Plant-based efficient water body nitrite bio-adsorbent and preparation method thereof
By using modified plant-based materials to prepare water nitrite bioadsorbents with high specific surface area, the problems of high dosage and cost of existing adsorbents are solved, and the effect of efficient removal of nitrite in water is achieved.
Patent Information
- Application Number
- CN202411684701.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-03-11
AI Technical Summary
The existing nitrite adsorbents have high usage and cost problems in removing nitrites in water, and it is difficult to effectively reduce the concentration of nitrites in water.
Plant-based materials, such as neem leaves, Buddha-head fruit leaves, guava leaves, orange peels and mango leaves, are prepared with high specific surface area of plant-based water nitrite biosorbents through pre-drying, soaking, modification treatment and ball milling.
A higher nitrite removal rate was achieved. The removal rate of nitrite by biosorbent prepared from neem leaves, guava leaves, orange peels and mango leaves exceeded 70%. Among them, the biosorbent of guava leaves and guava leaves can reach 100% adsorption rate at 5g, and is low in cost and easy to obtain raw materials.
Smart Images
Figure CN119588319A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of environmental protection, and in particular relates to a plant-based high-efficiency water nitrite biosorbent and a preparation method thereof. Background Art
[0002] Nitrite is often found in environmental waters and sewage due to inadequate oxidation of nitrogen compounds. Nitrite pollution is mainly caused by industrial wastewater and the use of agricultural fertilizers. These pathways can produce wastewater containing dangerous levels of nitrite. Nitrite in the environment can be actively absorbed by aquatic organisms through the gill epithelium, leading to significantly elevated concentrations in body fluids. Studies have shown that nitrite causes physiological disorders in fish and crustaceans, seriously affecting their reproductive cycles. Nitrite can be converted into nitrosamines (strong carcinogens) in the human body. Long-term intake of foods containing nitrite may increase the risk of cancers such as gastric cancer and intestinal cancer. Long-term intake of foods containing nitrite by pregnant women may cause adverse effects on the fetus, such as developmental delay and deformity.
[0003] Common nitrite adsorbents include zeolite powder, activated carbon, metal oxides, silica gel, sepiolite, etc. These adsorbents absorb nitrite in water into their structures through physical adsorption, thereby reducing the nitrite concentration in water. These adsorbents are widely used in production with good effects, but their high dosage and cost are the main drawbacks of these common adsorbents. Summary of the invention
[0004] In view of the defects of the prior art, the object of the present invention is to provide a plant-based high-efficiency water nitrite biosorbent and a preparation method thereof.
[0005] To achieve the above purpose, the solution adopted by the present invention is as follows:
[0006] In a first aspect, the present invention provides a method for preparing a plant-based high-efficiency water nitrite biosorbent, comprising the following steps:
[0007] Step (1), drying the plant branches and leaves or plant epidermis in advance, first soaking them in distilled water for purification, then soaking them in 0.5%-1% w / w dilute hydrochloric acid for modification, and then heating them until the water is completely evaporated;
[0008] Step (2), putting the plant branches and leaves or plant epidermis obtained in step (1) into a grinding device for grinding, and then repeatedly rinsing the plant-based powder with distilled water again until the rinsing water no longer contains impurities, thereby obtaining an adsorbent powder.
[0009] Preferably, the plant branches and leaves or plant epidermis are selected from one or more of neem leaves, guava leaves, orange peels and mango leaves.
[0010] According to the preparation method of the present invention, neem leaves, guava leaves, orange peels or mango leaves are preferably used as raw materials for the plant-based water nitrite biosorbent. Such materials are commonly grown in Asia, especially in China, and have higher selectivity and lower price than traditional activated carbon adsorbents, and have good economic benefits and promotion potential.
[0011] Preferably, in step (1), the pre-drying time is 3-6 days to ensure that the moisture in the plant branches and leaves or plant epidermis is basically lost; the soaking time in distilled water is 30-60 minutes to remove impurities on the plant branches and leaves or plant epidermis; the soaking time in 0.5%-1% w / w dilute hydrochloric acid is 15-30 minutes to make the fibrous tissue of the plant branches and leaves or plant epidermis loose.
[0012] According to the preparation method of the present invention, in this step, 0.5%-1% w / w dilute hydrochloric acid is used to modify the plant branches and leaves or plant epidermis, which can not only destroy the crystallinity of the fibrous tissue of the plant branches and leaves or plant epidermis, but also destroy the keratin and wax layers of the fibrous tissue, so that the adsorbent is exposed to the outside, thereby increasing the specific surface area of the powder after subsequent grinding, thereby increasing the contact area with the adsorbed substance and improving the adsorption performance.
[0013] Preferably, in step (2), the grinding device is a ball mill, the particle size of the plant-based powder after ball milling is 50-100 mm, and the specific surface area of the plant-based powder after ball milling is 1870-2090 m 2 / g, and the mass of the finally obtained adsorbent powder is not less than 500g.
[0014] According to the preparation method of the present invention, in this step, the plant branches and leaves or plant epidermis obtained in step (1) is put into a ball mill for grinding. Compared with a commonly used grinder, the grinding efficiency of the ball mill is higher, and the particle size of the plant-based powder after grinding is smaller and the specific surface area is larger. Dry ball milling or wet ball milling can be used, the ball milling speed can be 300-500rpm, and the ball milling time can be 30-60min.
[0015] In a second aspect, the present invention also provides a plant-based high-efficiency water nitrite biosorbent obtained by the preparation method as described above.
[0016] Preferably, the removal effect of nitrite by the plant-based high-efficiency water nitrite biosorbent is analyzed by chemical indicator colorimetry, and the results show that when the dosage of the biosorbent is 5g, the removal rate of nitrite by the biosorbent prepared from neem leaves, guava leaves, orange peels and mango leaves is greater than 70%, among which the adsorption rate of nitrite by the biosorbent prepared from guava leaves and guava leaves can reach 100% when the dosage is 5g.
[0017] Preferably, the chemical indicator colorimetric method is used to analyze the removal effect of the plant-based high-efficiency water nitrite biosorbent on nitrite, which comprises the following steps:
[0018] S1, prepare indicator solution: add 5 drops of nitrite indicator to 5 ml of water sample;
[0019] S2, evenly mix 1 mg of nitrite into 1 L of distilled water, and divide the water sample into 5 equal parts, add the indicator solution prepared in step S1, and compare with the nitrite colorimetric card to obtain the nitrite background value;
[0020] S3, 1 mg of nitrite is evenly mixed into 1 L of distilled water, and the water sample is divided into 5 portions, 1 g, 2 g, 3 g, 4 g, and 5 g of the above-mentioned biosorbent are added to the 5 water samples, and fully mixed for 1-2 hours. After adding the indicator solution prepared in step S1, the final nitrite value is obtained by comparing with the nitrite colorimetric card, and the nitrite removal rate is obtained according to the formula (nitrite background value-nitrite final value) / nitrite background value×100%.
[0021] Preferably, in step S1, the main components of the nitrite indicator are 50% w / w p-aminobenzenesulfonamide and 50% w / w naphthylethylenediamine hydrochloride.
[0022] Preferably, in step S2, the main components of the nitrite are 70% w / w sodium nitrite, 20% w / w potassium nitrite and 10% w / w calcium nitrite.
[0023] Preferably, in step S3, the mixing speed is 80-100 rpm, the solution pH is 7-8, and the mixing temperature is 25-30°C.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] The plant-based high-efficiency water nitrite biosorbent prepared by the present invention has a larger specific surface area than traditional biosorbents, and can effectively remove nitrite in water. The five raw materials of neem leaves, custard apple leaves, guava leaves, orange peels and mango leaves can all achieve a removal rate of more than 70%, among which the biosorbent prepared from custard apple leaves and custard apple leaves can achieve an adsorption effect of 100% on nitrite in sewage. The branches, leaves or epidermis of the five plants are all selected, the raw material cost is extremely low, the raw material sources are diverse and easy to obtain, and can also be obtained from fallen leaves and domestic garbage collected daily, thereby realizing efficient resource utilization of domestic garbage and having good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a scanning electron microscope image of the plant-based high-efficiency water nitrite biosorbent involved in the present invention.
[0027] Figure 2 The figure is a graph showing the change in nitrite removal rate of the plant-based high-efficiency water nitrite biosorbent prepared from different raw materials involved in the present invention as a function of the amount of the sorbent used. DETAILED DESCRIPTION
[0028] The present invention is further described below in conjunction with examples, the purpose of which is to better understand the content of the present invention and reflect the essential characteristics of the present invention, so the examples cited should not be regarded as limiting the scope of protection of the present invention. It is also particularly pointed out here that the specific experimental methods and equipment involved in the examples are conventional methods or implemented under the conditions recommended by the manufacturer's instructions unless otherwise specified, and the reagents involved are commercially available unless otherwise specified.
[0029] Example 1
[0030] This embodiment provides a plant-based high-efficiency water nitrite biosorbent, the preparation method of which comprises the following steps:
[0031] Step S1: 2 kg of neem leaves are pre-dried, first soaked in distilled water for 45 minutes for purification to remove impurities on plant branches and leaves or plant epidermis, then soaked in 1% w / w dilute hydrochloric acid for 20 minutes for modification to make the fibrous tissue of the plant branches and leaves or plant epidermis loose, and then heated until the water is completely evaporated.
[0032] Step S2: The dehydrated plant epidermis is put into a ball mill and ground to 900 g, with a specific surface area of 1910 m 2 / g, and the ground product is repeatedly rinsed with distilled water again until the rinse water no longer contains impurities.
[0033] Step S3: The adsorbent powder is placed in a plastic reagent bottle for storage, and a nitrite adsorption and removal test is performed on the bottle to verify the adsorbent effect.
[0034] Example 2
[0035] This embodiment provides a plant-based high-efficiency water nitrite biosorbent, the preparation method of which comprises the following steps:
[0036] Step S1: 2 kg of chrysanthemum leaves are dried in advance, first soaked in distilled water for 50 minutes for purification to remove impurities on plant branches and leaves or plant epidermis, then soaked in 0.5% w / w dilute hydrochloric acid for 25 minutes for modification to make the fibrous tissue of the plant branches and leaves or plant epidermis loose, and then heated until the water is completely evaporated.
[0037] Step S2: The dehydrated plant epidermis is put into a ball mill and ground to 850 g, with a specific surface area of 1960 m 2 / g, and the ground product is repeatedly rinsed with distilled water again until the rinse water no longer contains impurities.
[0038] Step S3: The adsorbent powder is placed in a plastic reagent bottle for storage, and a nitrite adsorption and removal test is performed on the bottle to verify the adsorbent effect.
[0039] Example 3
[0040] This embodiment provides a plant-based high-efficiency water nitrite biosorbent, the preparation method of which comprises the following steps:
[0041] Step S1: 2 kg of guava leaves are dried in advance, first soaked in distilled water for 60 minutes for purification to remove impurities on plant branches and leaves or plant epidermis, then soaked in 1% w / w dilute hydrochloric acid for 30 minutes for modification to make the fibrous tissue of the plant branches and leaves or plant epidermis loose, and then heated until the water is completely evaporated.
[0042] Step S2: The dehydrated plant epidermis is put into a ball mill and ground to 800 g, with a specific surface area of 2000 m 2 / g, and the ground product is repeatedly rinsed with distilled water again until the rinse water no longer contains impurities.
[0043] Step S3: The adsorbent powder is placed in a plastic reagent bottle for storage, and a nitrite adsorption and removal test is performed on the bottle to verify the adsorbent effect.
[0044] Example 4
[0045] This embodiment provides a plant-based high-efficiency water nitrite biosorbent, the preparation method of which comprises the following steps:
[0046] Step S1: 2 kg of orange peels are pre-dried, first soaked in distilled water for 30 minutes for purification to remove impurities on plant branches and leaves or plant epidermis, then soaked in 1% w / w dilute hydrochloric acid for 15 minutes for modification to make the fibrous tissue of the plant branches and leaves or plant epidermis loose, and then heated until the water is completely evaporated.
[0047] Step S2: The dehydrated plant epidermis is put into a ball mill and ground to 950 g, with a specific surface area of 2040 m 2 / g, and the ground product is repeatedly rinsed with distilled water again until the rinse water no longer contains impurities.
[0048] Step S3: The adsorbent powder is placed in a plastic reagent bottle for storage, and a nitrite adsorption and removal test is performed on the bottle to verify the adsorbent effect.
[0049] Example 5
[0050] This embodiment provides a plant-based high-efficiency water nitrite biosorbent, the preparation method of which comprises the following steps:
[0051] Step S1: 2 kg of mango leaves are pre-dried, first soaked in distilled water for 40 minutes for purification to remove impurities on plant branches and leaves or plant epidermis, then soaked in 0.5% w / w dilute hydrochloric acid for 20 minutes for modification to make the fibrous tissue of the plant branches and leaves or plant epidermis loose, and then heated until the water is completely evaporated.
[0052] Step S2: The dehydrated plant epidermis is put into a ball mill and ground to 1000 g, with a specific surface area of 1870 m 2 / g, and the ground product is repeatedly rinsed with distilled water again until the rinse water no longer contains impurities.
[0053] Step S3: The adsorbent powder is placed in a plastic reagent bottle for storage, and a nitrite adsorption and removal test is performed on the bottle to verify the adsorbent effect.
[0054] Detection of the adsorption and removal effect of nitrite by the biosorbent prepared in Examples 1-5:
[0055] The detection steps include:
[0056] S1, prepare indicator solution: add 5 drops of nitrite indicator to 5 ml of water sample, the main components of nitrite indicator are 50% w / w p-aminobenzenesulfonamide and 50% w / w naphthylethylenediamine hydrochloride;
[0057] S2, evenly mix 1 mg of nitrite into 1 L of distilled water, and divide the water sample into 5 equal parts, add the indicator solution prepared in step S1, and compare with the nitrite colorimetric card to obtain the nitrite background value;
[0058] S3, 1 mg of nitrite is uniformly mixed into 1 L of distilled water, and the water sample is divided into 5 portions, 1 g, 2 g, 3 g, 4 g, and 5 g of the biosorbent prepared in the above embodiment are added to the 5 portions of the water sample, and fully mixed for 1.5 h, the mixing speed is 80-100 rpm, the solution pH value is 7-8, the mixing temperature is 25-30 ° C, after adding the indicator solution prepared in step S1, the final nitrite value is obtained by comparing the nitrite colorimetric card, and the nitrite removal rate is obtained according to the formula (nitrite background value-nitrite final value) / nitrite background value×100%.
[0059] In the above detection steps, the main components of the nitrite used are 70% w / w sodium nitrite, 20% w / w potassium nitrite and 10% w / w calcium nitrite.
[0060] The adsorption removal rate of nitrite by the biosorbent prepared in Examples 1-5 varies with the amount of adsorbent used. Figure 2 shown.
[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for preparing a plant-based high-efficiency water nitrite biosorbent, characterized in that: The steps include: Step (1), drying the plant branches and leaves or plant epidermis in advance, first soaking them in distilled water for purification, then soaking them in 0.5%-1% w / w dilute hydrochloric acid for modification, and then heating them until the water is completely evaporated; Step (2), putting the plant branches and leaves or plant epidermis obtained in step (1) into a grinding device for grinding, and then repeatedly rinsing the plant-based powder with distilled water again until the rinsing water no longer contains impurities, thereby obtaining an adsorbent powder.
2. The preparation method according to claim 1, characterized in that: The plant branches and leaves or plant epidermis are selected from one or more of neem leaves, guava leaves, orange peels and mango leaves.
3. The preparation method according to claim 1, characterized in that: In step (1), the pre-drying time is 3-6 days to ensure that the moisture in the plant branches and leaves or plant epidermis is basically lost; the soaking time in distilled water is 30-60 minutes to remove impurities on the plant branches and leaves or plant epidermis; the soaking time in 0.5%-1% w / w dilute hydrochloric acid is 15-30 minutes to make the fibrous tissue of the plant branches and leaves or plant epidermis loose.
4. The preparation method according to claim 1, characterized in that: In step (2), the grinding device is a ball mill, the particle size of the plant-based powder after ball milling is 50-100 mm, and the specific surface area of the plant-based powder after ball milling is 1870-2090 m 2 / g, and the mass of the finally obtained adsorbent powder is not less than 500g.
5. A plant-based high-efficiency water nitrite biosorbent obtained by the preparation method according to any one of claims 1 to 4.
6. The plant-based high-efficiency water nitrite biosorbent according to claim 5, characterized in that: The results of chemical indicator colorimetric analysis of the nitrite removal effect of the plant-based high-efficiency water nitrite biosorbent show that when the dosage of the biosorbent is 5g, the nitrite removal rate of the biosorbent prepared from neem leaves, guava leaves, orange peels and mango leaves is greater than 70%, among which the adsorption rate of nitrite of the biosorbent prepared from guava leaves and guava leaves can reach 100% when the dosage is 5g.
7. The plant-based high-efficiency water nitrite biosorbent according to claim 6, characterized in that: The chemical indicator colorimetric method is used to analyze the removal effect of the plant-based high-efficiency water nitrite biosorbent on nitrite, which includes the following steps: S1, prepare indicator solution: add 5 drops of nitrite indicator to 5 ml of water sample; S2, evenly mix 1 mg of nitrite into 1 L of distilled water, and divide the water sample into 5 equal parts, add the indicator solution prepared in step S1, and compare with the nitrite colorimetric card to obtain the nitrite background value; S3, 1 mg of nitrite is uniformly mixed into 1 L of distilled water, and the water sample is divided into 5 portions, 1 g, 2 g, 3 g, 4 g, and 5 g of the biosorbent as claimed in claim 5 are added to the 5 portions of the water sample, and are fully mixed for 1-2 hours. After adding the indicator solution prepared in step S1, the final nitrite value is obtained by comparing with the nitrite colorimetric card, and the nitrite removal rate is obtained according to the formula (nitrite background value-nitrite final value) / nitrite background value×100%.
8. The plant-based high-efficiency water nitrite biosorbent according to claim 7, characterized in that: In step S1, the main components of the nitrite indicator are 50% w / w p-aminobenzenesulfonamide and 50% w / w naphthylethylenediamine hydrochloride.
9. The plant-based high-efficiency water nitrite biosorbent according to claim 7, characterized in that: In step S2, the main components of the nitrite are 70% w / w sodium nitrite, 20% w / w potassium nitrite and 10% w / w calcium nitrite.
10. The plant-based high-efficiency water nitrite biosorbent according to claim 7, characterized in that: In step S3, the mixing speed is 80-100 rpm, the solution pH is 7-8, and the mixing temperature is 25-30°C.