A sulfur-tolerant gaseous arsenic adsorption material, a preparation method and application thereof

Abstract

The present application belongs to the technical field of gaseous arsenic adsorption, and particularly relates to a sulfur-tolerant gaseous arsenic adsorption material, a preparation method and application thereof. Manganese oxide and an iron source are mixed and placed in a ball mill jar, then the ball mill jar is sealed, argon is filled into the jar, and the iron-modified manganese oxide adsorption material is obtained by ball milling. The addition of iron improves the sulfur tolerance of manganese oxide, so that the adsorbent still has high gaseous arsenic adsorption capacity under high-concentration SO2 conditions, and is suitable for the removal of gaseous arsenic in typical high-SO2 flue gas, i.e. non-ferrous smelting flue gas. The preparation method is simple, the cost is low, the gaseous arsenic adsorption capacity is large, and the present application has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gaseous arsenic adsorption, in particular to a sulfur-tolerant gaseous arsenic adsorption material, a preparation method and application thereof. BACKGROUND

[0002] Arsenic, as a metalloid, is one of the most important carcinogens in the environment, which can cause a series of health risks. In recent years, the harm of arsenic in the atmosphere has attracted more and more attention. In 2015, the global population facing cancer risk due to inhalation of atmospheric arsenic reached 4.09 billion, accounting for 56% of the total global population.

[0003] Non-ferrous smelting is the main human source of arsenic emission in the atmosphere, which emits up to 12800 tons of arsenic into the atmosphere every year. In the process of copper smelting, most of the arsenic is volatilized into flue gas. Subsequently, part of the arsenic in the flue gas is captured together with dust by air pollution control devices (APCD), such as electrostatic precipitators, bag filters, etc. However, the current ACPD has low efficiency in capturing gaseous arsenic in flue gas. The arsenic in the flue gas entering the subsequent section not only reduces the grade of by-product sulfuric acid, but also some arsenic is released into the environment with the flue gas, causing great environmental risk. Existing studies show that using adsorbents to capture gaseous arsenic in flue gas is an effective means to control atmospheric arsenic pollution. Compared with wet scrubbing process, solid-phase adsorption has the advantages of simple process and no impact on the quality of subsequent by-products. In addition, arsenic resources can be effectively recovered from used adsorbents. At present, many metal oxides, such as alumina, iron oxide, calcium oxide, etc. are used for gaseous arsenic adsorption. However, these adsorbents have the problem of low arsenic adsorption capacity. Moreover, due to the concentration of SO2 in non-ferrous smelting flue gas is often several orders of magnitude higher than that of gaseous arsenic, the performance of these adsorbents for adsorbing arsenic will be inhibited.

[0004] CN 115646431 A discloses the preparation of amorphous iron-manganese oxide used as a gaseous arsenic adsorption material by dropping ferrous salt into a potassium permanganate stock solution. However, this method needs to strictly control the dropping speed and pH parameters of the reaction process, which is complicated to operate and not conducive to large-scale production. Moreover, the adsorption capacity of the adsorbent prepared by this method for gaseous arsenic decreases under the influence of SO2.

[0005] Therefore, it is necessary to develop a gaseous arsenic adsorption material with simple preparation method and better performance in high SO2 atmosphere. SUMMARY

[0006] In view of the problems existing in the prior art, the purpose of the present application is to provide a sulfur-tolerant gaseous arsenic adsorption material, a preparation method and application thereof. The adsorption material has excellent adsorption capacity and sulfur tolerance; the preparation method is simple; and the application of the gaseous arsenic adsorption material in adsorbing gaseous arsenic in high-sulfur flue gas is provided.

[0007] In order to achieve the above object, the application provides a preparation method of a sulfur-resistant gaseous arsenic adsorption material, in which a manganese oxide and an iron source are mixed and then placed in a ball mill tank, the ball mill tank is sealed, argon is filled into the tank, and the iron-modified manganese oxide sulfur-resistant gaseous arsenic adsorption material is obtained by ball milling.

[0008] Preferably, the ball-to-material mass ratio in the ball milling process is 20:1-2, the ball milling time is 30-60 min, and the ball milling rotation speed is 250-500 r / min.

[0009] Preferably, the doping amount of the iron source is 1-3:10.

[0010] Preferably, the iron source includes at least one of iron oxide and ferroferric oxide, and the manganese oxide is at least one of MnO2 and Mn3O4.

[0011] Preferably, the iron source is iron oxide, and the manganese oxide is MnO2.

[0012] As a general technical concept, the application also provides the sulfur-resistant gaseous arsenic adsorption material prepared by the above preparation method.

[0013] As a general technical concept, the application also provides the application of the above sulfur-resistant gaseous arsenic adsorption material as an adsorbent in the treatment of gaseous arsenic-containing flue gas, and the gaseous arsenic-containing flue gas is non-ferrous metal smelting flue gas or coal-fired flue gas.

[0014] Preferably, the gaseous arsenic is at least one of As2O3(g) and AsH3(g).

[0015] Preferably, the gaseous arsenic-containing flue gas also contains sulfur dioxide, and the content of the sulfur dioxide is 2.5%-7.5%.

[0016] Preferably, the temperature in the adsorption process is 250-600 ℃, and preferably 250-400 ℃. That is, it can be understood that the temperature of the arsenic-containing flue gas to be treated can be 250-600 ℃, and preferably 250-400 ℃.

[0017] The application uses manganese oxide as a carrier and uses a mechanical ball milling method to incorporate an iron source into the manganese oxide. The incorporation of iron promotes the electron transfer capacity of the adsorbent, improves the adsorption capacity of the adsorbent for gaseous arsenic, and on the other hand, the incorporated iron acts as a sacrificial agent to protect the manganese in the adsorbent from SO2 poisoning, improves the tolerance of the adsorbent to SO2, and enables the adsorbent to effectively remove gaseous arsenic under the influence of high-concentration SO2. The preparation method of the gaseous arsenic adsorption material disclosed in the application is simple, low in cost, high in adsorption capacity for gaseous arsenic, strong in tolerance to SO2, and has a good application prospect.

[0018] Compared with the prior art, the present application has the advantages of:

[0019] (1) In view of the defects of the prior manganese oxide adsorbent, such as low tolerance to SO2 and low capture capacity for gaseous arsenic, the present application provides a simple method for synthesizing a novel iron-doped manganese oxide gaseous arsenic adsorbent. Thanks to mechanical ball milling, the metal is uniformly distributed on the surface of the manganese oxide, effectively improving the electron transfer between the two metals and promoting the adsorption capacity of the adsorbent for gaseous arsenic. Moreover, the doped metal acts as a sacrificial agent to protect the manganese in the adsorbent from SO2 poisoning, thereby improving the tolerance of the adsorbent to SO2.

[0020] (2) The gaseous arsenic is fixed in the form of stable arsenate on the surface of the adsorbent, effectively removing the gaseous arsenic and reducing the environmental risk of arsenic.

[0021] (3) The mechanical ball milling method provided by the present application for preparing the gaseous arsenic adsorbent is simple, the raw materials are easy to obtain, the preparation period is short, the energy consumption is low, and the cost is greatly reduced. At the same time, the preparation method is environmentally friendly and does not produce toxic and harmful by-products, is suitable for large-scale preparation, and meets the needs of actual production. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application.

[0023] Figure 1 XRD pattern of the sulfur-tolerant gaseous arsenic adsorbent prepared under the best conditions of the present application;

[0024] Figure 2 (a) SEM pattern, (b) Fe element mapping pattern, (c) O element mapping pattern, and (d) Mn element mapping pattern of the sulfur-tolerant gaseous arsenic adsorbent prepared under the best conditions of the present application;

[0025] Figure 3 Adsorption capacity of the sulfur-tolerant gaseous arsenic adsorbent prepared under the best conditions of the present application for gaseous arsenic in sulfur-containing flue gas;

[0026] Figure 4 Adsorption capacity of the sulfur-tolerant gaseous arsenic adsorbent prepared under the best conditions of the present application for gaseous arsenic under different SO2 concentrations;

[0027] Figure 5(a) SEM image of the sulfur-tolerant gaseous arsenic adsorption material prepared under the optimal conditions of the present application after adsorbing gaseous arsenic in sulfur-containing flue gas; (b) mapping image of Fe element; (c) mapping image of Mn element; (d) mapping image of As element; (e) mapping image of S element; (f) mapping image of O element;

[0028] Figure 6 XRD image of the sulfur-tolerant gaseous arsenic adsorption material prepared under the optimal conditions of the present application after adsorbing gaseous arsenic in sulfur-containing flue gas; DETAILED DESCRIPTION

[0029] The present application is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present application is not limited thereby.

[0030] The raw materials and instruments used in the following examples are commercially available. In the examples of the present application, if not specifically stated, the processes used are conventional processes, the equipment used is conventional equipment, and the data obtained are the average values of three or more repeated experiments.

[0031] Example 1

[0032] A method for preparing a sulfur-tolerant gaseous arsenic adsorption material, the specific steps being as follows: 3.6 g of MnO2 and 0.4 g of Fe2O3 (total 4 g, the doping amount of iron source being 1:10) are mixed and then placed in a ball mill jar, a certain amount of small balls are put in, the ball-to-material ratio being 20:1-2, then the ball mill jar is sealed, argon gas is filled into the jar, the rotation speed of the ball mill is set to 250 r / min, the ball milling time is set to 60 min, then the ball mill is started to begin ball milling, and after the ball milling is completed, the mixture is taken out, and finally the gaseous arsenic adsorption material is obtained.

[0033] The adsorption amounts of the gaseous arsenic adsorption material prepared in this example for gaseous arsenic in sulfur-containing flue gas (SO2 content being 2.5%) are 16.3 mg / g (ball-to-material ratio being 20:1) and 10.9 mg / g (ball-to-material ratio being 10:1), respectively.

[0034] Example 2

[0035] A method for preparing a sulfur-tolerant gaseous arsenic adsorption material, the specific steps being as follows: 3.6 g of MnO2 and 0.4 g of Fe2O3 (the doping amount of iron source being 1:10) are mixed and then placed in a ball mill jar, 80 g of small balls are put in, the ball-to-material ratio being 20:1, then the ball mill jar is sealed, argon gas is filled into the jar, the rotation speed of the ball mill is set to 250 r / min-500 r / min, the ball milling time is set to 60 min, then the ball mill is started to begin ball milling, and after the ball milling is completed, the mixture is taken out, and finally the gaseous arsenic adsorption material is obtained.

[0036] The gaseous arsenic adsorption material prepared in this embodiment has an adsorption capacity of 16.3 mg / g (ball milling speed of 250 r / min) and 13.2 mg / g (ball milling speed of 500 r / min) for gaseous arsenic in sulfur-containing flue gas (SO2 content of 2.5%).

[0037] Example 3

[0038] A method for preparing a sulfur-tolerant gaseous arsenic adsorption material includes the following specific steps: weighing 3.6 g of MnO2 and 0.4 g of Fe2O3 (doping amount of iron source of 1:10), mixing them, and then placing them in a ball mill tank; placing 80 g of small balls in the tank, with a ball-to-material ratio of 20:1; then sealing the ball mill tank, filling the tank with argon, setting the ball mill speed to 250 r / min, and setting the ball milling time to 30 min to 60 min; then starting the ball mill to begin ball milling; after the ball milling is completed, removing the mixture; and finally obtaining the gaseous arsenic adsorption material.

[0039] The gaseous arsenic adsorption material prepared in this embodiment has an adsorption capacity of 16.3 mg / g (ball milling time of 60 min) and 11.4 mg / g (ball milling time of 30 min) for gaseous arsenic in sulfur-containing flue gas (SO2 content of 2.5%).

[0040] Example 5

[0041] A method for preparing a sulfur-tolerant gaseous arsenic adsorption material includes the following specific steps: weighing a certain amount of Fe2O3 and MnO2 (total of 4 g, doping amount of iron source of 1-3:10), mixing them, and then placing them in a ball mill tank; placing 80 g of small balls in the tank, with a ball-to-material ratio of 20:1; then sealing the ball mill tank, filling the tank with argon, setting the ball mill speed to 250 r / min, and setting the ball milling time to 60 min; then starting the ball mill to begin ball milling; after the ball milling is completed, removing the mixture; and finally obtaining the gaseous arsenic adsorption material.

[0042] The gaseous arsenic adsorption material prepared in this embodiment has an adsorption capacity of 16.3 mg / g (doping amount of iron source of 1:10), 10.5 mg / g (doping amount of iron source of 2:10), and 14.3 mg / g (doping amount of iron source of 3:10) for gaseous arsenic in sulfur-containing flue gas (SO2 content of 2.5%).

[0043] Example 6

[0044] A preparation method of a sulfur-tolerant gaseous arsenic adsorption material, the specific steps are as follows: a certain amount of Fe2O3 and Mn3O4 (total 4g, the doping amount of iron source is 1:10) is mixed and placed in a ball mill jar, 80g of small balls are put in, the ball-to-material ratio is 20:1, then the ball mill jar is sealed, the jar is filled with argon, the rotation speed of the ball mill is set to 250r / min, the ball milling time is set to 60min, then the ball mill is started to begin ball milling, and after the ball milling is completed, the mixture is taken out, and finally the gaseous arsenic adsorption material is obtained.

[0045] The sulfur-tolerant gaseous arsenic adsorption material prepared in the embodiment has an adsorption capacity of 15.2mg / g for gaseous arsenic in sulfur-containing flue gas, which is 2.9mg / g higher than that of Mn3O4 in Comparative Example 2.

[0046] Comparative Example 1

[0047] The material of the present comparative example is MnO2 used in Example 1.

[0048] The gaseous arsenic adsorption material prepared in the present comparative example has an adsorption capacity of 13.6mg / g for gaseous arsenic in sulfur-containing flue gas.

[0049] Comparative Example 2

[0050] The material of the present comparative example is Mn3O4 used in Example 4.

[0051] The gaseous arsenic adsorption material prepared in the present comparative example has an adsorption capacity of 12.3mg / g for gaseous arsenic in sulfur-containing flue gas.

[0052] In summary, it is found that under the conditions of selecting Fe2O3 as the iron source, selecting MnO2 as the manganese oxide, the doping amount of the iron source being 1:10, the ball-to-material mass ratio being 20:1, the ball milling time being 60min, and the ball milling rotation speed being 250r / min, the sulfur-tolerant gaseous arsenic adsorption material with the best performance can be obtained. Figure 1 As shown in FIG. 1, the gaseous arsenic adsorption material prepared under the above conditions presents a mixture phase of α-Fe2O3 and β-MnO2. Figure 2 As shown in FIG. 2, the prepared gaseous arsenic adsorption material presents a loose and porous structure, and the particles of various sizes are stacked with each other, resulting in a developed pore of the prepared gaseous arsenic adsorption material. The EDS results show that the distributions of iron, manganese and oxygen elements on the surface of the adsorbent are highly consistent, and the iron oxide and manganese oxide are embedded with each other. At this time, the adsorption capacity of the adsorbent for gaseous arsenic in sulfur-containing flue gas (SO2 content is 2.5%) is 16.3mg / g.

[0053] Example 7

[0054] The application of a sulfur-tolerant gaseous arsenic adsorption material as an adsorbent in capturing gaseous arsenic in high-temperature industrial flue gas, specifically the application of the sulfur-tolerant gaseous arsenic adsorption material in adsorbing As2O3(g) in flue gas at high temperature, comprising the following steps: 0.1 g of the sulfur-tolerant gaseous arsenic adsorption material prepared under optimal conditions is taken and added to a specially designed fixed-bed reactor, evenly laid, and the reactor is placed in a reaction furnace; then the concentration of As2O3(g) in the simulated flue gas is controlled to be 0.5 mg / L by a hydride generator, and then the gas components of the simulated flue gas are configured by a gas distribution system; then As2O3(g) in the flue gas is carried by the gas flow to the reaction furnace to be captured by the prepared sulfur-tolerant gaseous arsenic adsorption material, the reaction time is 60 min, and the tail gas is discharged after two-stage washing.

[0055] Further, the reaction temperature of the lower section of the tube furnace is 250-400℃.

[0056] The simulated flue gas components are 92.5% argon + 5% oxygen + 2.5% SO2, and the flue gas flow rate is 400 mL / min;

[0057] After the reaction is completed, the used sulfur-tolerant gaseous arsenic adsorption material is taken out, diluted by digestion with a specific method, a certain amount of the digestion solution is filtered with a 0.45 μm filter membrane, the concentration of arsenic in the filtrate is determined by ICP-OES, and then the adsorption capacity of the sulfur-tolerant gaseous arsenic adsorption material for arsenic is calculated.

[0058] As Figure 3 shown, the adsorption capacity of the sulfur-tolerant gaseous arsenic adsorption material prepared under optimal conditions for gaseous arsenic in sulfur-containing flue gas increases with increasing temperature in the range of 250-400℃, and finally reaches a peak (16.3 mg / g) at 400℃.

[0059] Example 8

[0060] The application of a gaseous arsenic adsorption material in capturing gaseous arsenic in high-temperature high-sulfur industrial flue gas, specifically the application of the gaseous arsenic adsorption material prepared under optimal preparation conditions in adsorbing As2O3(g) in flue gas of different atmospheres at high temperature. The temperature used in this example is 400℃, the flue gas flow rate is 400 mL / min, and the simulated flue gas components used are argon + 5% oxygen + SO2.

[0061] The simulated flue gas is mixed with different proportions of SO2, and further preferred is an atmosphere containing 0%, 2.5%, 5%, and 7.5% SO2.

[0062] As Figure 4As shown, the arsenic adsorption capacity of the sulfur-tolerant gaseous arsenic adsorbent prepared under the optimal conditions in the sulfur-containing flue gas was 16.3 mg / g, which was almost the same as the arsenic adsorption capacity in the flue gas without sulfur. When the SO2 concentration was further increased to 7.5%, the arsenic adsorption capacity of the sulfur-tolerant gaseous arsenic adsorbent was significantly increased (20.9 mg / g). This means that the prepared gaseous arsenic adsorbent has good SO2 tolerance and can effectively adsorb gaseous arsenic under high SO2 concentration conditions. Figure 5 The SEM-EDS diagram of the sulfur-tolerant gaseous arsenic adsorbent prepared under the optimal conditions after adsorbing gaseous arsenic in the sulfur-containing flue gas. As can be seen from the diagram, the distribution of S element and Fe element is highly consistent, which proves that iron plays a sacrificial role in the adsorbent. Figure 6 The XRD diagram of the sulfur-tolerant gaseous arsenic adsorbent prepared under the optimal conditions after adsorbing gaseous arsenic in the sulfur-containing flue gas. The characteristic peak of manganese arsenate appears in the diagram, which proves that arsenic is mainly adsorbed by the adsorbent in the form of arsenate.

[0063] The above examples are only preferred embodiments of the present application, and the protection scope of the present application is not limited to the above examples. Any technical solutions falling within the concept of the present application shall fall within the protection scope of the present application. It should be pointed out that improvements and refinements made by ordinary skilled in the art without departing from the principles of the present application shall also be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing a sulfur tolerant gaseous arsenic adsorbent material, characterized by, The manganese oxide and the iron source are mixed and placed in a ball mill tank, the mass ratio of the amount of the iron source to the total amount of the manganese oxide and the iron source is 1:10, the mass ratio of the ball to the material is 20:1, the ball milling time is 60 min, the ball milling speed is 250 r / min, then the ball mill tank is sealed, the tank is filled with argon, and the iron modified manganese oxide sulfur-resistant gaseous arsenic adsorption material is obtained by ball milling; the iron source is iron oxide, the manganese oxide is MnO2, and the gaseous arsenic is at least one of As2O3(g) and AsH3(g).

2. A sulfur-resistant gaseous arsenic adsorption material prepared by the preparation method in claim 1.

3. Use of the sulphur-resistant gaseous arsenic adsorbent material according to claim 2 as an adsorbent in the treatment of sulphur-containing gaseous arsenic fumes, characterised in that, The gaseous arsenic flue gas is non-ferrous metal smelting flue gas or coal-fired flue gas, the gaseous arsenic is at least one of As2O3(g) and AsH3(g), the gaseous arsenic flue gas also contains sulfur dioxide, and the temperature of the adsorption process is 250-600 DEG C.

4. Use according to claim 3, characterized in that, The temperature of the adsorption process is 250-400 DEG C. The temperature of the adsorption process is 250-400 DEG C.

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