Process for preparing liquid fertilizer by utilizing vitamin C fermentation waste liquid

Abstract

The invention discloses a process for preparing a liquid fertilizer by utilizing vitamin C fermentation waste liquid, and relates to the technical field of fertilizer preparation. The process has the advantages that the conversion efficiency of components in the waste liquid into nutritional components can be improved through an innovative conversion process combining biological enzyme catalysis and chemical catalysis; specific oxidoreductase is screened from thermophilic bacteria and produced through genetic engineering, has high catalytic activity on benzene ring-containing compounds in waste liquid and can efficiently convert the benzene ring-containing compounds into easily-absorbed micromolecular nutrient substances, the conversion rate can reach 80% or above, an auxiliary chemical catalyst is composed of treated transition metal oxide and an organic complexing agent according to the ratio of 2: 1, and the specific oxidoreductase has high catalytic activity on the benzene ring-containing compounds in the waste liquid. The reaction is further promoted on the premise of not changing the activity of the biological enzyme, meanwhile, the content of side reaction products is reduced, the nutritional quality and the utilization rate of the fertilizer are remarkably improved, micro-particles and insoluble impurities are further removed through the microporous filtration membrane, the waste liquid is deeply purified, and the pollution to the environment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, in particular to a process for preparing liquid fertilizer by utilizing vitamin C fermentation waste liquid. Background Art

[0002] Vitamin C, as an essential nutrient for the human body, is widely used in many fields such as medicine, food, and beverages. Its production process usually adopts fermentation technology, which will produce a large amount of waste liquid. These vitamin C fermentation waste liquids contain rich organic matter, nitrogen, phosphorus, potassium and other nutrients, and have certain potential resource value. However, at the same time, the waste liquids inevitably contain some harmful substances, such as heavy metal ions, residual chemical reagents, etc. If these waste liquids are discharged directly without treatment, it will cause serious pollution to the environment, not only destroying the ecological balance, but also posing a threat to human health. In addition, direct discharge also means a great waste of useful resources, which is not in line with the concept of sustainable development. The existing method of preparing liquid fertilizer using vitamin C fermentation waste liquid has certain defects. First, the existing waste liquid conversion efficiency is low and there are many side reactions, resulting in low nutritional quality and utilization rate of the fertilizer. Secondly, the current treatment technology is difficult to effectively remove impurities and harmful substances in the waste liquid, causing pollution to the environment. Furthermore, the stabilizer effect of the existing technology is not good, the nutritional components of the fertilizer are easily affected by external factors, and the storage period is short. For this reason, we propose a process for preparing liquid fertilizer using vitamin C fermentation waste liquid. Summary of the invention

[0003] The purpose of the present invention is to provide a process for preparing liquid fertilizer by utilizing vitamin C fermentation waste liquid.

[0004] In order to solve the problems raised in the above background technology, the present invention provides the following technical solution: a process for preparing liquid fertilizer using vitamin C fermentation waste liquid, the process comprising the following specific steps: Step 1, take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring functions, first perform preheating treatment, and add 5-10 parts of adsorbent after preheating. The adsorbent is made of specially treated activated carbon and nano adsorption material mixed in a ratio of 3:2. The nano adsorption material uses low-cost natural zeolite and is activated at 500°C-600°C for 2h-3h. The activated zeolite adsorbs heavy metal ions and macromolecular organic impurities in the waste liquid, and stirs at a speed of 60r / min-80r / min for 30min-60min at 30°C-40°C to remove impurities and harmful substances. Step 2: Add 3-5 parts of a specific oxidoreductase and 1-2 parts of an auxiliary chemical catalyst to the treated waste liquid, screen and prepare a specific oxidoreductase from an extreme environment microorganism through genetic engineering production, which has high catalytic activity for the difficult-to-degrade benzene ring-containing compounds of complex organic macromolecular compounds in the waste liquid, and react for 2h-3h for conversion under the conditions of pH 6-8 and temperature 35°C-40°C; Step 3: adding a stabilizer composed of an antioxidant and an EDTA (ethylenediaminetetraacetic acid) chelating agent in a ratio of 1:1, using the antioxidant to prevent the nutrients in the fertilizer from being oxidized, and using the chelating agent to stabilize the metal ions to prevent their precipitation, and then stirring at a speed of 80r / min-100r / min for 20min-30min to evenly disperse the stabilizer to obtain a pre-liquid fertilizer; Step 4: Filter the pre-liquid fertilizer through a microporous filter membrane with a pore size of 0.2 μm-0.5 μm to remove tiny particles and insoluble impurities, and package it with a multi-layer barrier plastic packaging material to obtain liquid fertilizer.

[0005] As a further solution of the present invention: in the step 1, when the natural zeolite is activated at high temperature, the temperature is controlled at 500°C-600°C, and the activation time is 2h-3h, so that the internal structure of the zeolite is optimized, more active sites are generated, and it helps to efficiently adsorb heavy metal ions and macromolecular impurities.

[0006] As a further scheme of the present invention: in the step 2, the specific oxidoreductase is screened from thermophilic bacteria in hot springs, extreme environment samples are collected, enriched and cultured in a selective culture medium containing vitamin C fermentation waste liquid, single colonies are separated by a gradient dilution method, enzyme activity of the single colonies is detected, strains with high catalytic activity for organic macromolecular compounds in the waste liquid are screened, genes of the strains are extracted, and they are introduced into an Escherichia coli expression vector of a high-efficiency expression vector by genetic engineering technology, and fermentation production is carried out under fermentation conditions with glucose and yeast extract as main nutrients, temperature of 30°C-37°C, pH6.5-7.5, and dissolved oxygen controlled at 5mg / L-10mg / L to obtain a specific oxidoreductase, and the conversion of benzene ring compounds in the vitamin C fermentation waste liquid is catalyzed by the specific oxidoreductase to improve the availability of fertilizer nutrients.

[0007] As a further solution of the present invention: in the step three, the amount of the stabilizer added is 0.5-1 part, the antioxidant is obtained by extracting the ferrous sulfate waste residue generated in the industrial production of titanium dioxide by the method of acid dissolution and recrystallization, and the EDTA chelating agent is obtained by extracting from the wastewater of the electroplating industry by the ion exchange resin method.

[0008] As a further scheme of the present invention: in the step one, the raw materials of the adsorbent, activated carbon and nano-adsorbent material, are treated in a special way. The activated carbon is activated by high-temperature steam and maintained at a temperature of 700°C-800°C for 2h-3h to increase the specific surface area of ​​the activated carbon and enhance the adsorption capacity of harmful substances in the waste liquid. The natural zeolite selected as the nano-adsorbent material is first pre-treated by acid leaching, and is soaked in a hydrochloric acid solution with a concentration of 3mol / L-5mol / L at 40°C-50°C for 1h-2h, and then subjected to a high-temperature activation treatment at 500°C-600°C for 2h-3h. The treated activated carbon and nano-adsorbent material are mixed in a ratio of 3:2.

[0009] As a further solution of the present invention: in the step 1, when adding the adsorbent, it is slowly added in batches, once every 5 minutes to 10 minutes, and added to the reaction container in 3-4 times.

[0010] As a further scheme of the present invention: in the step 2, the auxiliary chemical catalyst is a complex composed of a treated transition metal oxide and an organic complexing agent in a ratio of 2:1. The transition metal oxide is first ground and refined to a particle size of 50nm-100nm to increase its specific surface area and reaction activity. The organic complexing agent is purified to remove impurities and increase the purity to more than 99%. When adding the auxiliary chemical catalyst, it is dripped into the reaction container within 10min-15min in a uniform speed dripping manner, and the dripping speed is 0.5ml / min-1l / min.

[0011] As a further solution of the present invention: in the step three, during the process of adding the stabilizer, the adding speed of the stabilizer is controlled at 0.01-0.02 parts per minute, and the stirring intensity is controlled at 80r / min-100r / min, so that the stabilizer can be evenly and quickly mixed with the liquid fertilizer.

[0012] As a further scheme of the present invention: in the step 1, after the vitamin C fermentation waste liquid is placed in the reaction container, it is first preheated. By surrounding the electric heating belt on the outside of the reaction container, the temperature of the waste liquid is slowly increased to 25°C-30°C and maintained for 10min-15min, so that the fluidity of the waste liquid is enhanced, which is conducive to better dispersion of the subsequent adsorbent. At the same time, after the adsorbent is added, the ultrasonic auxiliary device is started to use ultrasound to promote the full combination of the adsorbent with impurities and harmful substances in the waste liquid. The ultrasonic frequency is controlled at 30kHz-40kHz, and the action time is 20min-30min.

[0013] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are: 1. The present invention can improve the conversion efficiency of components in waste liquid into nutrients through an innovative conversion process combining biological enzyme catalysis with chemical catalysis. The specific oxidoreductase is screened from thermophilic bacteria and produced through genetic engineering. It has high catalytic activity for benzene ring compounds in waste liquid and can efficiently convert them into easily absorbable small molecule nutrients with a conversion rate of more than 80%. The auxiliary chemical catalyst is composed of a treated transition metal oxide and an organic complexing agent in a ratio of 2:1, which further promotes the reaction without changing the activity of the biological enzyme, while reducing the content of side reaction products, significantly improving the nutritional quality and utilization rate of the fertilizer; 2. The present invention realizes efficient pretreatment of vitamin C fermentation waste liquid through adsorbent treatment and advanced filtering technology. In the adsorbent, the activated carbon is treated with high-temperature steam activation, and the specific surface area is significantly increased, thereby enhancing the adsorption capacity of harmful substances in the waste liquid. The zeolite is treated with acid leaching pretreatment and high-temperature activation, and the adsorption performance is greatly improved. The two are mixed in a specific ratio of 3:2, and are added slowly in batches, with an ultrasonic auxiliary device, which can effectively remove a large amount of impurities and harmful substances in the waste liquid. At the same time, the microporous filtration membrane further removes tiny particles and insoluble impurities, so that the waste liquid is deeply purified, providing high-quality raw materials for subsequent processes and reducing pollution to the environment. 3. The present invention uses natural antioxidants and chelating agents as stabilizers, which can form stable chelates with metal ions to avoid metal ion precipitation. By accurately controlling the addition speed and stirring intensity of the stabilizer, the stabilizer can be evenly and quickly mixed with the liquid fertilizer to give full play to the stabilizing effect. At the same time, the use of special multi-layer barrier plastic packaging materials can effectively block the entry of oxygen, moisture and light, further reducing the impact of external factors on the nutritional components of the fertilizer, ensuring the high-quality effect and long storage period of the fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the process steps in an embodiment of the present invention; Figure 2 It is a schematic diagram for comparing embodiments in the embodiments of the present invention. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0016] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0017] Please see attached Figure 1 -Attached Figure 2The present invention provides a process for preparing liquid fertilizer by using vitamin C fermentation waste liquid, and the process comprises the following specific steps: Step 1, take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring functions, first perform preheating treatment, and add 5-10 parts of adsorbent after preheating. The adsorbent is made of specially treated activated carbon and nano adsorption material mixed in a ratio of 3:2. The nano adsorption material uses low-cost natural zeolite and is activated at 500°C-600°C for 2h-3h. The activated zeolite adsorbs heavy metal ions and macromolecular organic impurities in the waste liquid, and stirs at a speed of 60r / min-80r / min for 30min-60min at 30°C-40°C to remove impurities and harmful substances. Step 2: Add 3-5 parts of a specific oxidoreductase and 1-2 parts of an auxiliary chemical catalyst to the treated waste liquid, screen and prepare a specific oxidoreductase from an extreme environment microorganism through genetic engineering production, which has high catalytic activity for the difficult-to-degrade benzene ring-containing compounds of complex organic macromolecular compounds in the waste liquid, and react for 2h-3h for conversion under the conditions of pH 6-8 and temperature 35°C-40°C; Step 3: adding a stabilizer composed of an antioxidant and an EDTA (ethylenediaminetetraacetic acid) chelating agent in a ratio of 1:1, using the antioxidant to prevent the nutrients in the fertilizer from being oxidized, and using the chelating agent to stabilize the metal ions to prevent their precipitation, and then stirring at a speed of 80r / min-100r / min for 20min-30min to evenly disperse the stabilizer to obtain a pre-liquid fertilizer; Step 4: Filter the pre-liquid fertilizer through a microporous filter membrane with a pore size of 0.2 μm-0.5 μm to remove tiny particles and insoluble impurities, and package it with a multi-layer barrier plastic packaging material to obtain liquid fertilizer.

[0018] In one embodiment of the present invention: in step one, when natural zeolite is activated at high temperature, the temperature is controlled at 500°C-600°C, and the activation time is 2h-3h, so that the internal structure of the zeolite is optimized, more active sites are generated, and it helps to efficiently adsorb heavy metal ions and macromolecular impurities.

[0019] In one embodiment of the present invention: in step 2, a specific oxidoreductase is screened from thermophilic bacteria in a hot spring, extreme environment samples are collected, and enriched and cultured in a selective culture medium containing vitamin C fermentation waste liquid, and single colonies are separated by a gradient dilution method. The enzyme activity of the single colonies is detected, and strains with high catalytic activity for organic macromolecular compounds in the waste liquid are screened, and the genes of the strains are extracted, and the strains are introduced into an Escherichia coli expression vector of a high-efficiency expression vector using genetic engineering technology. Fermentation production is carried out under fermentation conditions with glucose and yeast extract as the main nutrients, temperature 30°C-37°C, pH 6.5-7.5, and dissolved oxygen controlled at 5mg / L-10mg / L to obtain a specific oxidoreductase, and the conversion of benzene ring compounds in the vitamin C fermentation waste liquid is catalyzed by the specific oxidoreductase to improve the availability of fertilizer nutrients.

[0020] In one embodiment of the present invention: in step three, the amount of stabilizer added is 0.5-1 part, the antioxidant is extracted from ferrous sulfate waste residue generated in the industrial production of titanium dioxide by the method of acid dissolution and recrystallization, and the EDTA chelating agent is extracted from electroplating industry wastewater by ion exchange resin method.

[0021] In one embodiment of the present invention: in step one, the raw materials of the adsorbent, activated carbon and nano-adsorbent material, are specially treated. The activated carbon is activated by high-temperature steam and maintained at a temperature of 700°C-800°C for 2h-3h to increase the specific surface area of ​​the activated carbon and enhance the adsorption capacity of harmful substances in the waste liquid. The natural zeolite selected as the nano-adsorbent material is first pre-treated by acid leaching, and is soaked in a hydrochloric acid solution with a concentration of 3mol / L-5mol / L at 40°C-50°C for 1h-2h, and then subjected to a high-temperature activation treatment at 500°C-600°C for 2h-3h. The treated activated carbon and nano-adsorbent material are mixed in a ratio of 3:2.

[0022] In one embodiment of the present invention: in step 1, when adding the adsorbent, it is slowly added in batches, added once every 5 minutes to 10 minutes, and added to the reaction container in 3-4 times.

[0023] In one embodiment of the present invention: in step 2, the auxiliary chemical catalyst is a complex composed of a treated transition metal oxide and an organic complexing agent in a ratio of 2:1. The transition metal oxide is first ground and refined to a particle size of 50nm-100nm to increase its specific surface area and reaction activity. The organic complexing agent is purified to remove impurities and increase the purity to more than 99%. When adding the auxiliary chemical catalyst, it is dripped into the reaction container within 10min-15min in a uniform rate of dropwise addition, and the dripping speed is 0.5ml / min-1l / min.

[0024] In one embodiment of the present invention: in step three, during the process of adding the stabilizer, the adding speed of the stabilizer is controlled at 0.01-0.02 parts per minute, and the stirring intensity is controlled at 80r / min-100r / min, so that the stabilizer can be evenly and quickly mixed with the liquid fertilizer.

[0025] In one embodiment of the present invention: in step one, after the vitamin C fermentation waste liquid is placed in the reaction container, it is first preheated by surrounding the electric heating belt on the outside of the reaction container to slowly increase the temperature of the waste liquid to 25°C-30°C and maintain it for 10min-15min, so that the fluidity of the waste liquid is enhanced, which is conducive to better dispersion of the subsequent adsorbent. At the same time, after the adsorbent is added, the ultrasonic auxiliary device is started to use ultrasound to promote the full combination of the adsorbent with impurities and harmful substances in the waste liquid. The ultrasonic frequency is controlled at 30kHz-40kHz, and the action time is 20min-30min.

[0026] Example 1, please refer to the attached Figure 1 -Attached Figure 2 , take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring functions, first, by surrounding the outside of the reaction container with an electric heating belt, slowly raise the waste liquid temperature to 30°C and keep it for 15 minutes for preheating treatment, then, add a total of 8 parts of adsorbent every 5min-10min for 3-4 times, the adsorbent is composed of activated carbon treated with high-temperature steam activation at 800°C for 2h and natural zeolite treated with 5mol / L hydrochloric acid solution at 40°C for 1.5h and then at 600°C for 3h, accurately mixed in a ratio of 3:2, stirred at 80r / min at 40°C for 50min, and started the ultrasonic auxiliary device at the same time, using 30kHz ultrasonic waves for 30min to remove impurities and harmful substances, then, 5 parts of thermophilic bacteria screened from hot springs and produced by genetic engineering were uniformly added to the treated waste liquid. The specific oxidoreductase produced and 1.5 parts of an auxiliary chemical catalyst composed of a transition metal oxide with a particle size of 80 nm and an organic chelating agent with a purity of more than 99% in a ratio of 2:1 are reacted at a pH of 7 and a temperature of 35°C for 3 hours for conversion. After that, 1 part of a stabilizer composed of an antioxidant extracted from ferrous sulfate waste residue generated in the industrial production of titanium dioxide and an EDTA chelating agent extracted from electroplating industry wastewater using an ion exchange resin method in a ratio of 1:1 is added, the addition rate of the stabilizer is controlled at 0.02 parts per minute, and the mixture is stirred at a speed of 80 r / min for 30 minutes to uniformly disperse the stabilizer to obtain a pre-liquid fertilizer. Finally, the pre-liquid fertilizer is filtered through a microporous filtration membrane with a pore size of 0.5 μm to remove tiny particles and insoluble impurities, and is packaged with a multi-layer barrier plastic packaging material to obtain a liquid fertilizer.

[0027] Example 2, please refer to the attached Figure 1 -Attached Figure 2 , take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring functions, first, by surrounding the electric heating belt outside the reaction container, slowly raise the temperature of the waste liquid to 30°C and keep it for 15 minutes for preheating treatment, then, add a total of 8 parts of adsorbent every 10 minutes for 4 times, the adsorbent is composed of activated carbon maintained at 700°C for 1.5 hours and natural diatomaceous earth soaked in 4 mol / L hydrochloric acid solution at 35°C for 1 hour and then activated at 500°C for 2 hours in a ratio of 3:2, stir at 35°C at a speed of 70r / min for 40 minutes, start the ultrasonic auxiliary device at the same time, use 25kHz ultrasonic action for 25 minutes to remove impurities and harmful substances, then, add 4 parts of microorganisms from ordinary environment to the treated waste liquid at a uniform speed The oxidoreductase screened from the organism and produced by traditional fermentation and 1 part of the auxiliary chemical catalyst composed of a transition metal oxide with a particle size of 60nm and an organic chelating agent with a purity of 95% in a ratio of 2:1 are reacted for 2.5 hours at a pH value of 6.5 and a temperature of 30°C for conversion. After that, 0.8 parts of a stabilizer composed of an antioxidant extracted from industrial production wastewater and an EDTA chelating agent extracted from electroplating industry wastewater using a conventional extraction method in a ratio of 1:1 are added. The addition rate of the stabilizer is controlled at 0.015 parts per minute, and the mixture is stirred at a speed of 70r / min for 25 minutes to uniformly disperse the stabilizer to obtain a pre-liquid fertilizer. Finally, the pre-liquid fertilizer is filtered through a microporous filtration membrane with a pore size of 0.4μm to remove tiny particles and insoluble impurities to obtain a liquid fertilizer.

[0028] Example 3, please refer to the attached Figure 1 -Attached Figure 2, take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring function, then, add a total of 8 parts of adsorbent every 5min-10min for 3-4 times, the adsorbent is composed of activated carbon treated with high-temperature steam activation at 600℃ for 1h and natural kaolin treated with 3mol / L hydrochloric acid solution at 30℃ for 0.5h and then activated at 400℃ for 1h in a ratio of 3:2, stir at 30℃ at a speed of 60r / min for 30min, start the ultrasonic auxiliary device at the same time, use 20kHz ultrasonic action for 20min to remove impurities and harmful substances, then, add 3 parts of redox produced by simple fermentation screened from general soil to the treated waste liquid at a uniform speed The enzyme and 0.8 parts of an auxiliary chemical catalyst composed of a transition metal oxide with a particle size of 50 nm and an organic chelating agent with a purity of 90% in a ratio of 2:1 are reacted at a pH of 6 and a temperature of 25°C for 2 hours for conversion. After that, 0.6 parts of a stabilizer composed of an antioxidant extracted from a common plant and an EDTA chelating agent extracted from electroplating industry wastewater using a traditional extraction method in a ratio of 1:1 are added. The addition rate of the stabilizer is controlled at 0.01 parts per minute, and the mixture is stirred at a speed of 60 r / min for 20 minutes to uniformly disperse the stabilizer to obtain a pre-liquid fertilizer. Finally, the pre-liquid fertilizer is filtered through a microporous filtration membrane with a pore size of 0.3 μm to remove tiny particles and insoluble impurities to obtain a liquid fertilizer.

[0029] Take the same equal parts of the liquid fertilizers prepared in Example 1, Example 2 and Example 3, plant seedlings of the same variety, black soil samples collected from the same sampling site, and prepare the testing instruments: element analyzer, heavy metal detector, pH meter; Experimental steps: Step 1: Divide the seedlings of the same species into three groups and plant them in soil with the same conditions; Step 2: applying the liquid fertilizer prepared in Example 1, Example 2, and Example 3 to the three groups of soils respectively, with the same fertilizer amount; Step 3: Under the same growing conditions, regularly observe and record the growth of the plants, including plant height, leaf number, color, and fruit yield; Step 4: After a certain growth period, collect plant samples and soil samples and test them separately: Use element analyzer to detect the content of various nutrient elements in plant samples and evaluate the nutritional quality index and utilization rate of fertilizers; Fertilizer nutritional quality index = (detected nitrogen content × nitrogen weight + detected phosphorus content × phosphorus weight + detected potassium content × potassium weight) / total weight; Fertilizer utilization rate = (nutrient content in plants after fertilization - nutrient content in plants before fertilization) / fertilizer amount × 100%; Use a heavy metal detector to detect the content of heavy metals in soil samples, and use a pH meter to detect the pH value of the soil to comprehensively assess the degree of environmental pollution caused by the waste liquid; Step 5. At the same time, the liquid fertilizers prepared in Example 1, Example 2, and Example 3 are stored separately, and samples are taken at different time points to detect changes in their nutrient components, changes in pH values, and whether precipitation and stratification occur, so as to evaluate the storage stability and storage time of the liquid fertilizers.

[0030] Plant growth: Plant height (average): The plant height value reflects the growth height of the plant. A higher plant height indicates good plant growth, which means that the fertilizer provides sufficient nutrients to support plant growth. Number of leaves (average): The number of leaves is related to the photosynthesis capacity of the plant. More leaves can absorb more sunlight, perform photosynthesis, and provide energy and nutrients for plant growth. Fruit yield (average): Fruit yield is directly related to the economic value of crops. Higher fruit yield means that fertilizers can help increase crop yields, which is of great significance to agricultural production. Fertilizer nutritional quality: Nitrogen content, phosphorus content, potassium content: These nutrients are necessary for plant growth. Their content reflects the richness of nutrients in the fertilizer. A higher content usually means that the fertilizer has better nutritional quality and can provide sufficient nutrients for plants. Environmental pollution caused by wastewater (heavy metal content, soil pH value): Heavy metal content: The accumulation of heavy metals in the soil will harm the ecological environment and affect soil quality and ecological balance. Lower heavy metal content means that the waste liquid has less pollution to the environment and the soil is healthier; Soil pH: Soil pH has an important influence on plant growth and soil microbial activity. The appropriate pH range helps plants absorb nutrients and maintain the stability of the soil ecosystem. Storage stability: Storage time: refers to the length of time that the liquid fertilizer maintains stable quality during storage; Changes in nutrients: The loss rate of nutrients reflects the retention of nutrients during storage. A lower loss rate indicates better storage stability of the fertilizer. Whether there is sedimentation or stratification: The occurrence of these phenomena indicates that there may be problems with the physical stability of the fertilizer, which may affect the use effect and quality of the fertilizer.

[0031] As attached Figure 2As shown, through the above tests and records, the differences in various aspects between the liquid fertilizer prepared by the present invention and the liquid fertilizer of the control group can be comprehensively evaluated, thereby effectively proving the significant advantages of the process of Example 1 in improving the nutritional quality of fertilizers, reducing environmental pollution and extending storage time. The lower heavy metal content indicates that the liquid fertilizer has less heavy metal pollution to the soil during use, which helps to protect the health of the soil ecosystem, reduce the accumulation of heavy metals in the soil, and reduce the potential harm to soil microorganisms, plants and other organisms. At the same time, it is also conducive to producing safe and pollution-free agricultural products and ensuring the quality and safety of agricultural products. The soil pH value of Example 1 is 7.2, which is in a more suitable range. The suitable soil pH value helps to maintain the effectiveness of nutrients in the soil and the activity of microorganisms, and promotes the absorption and utilization of nutrients by plants. This is very important for agricultural production, and can improve the utilization rate of fertilizers, promote plant growth and development, and increase the yield and quality of crops.

[0032] Although the present invention is disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A process for preparing liquid fertilizer using vitamin C fermentation waste liquid, characterized in that: The process comprises the following specific steps: Step 1, take 100 parts of vitamin C fermentation waste liquid and place it in a reaction container with constant temperature heating and stirring functions, first perform preheating treatment, and add 5-10 parts of adsorbent after preheating. The adsorbent is made of specially treated activated carbon and nano adsorption material mixed in a ratio of 3:

2. The nano adsorption material uses low-cost natural zeolite and is activated at 500°C-600°C for 2h-3h. The activated zeolite adsorbs heavy metal ions and macromolecular organic impurities in the waste liquid, and stirs at a speed of 60r / min-80r / min for 30min-60min at 30°C-40°C to remove impurities and harmful substances. Step 2: Add 3-5 parts of a specific oxidoreductase and 1-2 parts of an auxiliary chemical catalyst to the treated waste liquid, screen and prepare a specific oxidoreductase from an extreme environment microorganism through genetic engineering production, which has high catalytic activity for the difficult-to-degrade benzene ring-containing compounds of complex organic macromolecular compounds in the waste liquid, and react for 2h-3h for conversion under the conditions of pH 6-8 and temperature 35°C-40°C; Step 3: adding a stabilizer composed of an antioxidant and an EDTA (ethylenediaminetetraacetic acid) chelating agent in a ratio of 1:1, using the antioxidant to prevent the nutrients in the fertilizer from being oxidized, and using the chelating agent to stabilize the metal ions to prevent their precipitation, and then stirring at a speed of 80r / min-100r / min for 20min-30min to evenly disperse the stabilizer to obtain a pre-liquid fertilizer; Step 4: Filter the pre-liquid fertilizer through a microporous filter membrane with a pore size of 0.2 μm-0.5 μm to remove tiny particles and insoluble impurities, and package it with a multi-layer barrier plastic packaging material to obtain liquid fertilizer.

2. A process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 1, when the natural zeolite is activated at high temperature, the temperature is controlled at 500° C.-600° C., and the activation time is 2 h-3 h.

3. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 2, a specific oxidoreductase is screened from thermophilic bacteria in hot springs, extreme environment samples are collected, enriched and cultured in a selective culture medium containing vitamin C fermentation waste liquid, single colonies are separated by a gradient dilution method, enzyme activity of the single colonies is detected, strains with high catalytic activity for organic macromolecular compounds in the waste liquid are screened, genes of the strains are extracted, and the strains are introduced into an Escherichia coli expression vector of a high-efficiency expression vector using genetic engineering technology. Fermentation production is carried out under fermentation conditions with glucose and yeast extract as main nutrients, temperature of 30°C-37°C, pH 6.5-7.5, and dissolved oxygen controlled at 5mg / L-10mg / L to obtain a specific oxidoreductase, and the conversion of benzene ring compounds in the vitamin C fermentation waste liquid is catalyzed by the specific oxidoreductase.

4. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step three, the amount of stabilizer added is 0.5-1 part, the antioxidant is extracted from ferrous sulfate waste residue generated in the industrial production of titanium dioxide by acid dissolution and recrystallization, and the EDTA chelating agent is extracted from electroplating industry wastewater by ion exchange resin method.

5. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 1, the raw materials of the adsorbent, activated carbon and nano-adsorbent material, are treated in a special manner. The activated carbon is activated by high-temperature steam and maintained at a temperature of 700°C-800°C for 2h-3h. The natural zeolite selected as the nano-adsorbent material is first pre-treated by acid leaching, and is soaked in a hydrochloric acid solution with a concentration of 3mol / L-5mol / L at 40°C-50°C for 1h-2h, and then activated at a high temperature of 500°C-600°C for 2h-3h. The treated activated carbon and nano-adsorbent material are mixed in a ratio of 3:

2.

6. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 1, when adding the adsorbent, it is added slowly in batches, once every 5 minutes to 10 minutes, and added to the reaction container in 3-4 times.

7. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 2, the auxiliary chemical catalyst is a complex composed of a treated transition metal oxide and an organic complexing agent in a ratio of 2:

1. The transition metal oxide is first ground and refined to a particle size of 50nm-100nm to increase its specific surface area and reaction activity. The organic complexing agent is purified to remove impurities and increase the purity to more than 99%. When adding the auxiliary chemical catalyst, it is dripped into the reaction container within 10min-15min in a uniform speed dropwise manner, and the dripping speed is 0.5ml / min-1l / min.

8. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 3, during the process of adding the stabilizer, the adding speed of the stabilizer is controlled at 0.01-0.02 parts per minute, and the stirring intensity is controlled at 80r / min-100r / min, so that the stabilizer can be evenly and quickly mixed with the liquid fertilizer.

9. The process for preparing liquid fertilizer using vitamin C fermentation waste liquid according to claim 1, characterized in that: In the step 1, after the vitamin C fermentation waste liquid is placed in the reaction container, it is first preheated by slowly raising the temperature of the waste liquid to 25°C-30°C by surrounding an electric heating belt on the outside of the reaction container and maintaining it for 10min-15min. At the same time, after the adsorbent is added, the ultrasonic auxiliary device is started to use ultrasound to promote the full combination of the adsorbent with impurities and harmful substances in the waste liquid. The ultrasonic frequency is controlled at 30kHz-40kHz, and the action time is 20min-30min.

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