Preparation method of decoloring agent for treating sodium formate waste salt

Abstract

The application discloses a preparation method of a decoloring agent for treating sodium formate waste salt, and the decoloring agent is prepared by using activated carbon as raw material and sequentially modifying the activated carbon by doping oxygen and doping sulfur. The prepared decoloring agent has strong decoloring capacity, can reduce the decoloring cost of by-product sodium formate, and provides a new possibility for high-value utilization of the by-product sodium formate. In addition, the preparation method of the decoloring agent is simple and easy to implement in industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemical industry, and particularly relates to a preparation method of a decoloring agent for treating waste sodium formate salt. BACKGROUND

[0002] Sodium formate, also known as sodium antimony, has a molecular formula of CHO2Na·2H2O, and contains two crystal waters in the crystal, and therefore is also known as sodium formate dihydrate, sodium formate dihydrate and sodium antimony dihydrate. Sodium formate is the simplest organic carboxylate salt, which is white crystals or powder, has a slight formic acid odor, has slight deliquescence and hygroscopicity. It is easily soluble in water and glycerol, slightly soluble in ethanol and octanol, and insoluble in diethyl ether, and the aqueous solution thereof is alkaline. Sodium formate is decomposed into hydrogen and sodium oxalate when heated, and then sodium carbonate is generated. Therefore, sodium formate is often used for producing prussiantype and oxalic acid. In the leather industry, it is used as a camouflage acid in the chrome leather method, a catalyst and a stable synthetic agent, and a reducing agent in the printing and dyeing industry.

[0003] The direct synthesis method of sodium formate is to use carbon monoxide and sodium hydroxide solution to react at 160-200 DEG C and 2 MPa pressure, so as to generate sodium formate, which has high purity and good color, and can be directly applied in industry, but has the disadvantage of high production cost.

[0004] In order to solve the problems of overcapacity of methanol production in China, extension of the green industrial chain of coal chemical industry and realization of coupling of economic circulation of coal chemical industry, many methanol production enterprises will use excess methanol and synthesis gas CO as raw materials to synthesize high value-added green fine chemical products formamide and N,N dimethylformamide by methanol carbonylation method. A large amount of by-product sodium formate is generated in the process of synthesizing formamide and N,N dimethylformamide, and the annual by-product sodium formate of a certain methanol production enterprise in Guizhou Province is more than 200 tons. However, due to the high content of metal impurities in the by-product sodium formate, especially the iron ions, the color is brownish yellow, the whiteness is not enough, and the indicators are lower than the industrial sodium formate standard HG / T5390-2018, which leads to the difficulty of direct sale of the by-product sodium formate. At present, the by-product sodium formate is mainly treated as hazardous waste, which undoubtedly increases the operating cost of the enterprise and affects the healthy development of the coal chemical industry chain.

[0005] Therefore, if the by-product sodium formate can be removed and meet the industrial sodium formate standard, it can be turned into treasure, improve the economic circulation benefit of methanol production enterprises, and has very important significance for promoting the development of the coupling economic circulation industry of China's coal chemical industry, and can greatly reduce the production cost of sodium formate.

[0006] But with different sources of sodium formate, the impurity composition is also different, so the sodium formate decolorization process is also different. Among the reported sodium formate decolorization methods, the most common is to use activated carbon for direct adsorption decolorization, which can remove some organic matter and other metal impurities, thereby improving the whiteness of sodium formate. But the researchers of this project found that when the activated carbon on the market was used to decolorize the aforementioned sodium formate, the decolorization effect was not ideal and did not meet the standard requirements.

[0007] In order to improve the decolorization effect of activated carbon on by-product sodium formate, the researchers of this project proposed in previous studies that the activated carbon was modified by oxygen doping. The modified activated carbon improved the decolorization effect of the by-product sodium formate to some extent, but the decolorization capacity still depended on the addition of a large amount of activated carbon, so the cost of decolorization treatment of by-product sodium formate was high, which still hindered the actual industrial application.

[0008] Therefore, it is necessary to further modify the activated carbon used for adsorption decolorization to further improve its decolorization capacity and reduce the decolorization cost of by-product sodium formate. SUMMARY

[0009] The purpose of the present application is to provide a preparation method of a decolorizing agent for treating sodium formate waste salt. The decolorizing agent prepared by the present application has strong decolorization capacity and can reduce the decolorization cost of by-product sodium formate, providing a new possibility for the high-value utilization of by-product sodium formate. In addition, the preparation method of the decolorizing agent of the present application is simple and easy to implement industrially.

[0010] The technical scheme of the present application is a preparation method of a decolorizing agent for treating sodium formate waste salt, which is prepared by sequentially modifying activated carbon with oxygen doping and sulfur doping.

[0011] The present scheme introduces a large number of oxygen-containing functional groups on the surface of activated carbon by oxygen doping treatment, and the introduction of oxygen-containing functional groups can complex with metal ions to achieve the purpose of adsorption, thereby removing metal impurities in sodium formate and achieving the purpose of decolorization. The difference between the present scheme and the prior art is that the activated carbon after oxygen doping is further treated with sulfur doping. The purpose of sulfur doping is to further improve the complexing sites on the surface of activated carbon by using sulfur-containing functional groups, thereby increasing the adsorption capacity of metal impurities and improving the decolorization effect. At the same time, under the condition of the same decolorization capacity, the use amount of the decolorizing agent prepared by the present scheme is less, and the decolorization cost is lower.

[0012] In a further scheme, the aforementioned preparation method of a decolorizing agent for treating sodium formate waste salt comprises the following steps:

[0013] (1) Take activated carbon and nitric acid solution;

[0014] (2) the activated carbon is dispersed in nitric acid solution, heated and refluxed, after the treatment, the solid is filtered and washed with water until neutral, and the activated carbon doped with oxygen is obtained after drying;

[0015] (3) the activated carbon doped with oxygen is dispersed in sulfosalicylic acid solution for reaction, after the reaction, the solid is filtered and washed with water until neutral, and the activated carbon doped with oxygen and sulfur is obtained after drying, which is the decoloring agent for treating sodium formate waste salt.

[0016] The preparation method is specifically described in the scheme, wherein the oxygen doping process is consistent with the previously reported process, and the sulfur doping process is to treat with sulfosalicylic acid solution, so that the sulfonic acid group is introduced into the oxygen-containing functional group of the activated carbon, and more oxygen-containing functional groups are introduced at the same time, thereby increasing the number of oxygen-containing functional groups and adding sulfur-containing functional groups, and further improving the adsorption capacity of metal impurities.

[0017] Meanwhile, in addition to the sulfonic acid group itself being able to complex with metal ions to achieve adsorption effect, the sulfonic acid group on the surface of the activated carbon will also hydrolyze in the process of adsorption and decoloration, and the surface of the activated carbon after hydrolysis is negatively charged, which attracts positively charged metal ions, thereby further improving the adsorption capacity of metal impurities and improving the decoloration effect.

[0018] In a further scheme, in the preparation method of the decoloring agent for treating sodium formate waste salt, the concentration of the nitric acid solution in step (1) is 10-50%, and the solid-liquid ratio of the activated carbon and the nitric acid solution is 1 kg: 8-12 L. Preferably, the concentration of the nitric acid solution is 30%, and the solid-liquid ratio of the activated carbon and the nitric acid solution is 1 kg: 10 L. Experiments have proved that when the concentration of the nitric acid solution is 30%, the amount of oxygen-containing functional groups is close to saturation, so 30% is selected as the optimal concentration of the nitric acid solution.

[0019] In a further scheme, in the preparation method of the decoloring agent for treating sodium formate waste salt, the heating reflux treatment in step (2) is heating to 50-70°C for 1-3 h. Preferably, the heating reflux treatment is heating to 60°C for 3 h. Experiments have proved that the heating temperature has an effect on the decoloration performance, and when the heating temperature is 60°C, the decoloration performance of the modified activated carbon is the best.

[0020] In a further scheme, in the preparation method of the decoloring agent for treating sodium formate waste salt, the concentration of the sulfosalicylic acid solution in step (3) is 5-15%; the solid-liquid ratio of the activated carbon doped with oxygen and the sulfosalicylic acid solution is 1 kg: 80-100 L; and the reaction time is 10-20 h. Preferably, the concentration of the sulfosalicylic acid solution is 10%; the solid-liquid ratio of the activated carbon doped with oxygen and the sulfosalicylic acid solution is 1 kg: 100 L; and the reaction time is 12 h.

[0021] In a further aspect, in the preparation method of the decoloring agent for treating sodium formate waste salt, the drying in step (2) and step (3) is drying at 90-110 DEG C until no mass change.

[0022] In a further aspect, in the preparation method of the decoloring agent for treating sodium formate waste salt, the activated carbon is powdered activated carbon, and the iodine value is 1150-1200 mg / g, and the methylene blue value is 16-18 ml / 0.1 g.

[0023] Advantages of the present application

[0024] 1. The present application introduces a large number of oxygen-containing functional groups on the surface of activated carbon by oxygen doping treatment, and the introduction of oxygen-containing functional groups can complex with metal ions to achieve the purpose of adsorption, thereby removing metal impurities in sodium formate and achieving the purpose of decolorization; and the difference between the present application and the prior art is that the activated carbon after oxygen doping is also subjected to sulfur doping treatment, the purpose of sulfur doping is to further improve the complexing sites on the surface of activated carbon by using sulfur-containing functional groups, thereby increasing the adsorption capacity of metal impurities and improving the decolorization effect, and in the case of the same decolorization capacity, the use amount of the decoloring agent prepared by the present application is less, and the decolorization cost is lower.

[0025] 2. The present application specifically describes the preparation method, wherein the oxygen doping process is consistent with the previously reported process, and the sulfur doping process is treated by using a sulfosalicylic acid solution, by introducing sulfonic acid groups to the oxygen-containing functional groups of activated carbon, more oxygen-containing functional groups are further introduced while the sulfur-containing functional groups are introduced, so that the number of oxygen-containing functional groups is increased, and the sulfur-containing functional groups are also increased, thereby further improving the adsorption capacity of metal impurities. At the same time, in addition to the adsorption effect of the sulfonic acid groups on metal ions, the sulfonic acid groups on the surface of activated carbon will also hydrolyze during the adsorption and decolorization process, and the surface of the hydrolyzed activated carbon is negatively charged, which attracts positively charged metal ions, thereby further improving the adsorption capacity of metal impurities and improving the decolorization effect.

[0026] 3. The present application adjusts the process parameters to prepare modified activated carbon with better sodium formate decolorization performance.

[0027] 4. The preparation process of the present application is simple and easy to implement industrially. BRIEF DESCRIPTION OF DRAWINGS

[0028] ATTACHMENT Figure 1 A comparison chart of metal impurity removal rate and adsorption amount of activated carbon modified by different modification methods when treating sodium formate waste salt; DETAILED DESCRIPTION

[0029] The application will be further described in connection with the following examples, but not as a limitation to the application.

[0030] Embodiments of the application

[0031] Example 1

[0032] The oxygen-doped activated carbon was prepared by the following method:

[0033]

[0034] The oxygen-doped activated carbon was prepared by the following method:

[0035] The oxygen-doped activated carbon was prepared by the following method:

[0036] The oxygen-doped activated carbon was prepared by the following method:

[0037] Example 2

[0038] The oxygen-doped activated carbon was prepared by the following method:

[0039] The oxygen-doped activated carbon was prepared by the following method:

[0040] The oxygen-doped activated carbon was prepared by the following method:

[0041] The oxygen-doped activated carbon was prepared by the following method:

[0042] Example 3

[0043] The oxygen-doped activated carbon was prepared by the following method:

[0044] A 20% nitric acid solution was mixed with commercially available activated carbon (powdered activated carbon, iodine value 1178 mg / g, methylene blue value 17 ml / 0.1 g) at a solid-liquid ratio of 1 kg: 11 L. The mixture was stirred and heated to 55 °C for 2.5 h. After the reaction was completed, the carbon was washed with water until neutral and then dried at 95 °C until there was no change in weight, thus obtaining oxygen-doped activated carbon.

[0045] The method for treating oxygen-doped activated carbon with sulfur is as follows:

[0046] Oxygen-doped activated carbon was dispersed in a 12% sulfosalicylic acid solution at a solid-liquid ratio of 1 kg: 85 L. The reaction was carried out at room temperature for 12 h. After the reaction was completed, the carbon was washed with water until neutral and then dried at 95 °C until there was no change in weight, thus obtaining oxygen-doped and sulfur-doped activated carbon.

[0047] Example 4

[0048] The activated carbon oxygenation treatment method is as follows:

[0049] A 40% nitric acid solution was mixed with commercially available activated carbon (powdered activated carbon, iodine value 1178 mg / g, methylene blue value 17 ml / 0.1 g) at a solid-liquid ratio of 1 kg: 9 L. The mixture was stirred and heated to 65 °C for 1.5 h. After the reaction was completed, the carbon was washed with water until neutral and then dried at 105 °C until there was no change in weight, thus obtaining oxygen-doped activated carbon.

[0050] The method for treating oxygen-doped activated carbon with sulfur is as follows:

[0051] Oxygen-doped activated carbon was dispersed in an 8% sulfosalicylic acid solution at a solid-liquid ratio of 1 kg: 95 L. The reaction was carried out at room temperature for 18 h. After the reaction was completed, the carbon was washed with water until neutral and then dried at 105 °C until there was no change in weight, thus obtaining oxygen-doped and sulfur-doped activated carbon.

[0052] Example 5

[0053] The activated carbon oxygenation treatment method is as follows:

[0054] A 50% nitric acid solution was mixed with commercially available activated carbon (powdered activated carbon, iodine value 1178 mg / g, methylene blue value 17 ml / 0.1 g) at a solid-liquid ratio of 1 kg: 8 L. The mixture was stirred and heated to 70 °C for 1 h. After the reaction was completed, the carbon was washed with water until neutral and then dried at 110 °C until there was no change in weight, thus obtaining oxygen-doped activated carbon.

[0055] The method for treating oxygen-doped activated carbon with sulfur is as follows:

[0056] Take the oxygen-doped activated carbon, according to the ratio of 1 kg:100 L of the concentration of 5% of the sulfonated salicylic acid solution, room temperature reaction 20 h, after the reaction, washing to neutral, then at 110 ℃ drying to weight no change, thus obtaining oxygen-doped sulfur-doped activated carbon.

[0057] Example 6

[0058] The decolorization method of sodium formate waste salt by-product of formamide synthesis, the steps are as follows:

[0059] (1) the by-product sodium formate waste salt is dissolved in water to obtain a sodium formate waste salt solution;

[0060] (2) the sodium formate waste salt solution is contacted with the oxygen-doped sulfur-doped activated carbon obtained in example 1, then the adsorbed solution is filtered and dried, and the purified and decolorized sodium formate is obtained.

[0061] The adsorption principle is as follows:

[0062]

[0063] Experimental example 1

[0064] 1, take the unmodified activated carbon AC-0 on the market, the N-doped activated carbon AC-N on the market, the oxygen-doped activated carbon AC-O-30 treated by the process of the application (nitric acid solution concentration is 30%, reaction temperature is room temperature), the oxygen-doped activated carbon AC-O-30-60 treated by the process of the application (nitric acid solution concentration is 30%, reaction temperature is 60℃), and the oxygen-doped sulfur-doped activated carbon AC-O-30-60-S prepared by example 1 of the application.

[0065] 2, 6 parts of 50 ml, concentration of 100 mg / L of iron ion solution is configured, 0.2 g of different types of activated carbon is taken respectively, and is placed in the iron ion solution respectively, and is adsorbed for 12 h, the adsorption process is carried out at 20℃, after adsorption, solid-liquid separation is carried out by filter paper, and the content of iron ion in the filtrate is determined, so as to obtain the adsorption capacity and removal rate of iron ion of each, and the results are shown in Figure 1 .

[0066] From Figure 1It can be seen that the adsorption capacity of the commercially available N-doped activated carbon is lower than that of the common unmodified activated carbon, which shows that not all doped modified activated carbons can improve the adsorption capacity of metal ions; the adsorption capacity of the activated carbon after oxygen doping is improved, which shows that the adsorption capacity of metal ions after oxygen doping is enhanced; at the same time, the adsorption capacity of the oxygen-doped activated carbon after 60 DEG C heating treatment is improved compared with that of the activated carbon without 60 DEG C heating treatment, and further, the adsorption capacity of the activated carbon after sulfur doping modification is further improved, which verifies the beneficial effects of the present application.

[0067] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes within the technical range disclosed in the present application according to the technical scheme and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A process for the preparation of a decolorizing agent for the treatment of sodium formate waste salt, characterized by: The method comprises the following steps: (1) taking activated carbon and nitric acid solution; (2) dispersing the activated carbon in the nitric acid solution, heating and refluxing, filtering out the solid after the treatment, washing with water until neutral, and drying to obtain oxygen-doped activated carbon; (3) taking the oxygen-doped activated carbon, dispersing it in a sulfosalicylic acid solution for reaction, filtering out the solid after the reaction, washing with water until neutral, and drying to obtain oxygen-doped sulfur-doped activated carbon, which is a decoloring agent for treating sodium formate waste salt; In step (1), the concentration of the nitric acid solution is 10-50%, and the solid-liquid ratio of the activated carbon and the nitric acid solution is 1 kg:8-12 L; In step (2), the heating and refluxing is heating to 50-70℃ for 1-3 h; In step (3), the concentration of the sulfosalicylic acid solution is 5-15%, the solid-liquid ratio of the oxygen-doped activated carbon and the sulfosalicylic acid solution is 1 kg:80-100 L, and the reaction time is 10-20 h.

2. The process for preparing the decolorizing agent for treating sodium formate waste salt according to claim 1, characterized by: The concentration of the nitric acid solution is 30%, and the solid-liquid ratio of the activated carbon and the nitric acid solution is 1 kg:10 L.

3. The process for preparing the decolorizing agent for treating sodium formate waste salt according to claim 1, characterized by: The heating and refluxing is heating to 60℃ for 3 h.

4. The process for preparing the decolorizing agent for treating sodium formate waste salt according to claim 1, characterized by: The concentration of the sulfosalicylic acid solution is 10%, the solid-liquid ratio of the oxygen-doped activated carbon and the sulfosalicylic acid solution is 1 kg:100 L, and the reaction time is 12 h.

5. The process for preparing the decolorizing agent for treating sodium formate waste salt according to claim 1, characterized by: In steps (2) and (3), the drying is carried out at 90-110℃ until no mass change occurs.

6. The process for the preparation of decolorizing agent for treatment of sodium formate waste salt as claimed in claim 1, wherein: The activated carbon is powdered activated carbon with an iodine value of 1150-1200 mg / g and a methylene blue value of 16-18 ml / 0.1 g.

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