阅读说明：本技术 高性能除Cr(VI)煤基功能材料的制备方法及使用方法 (Preparation method and use method of high-performance Cr (VI) removing coal-based functional material ) 是由 徐天缘 桂夏辉 邢耀文 李永改 王磊 徐梦迪 夏阳超 王连娟 于 2021-07-26 设计创作，主要内容包括：本发明公开一种高性能除Cr(VI)煤基功能材料的制备方法及使用方法,适用于含Cr(VI)污水处理。首先混合原料和过硫酸盐,然后将原料和过硫酸盐混合物加入纯水充分搅拌混合,之后对混合后的物料进行水热炭化反应,反应结束后自然冷却至室温,对冷却的物料进行抽滤,并利用超纯水去除物料中的硫酸根离子,最后将去除硫酸根离子的物料烘干碾磨得到高性能除Cr(VI)煤基功能材料；使用时将高性能除Cr(VI)煤基功能材料投入含Cr(VI)污水搅拌即可。其原料价廉易得,反应条件简单、适应范围广、反应速度快。(The invention discloses a preparation method and a use method of a high-performance Cr (VI) removing coal-based functional material, which are suitable for treating sewage containing Cr (VI). Firstly, mixing raw materials and persulfate, then adding a mixture of the raw materials and the persulfate into pure water, fully stirring and mixing, then carrying out hydrothermal carbonization reaction on the mixed materials, naturally cooling to room temperature after the reaction is finished, carrying out suction filtration on the cooled materials, removing sulfate ions in the materials by using the ultrapure water, and finally drying and grinding the materials from which the sulfate ions are removed to obtain the high-performance Cr (VI) removing coal-based functional material; when in use, the high-performance Cr (VI) removing coal-based functional material is put into the sewage containing Cr (VI) and stirred. The raw materials are cheap and easy to obtain, the reaction conditions are simple, the application range is wide, and the reaction speed is high.)

1. A preparation method of a high-performance Cr (VI) removing coal-based functional material is characterized by comprising the following steps: firstly, mixing raw materials and persulfate, then adding a mixture of the raw materials and the persulfate into pure water, fully stirring and mixing, then carrying out hydrothermal carbonization reaction on the mixed materials, naturally cooling to room temperature after the reaction is finished, vacuumizing the cooled materials, removing sulfate ions in the materials by using the ultrapure water after the vacuumizing is finished, and finally drying and grinding the materials from which the sulfate ions are removed to obtain the high-performance Cr (VI) removing coal-based functional material.

2. The preparation method of the high-performance Cr (VI) -removing coal-based functional material according to claim 1, which is characterized by comprising the following steps:

s1, firstly, mixing persulfate and coke powder according to the weight ratio of 2-8 mmol/g, and then adding the mixed material into ultrapure water according to the ratio of adding 1g of the mixed material into every 14mL of ultrapure water, and fully stirring and mixing;

s2, placing the ultrapure water mixed material after being fully stirred and mixed in a hydrothermal kettle, sealing the kettle for hydrothermal carbonization reaction, wherein the persulfate hydrothermal carbonization reaction increases the content of persistent free radicals and oxygen-containing functional groups on the surface of the coke powder, and meanwhile, the persulfate hydrothermal treatment reduces the ash content of the coke powder and dredges pores, so that the reduction of the coke powder on Cr (VI) and the adsorption effect on Cr (VI) and Cr (III) are improved;

after the hydrothermal reaction of S3, cooling the hydrothermal kettle reactor to room temperature;

s4, taking out the mixed material in the reaction kettle, carrying out suction filtration on the mixed material to realize solid-liquid separation, washing the mixed material by using ultrapure water to remove sulfate ions in the solid part, finally putting the solid mixed material from which the sulfate ions are removed into an oven for drying, and repeatedly grinding the dried material until all the material passes through a 100-mesh sieve to obtain the Cr (VI) removed coal-based functional material.

3. The method for preparing the high-performance coal-based functional material except Cr (VI) according to claim 2, which is characterized in that: the adopted coke powder is the undersize by-product of coke generated in the coal coking process, the granularity is firstly screened to be larger than 0.5mm, and then the coke powder with the granularity smaller than 0.045mm is obtained after grinding and screening by utilizing three crushing heads.

4. The method for preparing the high-performance coal-based functional material except Cr (VI) according to claim 2, which is characterized in that: persulfates include sodium persulfate, potassium persulfate, or ammonium persulfate.

5. The method for preparing the high-performance coal-based functional material except Cr (VI) according to claim 2, which is characterized in that: the hydrothermal carbonization is carried out at the speed of 3-5 ℃/min, the final temperature is set at 220 ℃, and the time is 8-24 hours.

6. The method for preparing the high-performance coal-based functional material except Cr (VI) according to claim 2, which is characterized in that: the drying temperature of the oven is 100 +/-5 ℃, and the drying time is at least 24 h.

7. The method for preparing the high-performance coal-based functional material except Cr (VI) according to claim 2, which is characterized in that: the filtration is carried out by a sand core funnel, and the filter membrane is a 0.45 mu m water system filter membrane.

8. A high-performance Cr (VI) removing coal-based functional material prepared by the preparation method of the high-performance Cr (VI) removing coal-based functional material according to any one of the preceding claims.

9. The use method of the high-performance coal-based functional material for removing Cr (VI) according to claim 8 is characterized by comprising the following steps:

according to the concentration of Cr (VI) contained in the polluted wastewater, a proper amount of high-performance Cr (VI) removing coal-based functional material is put into the polluted wastewater containing Cr (VI), whether the proper amount of the put high-performance Cr (VI) removing coal-based functional material is used is judged according to the removal rate of Cr (VI), the polluted wastewater added with the high-performance Cr (VI) removing coal-based functional material is continuously stirred for reaction, and-OH groups in the high-performance Cr (VI) removing coal-based functional material form inner layer complexation with Cr (VI) in the polluted wastewater in the reaction process, so that interface electron transfer is enhanced, and two processes of adsorption and toxicity reduction are carried out simultaneously: the toxicity reduction process is that the Cr (VI) with high toxicity adsorbed on the surface of the coal-based functional material with high performance except Cr (VI) or in the solution is reduced into Cr (III) with lower toxicity and weaker mobility through a reduction way; the adsorption process is to adsorb Cr (VI) in the solution by the high-performance Cr (VI) removing coal-based functional material and adsorb the reduced Cr (III) to the surface or pores of the high-performance Cr (VI) removing coal-based functional material, thereby realizing the removal of Cr (VI) in the wastewater.

10. Use according to claim 8, characterized in that: the relation between the concentration of the simulated polluted wastewater containing Cr (VI) and the put quantity of the high-performance Cr (VI) removing coal-based functional material is as follows: when the concentration of the polluted wastewater is 10-50 mg/L, 2-6 g/L of the added high-performance Cr (VI) removing coal-based functional material is added; when the pH value of the polluted wastewater is 2-8, the high-performance Cr (VI) removing coal-based functional material can be directly added for use without pH adjustment.

Technical Field

The invention relates to a preparation method and a use method of a Cr (VI) removing coal-based functional material, in particular to a preparation method and a use method of a high-performance Cr (VI) removing coal-based functional material which is suitable for Cr (VI) containing sewage treatment.

Background

In recent years, with the rapid development of industry, the problem of heavy metal pollution caused by industrial wastewater is increasingly severe. Electroplating, metal processing, textile processing, leather processing and the like result in the production of a large amount of Cr (VI) -containing wastewater, Cr (VI) has relatively high degradability, high toxicity and high carcinogenicity in a water body, and long-time irreversible damage to aquatic animals and plants can be caused when the Cr (VI) is accumulated in the water body to a certain limit, and the Cr (VI) in the water can enter a human body through a food chain to influence the health of people, so that the removal of the Cr (VI) in the water becomes a hot point of attention.

The corn stalk biochar generated by KOH activation has larger specific surface area and more micropore structures, the effective Cr (VI) combination is realized mainly through chemical adsorption including ion exchange, electrostatic action, complexation and reduction, and the interaction of oxygen-containing group lone pair electrons and Cr (VI) can form a compound. But the high-temperature pyrolysis of the corn straw biochar has the defects of high energy consumption, complex reaction conditions, higher cost and the like; humic acid and Cr (VI) coordination sites are groups such as carbonyl, carboxyl and carbon-oxygen bonds in humic acid molecules, and chelation occurs between C ═ O and Cr (VI). The conjugation effect between benzene rings is enhanced after the adsorption of Cr (VI). Reducing component-CH in lignite structure₃、-CH₂C-O and Ar-OH provide a large number of electrons during the reaction, participate in the reduction of cr (vi) to cr (iii), and are themselves oxidized to C ═ O and O — C ═ O groups. However, due to the structural characteristics of lignite, the adsorption capacity of lignite on Cr (VI) is limited, and in order to improve the adsorption of lignite on Cr (VI)The performance is that a large amount of nitric acid or concentrated sulfuric acid is added to modify the lignite through nitration or sulfonation, the reaction conditions of the lignite and humic acid for removing Cr (VI) are harsh, and enough H needs to be contained in the solution⁺I.e., a strong acid environment is required, greatly limiting the application range of the reaction.

The coke powder is used as a byproduct generated in the coking process of a coking enterprise with low added value, the utilization rate is extremely low, a large amount of coke powder is accumulated in the open air to generate serious pollution, and the life quality of surrounding residents is seriously influenced. On the other hand, however, coke powder is often used as a raw material for activated carbon because of its high fixed carbon content. In addition, due to their developed pore structure and special surface properties, are often used as adsorbents for organic pollutants. Therefore, the low-cost coke powder is used as a pollution control material, so that the working environment of a coking plant area and surrounding residents can be improved, waste materials can be changed into valuable materials for efficient environmental restoration, and resource recycling is realized.

Disclosure of Invention

Aiming at the technical problems, the preparation method and the use method of the high-performance Cr (VI) removing coal-based functional material are provided, and the method has the advantages of cheap and easily-obtained raw materials, simple reaction conditions, wide application range and high reaction speed.

In order to realize the technical purpose, the preparation method of the high-performance coal-based functional material for removing Cr (VI) comprises the steps of firstly mixing raw materials and persulfate, then adding a mixture of the raw materials and the persulfate into pure water, fully stirring and mixing, then carrying out hydrothermal carbonization reaction on the mixed materials, naturally cooling to room temperature after the reaction is finished, carrying out vacuum-pumping filtration on the cooled materials, removing sulfate ions in the materials by using ultrapure water after the vacuum-pumping is finished, and finally drying and grinding the materials from which the sulfate ions are removed to obtain the coal-based functional material.

Further, the method comprises the following specific steps:

s1, firstly, mixing persulfate and coke powder according to the weight ratio of 2-8 mmol/g, and then adding the mixed material into ultrapure water according to the ratio of adding 1g of the mixed material into every 14mL of ultrapure water, and fully stirring and mixing;

s2, placing the ultrapure water mixed material after being fully stirred and mixed in a hydrothermal kettle, sealing the kettle for hydrothermal carbonization reaction, wherein the persulfate hydrothermal carbonization reaction increases the content of persistent free radicals and oxygen-containing functional groups on the surface of the coke powder, and meanwhile, the persulfate hydrothermal treatment reduces the ash content of the coke powder and dredges pores, thereby improving the reduction of Cr (VI) and the adsorption effects of Cr (VI) and Cr (III) by the coke powder;

after the hydrothermal reaction of S3, cooling the hydrothermal kettle reactor to room temperature;

s4, taking out the mixed material in the reaction kettle, carrying out suction filtration on the mixed material to realize solid-liquid separation, washing the mixed material by using ultrapure water to remove sulfate ions in the solid part, finally putting the solid mixed material from which the sulfate ions are removed into an oven for drying, and repeatedly grinding the dried material until all the material passes through a 100-mesh sieve to obtain the Cr (VI) removed coal-based functional material.

Furthermore, the adopted coke powder is the undersize by-product of coke generated in the coal coking process, the granularity is firstly screened to be larger than 0.5mm, and then the crushed three-head grinding and screening are utilized to obtain the coke powder with the granularity smaller than 0.045 mm.

Further, the persulfate includes sodium persulfate, potassium persulfate, or ammonium persulfate.

Further, the hydrothermal carbonization is carried out at the speed of 3-5 ℃/min, the final temperature is set at 220 ℃ and the time is 8-24 h.

Furthermore, the drying temperature of the oven is 100 +/-5 ℃, and the drying time is at least 24 h.

Furthermore, a sand core funnel is adopted for suction filtration, and the filter membrane is a 0.45-micron water system filter membrane.

A high-performance Cr (VI) removing coal-based functional material prepared by a preparation method of the high-performance Cr (VI) removing coal-based functional material.

A sewage treatment method of a high-performance Cr (VI) removing coal-based functional material comprises the following steps:

according to the concentration of Cr (VI) contained in the polluted wastewater, a proper amount of high-performance Cr (VI) removing coal-based functional material is put into the polluted wastewater containing Cr (VI), whether the adding amount of the high-performance Cr (VI) removing coal-based functional material is enough is determined according to the removal rate of Cr (VI), the polluted wastewater added with the high-performance Cr (VI) removing coal-based functional material is stirred and reacted, and in the reaction process, the-OH groups in the high-performance Cr (VI) removing coal-based functional material are enabled to form inner layer complexation with Cr (VI) in the polluted wastewater, the interface electron transfer is enhanced, and the two processes of adsorption and toxicity reduction are carried out simultaneously: the toxicity reduction process is that the Cr (VI) with high toxicity adsorbed on the surface of the coal-based functional material with high performance except Cr (VI) or in the solution is reduced into Cr (III) with lower toxicity and weaker mobility through a reduction way; the adsorption process is to adsorb Cr (VI) in the solution by the high-performance Cr (VI) removing coal-based functional material and adsorb the reduced Cr (III) to the surface or the pores of the high-performance Cr (VI) removing coal-based functional material, thereby realizing the removal of the Cr (VI) in the wastewater. .

Further, the relation between the concentration of the simulated polluted wastewater containing Cr (VI) and the input amount of the high-performance Cr (VI) removing coal-based functional materials is as follows: when the concentration of the polluted wastewater is 10-50 mg/L, 2-6 g/L of the added high-performance Cr (VI) removing coal-based functional material is added; when the pH value of the polluted wastewater is 2-8, the high-performance Cr (VI) removing coal-based functional material can be directly added for use without pH adjustment.

Has the advantages that:

1. according to the method, pores of the coke powder are dredged by utilizing persulfate hydrothermal treatment, the ash content is reduced, and the adsorption capacity on Cr (VI) is improved; meanwhile, the content of the coke powder persistent free radicals and the surface oxygen-containing functional groups is improved through the persulfate hydrothermal treatment, the interface electron transfer is enhanced, Cr (VI) is reduced into Cr (III) with lower toxicity and weaker mobility, and the Cr (VI) is finally removed through the reduction and adsorption combined action. The method has the advantages of cheap and easily-obtained raw materials, simple reaction conditions, wide application range and high reaction speed.

By introducing-OH groups to form inner-layer complexation with Cr (VI), interface electron transfer is enhanced, and Cr (VI) is reduced into Cr (III) with lower toxicity and weaker mobility; on the other hand, the persulfate hydrothermal treatment can reduce ash content of the coke powder and dredge pores, so that the adsorption quantity of the coke powder to Cr (VI) and Cr (III) reduced to low toxicity is effectively improved.

2. The method can achieve high-efficiency treatment effect on the industrial wastewater containing Cr (VI), such as electroplating, metal processing, textile processing, leather processing and the like.

3. The method has the advantages of simple reaction conditions, wide pH application range, high-efficiency utilization of the coking byproduct with low additional value as a resource, no secondary pollution and good application prospect.

4. The method develops the potential of the persulfate-assisted hydrothermal carbonization modified material, and has good application prospect.

Detailed Description

The present invention will be further described with reference to specific examples.

The invention relates to a preparation method of a high-performance coal-based functional material for removing Cr (VI), which comprises the steps of firstly mixing raw materials and persulfate, then adding a mixture of the raw materials and the persulfate into pure water, fully stirring and mixing, then carrying out hydrothermal carbonization reaction on the mixed materials, naturally cooling to room temperature after the reaction is finished, carrying out vacuum-pumping filtration on the cooled materials, removing sulfate ions in the materials by using ultrapure water after the vacuum-pumping is finished, and finally drying and grinding the materials from which the sulfate ions are removed to obtain the coal-based functional material.

The method comprises the following specific steps:

s1, firstly, mixing persulfate and coke powder according to the weight ratio of 2-8 mmol/g, then adding the mixed material into ultrapure water according to the ratio of adding 1g of the mixed material into every 14mL of ultrapure water, and fully stirring and mixing, wherein the rotation speed of the stirring reaction is 400-600 r/min; the adopted coke powder is the undersize by-product of coke generated in the coal coking process, the particle size is firstly screened to be larger than 0.5mm, then the coke powder with the particle size smaller than 0.045mm is obtained after grinding and screening by utilizing three crushing heads, and the persulfate is sodium persulfate, potassium persulfate or ammonium persulfate;

s2, placing the ultrapure water mixed material after being fully stirred and mixed in a hydrothermal kettle, sealing and carrying out hydrothermal carbonization reaction, wherein the temperature of hydrothermal carbonization is 3-5 ℃/min, heating, and setting the final temperature at 220 ℃ for 8-24 h; the persulfate hydrothermal carbonization reaction increases the content of persistent free radicals and oxygen-containing functional groups on the surface of the coke powder, and meanwhile, the persulfate hydrothermal treatment reduces the ash content of the coke powder and dredges pores, so that the reduction of Cr (VI) and the adsorption effects of Cr (VI) and Cr (III) on the coke powder are improved;

after the hydrothermal reaction of S3, cooling the hydrothermal kettle reactor to room temperature;

s4, taking out the mixed material in the reaction kettle, and performing suction filtration on the mixed material to realize solid-liquid separation, wherein the suction filtration adopts a sand core funnel, and the used filter membrane is a 0.45 mu m water system filter membrane; and then washing the mixed material by using ultrapure water to remove sulfate ions in the solid part, finally putting the solid mixed material from which the sulfate ions are removed into an oven for drying at the drying temperature of 100 +/-5 ℃ for at least 24h, and repeatedly grinding the dried material until all the material passes through a 100-mesh sieve to obtain the Cr (VI) removed coal-based functional material.

A high-performance Cr (VI) removing coal-based functional material prepared by the preparation method of the high-performance Cr (VI) removing coal-based functional material.

A sewage treatment method using high-performance Cr (VI) removing coal-based functional materials comprises the following steps:

according to the concentration of Cr (VI) contained in the polluted wastewater, a proper amount of high-performance Cr (VI) removing coal-based functional material is put into the polluted wastewater containing Cr (VI), whether the adding amount of the high-performance Cr (VI) removing coal-based functional material is enough is determined according to the removal rate of Cr (VI), the polluted wastewater added with the high-performance Cr (VI) removing coal-based functional material is stirred and reacted, and in the reaction process, the-OH groups in the high-performance Cr (VI) removing coal-based functional material are enabled to form inner layer complexation with Cr (VI) in the polluted wastewater, the interface electron transfer is enhanced, and the two processes of adsorption and toxicity reduction are carried out simultaneously: the toxicity reduction process is that the Cr (VI) with high toxicity adsorbed on the surface of the coal-based functional material with high performance except Cr (VI) or in the solution is reduced into Cr (III) with lower toxicity and weaker mobility through a reduction way; the adsorption process is to adsorb Cr (VI) in the solution by the high-performance Cr (VI) removing coal-based functional material and adsorb the reduced Cr (III) to the surface or the pores of the high-performance Cr (VI) removing coal-based functional material, thereby realizing the removal of the Cr (VI) in the wastewater. (ii) a

The relation between the concentration of the simulated polluted wastewater containing Cr (VI) and the put quantity of the high-performance Cr (VI) removing coal-based functional material is as follows: when the concentration of the polluted wastewater is 10-50 mg/L, 2-6 g/L of the added high-performance Cr (VI) removing coal-based functional material is added; when the pH value of the polluted wastewater is 2-8, the high-performance Cr (VI) removing coal-based functional material can be directly added without pH adjustment for use, the stirring reaction is carried out at the rotating speed of 400-600r/min, the Cr (VI) in the wastewater is removed by adsorption reduction, and the removal rate of the Cr (VI) in the wastewater reaches 99% after 24 hours.

The invention provides a method for preparing a high-performance Cr (VI) removing coal-based functional material by utilizing the hydrothermal modification of persulfate to obtain the coal-based functional material. The developed coal-based functional material is put into polluted wastewater containing Cr (VI), and the pores of coke powder are dredged by the persulfate hydrothermal treatment, so that the adsorption capacity to Cr (VI) is improved; meanwhile, the content of the persistent free radicals and the oxygen-containing functional groups on the surface of the coke powder is improved by the persulfate hydrothermal treatment, Cr (VI) is reduced into Cr (III) with lower toxicity and weaker mobility, and finally, the Cr (VI) is removed by utilizing the reduction and adsorption effects.

The content of persistent free radicals and oxygen-containing functional groups on the surface of the coke powder is increased through the specific persulfate hydrothermal treatment, and the-OH groups are introduced to form inner layer complexation with Cr (VI), so that interface electron transfer is enhanced, and Cr (VI) is reduced into Cr (III) with lower toxicity and weaker mobility; on the other hand, the persulfate hydrothermal treatment can reduce ash content of the coke powder and dredge pores, so that the adsorption quantity of the coke powder to Cr (VI) and Cr (III) reduced to low toxicity is effectively improved. Finally, the prepared novel coal-based functional material can remove Cr (VI) by the combined action of reduction and adsorption.

Example 1

The invention discloses a method for preparing a high-performance Cr (VI) removing coal-based functional material by persulfate hydrothermal modification, which comprises the following steps:

1) weighing 10g of coke powder with the initial particle size of more than 0.5mm, grinding and screening by three crushing heads, taking coke powder with the particle size of less than 0.045mm, 60mmol of sodium persulfate and 140mL of ultrapure water, fully stirring and mixing, and then placing the mixed material in a 200mL hydrothermal kettle for sealing

2) And (3) putting the hydrothermal kettle into an oven, heating to 220 ℃ at the speed of 3 ℃/min, and carrying out hydrothermal carbonization reaction for 12 hours.

3) After the hydrothermal reaction is finished, when the reactor is cooled to room temperature, pouring the mixed materials in the reaction kettle out, performing vacuum filtration by using a sand core funnel and a 0.45 mu m water system filter membrane, washing the obtained solid product to be neutral, and drying for later use.

4) Putting the developed coal-based functional material into polluted wastewater containing Cr (VI), stirring at the rotating speed of 400r/min, and removing the Cr (VI) in the wastewater through the adsorption and synergetic reduction effects.

Experiment on treatment of Cr (VI) -containing wastewater

In this example, the removal rates of removing cr (vi) from coke powder, coke powder added sodium persulfate, and sodium persulfate hydrothermally modified coke powder by using coke powder alone are compared with the removal rates of removing cr (vi) from the high-performance coal-based functional material prepared by removing cr (vi) by using the persulfate hydrothermally modified coke powder of the present invention:

the experimental method comprises the following steps: 0.2g of the material obtained in example 1 is added into polluted Cr (VI) -containing wastewater with the pH value of 7 of 100ml and the concentration of 10mg/L, and after 36 hours of stirring reaction, the material achieves the removal rate of Cr (VI) of 99 percent, which shows that the coke powder after heat treatment of sulfate water has excellent performance of removing Cr (VI).

Comparative example 1

0.2g of unmodified coke powder is added into polluted wastewater containing Cr (VI) with the pH of 100ml and the concentration of 7 and the concentration of 10mg/L, and after stirring reaction for 36 hours, the material has a Cr (VI) removal rate of 19 percent, which indicates that the original coke powder has weak capability of removing Cr (VI).

Comparative example 2

After 0.2g of unmodified coke powder and 0.29g of sodium persulfate are added into the polluted wastewater containing Cr (VI) with the pH of 100ml and the concentration of 7 and the polluted wastewater containing Cr (VI) and the stirring reaction is carried out for 36 hours, the removal rate of Cr (VI) is 24 percent, which shows that the mere combination of the coke powder and the persulfate can not improve the Cr (VI) removal capability of the coke powder.

In conclusion, the coal-based functional material prepared by the method has better effect of removing Cr (VI) than that of the unmodified coke powder, the unmodified coke powder and sodium persulfate, and the Cr (VI) is completely removed, the reaction condition is simple, the application range is wide, no secondary pollution is generated, and the low-added-value resources are efficiently utilized.