Preparation method and application of iron-straw biochar micro-electrolysis filler

Abstract

The invention discloses a preparation method and application of an iron-straw biochar micro-electrolysis filler, and the preparation method comprises the following steps: taking sponge iron and straw as carbon raw materials, adding a certain amount of a binder and a catalyst, uniformly mixing, granulating, carrying out anaerobic high-temperature roasting, sintering, and granulating to form the regular iron-carbon micro-electrolysis filler. The iron-carbon micro-electrolysis filler overcomes the defects that the existing iron-carbon filler is low in cost and easy to harden and passivate, the treatment efficiency of the iron-carbon micro-electrolysis filler applied to electroplating wastewater reaches 80%-92.5%, and the COD (Chemical Oxygen Demand) index of the wastewater reaches the national electroplating pollutant discharge standard GB 21900-2008.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and more specifically to a preparation method of an iron-straw biochar micro-electrolysis filler and an application thereof. Background Art

[0002] At present, the pollution of industrial wastewater in my country is severe. Among the more than 500 major rivers in the country, more than 80% of the rivers are polluted to a considerable extent. The electroplating industry is one of the three major industrial wastewater pollutants in the world today. Its wastewater discharge accounts for about 10% of the total industrial wastewater discharge, and less than 50% of the wastewater is effectively treated before discharge. At present, with the increasing scale of electroplating enterprises, the composition of the wastewater generated is becoming more and more complex, and the difficulty of treatment is increasing. The problem of wastewater pollution has seriously restricted the survival and development of my country's electroplating enterprises. In addition, the discharge of untreated wastewater seriously affects my country's water environment and human health, and also greatly restricts the sustainable development of related industries in my country. Therefore, it is particularly necessary to study the treatment technology and process of comprehensive electroplating wastewater with very complex components and high complex concentration.

[0003] Iron-carbon micro-electrolysis technology is a good process technology that uses the electrochemical corrosion principle of metals to treat pollutants in sewage. The closely contacted iron and carbon are immersed in the wastewater. Since there is a potential difference of about 1.2V between the iron and carbon, countless micro-galvanic cells are formed to accelerate the reaction. The relevant mechanism is roughly as follows: the anode iron loses electrons and dissolves Fe 2+ , under acidic aerobic conditions, cathode carbon obtains electrons to form H2O2, Fe 2+ It forms a Fenton system with H2O2 to oxidize pollutants. In addition, Fe 2+ Can be oxidized to Fe 3+ , the pollutant particles are condensed together and the suspended colloids are precipitated through adsorption, sweeping and other effects.

[0004] At present, a large number of experimental studies have shown that the traditional electrolysis technology formed by simply mixing reducing iron powder and activated carbon powder often has the disadvantages of filler compaction and passivation, which in turn leads to a decrease in micro-electrolysis efficiency and affects the treatment effect. Summary of the invention

[0005] The invention discloses a preparation method of an iron-straw biochar micro-electrolysis filler and application thereof, so as to solve any of the above and other potential problems in the prior art.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is: a method for preparing an iron-straw biochar micro-electrolysis filler, which takes sponge iron and straw as carbon raw materials, adds a certain amount of binder and catalyst, mixes them evenly, granulates them, and then calcines them at high temperature without oxygen, and granulates them after sintering to form regularized iron-carbon micro-electrolysis filler.

[0007] Furthermore, the weight proportion of the sponge iron is 30-65 parts, the weight proportion of the porous biochar prepared from straw is 35-60 parts, the weight proportion of the binder is 15-20 parts, and the weight proportion of the catalyst is 2-8 parts.

[0008] Furthermore, the binder is sodium silicate or bentonite; and the catalyst is zinc powder.

[0009] Furthermore, the oxygen-free high-temperature calcination is carried out in an inert atmosphere at a sintering temperature of 400-800°C.

[0010] Further, the particle size of the sponge iron is 110-170 mesh;

[0011] The particle size of porous biochar prepared from straw is 110-140 mesh;

[0012] The particle size of sodium carbonate or bentonite is 90-110 mesh;

[0013] The particle size of zinc powder is 110-170 mesh.

[0014] Furthermore, the preparation process of straw into porous carbon material is as follows: the straw is cut and crushed and placed in a quartz boat, and calcined in a tubular furnace at a temperature of 200-700°C for 2.5-4 hours under a nitrogen atmosphere. After the calcination, it is allowed to cool naturally to room temperature under a nitrogen atmosphere, and the sample is taken out and ground through a 100-150 mesh sieve to obtain porous biochar.

[0015] The beneficial effects of the present invention are: due to the adoption of the above technical scheme, the porosity of the iron-carbon micro-electrolysis filler of the present invention is not less than 65%; when re-treating electroplating wastewater, the COD content removal efficiency in the electroplating wastewater treated with the iron-straw biochar micro-electrolysis filler reaches 93%-99%, and the wastewater COD index meets the national electroplating pollutant emission standard "GB 21900-2008". DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0017] Example 1

[0018] In the preparation method of the iron-straw biochar micro-electrolysis filler of this embodiment, the mixing ratio of each material is 40 parts of sponge iron powder, 40 parts of biochar prepared from straw, 16 parts of sodium silicate, and 4 parts of zinc powder, and sintering is performed after granulation and drying, and the sintering temperature is 500° C. The porosity of the filler is 0.65 after testing.

[0019] Example 2

[0020] The preparation method of the iron-straw biochar micro-electrolysis filler in this embodiment is different from that in the aforementioned embodiments in that the material mixing ratio is 50 parts of sponge iron powder, 30 parts of biochar prepared from straw, 14 parts of sodium silicate, and 6 parts of zinc powder. The roasting temperature is set to 600°C, and the filler porosity is 0.66.

[0021] Example 3

[0022] The preparation method of the iron-straw biochar micro-electrolysis filler in this embodiment is different from the aforementioned embodiments in that the mixing ratio of the materials is 55 parts of reducing iron powder, 25 parts of biochar prepared from straw, 15 parts of bentonite, 5 parts of zinc powder, the sintering temperature is 800°C, and the filler porosity is 0.67.

[0023] The following embodiments are regularized iron-carbon micro-electrolysis materials prepared by the above-mentioned preparation method, which are applied to the treatment of electroplating wastewater.

[0024] Example 4

[0025] Accurately measure 500mL of electroplating wastewater with a COD content of 200mg / L, and weigh a certain mass of regularized iron-carbon micro-electrolysis filler to treat the wastewater. A large number of research tests have shown that when the dosage of regularized iron-carbon filler is 5g / L and the reaction time is 30min, the COD removal efficiency is as high as 80%, and the effect is good.

[0026] Table 1 shows the water quality indicators before and after the wastewater is treated with the iron-sludge-based biochar micro-electrolysis filler prepared in this embodiment.

[0027] pH COD Before wastewater treatment (mg / L) 3.2 200 Before wastewater treatment (mg / L) 4.0 40 Removal rate / 80％

[0028] Example 5

[0029] Accurately measure 500mL of electroplating wastewater with a COD content of 200mg / L, and weigh a certain mass of regularized iron-carbon micro-electrolysis filler to treat the wastewater. A large number of research tests have shown that when the dosage of regularized iron-carbon filler is 8g / L and the reaction time is 90min, the COD removal efficiency reaches 92.5%, with good results.

[0030]

[0031]

[0032] The above is a detailed introduction to the preparation method and application of an iron-straw biochar micro-electrolysis filler provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0033] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problems within a preset error range and basically achieve the technical effects. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be subject to that defined in the attached claims.

[0034] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0035] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A method for preparing an iron-straw biochar micro-electrolysis filler, characterized in that: The preparation method uses sponge iron and straw as carbon raw materials, adds a certain amount of binder and catalyst, mixes evenly, granulates, and then calcines at high temperature without oxygen, and granulates to form regular iron-carbon micro-electrolytic filler with a porosity of not less than 65%.

2. The preparation method according to claim 1, characterized in that: The weight proportion of the sponge iron is 30-65 parts, the weight proportion of the porous biochar prepared from straw is 35-60 parts, the weight proportion of the binder is 15-20 parts, and the weight proportion of the catalyst is 2-8 parts.

3. The preparation method according to claim 1, characterized in that: The binder is sodium silicate or bentonite; the catalyst is zinc powder.

4. The preparation method according to claim 1, characterized in that: The oxygen-free high-temperature calcination is carried out in an inert atmosphere at a sintering temperature of 400-800°C.

5. The preparation method according to claim 2, characterized in that: The particle size of the sponge iron is 110-170 mesh; The particle size of porous biochar prepared from straw is 110-140 mesh; The particle size of sodium carbonate or bentonite is 90-110 mesh; The particle size of zinc powder is 110-170 mesh.

6. The preparation method according to claim 2, characterized in that: The preparation process of straw into porous carbon material is as follows: the straw is cut and crushed and placed in a quartz boat, and then calcined in a tubular furnace at 200-700°C for 2.5-4 hours under a nitrogen atmosphere. After the calcination, it is allowed to cool naturally to room temperature under a nitrogen atmosphere, and the sample is taken out and ground through a 100-150 mesh sieve to obtain porous biochar.

7. An application of the iron-carbon micro-electrolysis filler prepared by the preparation method as described in any one of claims 1 to 6 in treating electroplating wastewater with high COD.

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