reducing the use of stripping agent materials during the stripping process, reducing the time required to remove iron deposits, shortening the protection period of marine organic matter cultural relics, and also providing a solution for removing iron deposits from marine organic matter cultural relics, and can be well applied to the protection of marine organic matter cultural relics.

Claims

1. A remover composition for removing iron deposits from organic cultural relics in marine effluent, comprising ascorbic acid and disodium ethylenediaminetetraacetate; wherein the molar ratio of disodium ethylenediaminetetraacetate to ascorbic acid is 50:1 - 10:

1.

2. The remover composition according to claim 1, wherein when used as a solution, the concentration of disodium ethylenediaminetetraacetate is controlled to be 10 mmol / L - 50 mmol / L, and the concentration of ascorbic acid is 1 mmol / L - 5 mmol / L, based on the total volume of the solution.

3. A method for removing iron deposits from organic cultural relics with marine effluent, characterized in that: Using the remover composition according to claim 1, the method comprises the following steps: (1). Add disodium ethylenediaminetetraacetate and ascorbic acid into deionized water to prepare a remover solution with a certain concentration; (2). Immerse the organic cultural relics to be treated in the remover solution of step (1); Or, spray the organic cultural relics to be treated with the remover solution of step (1) or apply a dressing soaked with the remover solution of step (1); (3). Take a certain amount of the soaking solution at regular intervals and measure the iron concentration therein. When the iron concentration in the solution no longer increases, then replace the remover solution and continue soaking; Or, take a certain amount of the sprayed effluent or the leaching solution from the applied dressing at regular intervals and measure the iron concentration therein. When the iron concentration in the solution no longer increases, then replace the remover solution and continue spraying or applying; (4). Repeat step (3) until the iron concentration in the solution is not greater than 10 mmol / L; (5). Take the cultural relics out of the soaking solution and rinse the surface of the cultural relics with deionized water; Or, in the case of spraying or applying, directly rinse the surface of the cultural relics with deionized water.

4. The method according to claim 3, wherein in step (1), the concentration of disodium ethylenediaminetetraacetate is 10 mmol / L - 50 mmol / L, and the concentration range of ascorbic acid is 1 mmol / L - 5 mmol / L, based on the total volume of the solution.

5. The method according to claim 3, wherein in step (3), the concentration of the disodium ethylenediaminetetraacetate / ascorbic acid solution in the used remover solution is the same as or different from that in step (1).

6. The method according to claim 3, wherein in step (3), before replacing the soaking solution and continuing soaking, soak the cultural relics in deionized water to dissolve the iron that has complexed with the complexing reagent but remains in the capillary structure of the material; Or, before replacing the remover solution and continuing spraying or applying, spray or wash with deionized water to dissolve the iron that has complexed with the remover but remains in the capillary structure of the material.

7. Use of the remover composition according to claim 1 or 2 for removing iron deposits from organic cultural relics in marine effluent.

8. The use according to claim 7, wherein the organic cultural relics in marine effluent include marine effluent wooden cultural relics, marine effluent bamboo cultural relics, marine effluent leather cultural relics, marine effluent lacquerware, and marine effluent plant fiber woven cultural relics.

9. The use according to claim 8, wherein the marine effluent wooden cultural relics include the hull of a sunken wooden ship in marine effluent and the attached wooden components of a sunken wooden ship in marine effluent.