CN115121235B - A method for recycling and utilizing heavy metal-adsorbing Auricularia biochar - Google Patents

Abstract

The invention discloses a regeneration and utilization method of Auricularia biochar adsorbing heavy metals. The regeneration and utilization method includes regenerating the Auricularia biochar adsorbing heavy metals, and includes the following steps: combining the Auricularia biochar adsorbing heavy metals with a hydrochloric acid solution Mix, stir, wash, filter, and dry to obtain regenerated fungus biochar. In the present invention, hydrochloric acid solution is used to regenerate the fungus biochar to restore and improve the adsorption capacity of the fungus biochar. It has the advantages of simple process, convenient operation, short time consumption, few types of chemical reagents, and no need for complicated special equipment. Not only can it effectively remove the heavy metals adsorbed in the fungus biochar, which is conducive to the recycling and reuse of heavy metals, but the regenerated fungus biochar can continue to be used to treat heavy metal wastewater, which is beneficial to reducing the treatment cost of heavy metal wastewater and has high use value. , good application prospects.

Description

A method for recycling and utilizing heavy metal-adsorbing Auricularia biochar

Technical field

The invention belongs to the technical field of heavy metal wastewater treatment, and relates to a regeneration and utilization method of biochar. Specifically, it relates to a regeneration and utilization method of Auricularia biochar that absorbs heavy metals.

Background technique

As a cheap, environmentally friendly heavy metal remediation agent, biochar is widely used to treat heavy metal pollution in industrial wastewater, surface water, groundwater and other water bodies. It has the advantages of low cost and good removal effect. At the same time, in order to further reduce treatment costs and avoid secondary pollution to the environment due to heavy metal leaching, researchers have proposed a strategy to recycle biochar that adsorbs heavy metals, and remove the heavy metals adsorbed in the biochar through corresponding means, and then Realize the regeneration and reuse of biochar, thereby minimizing secondary pollution to the environment during the treatment process while further reducing treatment costs.

At present, biochar regeneration technology includes thermal regeneration, biological regeneration, wet oxidation regeneration, ultrasonic regeneration, microwave regeneration, chemical regeneration, etc. However, existing biochar regeneration methods mainly use multiple methods for joint regeneration, and require special devices. If necessary, oxygen or nitrogen needs to be continuously introduced, which will greatly increase the cost of production. At the same time, biochar regeneration is The process may also cause secondary pollution. In addition, existing chemical regeneration methods require many types of reagents and take a long time, up to several hours or more than ten hours, which makes the biochar regeneration process complicated, regeneration time long, and regeneration cost high. It is not conducive to improving the regeneration efficiency of biochar. In addition, during the actual research process of the inventor of the present application, it was also found that for the Auricularia biochar that absorbs heavy metals, not all conventional chemical reagents can effectively restore the adsorption capacity of the Auricularia biochar, which is not conducive to improving the biochar of Auricularia biochar. The reusability of charcoal greatly limits the wide application of Auricularia auricula biochar in heavy metal wastewater treatment. Therefore, obtaining a regeneration method of Auricularia biochar that is simple in process, easy to operate, short in time, has few types of chemical reagents, and does not require complex special equipment will effectively restore the adsorption capacity of Auricularia biochar and improve the adsorption capacity of Auricularia biochar. It is of great significance to achieve repeatable performance and ultimately realize the widespread application of Auricularia auricula biochar in heavy metal wastewater treatment.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a regeneration and utilization method of Auricularia biochar that absorbs heavy metals with simple process, convenient operation, short time consumption, few types of chemical reagents and no need for complex special equipment.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A method for regenerating heavy metal-adsorbed Auricularia biochar. The regeneration method includes regenerating the heavy metal-adsorbed Auricularia biochar, including the following steps:

S1. Mix the heavy metal-adsorbed Auricularia biochar with hydrochloric acid solution, stir, wash, filter, and dry to obtain regenerated Auricularia biochar.

The above-mentioned regeneration method is further improved. In step S1, the concentration of the hydrochloric acid solution is 0.1mol/L~2.0mol/L; the stirring speed is 150r/min~200r/min; the stirring time The washing time is 15 min to 30 min; the washing is to clean the stirred solid material until the pH value of the washing liquid is 4 to 5.

The above-mentioned regeneration and utilization method is further improved. In step S1, the heavy metal-adsorbed Auricularia biochar is obtained by the following method:

(1) Use fungus as raw material, heat it to above 800°C for carbonization, grind and sieve to obtain carbonized fungus;

(2) Mix the carbonized agaricus obtained in step (1) with the hydrochloric acid solution, stir, wash and dry to obtain agaric biochar;

(3) Mix the Auricularia biochar obtained in step (2) with heavy metal wastewater for oscillation adsorption and solid-liquid separation to obtain Auricularia biochar that adsorbs heavy metals.

The above-mentioned recycling method is further improved. In step (1), before carbonization, the fungus is also subjected to the following processing: drying, grinding, and crushing the fungus to obtain agaric powder; the sieving is to grind the fungus. The final product is passed through a 20-200 mesh sieve; the carbonization is performed in a nitrogen atmosphere; the temperature rise rate during the carbonization process is 2°C/min-20°C/min; and the carbonization time is 1h-6h.

The above-mentioned regeneration method is further improved. In step (2), the concentration of the hydrochloric acid solution is 0.1mol/L~2.0mol/L; the stirring speed is 150r/min~200r/min; the stirring speed The time is 15min-30min; the washing is to clean the stirred solid material until the pH value of the washing liquid is 4-4.5.

The above-mentioned regeneration and utilization method, further improved, also includes step S2: mixing the regenerated agaric biochar obtained in step S1 with heavy metal wastewater for oscillation adsorption to complete the reuse treatment of heavy metal wastewater.

The above-mentioned regeneration method is further improved. In step S2, the ratio of the regenerated Agaricacea biochar to heavy metal wastewater is 0.05g~0.2g:30mL; the initial concentration of heavy metals in the heavy metal wastewater is 10mg/L~50mg. /L; the heavy metals in the heavy metal wastewater are chromium and/or arsenic.

The above regeneration method is further improved. In step S2, the oscillation adsorption process also includes adjusting the pH value of the heavy metal wastewater to 2 to 6; the oscillation adsorption is performed at a rotation speed of 150r/min to 200r/min; The temperature of the oscillating adsorption is 25°C; the time of the oscillating adsorption is 0.5h to 24h.

The above-mentioned regeneration method, further improved, also includes step S3: repeating step S1 and step S2 to repeatedly treat heavy metal wastewater.

The above-mentioned recycling method is further improved. In step S3, the number of repeated processes is 1 to 5 times.

Compared with the prior art, the advantages of the present invention are:

(1) The present invention provides a method for regenerating heavy metal-adsorbed Auricularia biochar, which includes regenerating the heavy metal-adsorbed Auricularia biochar, using hydrochloric acid solution as a regenerant, and restoring and improving it through the regeneration effect of the hydrochloric acid solution. The adsorption capacity of Auricularia biochar enables the regeneration of Auricularia biochar, which is beneficial to improving the reusability of Auricularia biochar for heavy metals, and is conducive to maximizing the treatment of heavy metal wastewater while further reducing treatment costs. And it can avoid secondary pollution to the environment during the treatment process. Compared with other regenerants (such as nitric acid solution, sulfuric acid solution and sodium hydroxide solution), the regeneration and utilization method of the present invention uses hydrochloric acid solution to regenerate the fungus biochar, which not only restores and improves the adsorption capacity of the fungus biochar, but also This regeneration treatment does not require special activation equipment and has strong practical operability. At the same time, the regeneration treatment requires a short time and has good economic and social benefits. The regeneration and utilization method of the present invention has the advantages of simple process, convenient operation, short time consumption, few types of chemical reagents, and no need for complicated special equipment. It can not only effectively remove heavy metals adsorbed in the auricularia biochar, and is conducive to the recovery and reuse of heavy metals, but also The regenerated agaric biochar can continue to be used to treat heavy metal wastewater, which is beneficial to reducing the cost of heavy metal wastewater treatment. It has high use value and good application prospects.

(2) In the regeneration method of the present invention, the concentration of the hydrochloric acid solution used in the regeneration process is optimized. By optimizing the concentration of the hydrochloric acid solution to 0.1 mol/L to 2.0 mol/L, the fungus can be treated under safer conditions. Effective regeneration of vegetable biochar. This is because too high a concentration will destroy the structure of the biochar and have an uncertain impact on subsequent recycling experiments. On the other hand, if the concentration is too low, the desorption effect of biochar will not be utilized, resulting in subsequent recycling. The efficiency is too low. In particular, when the concentration of the hydrochloric acid solution used is 1.2 mol/L, the adsorption performance of the regenerated fungus biochar is basically restored, and it can be used to treat heavy metal wastewater many times, and the repeated treatment effect is the best.

(3) The regeneration method of the present invention also includes using regenerated Auricularia biochar to reuse heavy metal wastewater. By using regenerated Agaric biochar and heavy metal wastewater to perform oscillation adsorption, the regeneration of heavy metal wastewater by Auricularia biochar can be achieved. Reuse, and then the use of fungus biochar to repeatedly treat heavy metal wastewater, can also further reduce the cost of heavy metal wastewater treatment. The regeneration method of the present invention has the advantages of strong reusability, low treatment cost, high treatment efficiency, and good removal effect. It can be widely used to treat heavy metal wastewater and is of great significance for achieving effective treatment of heavy metal wastewater.

Description of drawings

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

Figure 1 is an SEM image of the Auricularia biochar, the Auricularia biochar adsorbing chromium, and the Auricularia biochar adsorbing chromium and arsenic prepared in Example 1 of the present invention, in which (a) is the Auricularia biochar, (b) ) is a fungus biochar that adsorbs chromium, and (c) is a fungus biochar that adsorbs chromium and arsenic.

Figure 2 is an infrared spectrum of the Auricularia biochar (A) prepared in Example 1 of the present invention, the Auricularia biochar adsorbing chromium (B), and the Auricularia biochar adsorbing chromium and arsenic (C).

Figure 3 shows the repeated treatment effect of Auricularia auricula biochar on chromium and arsenic in wastewater in Example 2 of the present invention, where (a) is the control group and (b) is the experimental group.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments of the specification, but the protection scope of the present invention will not be limited thereby.

In the following examples, unless otherwise specified, the raw materials and instruments used are all commercially available, the process used is a conventional process, the equipment used is conventional equipment, and the data obtained are the average of more than three repeated experiments.

Example

A method for regenerating heavy metal-adsorbed Auricularia biochar. The regeneration method includes regenerating the heavy metal-adsorbed Auricularia biochar, including the following steps:

S1. Mix the heavy metal-adsorbed Auricularia biochar with hydrochloric acid solution, stir, wash, filter, and dry to obtain regenerated Auricularia biochar;

S2. Mix the regenerated agaric biochar obtained in step S1 with the heavy metal wastewater for oscillation adsorption to complete the reuse treatment of the heavy metal wastewater;

Repeat steps S1 and S2 to repeatedly treat heavy metal wastewater.

In order to further improve the regeneration effect of fungus biochar, the improved technical solutions adopted in this application are: in step S1, the concentration of the hydrochloric acid solution is 0.1 mol/L ~ 2.0 mol/L; the stirring speed is 150r /min～200r/min; the stirring time is 15min～30min; the washing is to clean the stirred solid material until the pH value of the washing liquid is 4～5.

In order to further improve the regeneration effect of Auricularia auricula biochar, the improved technical solutions adopted in this application are: In step S1, the Auricularia Auricularia biochar adsorbing heavy metals is obtained by the following method:

(1) Use fungus as raw material, heat it to above 800°C for carbonization, grind and sieve to obtain carbonized fungus;

(2) Mix the carbonized agaricus obtained in step (1) with the hydrochloric acid solution, stir, wash and dry to obtain agaric biochar;

(3) Mix the Auricularia biochar obtained in step (2) with heavy metal wastewater for oscillation adsorption and solid-liquid separation to obtain Auricularia biochar that adsorbs heavy metals.

In order to further improve the regeneration effect of fungus biochar, the improved technical solutions adopted in this application are: in step (1), before carbonization, the following treatment is also included on the fungus: drying, grinding, and pulverizing the fungus, Agaricacea powder is obtained; the sieving is to pass the ground product through a 20-200 mesh sieve; the carbonization is carried out under a nitrogen atmosphere; the temperature rise rate during the carbonization process is 2°C/min-20°C/min ; The carbonization time is 1h to 6h.

In order to further improve the regeneration effect of Agaricacea biochar, the improved technical solutions adopted in this application are: in step (2), the concentration of the hydrochloric acid solution is 0.1 mol/L ~ 2.0 mol/L; the stirring speed It is 150r/min～200r/min; the stirring time is 15min～30min; the washing is to clean the stirred solid material until the pH value of the washing liquid is 4～4.5.

In order to further improve the regeneration effect of fungus biochar, the improved technical solutions adopted in this application are: in step S2, the ratio of the regenerated fungus biochar to heavy metal wastewater is 0.05g~0.2g:30mL; the heavy metal The initial concentration of heavy metals in the wastewater is 10 mg/L to 50 mg/L; the heavy metals in the heavy metal wastewater are chromium and/or arsenic.

In order to further improve the regeneration effect of Agaricacea biochar, the improved technical solutions adopted in this application are: in step S2, the oscillation adsorption process also includes adjusting the pH value of heavy metal wastewater to 2 to 6; the oscillation adsorption in The rotation speed is 150r/min～200r/min; the temperature of the oscillation adsorption is 25°C; the time of the oscillation adsorption is 0.5h～24h.

In order to further improve the regeneration effect of Agaricacea biochar, the improved technical solutions adopted in this application are: in step S3, the number of repeated treatments is 1 to 5 times.

Example 1

A method for recycling heavy metal-adsorbed Auricularia biochar, wherein the Auricularia biochar adsorbing heavy metals includes Auricularia biochar adsorbing chromium and Auricularia biochar adsorbing chromium and arsenic (biochar that reaches adsorption saturation), including Following steps:

S1. Take 2g of chromium-adsorbed Auricularia biochar and 2g of Chromium- and arsenic-adsorbed Auricularia biochar, and mix them with a hydrochloric acid solution with a concentration of 1.2 mol/L respectively. The resulting mixture is stirred in a magnetic stirrer at 180 r/min. 15 minutes, wash with deionized water until the pH value of the washing liquid is 5, filter, and dry at 60°C to a constant weight to obtain regenerated Auricularia biochar, in which the regenerated Auricularia biochar after treating Cr(VI) pollutants The charcoal is marked as A1; the regenerated Agaricacea biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) is marked as B1. If the regeneration treatment is performed for the second time, the regenerated Agaricacea biochar after treating Cr(Ⅵ) pollutants and the regenerated Agaricacea biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) are respectively recorded as A2. , B2; for the third regeneration treatment, the regenerated Auricularia biochar after treating Cr(Ⅵ) pollutants and the regenerated Auricularia biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) are respectively recorded. They are A3 and B4, and the numbers of the regenerated Agaricacea biochar obtained after other regeneration treatments are numbered according to the above rules and so on.

Control group: The same concentration of sodium hydroxide solution, nitric acid solution and sulfuric acid solution were used instead of hydrochloric acid solution for regeneration treatment. Other conditions were the same. The regenerated auricularia biochar after treating Cr(VI) pollutants were numbered as C1 and C1, respectively. D1, E1; the regenerated Agaricacea biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) is numbered C2, D2, and E2 in sequence.

S2. Use the regenerated fungus biochar prepared in step S1 to treat heavy metal wastewater, specifically as follows:

Use regenerated fungus biochar (A1, C1, D1, E1) to treat chromium wastewater: Take 4 groups of chromium (Cr(VI)) wastewater (set three parallel samples for each group, and average the results), use 0.1mol/L Adjust the pH value of the wastewater to 3.5 with HCl solution or 0.1mol/L NaOH solution, adjust the volume to 30mL, and the initial concentration of Cr(VI) in the chromium (Cr(VI)) wastewater is 30mg/L, add 0.1 respectively. g The regenerated auricularia biochar (A1, C1, D1, E1) prepared in step S1 was vibrated and adsorbed in a shaking table with a rotation speed of 180 r/min and a constant temperature (25°C) for 8 hours to complete the removal of chromium from wastewater.

Use regenerated fungus biochar (B1, C2, D2, E2) to treat mixed wastewater of chromium and arsenic: Take 4 groups of mixed wastewater of chromium (Cr(VI)) and arsenic As(V) (set three parallel samples for each group) , average the results), adjust the pH value of the wastewater to 3.5 with 0.1mol/L HCl solution or 0.1mol/L NaOH solution, and adjust the volume to 30mL, and the concentration of Cr(VI) in the mixed wastewater is 30mg/L, the concentration of As(Ⅴ) is 20mg/L, add 0.1g of regenerated Agaricacea biochar (B1, C2, D2, E2) prepared in step S1 respectively, at a rotation speed of 180r/min and constant temperature ( 25°C) in a shaking table for 8 hours to complete the removal of chromium and arsenic from wastewater.

In this embodiment, the chromium-adsorbed Auricularia biochar and the Auricularia biochar adsorbing chromium and arsenic were prepared by the following methods:

The preparation method of Auricularia biochar adsorbing chromium includes the following steps: take chromium (Cr(VI)) wastewater (three parallel samples are set for each group, and the results are averaged), and use 0.1 mol/L HCl solution or 0.1 mol /L NaOH solution to adjust the pH value of the wastewater to 3.5, adjust the volume to 30mL, and the initial concentration of Cr(VI) in the chromium (Cr(VI)) wastewater is 30mg/L, add 0.1g Auricularia biochar, and The rotating speed is 180r/min and the constant temperature (25℃) shaker is used for oscillating adsorption. After 8 hours of reaction, the chromium-adsorbed Auricularia biochar is obtained.

Preparation method of Auricularia biochar adsorbing chromium and arsenic: Take the mixed wastewater of chromium (Cr(VI)) and arsenic As(V) (set three parallel samples for each group, and average the results), use 0.1mol/L Adjust the pH value of the wastewater to 3.5 with HCl solution or 0.1mol/L NaOH solution, and adjust the volume to 30mL. In the mixed wastewater, the concentration of Cr(VI) is 30mg/L, and the concentration of As(V) is 30mg/L. 20mg/L, add 0.1g of Auricularia biochar, shake and adsorb in a shaker with a rotation speed of 180r/min and a constant temperature (25°C). After 8 hours of reaction, the Auricularia biochar adsorbing chromium and arsenic is obtained.

In this example, the preparation method of Auricularia fungus biochar includes the following steps:

(1) Wash the collected raw materials (Auricularia auricula) with ultrapure water, place them in an oven and dry them at 60°C to a constant weight, and then grind them into powder with a grinder to obtain Auricularia auricula powder.

(2) Put the fungus powder obtained in step (1) into a quartz boat of suitable size and send it into the tubular heating furnace. Close the door of the tubular heating furnace and perform an air tightness test, and pass in N ₂ , after about 5 minutes, exhaust the oxygen in the furnace cabin and start the heating program. The tube furnace will gradually heat up from room temperature to the target temperature of 850°C at a rate of 10°C/min. After continuous carbonization at 850°C for 2 hours, it will Cool to room temperature at a rate of 10°C/min, grind, and pass through a 100-mesh sieve to obtain carbonized fungus.

(3) Soak the carbonized fungus obtained in step (2) in a HCl solution with a concentration of 1.2 mol/L, stir for 15 minutes under stirring conditions of 180 r/min, wash away excess impurities on the surface of the biochar, and use ultrapure Wash off the excess acid on the surface of the biochar powder with water until the pH value of the washing liquid is 4 to 4.5. The washed biochar is dried at 60°C to a constant weight to obtain the fungus biochar.

Figure 1 is an SEM image of the Auricularia biochar, the Auricularia biochar adsorbing chromium, and the Auricularia biochar adsorbing chromium and arsenic prepared in Example 1 of the present invention, in which (a) is the Auricularia biochar, (b) ) is a fungus biochar that adsorbs chromium, and (c) is a fungus biochar that adsorbs chromium and arsenic. It can be seen from Figure 1 that the agaric biochar prepared at 850°C has an obvious pore structure, and the pore structure of the biochar after adsorption of hexavalent chromium is reduced, and the pores of the biochar after adsorption of hexavalent chromium and pentavalent arsenic are reduced. The structure is visibly lost and the surface of the biochar appears smooth.

Figure 2 is an infrared spectrum of the Auricularia biochar (A) prepared in Example 1 of the present invention, the Auricularia biochar adsorbing chromium (B), and the Auricularia biochar adsorbing chromium and arsenic (C).

Table 1 Structural performance data of Agaricacea biochar in Example 1 of the present invention

It can be seen from Table 1 that the Auricularia biochar prepared at 850°C has a high specific surface area and abundant adsorption sites, which is very suitable for the adsorption of heavy metals, and the -OH and -COOH functional groups in the Auricularia biochar It is beneficial to the adsorption of heavy metals. At the same time, the specific surface area and functional group structure of the regenerated Auricularia biochar are basically restored, so it can be reused to treat heavy metal wastewater.

In this embodiment, after the oscillation adsorption in step S2 is completed, the solid-liquid separation is performed, the concentrations of chromium and arsenic in the solution are measured, and each regenerated auricularia biochar (A1, B1, C1, D1, E1, C2, D2, E2) The removal rate of chromium and arsenic in wastewater, the results are shown in Table 2.

Table 2 Removal rates of chromium and arsenic in wastewater by regenerated fungus biochar prepared under different regenerant conditions in Example 1 of the present invention

It can be seen from Table 2 that compared with alkaline desorbents, acidic desorbents are more conducive to the recovery and reuse of Auricularia biochar. The other three acidic desorbents have a negative impact on Auricularia biochar during the recovery of Auricularia biochar. The activation effect of carbon is in the order of hydrochloric acid > nitric acid > sulfuric acid. This may be due to changing the structure and functional groups of biochar under different acidic conditions, and even affecting the desorption of adsorbates.

Example 2

A method for recycling heavy metal-adsorbing Auricularia biochar, specifically using Auricularia biochar to adsorb heavy metals to repeatedly treat heavy metal wastewater, wherein the heavy metal-adsorbing Auricularia biochar includes chromium-adsorbing Auricularia biochar and chromium- and arsenic-adsorbing The fungus biochar (biochar that reaches adsorption saturation) includes the following steps:

S1. Take 2g of the chromium-adsorbing Auricularia biochar prepared in Example 1 and 2g of the Chromium- and arsenic-adsorbing Auricularia biochar prepared in Example 1, and mix them with a hydrochloric acid solution with a concentration of 1.2 mol/L respectively. The resulting mixed solution was stirred in a magnetic stirrer at 180 r/min for 15 minutes, washed with deionized water until the pH value of the washing solution was 5, filtered, and dried at 60°C to constant weight to obtain regenerated auricularia biochar. Among them, the regenerated Agaricus biochar after treating Cr(Ⅵ) pollutants is marked as A1; the regenerated Agaricacea biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) is marked as B1. If the regeneration treatment is performed for the second time, the regenerated Agaricacea biochar after treating Cr(Ⅵ) pollutants and the regenerated Agaricacea biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) are respectively recorded as A2. , B2; for the third regeneration treatment, the regenerated Auricularia biochar after treating Cr(Ⅵ) pollutants and the regenerated Auricularia biochar after treating mixed pollutants of As(Ⅴ) and Cr(Ⅵ) are respectively recorded. They are A3 and B4, and the numbers of the regenerated Agaricacea biochar obtained after other regeneration treatments are numbered according to the above rules and so on.

S2. Use the regenerated fungus biochar prepared in step S1 to treat heavy metal wastewater, specifically as follows:

Use regenerated fungus biochar (A1) to treat chromium wastewater: take chromium (Cr(VI)) wastewater (set three parallel samples for each group, and average the results), use 0.1mol/L HCl solution or 0.1mol/L Adjust the pH value of the wastewater to 3.5 with the NaOH solution, adjust the volume to 30mL, and the initial concentration of Cr(VI) in the chromium (Cr(VI)) wastewater is 30mg/L, add 0.1g of the regeneration prepared in step S1. Auricularia biochar (A1) was oscillated and adsorbed for 8 hours in a shaker with a rotation speed of 180 r/min and a constant temperature (25°C) to complete the removal of chromium from wastewater.

Use regenerated fungus biochar (B1) to treat mixed wastewater of chromium and arsenic: Take 4 groups of mixed wastewater of chromium (Cr(VI)) and arsenic As(V) (set three parallel samples for each group, and average the results) , use 0.1mol/L HCl solution or 0.1mol/L NaOH solution to adjust the pH value of the wastewater to 3.5, and adjust the volume to 30mL, and the concentration of Cr(VI) in the mixed wastewater is 30mg/L, As( The concentration of V) is all 20mg/L, add 0.1g of the regenerated Agaricacea biochar (B1) prepared in step S1, and oscillate and adsorb in a shaker with a rotation speed of 180r/min and a constant temperature (25°C) for 8h to complete the comparison. Removal of chromium and arsenic from wastewater.

S3. Repeat steps S1 and S2, and use regenerated fungus biochar to repeatedly treat heavy metal wastewater for a total of 5 times.

Control group: Use water instead of the hydrochloric acid solution in step S1 to regenerate the chromium-adsorbed Auricularia biochar and the Auricularia biochar adsorbing chromium and arsenic. Other conditions are the same.

After each oscillation adsorption is completed, the solid and liquid are separated, the concentrations of chromium and arsenic in the solution are measured, and the removal rate of chromium and arsenic in wastewater by regenerated agaric biochar is calculated. The results are shown in Figure 3.

Figure 3 shows the repeated treatment effect of Auricularia auricula biochar on chromium and arsenic in wastewater in Example 2 of the present invention, where (a) is the control group and (b) is the experimental group. It can be seen from Figure 3 that the Auricularia auricula biochar regenerated by hydrochloric acid solution in the present invention still has a good removal effect on heavy metals after five regeneration cycles, and the decrease in removal rate is small, while it is not achieved without hydrochloric acid solution. The regenerated Auricularia biochar has a poor cyclic removal effect of heavy metals, and the removal rate drops significantly. Specifically, the Auricularia biochar does not use hydrochloric acid to desorb heavy metals, so the recycling efficiency of the biochar is very low. The fungus vegetable charcoal after pickling did not even decrease in the first three cycles of recycling. This may be because the concentration of hydrochloric acid is relatively high, which can remove impurities adsorbed in the deeper pore structure, and even biochar The pores adsorbed by impurities are also cleaned before use, and the heavy metal adsorbates are desorbed by acid. The active sites of biochar are re-exposed, which is more conducive to the regeneration of biochar. However, after biochar has been reused many times, it has Multiple washings with acid and adsorption of heavy metals may damage the active sites and the structure and functional groups of biochar, which will reduce the regeneration efficiency of the biochar. In general, using hydrochloric acid as a regenerant can significantly improve the regeneration and recycling of biochar and realize the possibility of biochar recycling. At the same time, hydrochloric acid is safer than nitric acid and sulfuric acid.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited only to the above embodiments. All technical solutions falling under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, improvements and modifications may be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (5)

1. The regeneration and utilization method of the edible tree fungus charcoal for adsorbing heavy metals is characterized by comprising the following steps of:

s1, mixing the edible fungus charcoal adsorbing heavy metals with a hydrochloric acid solution, stirring, washing, filtering and drying to obtain regenerated edible fungus charcoal; the concentration of the hydrochloric acid solution is 0.1 mol/L-2.0 mol/L;

s2, mixing the regenerated agaric biochar obtained in the step S1 with heavy metal wastewater for oscillation adsorption, and finishing the reutilization treatment of the heavy metal wastewater; the ratio of the regenerated edible fungus charcoal to the heavy metal wastewater is 0.05 g-0.2 g:30 mL; the initial concentration of heavy metal in the heavy metal wastewater is 10 mg/L-50 mg/L; the heavy metals in the heavy metal wastewater are hexavalent chromium and pentavalent arsenic; the oscillating adsorption process also comprises the step of adjusting the pH value of the heavy metal wastewater to 3.5; the time of oscillation adsorption is 8-24 hours;

s3, repeating the step S1 and the step S2, and repeatedly treating the heavy metal wastewater;

the edible tree fungus charcoal for adsorbing heavy metals is prepared by the following steps:

(1) Taking the black fungus as a raw material, heating to 850 ℃ for carbonization, grinding and sieving to obtain carbonized black fungus;

(2) Mixing the carbonized black fungus vegetable obtained in the step (1) with a hydrochloric acid solution with the concentration of 0.1-2.0 mol/L, stirring for 15-30 min at the rotating speed of 150 r-200 r/min, cleaning the stirred solid material until the pH value of the washing solution is 4-4.5, and drying to obtain the black fungus vegetable biochar;

(3) Mixing the edible fungus charcoal obtained in the step (2) with heavy metal wastewater for vibration adsorption, and carrying out solid-liquid separation to obtain the edible fungus charcoal for absorbing heavy metal.

2. The recycling method according to claim 1, wherein in step S1, the stirring rotation speed is 150 r/min-200 r/min; the stirring time is 15-30 min; the washing is to wash the stirred solid material until the pH value of the washing liquid is 4-5.

3. The recycling method according to claim 1, wherein in step (1), the following treatment is further performed on the agaric before carbonization: drying the black fungus, grinding and crushing to obtain black fungus powder; the sieving is that the ground product is sieved by a sieve with 20 meshes to 200 meshes; the carbonization is performed under a nitrogen atmosphere; the heating rate in the carbonization process is 2-20 ℃/min; the carbonization time is 1-6 h.

4. The recycling method according to claim 1, wherein in step S2, the oscillation adsorption is performed at a rotation speed of 150r/min to 200r/min; the temperature of the oscillation adsorption is 25 ℃.

5. The recycling method according to claim 1, wherein in step S3, the number of times of the repeating process is 1 to 5 times.