Preparation method and application of heavy metal adsorbent

Abstract

The application discloses a preparation method and application of a heavy metal adsorbent, and belongs to the field of waste resource utilization and water treatment technology. The preparation method comprises the following steps: preparing bone charcoal by taking animal bones as raw materials, modifying the bone charcoal by using a surfactant to prepare modified bone charcoal, and loading magnetic nano-particles on the modified bone charcoal to obtain a magnetic biological adsorbent capable of effectively removing heavy metal ions in sewage. The prepared adsorbent has good adsorption performance and biodegradability, does not cause secondary pollution to the environment, greatly reduces the harm of heavy metal ions in sewage, and the magnetism of the adsorbent itself is beneficial to the collection and recycling of the adsorbent, and the utilization rate of the material is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste resource utilization and water treatment, and particularly relates to a preparation method and application of a heavy metal adsorbent. BACKGROUND

[0002] Water environmental pollution, especially heavy metal water pollution, is one of the most serious ecological problems that need to be solved by human beings at present, and the pollution rate of water quality of rivers, lakes and reservoirs is as high as 80.1%. Heavy metals have biological enrichment and no natural degradation, and can be enriched in human bodies through animals and plants, causing serious impact on human bodies. Among them, copper is one of the trace elements necessary for human bodies, but excessive intake will cause copper poisoning. In 2019, the World Health Organization formulated the discharge standard of copper as 2.0 mg / L, and 104 countries and regions also formulated the corresponding standards. The discharge standard of copper formulated by China is less than 0.5 mg / L. At present, the main sources of copper-containing wastewater include mining, smelting, metal plating, battery manufacturing, chemical industry, electrolysis and medicine, etc. Copper poisoning shows neurotoxicity, and the copper metabolism in the brain changes, which directly or indirectly increases the pressure on the oxidation of biological tissues, thereby causing neurologic diseases such as Parkinson's and Alzheimer's disease, in addition, copper poisoning can also cause liver damage.

[0003] How to eliminate the pollution of heavy metals to soil and water resources has become a problem to be solved in environmental protection at present. The currently widely used adsorbents are limited in source, high in cost and complex in preparation method. The traditional treatment method has low efficiency when the concentration of heavy metal ions is low, the process is complex, and secondary pollution is easily caused. Common adsorbents such as activated carbon and ion exchange resin are mostly limited in application due to high cost or complex production process.

[0004] Animal bones, as a kind of waste, are usually processed into products with low added value or feed, but most of them are still not fully utilized, causing great waste. The main component of animal bones is calcium carbonate, so they can be used as adsorbents. In order to improve the adsorption performance of animal bones, modifiers are usually used, but the prepared adsorbents have a series of problems such as single function, high price, even toxicity, corrosion, difficult degradation and secondary pollution. How to select suitable reagents and suitable preparation process parameters to prepare the best performance, reusable and environmentally friendly adsorbents has become a difficult problem to be solved by the technical personnel in the field. SUMMARY

[0005] The purpose of the present application is to provide a preparation method and application of a heavy metal adsorbent to solve the problems existing in the prior art, and to achieve the purpose of preparing a heavy metal adsorbent which is non-toxic, harmless, stable in properties and reusable by selecting raw materials and adjusting the preparation method.

[0006] To achieve the above object, the present application provides the following scheme:

[0007] One of the technical solutions of the present application is a preparation method of a heavy metal adsorbent, characterized in that the method comprises the following steps: preparing bone charcoal from animal bones, modifying the bone charcoal by using a surfactant to prepare modified bone charcoal, and loading magnetic nanoparticles on the modified bone charcoal to obtain the heavy metal adsorbent.

[0008] Further, the animal bones include one or more of chicken bones, duck bones, fish bones, pig bones, cow bones and sheep bones; and the preparation of the bone charcoal specifically comprises: crushing the animal bones and then heat treating at 500 DEG C for 1 h.

[0009] Further, the surfactant includes one or more of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium diisooctyl sulfosuccinate and fatty alcohol polyoxyethylene ether sulfate; and the preparation of the modified bone charcoal specifically comprises: mixing the bone charcoal and the surfactant in water, stirring at a speed of 100-250 r / min for 24-60 h, and repeatedly washing with deionized water until the pH is stable at neutral.

[0010] Further, the concentration of the surfactant is 0.001-0.1 mol / L.

[0011] Further, the magnetic nanoparticles are ferroferric oxide.

[0012] Further, the preparation of the magnetic nanoparticles specifically comprises: mixing and dissolving ferric chloride and ferrous sulfate at a mass ratio of 5:3-3:1, and adjusting the pH value to alkaline by using a pH adjuster to obtain the magnetic nanoparticles.

[0013] Further, the pH adjuster includes one or more of ammonia, sodium hydroxide, sodium carbonate and potassium carbonate.

[0014] Further, the method for loading the magnetic nanoparticles on the modified bone charcoal specifically comprises: uniformly mixing the modified bone charcoal and the magnetic nanoparticles at a mass ratio of 1:0.2, ultrasonic dispersion for 1-4 h, and pyrolysis at 500 DEG C for 1-4 h.

[0015] The second technical solution of the present application is a heavy metal adsorbent.

[0016] The third technical solution of the present application is an application of the heavy metal adsorbent in heavy metal pollution.

[0017] The present application discloses the following technical effects:

[0018] The application provides a preparation method and application of an ecological and environment-friendly adsorbent suitable for adsorbing heavy metals in water. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative effort.

[0020] Figure 1 It is a preparation method flowchart of the adsorbent of the embodiment 1 of the present application.

[0021] Figure 2 It is a physical map of the adsorbent prepared in the embodiment 1 of the present application.

[0022] Figure 3 It is a SEM map of the adsorbent prepared in the embodiment 1 of the present application.

[0023] Figure 4 It is a regeneration performance diagram of the adsorbent prepared in the embodiment 1 of the present application. DETAILED DESCRIPTION

[0024] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application.

[0025] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the range and any other stated value or intermediate value in the range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0026] Unless otherwise indicated, all technical and scientific terms have the same meaning as those one of ordinary skill in the art of the disclosure would understand. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure. All documents mentioned herein are incorporated by reference to disclose and describe in further detail the methods and / or materials associated with the documents. In the case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification controls.

[0027] Many modifications and variations of the present disclosure described in the detailed description of the specification can be made without departing from the scope or spirit of the present disclosure, which will be apparent to those skilled in the art. Other implementations of the disclosure will be apparent to those skilled in the art from the specification. The specification and examples of the present disclosure are merely illustrative.

[0028] As used herein, "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", and the like, are open-ended terms that are intended to mean including, but not limited to.

[0029] Example 1

[0030] A method for preparing a heavy metal adsorbent:

[0031] (1) The chicken bones were washed and boiled in deionized water to remove residual fat and protein, then dried at 80°C, cut into small pieces of about 1 cm, and put into a pulverizer for crushing. The crushed chicken bones were heated to 500°C in a muffle furnace for 1 h, then cooled to room temperature, washed with deionized water until no impurities were visible, and dried in a drying oven at 80°C. The dried chicken bones were sieved through a 60-mesh sieve to obtain chicken bone charcoal.

[0032] (2) 25 g of the chicken bone charcoal was added to 500 mL of a sodium dodecyl sulfonate solution with a concentration of 0.004 mol / L, and stirred at 150 r / min at 25°C for 48 h. After filtration, the filter residue was repeatedly washed with deionized water until the pH was neutral, and dried at 105°C for 24 h to obtain modified chicken bone charcoal.

[0033] (3) 14.25 g of ferric chloride hexahydrate and 6.75 g of ferrous sulfate heptahydrate were added to 250 mL of deionized water, and after dissolution, ammonia water with a pH of 10 was added to form magnetic nanoparticles. The magnetic nanoparticles were washed with deionized water 5 times and with methanol 5 times.

[0034] (4) 25 g of the modified chicken bone charcoal and 5 g of the magnetic nanoparticles were mixed uniformly and ultrasonically dispersed for 2 h, dried in a 110°C drying oven for 12 h, pyrolyzed in a muffle furnace at a temperature of 500°C for 2 h, washed with deionized water 3 times after cooling to room temperature, and dried in a 60°C drying oven for 12 h. The heavy metal adsorbent was sieved through a 60-mesh sieve.

[0035] The specific preparation process of the adsorbent is shown in Figure 1 The physical map of the adsorbent is shown in Figure 2 The SEM image of the adsorbent is shown in Figure 3 The regeneration performance of the adsorbent is shown in Figure 4

[0036] Example 2

[0037] A method for preparing a heavy metal adsorbent comprises the following steps:

[0038] The same as example 1, except that the concentration of sodium dodecyl sulfonate in step (2) is 0.05 mol / L.

[0039] Example 3

[0040] A method for preparing a heavy metal adsorbent comprises the following steps:

[0041] The same as example 1, except that the concentration of sodium dodecyl sulfonate in step (2) is 0.1 mol / L.

[0042] Example 1

[0043] The heavy metal adsorbents prepared in example 1, example 2 and example 3 were respectively put into copper ion-containing wastewater solutions with different pH values, and the removal rates of copper ions in the wastewater were measured. The calculation formula of the removal rate is as follows, and the results are shown in Table 1.

[0044]

[0045] Wherein, C0 is the concentration of Cu2+ ions in the initial solution (mg / L); C is the concentration of Cu2+ ions in the solution at equilibrium (mg / L). 2+ e 2+

[0046] Table 1 Removal rate of copper ions in wastewater

[0047]

[0048]

[0049] Example 2

[0050] The regeneration performance experiment was carried out under the condition that the heavy metal adsorbent prepared in example 1 was regenerated with HNO3 solution as the desorbent, and the results are shown in Table 2.

[0051] Table 2 Regeneration performance of heavy metal adsorbent

[0052]

[0053] ​​​​Table 1 shows that the magnetic bone char modified with sodium dodecyl sulfonate has a high removal rate of copper ions in wastewater. When using sodium dodecyl sulfonate at a concentration of 0.004 mol / L, the removal rate of copper ions can reach 99.98%. Furthermore, the surfactant sodium dodecyl sulfonate used in this invention is non-toxic and harmless compared to other types of surfactants, which is more in line with the concept of green development.

[0054] Table 2 shows that after five repeated experiments, the adsorbent still achieved a high removal rate for copper ions. Therefore, 0.004 mol / L sodium dodecyl sulfate was selected as the modifier, resulting in the best modification effect. This invention significantly improves the removal efficiency of the adsorbent for heavy metal ions and can effectively remove harmful ions from wastewater. The invention also exhibits good regeneration performance, greatly reducing material waste and thus lowering costs. Furthermore, the materials used in this invention are non-toxic and harmless, and facilitate waste recycling, overcoming the shortcomings of existing technologies.

[0055] Example 4

[0056] Same as Example 1, except that the chicken bones were soaked in a 0.2% sodium hydroxide solution for 8 hours before being crushed.

[0057] Example 5

[0058] Similar to Example 1, the difference is that the chicken bone crushing also includes the following steps: mixing crushed chicken bones with 85% phosphoric acid at a mass ratio of 1:2.5 and soaking for 10 hours, followed by pyrolysis.

[0059] Example 6

[0060] Same as Example 1, except that step (2) specifically involves taking 25g of the above-mentioned chicken bone charcoal, adding 120mL of 12% sodium chloride solution and soaking for 8h, filtering, drying the filter cake at 85℃, calcining at 300℃ for 2h, and naturally cooling to prepare modified chicken bone charcoal.

[0061] Comparative Example 1

[0062] (1) After cleaning the chicken bones, boil them with deionized water to remove residual fat and protein, dry them at 80°C, cut them into small pieces of about 1cm and grind them in a grinder. Place the ground chicken bones in a muffle furnace and heat them to 500°C. Keep them at 1h and then cool them to room temperature. Take them out, wash them several times with deionized water, and dry them in a drying oven at 80°C. Pass them through a 60-mesh sieve to obtain chicken bone charcoal.

[0063] (2) Add 14.25g of ferric chloride hexahydrate and 6.75g of ferrous sulfate heptahydrate to 250mL of deionized water, dissolve them, and then add ammonia water with pH 10 to form magnetic nanoparticles. Wash the magnetic nanoparticles 5 times with deionized water and 5 times with methanol.

[0064] (3) Take 25 g of the above charcoal and 5 g of magnetic nanoparticles into 500 mL of a 0.004 mol / L sodium dodecyl sulfonate solution, stir at 150 r / min at 25°C for 48 h, uniformly ultrasonic disperse for 2 h, dry in a 110°C drying oven for 12 h, pyrolyze in a muffle furnace at a temperature of 500°C for 2 h, wash with deionized water 3 times after cooling to room temperature, dry in a 60°C drying oven for 12 h, and sieve through a 60 mesh sieve to obtain a heavy metal adsorbent.

[0065] Comparative Example 2

[0066] The same as Example 1, except that the sodium dodecyl sulfonate in step (2) is replaced by sodium dodecyl sulfate.

[0067] Comparative Example 3

[0068] The same as Example 1, except that the operation of step (2) is not performed.

[0069] Example 3

[0070] The heavy metal adsorbents of Examples 4-6 and Comparative Examples 1-3 are respectively placed into copper ion-containing wastewater solutions with different pH values, and the removal rates of copper ions in the wastewater are measured, and the results are shown in Table 3.

[0071] Table 3 Removal rate of copper ions in wastewater

[0072]

[0073] As can be seen from Example 1 of Table 1 and Example 4 of Table 3, the step of adding sodium hydroxide soaking before animal bone crushing is beneficial to putrefaction of soft tissues attached to the bone. After the bone is soaked in the sodium hydroxide solution, the broken putrefactive meat on the bone is transparent, and the bone can be cleaned with water to remove the putrefactive meat. The bone with removed putrefactive meat has less impurities and better adsorption effect.

[0074] As can be seen from Example 1 and Example 4, the adsorbent prepared from the chicken bone treated with phosphoric acid still has good adsorption effect under the condition that the pH of the wastewater is high. The reason is that the activation of phosphoric acid makes the charcoal have a larger surface area, and thus the adsorption performance is significantly improved.

[0075] As can be seen from Example 6, the charcoal treated with sodium chloride has good adsorption performance for copper ions. The reason is that sodium chloride can modify the charcoal to have more pores and increase the surface area, so that a better adsorption effect can be achieved.

[0076] It can be seen from the adsorption effect of the heavy metal copper ions under different pH conditions by the example 1 and the comparative example 1 that the effect of the adsorbent prepared by the modification of the surfactant and the loading of the magnetic nanoparticles together on the adsorption of the copper ions is not ideal, because the modification of the bone charcoal and the loading of the magnetic nanoparticles on the bone charcoal are performed at the same time, and the modification of the bone charcoal and the loading of the magnetic nanoparticles on the bone charcoal affect each other, the modification effect of the bone charcoal is poor, the effect of the loading of the magnetic nanoparticles on the bone charcoal is correspondingly poor, and if the bone charcoal is loaded with the magnetic nanoparticles first, the bone charcoal cannot be modified by the surfactant well, so the effect of the prepared adsorbent is not ideal.

[0077] The above-described examples only describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for producing a heavy metal adsorbent, characterized by, The steps are as follows: (1) After washing the chicken bones, boil them in deionized water to remove residual fat and protein, dry them at 80°C, then cut them into small pieces of about 1 cm and put them into a pulverizer to be pulverized, put the pulverized chicken bones into a muffle furnace and heat them to 500°C for 1 h, then cool them to room temperature, take them out, wash them with deionized water until no impurities are visible, dry them in a drying oven at 80°C, and sieve them through a 60-mesh sieve to obtain chicken bone charcoal; (2) Take 25 g of the chicken bone charcoal and soak it in 120 mL of a 12% sodium chloride solution for 8 h, filter it, dry the filter cake at 85°C, then calcine it at 300°C for 2 h, and cool it naturally to obtain modified chicken bone charcoal; (3) Add 14.25 g of iron(III) chloride hexahydrate and 6.75 g of ferrous sulfate heptahydrate to 250 mL of deionized water, dissolve them, then add ammonia water with a pH of 10 to form magnetic nanoparticles, wash the magnetic nanoparticles with deionized water 5 times and with methanol 5 times; (4) Take 25 g of the modified chicken bone charcoal and 5 g of the magnetic nanoparticles, mix them evenly, ultrasonically disperse them for 2 h, dry them in a 110°C drying oven for 12 h, then pyrolyze them in a muffle furnace at a temperature of 500°C for 2 h, cool them to room temperature, wash them with deionized water 3 times, dry them in a 60°C drying oven for 12 h, and sieve them through a 60-mesh sieve to obtain a heavy metal adsorbent.

2. A heavy metal adsorbent prepared by the method of claim 1.

3. Use of the heavy metal adsorbent of claim 2 in heavy metal pollution.

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