An in-situ regenerable adsorbent, its preparation method and application

Abstract

This invention relates to the field of functional adsorbent technology, and particularly to an in-situ regenerable adsorbent, its preparation method, and its application. The preparation method of the adsorbent includes: 1) mixing manganese sand, dewatered sludge from a water treatment plant, silicate materials, and a binder, followed by high-temperature calcination to obtain the adsorbent material; wherein the density of the silicate material is 0.4–1.2 g / cm³. 3 2) Manganese-oxidizing bacteria are attached to the surface of the adsorbent material under aerobic conditions. This invention uses manganese sand and dewatered sludge from a water treatment plant as the main raw materials to prepare a novel adsorbent material. Combined with manganese-oxidizing bacteria, a novel adsorbent material with high adsorption capacity and in-situ regeneration can be prepared, which can solve the problem of regular replacement in engineering applications caused by the limited adsorption capacity, easy saturation, and secondary pollution of traditional materials.

Description

Technical Field

[0001] This invention relates to the field of functional adsorbent technology, and particularly to an in-situ regenerable adsorbent, its preparation method, and its application. Background Technology

[0002] Adsorption is an effective method for treating heavy metals in wastewater due to its advantages of simple operation and low cost. The adsorbent, as the core component of this method, directly affects and restricts the removal efficiency of the process. However, traditional adsorbents, such as manganese sand, often suffer from limitations such as limited adsorption capacity, easy saturation, short service life, and the potential for secondary pollution, necessitating periodic replacement in engineering applications.

[0003] In existing technologies, microbial transformation adsorbents, represented by bio-manganese oxides, have attracted much attention due to their high adsorption capacity and important role in the biogeochemical cycle of heavy metals. The papers "Removal Effect and Mechanism of In-situ Formed Bio-manganese Oxides for Arsenic (III / V)" (Wu Yajing, Wang Huawei, Sun Yingjie, et al., *Journal of Environmental Science*, 2021, 41(02): 526-535) and "Study on Adsorption Characteristics of Bio-manganese Oxides for Four Heavy Metals" (Yi Chunlong, Ye Xin, Li Tailai, et al., *Industrial Safety and Environmental Protection*, 2021, 47(03): 94-98) disclose the adsorption results of directly prepared bio-manganese oxides for Cu(II), Zn(II), Cr(III), and As(III / V). However, the bio-manganese oxides prepared in these papers require continuous addition of Mn. 2+ Because these adsorbents are constantly being generated, they cannot achieve continuous and stable application. Therefore, it is crucial to find inexpensive and readily available adsorbents that can be regenerated in situ without the need for external chemicals for long-term removal of heavy metals.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] Existing technologies have been disclosed. Manganese sand itself has characteristics such as a large specific surface area, abundant pore structure, high negative charge, and low charge zero point, thus it has a strong adsorption and enrichment capacity for heavy metal ions. However, there are four main problems in its application: (1) Manganese sand is expensive, resulting in high application costs; (2) After adsorbing heavy metals, manganese sand easily releases divalent manganese ions, increasing their content in water and causing secondary pollution and health risks; (3) The adsorption effect of manganese sand is not stable enough when dealing with the coexistence of organic and inorganic pollutants in natural water bodies; (4) When using manganese sand with other inexpensive adsorbents to prepare composite adsorbents, the adsorption effect is difficult to guarantee. Therefore, the above four problems need to be solved when applying manganese sand.

[0006] This invention discovers that the combined use of manganese-oxidizing bacteria and manganese sand can not only eliminate the Mn produced when manganese sand adsorbs heavy metals, but also... 2+ The problem of secondary pollution can also induce bio-manganese oxidizing bacteria to continuously reduce Mn. 2+ The process transforms manganese sand into bio-manganese oxides, promoting the continuous in-situ generation of highly adsorbent bio-manganese oxides and achieving in-situ regeneration of the adsorbent. In other words, using manganese sand as an adsorbent to adsorb heavy metals involves a redox reaction, continuously releasing Mn. 2+ The characteristics of this process induce and drive the continuous oxidation of manganese by bio-manganese bacteria. 2+ The process transforms the manganese into bio-manganese oxide, achieving sustained and stable adsorption performance. Simultaneously, a composite adsorbent is prepared using manganese sand, water treatment plant sludge, and a first silicate material at the specified density as raw materials. This significantly improves the porosity and adsorption capacity of the adsorbent, facilitating the adsorption reaction. Among these, the dewatered sludge from the water treatment plant has a large specific surface area and well-developed pores, exhibiting excellent adsorption properties for various pollutants in water, including total phosphorus, ammonia nitrogen, and heavy metals. Furthermore, it is inexpensive and readily available; it can partially replace manganese sand as a supplementary adsorbent, solving the problem of excessively high costs associated with using only manganese sand.

[0007] The specific technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing an in-situ regenerable adsorbent, comprising:

[0009] 1) Manganese sand, dewatered sludge from a water treatment plant, a first silicate material, and a binder are mixed, and then calcined at high temperature to obtain the adsorbent material; wherein, the density of the first silicate material is 0.4–1.2 g / cm³. 3 ;

[0010] 2) Under aerobic conditions, manganese-oxidizing bacteria are attached to the surface of the adsorbent material to obtain the in-situ regenerable adsorbent.

[0011] In practical application, when the in-situ regenerable adsorbent described in this invention adsorbs heavy metal ions in water, the heavy metal pollutants in the water are adsorbed onto the surface of the adsorbent and removed, while the manganese sand in the adsorbent releases Mn during this process. 2+ soluble Mn 2+ Under the influence of manganese-oxidizing microorganisms (i.e., manganese-oxidizing bacteria) loaded on the material surface, manganese is further oxidized into bio-manganese oxides (BioMnO) with higher oxidation activity and larger specific surface area than manganese sand. x Bio-based manganese oxides can further remove heavy metal pollution and release Mn through chemical oxidation. 2+ The manganese-oxidizing microorganisms continue to utilize it, thereby achieving "Mn 2+ —The recycling of bio-manganese oxides and the in-situ regeneration of materials.

[0012] In this invention, the sludge from the water treatment plant refers to the large amount of sludge generated by the coagulant added during the coagulation and sedimentation process of the water treatment plant, which is an amorphous, non-crystalline structure.

[0013] Preferably, the first silicate material includes one or more of expanded perlite, lightweight ceramics, and lightweight glass.

[0014] Preferably, when the mass ratio of the manganese sand, the dewatered sludge from the water supply plant, and the first silicate material is (20-40):(35-45):(5-15), the adsorption effect can be further improved.

[0015] Preferably, the renewable adsorbent further includes a second silicate material, which includes clay.

[0016] More preferably, the mass ratio of the manganese sand, the dewatered sludge from the water supply plant, the first silicate material, and the second silicate material is (20-40):(35-45):(5-15):(5-40).

[0017] More preferably, the mass ratio of the manganese sand, the dewatered sludge from the water supply plant, the first silicate material, and the second silicate material is (30-40):(40-45):(10-15):(5-10).

[0018] In this invention, those skilled in the art can select conventional adhesives in the field, such as sodium silicate solution, calcium silicate solution, or water glass, depending on the actual situation; more preferably, sodium silicate solution is used.

[0019] Preferably, in step 1), before mixing the manganese sand, silicate material and binder, the particle size of the manganese sand and silicate material is controlled to be 2-10 mm.

[0020] Preferably, the high-temperature calcination includes: drying at 100-105°C, preheating at 250-350°C, and finally calcining at 900-1100°C.

[0021] More preferably, the high-temperature calcination includes: drying at 100–105°C for 110–130 min, then preheating at 250–350°C for 15–25 min, and finally calcining at 900–1100°C for 1–3 h.

[0022] Most preferably, the high-temperature calcination includes: drying at 100-105°C for 110-130 min, then preheating at 250-350°C for 15-25 min, and finally calcining at 900-1000°C for 1-3 h.

[0023] In this invention, those skilled in the art can select commercially available manganese-oxidizing bacteria according to the actual situation, without making specific limitations.

[0024] Preferably, the present invention also provides a method for screening and culturing manganese-oxidizing bacteria, comprising: taking the test bacteria source from activated sludge in the aerobic zone of a wastewater treatment plant, and inoculating 20 ml of the above sludge into a liquid culture medium containing 100 mL of high-temperature sterilized liquid. The composition of the culture medium is: 2 g / L ferric ammonium citrate, 2 g / L manganese carbonate, 0.2 g / L sodium chloride, 0.5 g / L magnesium sulfate, 0.5 g / L potassium hydrogen phosphate, and 0.5 g / L ammonium sulfate, adjusting the pH to 6.8–7.2. The culture medium is placed on a constant temperature shaker (25℃, 150 r / min) and cultured, with the Mn content in the culture medium monitored in a 5-day cycle. 2+ The concentration and pH were adjusted, and after each cycle, the culture medium was centrifuged and fresh culture medium was added again for further cultivation. After 5-6 cycles of cultivation, when the manganese removal rate in the supernatant of the culture medium in the conical flask reached 80-90%, it was considered that an autotrophic high-efficiency manganese-oxidizing bacteria culture had been screened.

[0025] Preferably, the adsorbent material is cleaned before step 2); preferably, it is cleaned 2 to 3 times with 0.5 to 1.5% nitric acid and deionized water.

[0026] Preferably, the concentration of reactive oxygen species under the aerobic conditions is 5% to 21%.

[0027] More preferably, step 2) includes: uniformly adhering the manganese oxidizing bacteria solution to the surface of the adsorbent material, loading it into an aerated biofilter column and compacting it, and using a peristaltic pump to flow the liquid culture medium from the bottom to the top of the biofilter column at a filtration rate of 1.5–2.5 ml / min. The culture medium is replaced in a 3-day cycle, and the pH and divalent manganese concentration of the effluent from the biofilter column are monitored daily. The loading of manganese oxidizing bacteria is completed when the removal rate of divalent manganese in the culture medium reaches 80–90%.

[0028] In a preferred embodiment of the present invention, the method for preparing the in-situ regenerable adsorbent includes:

[0029] 1) Manganese sand, water treatment plant sludge, expanded perlite, and clay in a mass ratio of (30-40):(40-45):(10-15):(5-10) are mixed, stirred into balls, and then a binder is added to obtain spherical particles; then the spherical particles are subjected to three-stage heating and calcination to obtain an adsorbent material; wherein the three-stage heating and calcination includes: first drying at 100-105℃, then preheating at 250-350℃, and finally calcining at 900-1100℃;

[0030] 2) Manganese-oxidizing bacteria are attached to the surface of the adsorbent material under aerobic conditions.

[0031] Secondly, the present invention provides an in-situ regenerable adsorbent, which is prepared by the above-described preparation method.

[0032] Thirdly, the present invention provides the application of the in-situ regenerable adsorbent in the removal of metal ions from water.

[0033] Preferably, the in-situ regenerable adsorbent has adsorption capacities of 3.19–4.23 mg / g, 2.29–3.05 mg / g, and 2.13–2.79 mg / g, respectively, when removing copper ions, zinc ions, and lead ions from water at 20–30°C.

[0034] The in-situ regenerable adsorbent described above can achieve adsorption capacities of up to 4.23, 3.05, and 2.79 mg / g, respectively, when removing copper, zinc, and lead ions from water at 298 K.

[0035] In specific implementation, the in-situ regenerable adsorbent can achieve adsorption rates of 97.8%, 92.5%, and 90.7% for 10 mg / L copper ion, zinc ion, and lead ion solutions, respectively; and after five cycles of repeated adsorption and utilization, the adsorbent can still achieve an adsorption rate of over 80% for heavy metal ions in the solution.

[0036] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0037] This invention uses manganese sand and dewatered sludge from water treatment plants as the main raw materials to prepare a novel adsorbent material. When combined with manganese oxidizing bacteria, a novel adsorbent material with high adsorption capacity and in-situ regeneration can be prepared, which can solve the problems of limited adsorption capacity, easy saturation, inability to be regenerated in-situ, and secondary pollution of traditional materials. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of the aerated biological filter column in Embodiment 1 provided by the present invention;

[0040] Figure 2The results show the effect of adsorption time on the adsorption performance of the control adsorbent material (SGP-M) without manganese oxidizing bacteria and the in-situ regenerable adsorbent (SGP-MB) prepared in Example 1 of this invention; wherein, (a) is the effect of adsorption time of SGP-M and SGP-MB on the adsorption performance of copper ions; (b) is the effect of adsorption time of SGP-M and SGP-MB on the adsorption performance of zinc ions; and (c) is the effect of adsorption time of SGP-M and SGP-MB on the adsorption performance of lead ions.

[0041] Figure 3 This is the result of the influence of coexisting metal ions on the adsorption performance of SGP-MB prepared in Example 1 of this invention;

[0042] Figure 4 This describes the effect of cyclic adsorption of SGP-MB prepared in Example 1 of this invention;

[0043] Figure 5 This is a scanning electron microscope image of the SGP-MB prepared in Example 1 of the present invention;

[0044] Figure 6 The XPS characterization results are those of the SGP-MB prepared in Example 1 of this invention and the adsorbent (SGP-MB-Pb) after adsorbing lead ions.

[0045] Figure 7 These are the XPS characterization results of manganese element in SGP-M, SGP-MB and SGP-MB-Pb prepared in Example 1 of this invention;

[0046] Figure 8 This is a flowchart of the manganese recycling mechanism of SGP-MB prepared in Example 1 of the present invention.

[0047] Figure 1 Figure label:

[0048] 1: Aeration pump; 2: Sampling point; 3: Manganese sand sludge-based adsorption granular column; 4: Peristaltic pump; 5: Water tank. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0050] Unless otherwise specified, all raw materials used in the embodiments are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0051] In the following embodiments, the specific surface area of ​​the water treatment plant sludge is 24.5261 m². 2 The density of the expanded perlite is 0.6 g / cm³. 3 .

[0052] Example 1

[0053] (1) Preparation of manganese sand sludge-based adsorbent materials:

[0054] Manganese sand, water treatment plant sludge, expanded perlite, and clay were weighed in a mass ratio of 30:45:15:10, and mixed with sodium silicate solution until homogeneous. The mixture was then made into spherical particles with a particle size of 2-10 mm. The particles were dried at 105 °C for 2 h, preheated in a muffle furnace at 400 °C for 15 min, and then calcined in a muffle furnace at 900 °C for 60 min. After cooling, the manganese sand sludge granular adsorbent material (SGP-M) was obtained.

[0055] (2) Enrichment culture of manganese-oxidizing bacteria:

[0056] 20 mL of activated sludge from the aerobic zone of a wastewater treatment plant was inoculated into 100 mL of autoclaved liquid culture medium. The culture medium consisted of: 2 g / L ferric ammonium citrate, 2 g / L manganese carbonate, 0.2 g / L sodium chloride, 0.5 g / L magnesium sulfate, 0.5 g / L potassium hydrogen phosphate, and 0.5 g / L ammonium sulfate, with the pH adjusted to 6.8-7.2. The medium was incubated on a constant-temperature shaker (25℃, 150 rpm), and the Mn content in the culture medium was monitored every 5 days. 2+ The concentration and pH were adjusted, and fresh culture medium was added after each centrifugation cycle. After 5-6 cycles of cultivation, when the manganese removal rate in the supernatant of the culture medium in the conical flask reached 80-90%, the autotrophic high-efficiency manganese-oxidizing bacteria culture was obtained.

[0057] (3) Manganese-oxidizing bacteria loaded on the surface of the adsorption material

[0058] To remove impurities from the manganese sand sludge-based material, the prepared material was washed three times with 1% nitric acid and deionized water. Then, the cultured bacterial solution was evenly adhered to the surface of the material and packed into an aerated biological filter column, compacted, and the liquid culture medium from step (2) was pumped upwards from the bottom of the biological filter column using a peristaltic pump at a filtration rate of 2 ml / min. The culture medium was replaced in a 3-day cycle, and the pH and divalent manganese concentration of the effluent from the biological filter column were monitored daily. When the removal rate of divalent manganese in the culture medium reached 80-90%, the loading of manganese-oxidizing bacteria was completed, and the in-situ regenerable adsorbent (SGP-MB) was obtained. A schematic diagram of the aerated biological filter column structure is shown below. Figure 1 .

[0059] (4) Prepare 40 ml of a lead-containing solution with a concentration of 80 mg / L in centrifuge tubes, adjust the pH to 6, then add 1 g of SGP-MB, and place the tubes on a shaker at 298 K and 105 r / min. After 180 min, take samples, filter them through a 0.22 μm filter membrane, and determine the concentration of residual lead ions in the water samples using inductively coupled plasma mass spectrometry (Agilent 7900, Japan). The adsorption capacity of the adsorbent can reach 2.79 mg / g, and the adsorption rate is 87.2%.

[0060] Furthermore, Table 1 lists the different dosage relationships tried by the inventors, as well as the indicators and adsorption effects on lead ions of the in-situ regenerable adsorbent (SGP-MB) obtained at the sintering temperature. All were tested according to the preparation method in Example 1 and the parameter data given in Table 1. The mass ratio refers to the mass ratio of manganese sand, water treatment plant sludge, expanded perlite, and clay. In Example 3, clay was not included; the mass ratio refers to the mass ratio of manganese sand, water treatment plant sludge, and expanded perlite.

[0061] Table 1

[0062]

[0063]

[0064] Comparative Example 1

[0065] This comparative example provides an adsorbent whose preparation method differs from that of Example 1 only in that the sintering temperature is 1100℃, and the expanded perlite is replaced with an equal amount of perlite with a density of 1.70 g / cm³. 3 The bulk density of the adsorbent material was determined to be 0.78 g / cm³. 3 The apparent density is 2.08 g / cm³. 3The water absorption rate is 47.8%, the water retention rate is 62.5%, the porosity is 57.5%, the loss rate is 3.85%, and the equilibrium adsorption capacity of the adsorbent for lead ions at 298K can reach 1.93 mg / g, with an adsorption rate of 60.5%.

[0066] Test case

[0067] 1. This invention analyzes the adsorption performance of an adsorbent by varying the contact time between a heavy metal-containing solution and an in-situ regenerable adsorbent:

[0068] 40 ml solutions of copper, zinc, and lead (10 mg / L each) were prepared in centrifuge tubes, and the pH was adjusted to 6. Then, 1 g of the control material SGP-M (without manganese-oxidizing bacteria) and the in-situ regenerable adsorbent SGP-MB (prepared in Example 1) were added respectively. The tubes were placed on a shaker at 298 K and 105 r / min, and samples were taken at regular intervals (t = 0, 5, 10, 20, 30, 60, 90, 180, 300, 480, 720, and 1440 min). After filtration through a 0.22 μm filter, the concentration of residual heavy metal ions in the water samples was determined using inductively coupled plasma mass spectrometry (Agilent 7900, Japan). The results are as follows: Figure 2 As shown in the figure. Experimental data indicate that the adsorbent exhibits rapid adsorption characteristics for the three heavy metal ions, reaching 85% of the equilibrium adsorption capacity within 180 minutes. Furthermore, the adsorption capacity of SGP-MB for each heavy metal ion is higher than that of SGP-M.

[0069] 2. Adsorption performance test of the in-situ regenerable adsorbent of the present invention for various metal ions.

[0070] Take 1g of the adsorbent SGP-MB prepared in Example 1 and add it to 40ml of a prepared Cu solution with a concentration of 10mg / L. 2+ Zn 2+ and Pb 2+ In mixed solutions of two or more elements, the samples were placed on a shaker at 298 K and 105 r / min for 24 hours, then filtered through a 0.22 μm filter. The residual lead, copper, and zinc ion concentrations in the water samples were determined using inductively coupled plasma mass spectrometry (Agilent 7900, Japan). The results are as follows: Figure 3 As shown in the figure. Experimental data indicate that when multiple heavy metal ions coexist, the adsorption of various heavy metal ions by the adsorbent is inhibited, but the inhibition effect is not significant. Furthermore, the adsorbent can simultaneously adsorb and remove multiple heavy metal ions, indicating that the adsorbent is suitable for removing heavy metal pollution in water bodies with complex pollution conditions.

[0071] 3. Testing the cyclic adsorption performance of the in-situ regenerable adsorbent for heavy metal ions.

[0072] Weigh 1g of the adsorbent SGP-MB prepared in Example 1 and add it to 40mL of Cu with a concentration of 10mg / L. 2+ Zn 2+ and Pb 2+ The solution was placed in a constant-temperature shaker and continuously shaken for 24 hours (298 K, 105 r / min). The supernatant was then collected, filtered through a 0.22 μm filter, and the concentration of remaining heavy metal ions in the solution was determined using inductively coupled plasma mass spectrometry (Agilent 7900, Japan). Furthermore, this experiment was repeated five times, with the material allowed to stand for 24 hours after each experiment before the next. The experimental results are as follows: Figure 4 As shown, during the first cycle experiment, the adsorption rates of the adsorbent for copper ions, zinc ions, and lead ions reached 97.8%, 92.5%, and 90.7%, respectively. After five cycles of reuse, the adsorbent's adsorption and removal rate for the three heavy metal ions in the solution could still reach over 80%, indicating that the prepared SGP-MB does not require chemical regeneration and can be directly regenerated and reused in situ.

[0073] 4. Characterization Analysis

[0074] The adsorbent SGP-MB prepared in Example 1 was observed by scanning electron microscopy, and the adsorbent after adsorbing lead ions (SGP-MB-Pb) was observed and analyzed by X-ray diffraction. The results are as follows: Figure 5 and Figure 6 As shown in the figure, SGP-MB has a rough surface and well-developed pores, exhibiting a large number of layered polymeric fibrous pore structures, indicating that the adsorbent possesses numerous adsorption sites. SGP-MB is mainly composed of O, Mn, Fe, Al, and Si. After adsorbing lead ions, a Pb4f peak appeared in the spectrum of SGP-MB-Pb. To further understand the oxidation state of manganese in the adsorbent and the valence state transformation process of manganese during adsorption, fitting analysis was performed on the Mn2p region in the XPS spectra of SGP-M, SGP-MB, and SGP-MB-Pb, as shown in the figure. Figure 7 As shown, compared with SGP-M, SGP-MB exhibits the characteristic MnO2 of bio-manganese oxides during the adsorption of lead ions. 3+ Moreover, Mn 3+ As a transitional oxidation state of manganese oxides, it possesses the potential to be converted into divalent and tetravalent manganese oxides through disproportionation reactions, thus providing a basis for the in-situ recycling and regeneration of manganese in the adsorbent. Furthermore, Mn in SGP-MB... 4+The increased proportion indicates a decrease in the average manganese oxidation state (Mn AOS) of the SGP-MB adsorbent. This means that more hydroxyl groups will bind to the coordination vacancies on the SGP-MB surface, and the lower average manganese oxidation state leads to a higher oxygen vacancy concentration. To maintain charge balance, the adsorbent surface will adsorb more lead ions, thus increasing the adsorption capacity of SGP-MB for Pb. 2+ It has a high adsorption capacity.

[0075] Therefore, in the water purification process, the adsorbent described in this invention adsorbs heavy metal pollutants in the water onto the surface of the adsorbent and removes them, while the manganese sand in the adsorbent releases Mn during this process. 2+ soluble Mn 2+ Under the utilization of manganese-oxidizing microorganisms loaded on the material surface, it is further oxidized into bio-manganese oxide (BioMnOx), which has higher oxidation activity and larger specific surface area than manganese sand. Bio-manganese oxide can further remove heavy metal pollution and release Mn through chemical oxidation. 2+ The manganese-oxidizing microorganisms continue to utilize it, thereby achieving "Mn 2+ The recycling mechanism of "bio-manganese oxides" and in-situ regeneration of materials is illustrated in the following diagram. Figure 8 As shown. In addition, under the action of microbial manganese reductase, bio-manganese oxides can also degrade complex trace organic pollutants into low molecular weight organic matter that can be utilized by manganese-oxidizing microorganisms, which provides the necessary energy for the survival and reproduction of manganese-oxidizing microorganisms on the material surface.

[0076] As can be seen from the above implementation examples, the adsorbent of the present invention can be used for the adsorption of heavy metals such as lead, copper and zinc in wastewater, with an adsorption removal rate of over 90%. Moreover, the adsorbent can be regenerated and recycled in situ, which not only prevents secondary pollution to the environment but also reduces the preparation cost, and has good application prospects.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing an adsorbent regenerable in situ, characterized in that, Comprise: 1) mixing manganese sand, dewatered sludge from a waterworks, a first silicate material, a second silicate material, and a binder, and then performing high-temperature calcination to obtain an adsorbing material; wherein the first silicate material has a density of 0.4-1.2 g / cm 3 ; 2) attaching manganese-oxidizing bacteria to the surface of the adsorbent material under aerobic conditions; the first silicate material is expanded perlite, and the second silicate material is clay; the mass ratio of the manganese sand, dewatered sludge from a water treatment plant, first silicate material, and second silicate material is (20-40):(35-45):(5-15):(5-40); the binder is a sodium silicate solution; the high-temperature calcination comprises drying at 100-105°C, preheating at 250-350°C, and finally calcining at 900-1100°C.

2. An adsorbent regenerable in situ, characterized in that, which is prepared by the method of claim 1.

3. Use of the in-situ regenerable adsorbent of claim 2 for removing metal ions from a water body.

4. Use according to claim 3, characterized in that, When the in-situ regenerable adsorbent is used to remove copper ions, zinc ions, and lead ions from a water body at 20-30°C, the adsorption capacity is 3.19-4.23 mg / g, 2.29-3.05 mg / g, and 2.13-2.79 mg / g, respectively.

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