Method for synergistically preparing zero-valent iron / porous ceramic composite material from multi-source solid waste and application of zero-valent iron / porous ceramic composite material

Abstract

The invention provides a method for synergistically preparing a zero-valent iron / porous ceramic composite material from multi-source solid wastes and an application of the zero-valent iron / porous ceramic composite material. The zero-valent iron / porous ceramic composite material is prepared by taking multi-source solid wastes such as iron tailings, coal gangue, glass powder and corn straws as main materials and adopting a sintering method. The mesoporous specific surface area of the prepared composite material is 17.40 m < 2 > / g, the average mesoporous diameter is 6.19 nm, the visible porosity is 56.22%, the compressive strength is 1.01 MPa, and the apparent density is 1.21 g / cm < 3 >. Compared with the traditional water treatment porous ceramic material, the water treatment porous ceramic material has the advantages of zero-valent iron catalyst, larger specific surface area, abundant functional groups and higher pollutant removal capacity. The material has high removal capacity on antibiotics, and the maximum removal amount of chlortetracycline hydrochloride under the optimal pH value can reach 234.41 mg / g.

Description

Technical Field

[0001] This invention belongs to the field of porous ceramic water treatment technology, and relates to a method and application for the synergistic preparation of zero-valent iron / porous ceramic composite materials from multiple sources of solid waste. Background Technology

[0002] With the acceleration of global industrialization, the disposal and reuse of industrial solid waste has become a key issue for environmental protection and sustainable development. Iron tailings, coal gangue, and waste glass powder, as three common industrial solid wastes, not only occupy large amounts of land resources but also pose a potential pollution threat to surrounding water bodies, soil, and the atmosphere. However, these wastes are rich in components such as silicon, aluminum, and iron, and can serve as alternative mineral resources. Currently, the main methods for utilizing these wastes include extracting valuable elements, extracting mineral components, producing building materials, and landfilling mined-out areas.

[0003] Porous ceramics are ceramic materials with unique pore structures. Due to their unique properties, especially their large specific surface area and well-developed pore structure, porous ceramics have been widely used in various fields such as catalyst supports, filter components, and thermal insulation and sound-absorbing building materials. Currently, the preparation of porous ceramics from solid waste and their application in the removal of emerging pollutants from water has become a research hotspot. The overuse of antibiotics (such as chloramphenicol hydrochloride) in healthcare and animal husbandry has become a global challenge. This is because antibiotics are difficult to biodegrade and have strong persistence. Once they enter the environment, they are difficult to completely break down, thus accumulating in ecosystems and leading to particularly serious ecological risks.

[0004] However, current porous ceramic materials mainly rely on physical adsorption mechanisms for pollutant treatment, which limits their adsorption capacity to some extent, resulting in relatively low pollutant removal efficiency. To maximize the utilization of solid waste, the development of porous ceramic materials that can efficiently treat antibiotic pollutants through the synergistic preparation of multiple solid wastes has become an urgent technical challenge. Summary of the Invention

[0005] To address the problems of low porosity, small specific surface area, and low pollutant removal capacity in existing porous ceramics, a method and application for the synergistic preparation of zero-valent iron / porous ceramic composite materials from multiple solid waste sources are provided.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for the synergistic preparation of zero-valent iron / porous ceramic composite materials from multiple sources of solid waste. The method uses iron tailings, coal gangue, waste glass powder and biomass as raw materials, ball mills and sieves them, and obtains zero-valent iron / porous ceramic composite materials through mixing, granulation, high-temperature sintering and cooling.

[0008] The high-temperature sintering process is as follows: under a nitrogen atmosphere, the temperature is raised to a preheating temperature of 550-600℃ at a heating rate of 8-10℃ / min, held for 20-30min, and then raised to the sintering temperature at a heating rate of 3-5℃ / min, held for 20-40min.

[0009] The iron tailings mentioned are medium-silicon iron tailings.

[0010] Furthermore, the iron tailings contain 30-50% SiO2 and 14-18% Fe2O3 by mass; the coal gangue contains more than 85% SiO2 and Al2O3 by mass.

[0011] Furthermore, the chemical composition of the iron tailings, by mass percentage, includes: 40-45% SiO2, 10-12% Al2O3, 15-18% Fe2O3, 15-17% CaO, 1.5-2% Na2O, and 10-12% MgO; the chemical composition of the coal gangue, by mass percentage, includes: 60-65% SiO2, 25-28% Al2O3, 1-3% Fe2O3, 1-2% CaO, 0.8-1% Na2O, and 0.8-1.1% MgO.

[0012] Furthermore, the biomass is at least one of corn stalks, peanut shells, and cotton stalks;

[0013] The amount of biomass added is 20-25% of the total mass of iron tailings and coal gangue, and the amount of waste glass powder added is 10-20% of the total mass of iron tailings and coal gangue.

[0014] Furthermore, the mass ratio of iron tailings, coal gangue, waste glass powder, and biomass is 9–5:1–5:2:2.5; the sintering temperature is 1000–1100℃.

[0015] Secondly, the present invention provides a zero-valent iron / porous ceramic composite material prepared by the method described above, wherein the phase composition of the zero-valent iron / porous ceramic composite material is mainly zero-valent iron, quartz and diopside iron.

[0016] Furthermore, zero-valent iron is formed in situ inside and on the surface of the composite material, and -OH and benzene ring structures are present, allowing it to be stored at room temperature for at least one month.

[0017] Thirdly, the present invention provides a method for removing antibiotics from wastewater, wherein the removal method employs the aforementioned zero-valent iron / porous ceramic composite material.

[0018] Further, the antibiotic is chlortetracycline hydrochloride, and the removal process is as follows: 0.1-2g of zero-valent iron / porous ceramic composite material is added to 100mL of chlortetracycline hydrochloride solution with a concentration of 0-500mg / L, and the mixture is shaken for 96h at a shaking temperature of 25℃ and a shaking frequency of 150r / min. The concentration of pollutants in the remaining solution is measured. The maximum adsorption capacity of the zero-valent iron / porous ceramic composite material for chlortetracycline hydrochloride is not less than 170mg / g; preferably, the maximum adsorption capacity is not less than 190mg / g. Hydrogen bonds and π-π interactions occur between the composite material and chlortetracycline hydrochloride CTC.

[0019] Furthermore, the zero-valent iron / porous ceramic composite material has a compressive strength of not less than 0.7 MPa, a water absorption rate of not less than 40%, and an apparent porosity of not less than 55%.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) This invention employs a multi-solid waste co-processing strategy, using medium-silica iron tailings and coal gangue rich in SiO2 and Al2O3 as co-processing raw materials. By adjusting the ratio of the two, the composition requirements for preparing high-performance porous ceramic materials are achieved. Furthermore, the coal gangue mineral composition contains a certain amount of kaolin, which has the binding effect of clay and helps in the forming of ceramic bodies. Secondly, since sodium-calcium waste glass powder contains a large amount of active SiO2 and alkali metal oxides, it can not only lower the melting point but also provide a certain amount of sodium, reducing energy consumption and improving the performance of porous ceramic materials to a certain extent.

[0022] (2) Existing porous ceramic materials primarily rely on physical adsorption for treating wastewater containing antibiotics, resulting in less than ideal adsorption effects. The high reactivity of zero-valent iron (ZVFe) alone makes it prone to aggregation and oxidation, reducing reaction efficiency and stability. This invention utilizes a synergistic approach involving multiple solid waste sources such as iron tailings, coal gangue, waste glass powder, and corn stalks. By employing a coupled in-situ reduction and sintering process, ZVFe is generated in situ during the preparation of the porous ceramic matrix, effectively inhibiting its aggregation and oxidation, thus providing a new material option for wastewater treatment. The prepared composite material exhibits a larger specific surface area and porosity. Iron oxides in the iron tailings react with biochar (such as corn stalks) under a high-temperature nitrogen atmosphere to generate ZVFe, improving the treatment effect on pollutants.

[0023] (3) The method of the present invention not only improves the efficiency of resource utilization and reduces environmental pollution, but also optimizes the performance of products and reduces production costs. It is of great significance to promote sustainable development and green production, and provides a new way for the resource utilization of industrial solid waste. It can efficiently treat antibiotic substances and has advantages such as cost-effectiveness and high adsorption performance. Attached Figure Description

[0024] Figure 1 A schematic diagram illustrating the fabrication and application process of a zero-valent iron / porous ceramic composite material according to an embodiment of the present invention.

[0025] Figure 2 SEM images of composite materials from different embodiments, wherein (a) is the SEM image of the composite material of Example 4; (b) is the SEM image of the composite material of Example 1; (c) is the SEM image of the composite material of Example 5; and (d) is the SEM image of the composite material of Example 6.

[0026] Figure 3 The surface microstructure and elemental composition of the composite material in Example 1, wherein (a, c) SEM; (b) EDS; (d) TEM.

[0027] Figure 4 XRD comparison images of composite materials from different embodiments, wherein (a) is an XRD comparison image of composite materials prepared in Examples 1, 2 and 3, and (b) is an XRD comparison image of composite materials prepared in Examples 1, 4 and 5.

[0028] Figure 5 Effect of different initial concentrations on the removal of CTC-HCl from the composite material in Example 6.

[0029] Figure 6 Effect of different initial concentrations on the removal of CTC-HCl from the composite material in Example 1.

[0030] Figure 7 Effect of different solution pH on the removal of CTC-HCl by the composite material in Example 1.

[0031] Figure 8 XPS images of the composite material before and after interaction with CTC and its flocculents: (a) full spectrum; (b) C1s; (c) O1s; (d) Fe2p. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0033] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0034] The present invention discloses a method for the synergistic preparation of zero-valent iron / porous ceramic composite materials from multiple sources of solid waste, comprising the following steps:

[0035] (1) Ball milling and sieving: Take a certain amount of iron tailings, coal gangue and waste glass powder and put them into a ball mill and ball mill for 1 hour at a ball-to-material ratio of 3:1. After ball milling, the raw materials are sieved through a 200-mesh sieve for later use. The purchased biomass raw materials are cleaned and dried and then sieved through a 100-mesh sieve for later use.

[0036] (2) Weighing and mixing: Weigh a certain amount of iron tailings, coal gangue, waste glass powder and biomass after ball milling and sieving and put them into the ball mill for 20-30 minutes to make the raw materials fully mixed. After mixing, put the mixture into a mortar and add 30-40wt.% aqueous solution and stir evenly to form mud and age for 2 hours.

[0037] (3) Granulation and drying: The aged material is made into ceramic blanks with a weight of 0.2g and a diameter of about 5mm. The blanks are first dried at room temperature for 1 hour, and then dried in a drying oven at 105℃ for 2 hours to obtain raw ceramics.

[0038] (4) High-temperature sintering: The dried raw ceramic is heated to the preheating temperature of 600℃ at a rate of 10℃ / min under a nitrogen atmosphere, held for 30min, and then heated to the sintering temperature at a rate of 5℃ / min, held for 30min and then the operation is ended.

[0039] (5) Cooling treatment: After the sintering process is completed, the furnace is cooled. When the temperature inside the furnace drops to below 100°C, the fired ceramic is taken out and the ceramic preparation is completed.

[0040] Preferably, in step (2), the mass ratio of iron tailings, coal gangue, waste glass powder, and biomass is 9 to 5:1 to 5:2:2.5, such as 9:1:2:2.5, 8:2:2:2.5, 7:3:2:2.5, 6:4:2:2.5, and 5:5:2:2.5.

[0041] Preferably, the sintering temperature is 1000-1100℃.

[0042] The present invention discloses a method for removing antibiotics from wastewater, wherein the removal method uses the above-mentioned zero-valent iron / porous ceramic composite material: 0.1-2g of zero-valent iron / porous ceramic composite material is added to 100mL of an antibiotic solution with a concentration of 0-500mg / L, and the solution is shaken for 96h at a shaking temperature of 25℃ and a shaking frequency of 150r / min, and the concentration of pollutants in the remaining solution is measured.

[0043] Preferably, the pH of the antibiotic solution is 3-11.

[0044] In the following examples, the iron tailings used came from a typical mine in Chengde, Hebei Province, China; the coal gangue came from a typical mine in Shanxi Province, China; and the waste glass powder came from a glass group in Tianjin, China. Table 1 shows the main chemical composition of the selected materials.

[0045] Table 1. Main chemical composition (wt.%) of multi-source inorganic solid waste

[0046]

[0047] The chlortetracycline hydrochloride is from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 64-72-2.

[0048] Example 1:

[0049] (1) Weighing and mixing: Weigh 7g of iron tailings, 3g of coal gangue, 2g of waste glass powder and 2.5g of corn stalks and put them into a ball mill and mix for 20 minutes to make the raw materials fully mixed. After mixing, put the mixture into a mortar and add 5g of aqueous solution and stir evenly to form mud and age for 2 hours.

[0050] (2) Granulation and drying: The aged material is made into ceramic blanks with a weight of 0.2g and a diameter of about 5mm. The blanks are first dried at room temperature for 1 hour, and then dried in a drying oven at 105℃ for 2 hours to obtain raw ceramics.

[0051] (3) High-temperature sintering: The dried raw ceramic is heated to a preheating temperature of 600°C at a rate of 10°C / min in a nitrogen atmosphere (tube furnace), held for 30 min, and then heated to a sintering temperature of 1050°C at a rate of 5°C / min, held for 30 min and then the operation is ended.

[0052] (4) Cooling treatment: After the sintering process is completed, the furnace is cooled. When the temperature inside the furnace drops to below 100°C, the fired ceramics are taken out and the ceramic preparation is completed.

[0053] Example 2:

[0054] The steps in this embodiment are the same as in embodiment 1, except that the mass of iron tailings added is 9g and the mass of coal gangue added is 1g.

[0055] Example 3:

[0056] The steps in this embodiment are the same as those in Embodiment 1, except that the mass of iron tailings added is 5g and the mass of coal gangue added is 5g.

[0057] Example 4:

[0058] The steps in this embodiment are the same as in Embodiment 1, except that the sintering temperature is 1000℃.

[0059] Example 5:

[0060] The steps in this embodiment are the same as those in Embodiment 1, except that the sintering temperature is 1100℃.

[0061] Example 6:

[0062] The steps in this embodiment are the same as those in Embodiment 1, except that the high-temperature sintering is carried out in an air atmosphere (muffle furnace) until the sintering temperature reaches 1100°C.

[0063] (I) Physical Performance Testing

[0064] The physical properties (apparent porosity, water absorption, and compressive strength) of Examples 1-5 were tested in this invention, and the test results are shown in Table 2.

[0065] Table 2 Physical properties of zero-valent iron / porous ceramic composite materials

[0066]

[0067] Examples 1-5 show that the raw material ratio and sintering temperature have a significant impact on the compressive strength of the composite material, while the porosity and water absorption rate are relatively similar. Examples 5 and 6 show that the sintering atmosphere has a relatively small impact on the physical properties of the prepared composite material. In Example 4, due to the low sintering temperature, the composite material has poor strength when used in water treatment with vibration. The preferred raw material ratio is iron tailings: coal gangue: waste glass powder: corn stalks = 7:3:2:2.5, and the sintering temperature is 1050-1100℃, which better meets the requirements of water treatment ceramics.

[0068] (II) Scanning electron microscopy and transmission electron microscopy tests

[0069] Figure 2 Image (a) is a scanning electron microscope image of the composite material of Example 4. It shows a small amount of sintering, a loose surface, and a relatively developed pore structure. However, the degree of crystallization is low at this time, resulting in low compressive strength. The ceramic is prone to flaking, which is not conducive to its application in the field of water treatment. Figure 2 Image (b) is a scanned image of the composite material in Example 1. The sample shows increased sintering degree, increased compressive strength, and more abundant pores, meeting the physical performance requirements of water treatment ceramics. Figure 2 Image (c) is a scanning electron microscope image of the composite material of Example 5. The sintering phenomenon inside the sample is obvious, with particles melting into each other and an increase in the liquid phase inside the ceramic. On the one hand, the increase in liquid phase helps to encapsulate the gas and form larger pores. On the other hand, the generated liquid phase blocks the pores, reducing the size of small pores. The pore structure is mainly a macroporous structure. Figure 2 Image (d) is a scanning electron microscope image of the composite material from Example 6, compared with... Figure 2 Compared to (b), the sintering degree of the sample increased, and the porous ceramic surface prepared in Example 6 did not have a large number of spherical particles loaded on it. Figure 2 In the magnified view of (b), a large number of spherical particles can be seen. Figure 2 In the middle (d) section, the matrix surface remains relatively smooth at this multiplication factor.

[0070] Figure 3The surface microstructure and elemental composition of the composite material in Example 1 are shown. Figure 3 As can be seen in (a), the surface of this composite material possesses more pores and a richer pore structure, which can effectively capture pollutants and promote the adsorption process. The formation of pores is mainly attributed to the gases released during the high-temperature pyrolysis of the raw materials, and the reduction reaction of carbon derived from corn stalks with iron oxide, further generating gas and thus forming a large number of pores in the porous ceramic. Figure 3 As can be seen in (c), the surface of the dense ceramic structure is covered with a large number of irregular spherical particles with an average size of 250 nanometers. Combined with X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), these small particles can be identified as zero-valent iron. Figure 3 Image (d) is a transmission electron microscope image of the composite material prepared in Example 1. Combined with XRD and SEM images, it can be concluded that the microstructure of the ceramic is mainly composed of diopside phase and quartz phase. In addition, zero-valent iron nanostructures are scattered on the ceramic surface.

[0071] Adsorption-desorption tests showed that the mesoporous specific surface area of ​​the composite material in Example 1 was 17.40 m². 2 The average mesopore diameter is 6.19 nm, and the apparent density is 1.21 g / cm³. 3 .

[0072] (III) XRD Testing

[0073] Figure 4 (a) shows the XRD comparison of composite materials prepared with different formulations. It can be seen that the phase composition of the composite materials under the formulation of this application is mainly composed of zero-valent iron, quartz, and diopside iron. With the increase of coal gangue content, the content of zero-valent iron decreases and the content of quartz increases.

[0074] Figure 4 Figure (b) shows the XRD patterns of the composite materials prepared at different temperatures. It can be seen that as the sintering temperature increases, the elements in the raw materials redistribute or migrate within the mineral composition, leading to significant changes in the phase structure of the material before and after sintering. With increasing sintering temperature, the quartz content gradually decreases, while the zero-valent iron content gradually increases. In Example 5, when the sintering temperature reaches 1100℃, the quartz content decreases significantly, indicating that the quartz phase gradually melts, making the internal structure of the ceramic more compact, reducing porosity, and increasing compressive strength. Under a nitrogen atmosphere, iron oxide undergoes a reduction reaction with corn stalk-derived charcoal to generate zero-valent iron. When the sintering temperature is 1050℃, the crystal structure of zero-valent iron is relatively complete.

[0075] (iv) Adsorption performance test

[0076] In this invention, the composite materials of Examples 1 and 6 were used as adsorbents to conduct adsorption experiments.

[0077] 0.1 g of the composite material from Example 6 was added to 100 mL of chlortetracycline hydrochloride solutions with concentrations of 1 mg / L, 5 mg / L, 8 mg / L, 10 mg / L, 20 mg / L, and 50 mg / L, respectively. Without pH control, the solutions were shaken for 96 h at a shaking temperature of 25°C and a shaking frequency of 150 r / min. The concentration of contaminants in the remaining solutions was then measured. The experimental results are as follows: Figure 5 As shown. By Figure 5 It can be seen that the maximum adsorption capacity of the composite material for chlortetracycline hydrochloride is only 3.9 mg / g.

[0078] 0.1 g of the composite material from Example 1 was added to 100 mL of chlortetracycline hydrochloride solutions with concentrations of 10 mg / L, 50 mg / L, 80 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L, respectively. pH control was not performed. The solutions were shaken for 96 h at a shaking temperature of 25°C and a shaking frequency of 150 r / min. The concentration of contaminants in the remaining solutions was then measured. The experimental results are as follows: Figure 6 As shown. By Figure 6 It can be seen that the maximum adsorption capacity of the composite material for chlortetracycline hydrochloride is 193.53 mg / g, which is much higher than the adsorption capacity of other adsorbent materials for pollutants. Example 1 was able to adsorb more chlortetracycline hydrochloride.

[0079] 0.1 g of the composite material from Example 1 was added to 100 mL of a 400 mol / L chlortetracycline hydrochloride solution. The initial pH of the solution was adjusted to 2-12 using 0.1 mol / L HCl and 1 mol / L NaOH. The solution was shaken for 96 h at a shaking temperature of 25 °C and a shaking frequency of 150 r / min. The concentration of contaminants in the remaining solution was then measured. The experimental results are as follows: Figure 7 As shown in the figure, it can be seen that the composite material achieves the maximum removal of CTC-HCl at pH 7, which is 234.41 mg / g, and can maintain a high adsorption level at pH 5-9.

[0080] In the testing of this invention, different types of biomass were used to conduct adsorption tests under the same conditions. The adsorption effects varied slightly. Corn stalks, peanut shells, and cotton stalks could all ensure a maximum adsorption capacity of over 170 mg / g. However, the adsorption effect of SiC was very poor.

[0081] Existing methods for preparing water treatment ceramics from solid waste are mostly similar to those in Example 6. The composite material prepared in Example 1 of this invention has a rich mesoporous structure, which is more conducive to pollutant adsorption. A certain amount of zero-valent iron is attached to both the ceramic surface and interior, enabling it to undergo flocculation reactions with pollutants. This results in the composite material removing far more pollutants than in existing studies, demonstrating that the porous ceramics for water treatment prepared by this method have good application prospects. Furthermore, the composite material of this application can be stored for a long time at room temperature without vacuum preservation, and can be stored for at least one month. The presence of a large amount of zero-valent iron inside the ceramic does not affect the degradation effect after long-term storage.

[0082] (V) XPS Test

[0083] The present invention performs XPS tests on the composite material of Example 1 before and after adsorption performance testing, as well as on the flocculants generated during the adsorption process. The test results are as follows: Figure 8 As shown. By Figure 8 As can be seen in (a), the flocculants are mainly composed of Fe, C, O, Cl, and N elements, proving that the flocculants are complexes of Fe and CTC. In Example 1, CTC refers to the ceramsite composite material after the adsorption test, and flocculated CTC refers to the flocculants after the adsorption reaction.

[0084] Figure 8 Figure (b) shows the C1s spectrum, which has three characteristic peaks at 284.80 eV, 286.36 eV and 288.78 eV, corresponding to CC / C=C, CO and C=O, respectively. Figure 8 Figure (c) shows the O1s spectrum. Characteristic peaks appear around 532.06 eV and 533.53 eV, corresponding to CO / MO (M is a metal oxide) and C=O / -OH, respectively. These functional groups mainly originate from the biochar components remaining after the pyrolysis of corn straw biomass, indicating the presence of -OH and benzene ring structures in the composite material prepared in Example 1, which will undergo hydrogen bonding and π-π interactions with CTC.

[0085] Figure 8 The middle (d) spectrum shows the changes in the morphology of iron before and after the reaction. The characteristic peaks near 711 eV (Fe2p3 / 2) and 724 eV (Fe2p1 / 2) correspond to the iron oxidation product Fe2O3, the characteristic peaks near 715 eV (Fe2p3 / 2) and 725 eV correspond to the iron hydroxide (FeOOH), and the characteristic peaks near 720 eV and 730 eV correspond to the characteristic satellite peaks of Fe(II) and Fe(III).

[0086] The test results of the composite material sample before the reaction lacked the 705.53 eV peak because the zero-valent iron was oxidized during the sample preparation process, and the Fe peak did not appear near the binding energy of 705.53 eV. 0 The characteristic peak is due to Fe 0 Due to its high reactivity and easy oxidation, and because XPS can only measure elements on the sample surface, Fe on the sample surface mainly exists in the forms of Fe₂O₃ and FeOOH. 0 The content is low, and zero-valent iron is mainly present inside the material. In Example 1-CTC and flocculated-CTC, Fe exists in the forms of Fe2O3 and FeOOH, indicating that after the composite material prepared in Example 1 interacts with the antibiotic CTC, the Fe content in the sample is low. 0 Oxidized, Fe 0 The flocculation process mainly occurs between iron oxides and chlortetracycline hydrochloride.

[0087] The results indicate that the CTC removal mechanism of the composite material prepared in Example 1 mainly includes pore filling, complexation, electrostatic interaction, hydrogen bonding, π-π interaction, and flocculation, and also exhibits a certain degradation effect (due to the presence of zero-valent iron). The porous ceramic composite material prepared in this invention has a much higher application prospect in water treatment than existing research.

[0088] This invention utilizes a system formed by the complementary use of coal gangue and iron tailings, combined with waste glass powder and biomass added in a synergistic manner to replace pure materials. High-temperature sintering is carried out under a nitrogen atmosphere. During the high-temperature sintering process, the iron in the solid waste can be formed into zero-valent iron in situ. Zero-valent iron can be effectively maintained on both the surface and inside of the ceramsite, avoiding the agglomeration problem of zero-valent iron in existing ceramic materials. Corn stalks can play a role in reduction and synthesize zero-valent iron in situ.

[0089] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0090] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A method for synergistic preparation of zero-valent iron / porous ceramic composite materials from multiple sources of solid waste, characterized in that, The method uses iron tailings, coal gangue, waste glass powder and biomass as raw materials, ball mills and sieves them, and obtains zero-valent iron / porous ceramic composite material through mixing, granulation, high-temperature sintering and cooling. The high-temperature sintering process is as follows: under a nitrogen atmosphere, the temperature is raised to a preheating temperature of 550-600℃ at a heating rate of 8-10℃ / min, held for 20-30min, and then raised to the sintering temperature at a heating rate of 3-5℃ / min, held for 20-40min. The iron tailings mentioned are medium-silicon iron tailings.

2. The method according to claim 1, characterized in that, The iron tailings contain 30-50% SiO2 and 14-18% Fe2O3 by mass; the coal gangue contains more than 85% SiO2 and Al2O3 by mass.

3. The method according to claim 1, characterized in that, The chemical composition of the iron tailings, by mass percentage, includes: 40-45% SiO2, 10-12% Al2O3, 15-18% Fe2O3, 15-17% CaO, 1.5-2% Na2O, and 10-12% MgO; the chemical composition of the coal gangue, by mass percentage, includes: 60-65% SiO2, 25-28% Al2O3, 1-3% Fe2O3, 1-2% CaO, 0.8-1% Na2O, and 0.8-1.1% MgO.

4. The method according to claim 1, characterized in that, The biomass is at least one of corn stalks, peanut shells, and cotton stalks; The amount of biomass added is 20-25% of the total mass of iron tailings and coal gangue, and the amount of waste glass powder added is 10-20% of the total mass of iron tailings and coal gangue.

5. The method according to claim 1, characterized in that, The mass ratio of iron tailings, coal gangue, waste glass powder, and biomass is 9-5:1-5:2:2.5; the sintering temperature is 1000-1100℃.

6. A zero-valent iron / porous ceramic composite material prepared by the method according to any one of claims 1-5, characterized in that, The phase composition of the zero-valent iron / porous ceramic composite material is mainly zero-valent iron, quartz and diopside iron.

7. The composite material according to claim 6, characterized in that, The composite material has zero-valent iron formed in situ inside and on the surface, and contains -OH and benzene ring structures, and can be stored at room temperature for at least one month.

8. A method for removing antibiotics from wastewater, characterized in that, The removal method employs the zero-valent iron / porous ceramic composite material as described in claim 6 or 7.

9. The removal method according to claim 8, characterized in that, The antibiotic is chlortetracycline hydrochloride. The removal process is as follows: 0.1-2g of zero-valent iron / porous ceramic composite material is added to 100mL of chlortetracycline hydrochloride solution with a concentration of 0-500mg / L. The mixture is shaken for 96h at a shaking temperature of 25℃ and a shaking frequency of 150r / min. The concentration of pollutants in the remaining solution is measured. The maximum adsorption capacity of the zero-valent iron / porous ceramic composite material for chlortetracycline hydrochloride is not less than 170mg / g; preferably, the maximum adsorption capacity is not less than 190mg / g. Hydrogen bonds and π-π interactions occur between the composite material and chlortetracycline hydrochloride CTC.

10. The removal method according to claim 9, characterized in that, The zero-valent iron / porous ceramic composite material has a compressive strength of not less than 0.7 MPa, a water absorption rate of not less than 40%, and an apparent porosity of not less than 55%.

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