CN107539989A - The recoverying and utilizing method and soil of monkshood stalk or the restorative procedure of water body - Google Patents

Abstract

The invention provides a method for recycling aconite straw and a method for repairing soil or water body. The recycling method includes using an activator to activate the aconite stalks to obtain activated carbon. The restoration method uses the activated carbon prepared by the aforementioned method for recycling aconite stalks to restore soil or water. The method for recycling the aconite stalks of the invention realizes waste reuse, and provides a more environmentally friendly and sustainable solution for the efficient and harmless treatment and comprehensive utilization of the aconite stalks.

Description

Method for recycling aconite straw and method for repairing soil or water body

technical field

The invention belongs to the technical field of materials, and relates to a method for recycling aconite stalks. Specifically, the invention relates to a method for preparing activated carbon by using agricultural waste aconite stalks.

Background technique

my country is a large agricultural country, and aconite is widely planted as a traditional Chinese medicinal material. Aconite stalks are left as agricultural waste after harvesting. These aconite stalks cannot be used as fertilizers because of their inductive effects. At the same time, direct burning of aconite stalks will cause environmental pollution. Therefore, it is necessary to process the aconite stalks to realize its efficient application.

Contents of the invention

In view of the deficiencies in the prior art, one purpose of the present invention is to solve one or more problems in the above prior art. For example, one of the objectives of the present invention is to provide a method for preparing activated carbon from agricultural waste aconite stalks.

In order to achieve the above object, one aspect of the present invention provides a method for recycling aconite stalks. The recycling method includes activating the aconite stalks with an activator to obtain activated carbon.

In an exemplary embodiment of the present invention, the recycling method may further include pulverizing aconite stalks to obtain aconite stalk powder before the activation treatment step. Preferably, the particle size of the aconite stalk powder is not greater than 0.5 mm.

In an exemplary embodiment of the present invention, the step of obtaining the aconite stalk powder may further include: drying the aconite stalk. Wherein, the drying temperature may be 50°C to 120°C, preferably 80°C.

In an exemplary embodiment of the present invention, the recycling method may further include impregnating aconite stalks with an activating agent before the activating treatment step.

In an exemplary embodiment of the present invention, the mass ratio of the activator to the aconite stalk may be 1:1˜4.5:1.

In an exemplary embodiment of the present invention, the activator may be one of phosphoric acid, NaOH, K ₂ CO ₃ , and KOH. Phosphoric acid is preferred.

In an exemplary embodiment of the present invention, the concentration of the phosphoric acid may be 30wt%-60wt%.

In an exemplary embodiment of the present invention, the temperature of the activation treatment may be 400°C-600°C, and the activation temperature is more preferably 500°C.

In an exemplary embodiment of the present invention, the heating method of the high-temperature activation step may be a uniform heating method, and the heating rate may be 5°C/min-30°C/min, preferably 10°C/min.

In an exemplary embodiment of the present invention, the activation treatment process is performed under an inert atmosphere.

In an exemplary embodiment of the present invention, the recycling method may further include washing and/or drying the activated carbon obtained after the activation treatment.

In an exemplary embodiment of the present invention, the recycling method may further include crushing the activated carbon to obtain activated carbon powder.

In an exemplary embodiment of the present invention, the step of obtaining activated carbon powder may further include sieving the activated carbon powder.

Another aspect of the present invention provides a soil or water restoration method, the restoration method uses the activated carbon prepared by the aforementioned method of recycling aconite stalks to restore the soil or water.

Compared with the prior art, the method for recycling aconite stalks of the present invention has the following beneficial effects:

(1) The preparation process is simple, the cost is low, the corrosion to the equipment is small, the preparation speed is fast, and the large-scale technological production of activated carbon can be realized.

(2) The raw material is sufficient and the price is low, and the comprehensive utilization of the aconite straw can be realized; resources are saved and the ecological environment protection is beneficial.

(3) The prepared activated carbon has less harmful impurities, uniform quality, strong adsorption, can effectively remove harmful pollutants, etc., and is conducive to more practical and economical treatment of increasingly serious environmental pollution problems. For example, it can be used for heavy metals in the environment Soil and water pollution control and remediation.

Description of drawings

The above and other objects and features of the present invention will become clearer through the following description in conjunction with the accompanying drawings, wherein:

Figure 1 shows the process flow chart of preparing activated carbon from aconite stalks.

Figure 2 shows the adsorption results of methylene blue on aconite straw activated carbon prepared at different activation temperatures (using phosphoric acid activator).

Figure 3 shows the effect of the amount of activated carbon from aconite straw on the adsorption rate of heavy metal lead ions.

detailed description

In the following detailed description, the method for recycling aconite stalks and the method for repairing soil or water body according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

In the current situation of resource shortage, energy shortage, and environmental deterioration, one aspect of the present invention provides a method for recycling aconite stalks. The method uses discarded aconite stalks as raw materials, and is low-cost, simple, and mass-produced. Activated carbon that meets market demand and realizes waste reuse.

In an exemplary embodiment of the present invention, the method for recycling aconite stalks can be realized through, for example, the process flow shown in Figure 1, which specifically includes the following steps:

(1) Pretreatment: drying the aconite stalks to remove moisture in the stalks, for example, the drying temperature can be 50°C to 120°C, preferably 80°C; then crush and sieve to obtain the aconite straw powder. The crushing and sieving treatment is to improve the rate of the subsequent activation steps, the activation effect and the performance of the prepared activated carbon. Wherein, the pulverization method can adopt, for example, mechanical pulverization, ultrasonic pulverization and the like. When sieving the pulverized aconite stalks, the aconite stalk powder that can pass through a 35-mesh sieve is preferred, that is, the aconite stalk powder with a particle size not greater than 0.5 mm is selected. Small particle sizes are beneficial to the subsequent activation process, but the present invention The particle size of the aconite straw powder is not limited thereto.

(2) The activator was used to activate the aconite stalks at high temperature. The aconite straw powder obtained in the step (1) is mixed with an activator, and then activated at a high temperature to obtain the aconite straw activated carbon.

This step can be realized in the following manner: for example, blending the aconite stalk powder with an activator, and then placing it under high temperature conditions for direct activation treatment, and obtaining a block solid after activation.

But the present invention is not limited thereto, and it can also be realized in the following manner: for example, immersing the aconite straw powder in the activator for a certain period of time, taking it out and performing drying treatment, and then placing the dried aconite straw powder under high temperature conditions for activation treatment .

Here, the activator may be one of phosphoric acid, NaOH, K ₂ CO ₃ , KOH, preferably a phosphoric acid solution, wherein the concentration of the phosphoric acid solution may range from 30 wt% to 60 wt%. The mass ratio of phosphoric _acid and aconite straw powder can be 1.5-4.5 (i.e. 1.5:1-4.5: ₁ ). The ratio ranges from 1 to 4 (ie 1:1 to 4:1). When the mass ratio is too low, the degree of activation is insufficient and the adsorption performance of activated carbon is poor. If the activation ratio is too high, it may be overactivated, the yield of activated carbon will decrease, the surface area and pore volume will decrease, and the adsorption capacity will decrease. It should be noted that the activation ratio of the direct activation (directly mixing the activator with the aconite stalk powder) and the mass ratio of the dipping activation treatment can be the same. The purpose of impregnation treatment is to fully disperse the activator into the straw powder, which is beneficial to increase the subsequent high-temperature activation speed and activation effect, thereby increasing the specific surface area and pore volume of activated carbon. Of course, no impregnation treatment is required. During the immersion treatment, the immersion time should be at least 6 hours. If the immersion time is too short, the subsequent activation effect will be affected. If the immersion time is too long, the entire process time will be increased. Therefore, the preferred immersion time is 6 hours. In order to avoid the interference of the external environment on the impregnation process, the impregnation process can be sealed. The impregnation temperature can be selected as normal temperature, but in order to speed up the impregnation process, heating, stirring and other treatments can be carried out.

There are many ways to dry the process, for example, it can be carried out in a constant temperature drying oven. When drying in a constant temperature oven, the drying temperature can be 50 ° C to 120 ° C, preferably 80 ° C, and it can be dried to a constant weight. This application is to chemically activate activated carbon, and the undried water produces a large amount of water vapor at high temperature. Water vapor has a physical activation effect and affects the carbon yield. Therefore, this application performs drying to remove excess water during the impregnation process to avoid activation. The effect of water vapor, i.e. avoiding the reduction of char yield.

For the high temperature activation process, heating tools such as high temperature tube furnace and high temperature cylindrical kiln can be selected. There are various heating methods from room temperature to the required activation temperature. /min～30°C/min, preferably 10°C/min. Wherein, the required activation temperature may be 400°C to 600°C, preferably the activation temperature is 500°C. When the activation temperature is lower than 400°C, the activation effect is not ideal. When the activation temperature is higher than 600°C, problems such as high energy consumption and excessive activation will occur, thereby reducing the yield of activated carbon. When the temperature reaches the desired activation temperature, keep the activation temperature for a certain period of time to facilitate the activation process to proceed fully. At the same time, in order to prevent high-temperature oxidation and reduce the yield of activated carbon, the high-temperature activation process can be carried out under the protection of inert gases such as nitrogen and argon. After the activation process is over, block-shaped activated carbon solids can be obtained.

(3) Post-treatment: After the activated carbon obtained in step (2) high-temperature activation is taken out, it can also be washed, dried, crushed, sieved and other treatments to obtain activated carbon powder. Here, the activated carbon can be washed with distilled water, deionized water and other solvents to remove the active agent on the surface of the activated carbon. In the preparation process shown in Figure 1, the activated carbon after washing is dried. The purpose of drying is to reduce the moisture content of the activated carbon to below a certain range, such as below 5%. The moisture in the activated carbon can come from the moisture absorbed during the washing process, or from the moisture absorbed during the cooling process. There are many ways of drying. For example, you can choose to put it in a constant temperature box to accelerate drying. The drying temperature in the constant temperature box can be 50°C to 120°C, preferably 80°C, and it can be dried to a constant weight. The dried activated carbon is crushed to produce powdered activated carbon, wherein the crushing method can be mechanical crushing, ultrasonic crushing and the like. If there is a requirement for the particle size of activated carbon particles, standard sieves and other methods can be used to sieve to meet the requirements for particle size of activated carbon.

Here, the washing, crushing, and drying processes can be adjusted accordingly, and are not limited to the sequence described in the present invention. For example, it can be washed first to remove most of the remaining active agents on the surface, then ground and crushed, and then rinsed with distilled water and other solvents until it is near neutral. Then carry out drying treatment, and then carry out crushing treatment after drying.

At the same time, in order to speed up the cleaning process, treatment methods such as centrifugation and stirring can be adopted.

Because activated carbon has the characteristics of large surface area and high surface energy, these characteristics make activated carbon have strong adsorption performance, and can be widely used in decolorization, impurity removal and refining of food, medicine, monosodium glutamate and chemical products, and can also be used for water purification. , such as in the adsorption of heavy metals and other pollutants in wastewater has great potential. And the recycling method of aconite straw described in the present invention prepares activated carbon, by controlling the activation conditions, the activated carbon has a controllable pore structure, such as can obtain dominant microporous activated carbon or mesoporous activated carbon, and abundant activated carbon surface functional groups , therefore, it can also be widely used in food, medicine, chemical industry, environmental protection and other fields, for example, it can realize the restoration of soil or water body.

In order to make the object, technical solution and advantages of the present invention clearer, the exemplary embodiments of the present invention will be further described in detail below in combination with specific examples and accompanying drawings.

Example 1

The air-dried aconite stalks are peeled, crushed, dried to constant weight, passed through a 35-mesh standard sieve, and set aside. Weigh 10.00g of processed aconite stalk powder, put it into a 250mL beaker, then add the prepared 40wt% phosphoric acid solution into the beaker according to the mass ratio of phosphoric acid and aconite stalks at 2.5:1, stir evenly, and then cover with a parafilm Seal and soak at room temperature for 12 hours. Then put it into a constant temperature drying oven for drying, the drying temperature is set at 80° C., and the drying time is 5 hours. The dried sample was taken out, put into a porcelain boat (a layer of newspaper was laid under the porcelain boat), uncovered, and then put into a high-temperature tube furnace, and the temperature was raised at a rate of 10°C/min under the protection of nitrogen. The temperature is raised to the required activation temperature of 400°C, 500°C, 600°C, and the activation temperature is maintained for 2.5h. After the temperature in the tube furnace dropped, the activated sample was taken out from the tube furnace and cooled to room temperature. Then, wash the sample with distilled water to wash away most of the phosphoric acid on the surface, then put it into a mortar and grind it into powder, then use distilled water for centrifugal cleaning, centrifuge at 8000r/min for 10min in a centrifuge, and wash repeatedly until it is nearly neutral. Then put it into a constant temperature drying oven and dry at 100°C until constant weight. The dried sample is taken out, ground in a mortar, and passed through a 35-mesh standard sieve to obtain a black powdery activated carbon solid sample.

The specific surface area and total pore volume of activated carbon were measured by an automatic physical adsorption instrument (Tri Star II 3020 V1.03 type) at -196 °C in cryogenic liquid nitrogen adsorption isotherm. The samples were degassed in a vacuum environment at 300°C for 5 hours before testing to remove moisture and surface impurities. The adsorption data obtained by the aforementioned automatic physical adsorption instrument utilizes the Brunauer-Emmett-Teller (BET) method to calculate the specific surface area of activated carbon; the adsorption data obtained by _N2 isotherm adsorption is that the relative pressure is 0.973 The single-point adsorption method measures the total pore volume V . The measured results show that the surface area of the activated carbon in this example is 496.6-1121.4 m ² /g, and the total pore volume is between 0.52-1.15 cm ³ /g.

The methylene blue adsorption value of prepared aconite straw activated carbon was determined according to the national standard GB/T12496.8-1999. Methods as below:

Weigh 0.100g (accurate to 0.001mg) of each of the three groups of dried parallel samples, place them in a 100mL conical flask with a ground stopper, add an appropriate amount of methylene blue test solution with a burette, and wait until the samples are all wet, immediately Vibrate on an electric shaker for 20 minutes at an ambient temperature of (25±5)°C, then filter with a medium-speed qualitative filter paper with a diameter of 12.5cm. Put the filtrate in a colorimetric cuvette with an optical path of 1 cm, and compare it with the absorbance of the copper sulfate standard color filter solution (weigh 4.000 g of crystalline copper sulfate (CuSO ₄ ·H ₂ O) and dissolve it in 1000 mL of water) at a wavelength of 665 nm. For comparison, repeatedly adjust the volume of the methylene blue dropped until the absorbance difference with the copper sulfate color filter is within ±0.02, then the milliliter of the methylene blue test solution consumed is the methylene blue adsorption value of the sample.

Figure 2 shows the adsorption results of methylene blue on the activated carbon of aconite stalks prepared in Example 1 at different activation temperatures. In the process of activated carbon detection, the greater the methylene blue adsorption value, the more developed the mesopores and micropores inside the activated carbon, and the stronger the adsorption capacity. It can be seen from Figure 2 that when the activation temperature increases from 400°C to 500°C, the adsorption amount of activated carbon to organic methylene blue increases significantly, and further increases the activation temperature to 600°C, and the adsorption amount of activated carbon to methylene blue decreases. Therefore, the activated carbon activated at 500℃ has the highest removal efficiency of organic pollutants.

Aconite straw activated carbon prepared by activation at 500℃ was used for the treatment of wastewater containing heavy metal lead ions. The specific process is as follows: take six 100ml Erlenmeyer flasks respectively, and add aconite with a concentration of 1g/L, 2g/L, 3g/L, 4g/L, 5g/L, and 6g/L to the six Erlenmeyer flasks in sequence Activated carbon, marked as A1, A2, A3, A4, A5, A6, and then add 25ml of simulated lead-containing wastewater with a pre-configured 200mg/L lead ion content respectively. Put it into a shaker, set the speed of the shaker to 150r/min, shake and adsorb for 1 hour, and set the temperature to 25°C. After the shaking is completed, take it out and let it stand for ten minutes, filter it with a funnel and filter paper, take the supernatant to measure the concentration of lead ions in the solution after activated carbon adsorption. Using lead ions to form a colorless 1:1 stable complex with EDTA, use 0.2wt% xylenol orange (bright yellow) as indicator, add 20wt% hexamethylenetetramine or 3wt% nitric acid to adjust the pH value of the solution to 5-6. At this time, the lead ion and xylenol orange form a purple-red complex, and the solution appears purple-red. Then, it is titrated with EDTA standard solution until the solution changes from purple-red to bright yellow, that is, As the end point of the titration, the concentration of lead ions in the wastewater was measured. The results of adsorption of heavy metal lead ions in water by Aconite straw activated carbon are shown in Figure 3. Wherein, the adsorption condition in Fig. 3 is pH=5.

The results show that when the amount of activated carbon with aconite straw activated carbon as the adsorbent is 6g/L, the adsorption rate (removal rate) of lead ions in wastewater by aconite straw activated carbon reaches 99%. repair or management.

Example 2

The air-dried aconite stalks are peeled, crushed, dried to constant weight, passed through a 35-mesh standard sieve, and set aside. Weigh 10.00g of processed aconite straw powder, mix the aconite straw powder with KOH directly according to the mass ratio of KOH and aconite straw powder at 4: ₁ , or, according to the mass ratio _of K2CO3 and aconite straw powder The ratio is 1:1, the aconite stalk powder is directly mixed with K ₂ CO ₃ , the mixed sample is put into a porcelain boat (a layer of newspaper is laid under the porcelain boat), and then put into a high-temperature tube furnace without a lid In the process, under the protection of nitrogen, the temperature was raised at a rate of 10°C/min, from room temperature to the required activation temperature of 800°C, and the activation temperature was maintained for 2.5h. After the temperature in the tube furnace dropped, the activated sample was taken out from the tube furnace and cooled to room temperature. Then, wash the sample with distilled water to wash away most of the activators on the surface, then put it into a mortar and grind it into powder, then use distilled water for centrifugal cleaning, cool and centrifuge in a centrifuge at 8000r/min, 25°C for 10min, and wash repeatedly until nearly neutral. Then put it into a constant temperature drying oven and dry at 80°C until constant weight. The dried sample is taken out, ground in a mortar, and passed through a 200-mesh standard sieve to obtain a black powdery activated carbon solid sample. The surface area and pore volume of the activated carbon were measured by the aforementioned instrument for measuring the surface area and pore volume of the sample obtained by activation.

Under the above activation conditions, activated carbon with KOH had a surface area of 2762.5m ² /g and a total pore volume of 1.32cm ³ /g; activated carbon with K ₂ CO ₃ had a surface area of 1481.6m ² /g and a total pore volume of 1.32cm 3 /g. The volume is 0.86cm ³ /g.

Activated carbon has a wide range of woody raw materials, and now commonly used are: charcoal, coconut shells, wood chips, bark, walnut shells, fruit shells, cotton shells, rice husks, bamboo, coffee bean stems, oil palm shells, furfural slag and pulp waste liquid etc. Among them, coconut shells and walnut shells are the best, but the sources of these raw materials are limited in my country, and the cost is relatively high. The problem of raw materials and mass production restricts the development of activated carbon in my country, and the quality of domestically produced coal-based activated carbon is generally not high. , small pore volume, low specific surface area, poor adsorption performance, single variety, and unstable product quality, which has led to a certain gap between my country's activated carbon and other countries in terms of quantity and quality.

This application combines the high-efficiency and harmless treatment of aconite straw with the comprehensive utilization of resources of aconite straw, and directly carbonizes or activates the nearby aconite straw to produce high-performance activated carbon. The activated carbon produced can be used for environmental restoration of polluted soil and water bodies. The implementation of this method is of great significance to the sustainable planting of Sichuan Fuzi Chinese medicinal materials and the environmental governance of polluted soil and water bodies. Moreover, the activated carbon prepared by the present invention can be used in various fields such as environmental protection, chemical industry, medical treatment, etc., and provides a new choice of low-cost, low-corrosion, and harmless activated carbon.

In summary, the present invention uses discarded aconite stalks as raw materials, low-cost, simple, and large-scale preparation of activated carbon that can meet market demand, realizes waste recycling, and provides a source for efficient and harmless treatment and comprehensive utilization of aconite stalks A more environmentally friendly and sustainable solution.

Although the present invention has been described above in conjunction with the exemplary embodiments, it should be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the claims. Change.

Claims (10)

1. a kind of recoverying and utilizing method of monkshood stalk, it is characterised in that the recoverying and utilizing method includes using activator pair Monkshood stalk carries out activation process to obtain activated carbon.

2. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the temperature of the activation process For 400 DEG C~600 DEG C.

3. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the temperature of the activation process For 500 DEG C.

4. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the recoverying and utilizing method is also It is included in before the activation process step, monkshood stalk is impregnated using activator.

5. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the activator with it is described attached The mass ratio of sub- stalk is 1:1~4.5:1.

6. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the activator be phosphoric acid, NaOH、K₂CO₃Or KOH.

7. the recoverying and utilizing method of monkshood stalk according to claim 6, it is characterised in that the concentration of the phosphoric acid is 30wt%~60wt%.

8. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the recoverying and utilizing method is also It is included in before the activation process step, monkshood stalk is crushed, obtains the monkshood stalk that granularity is not more than 0.5mm Powder.

9. the recoverying and utilizing method of monkshood stalk according to claim 1, it is characterised in that the recoverying and utilizing method is also It is included in after the activation process step, one or more of is washed, dried, ground and sieved step.

10. the restorative procedure of a kind of soil or water body, it is characterised in that the restorative procedure is used as appointed in claim 1 to 9 The activated carbon that the recoverying and utilizing method of monkshood stalk described in meaning one is prepared is repaired to soil or water body.