Method for removing dye in water body

Abstract

The invention provides a method for removing dye in a water body, and relates to the technical field of wastewater treatment. The method for removing the dye in the water body comprises the following steps: adding a dye aqueous solution into a haematococcus pluvialis culture medium to obtain a mixed solution, and culturing to obtain the dye in the water body. According to the method for removing the dye in the water body, the dye in the water body is effectively removed through a biological method, the ecological environment is improved, and restoration of a degraded water ecological system is promoted.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for removing dyes from water. Background Technology

[0002] Synthetic dyes from industries such as textiles, printing, and painting, if discharged directly without adequate treatment, become significant chemical pollutants, damaging freshwater ecosystems. These pollutants easily accumulate in organisms, are stable to oxidants, and are difficult to degrade, seriously threatening aquatic safety and human health. For example, untreated reactive dyes can block sunlight from entering water bodies, reducing photosynthesis and dissolved oxygen levels, and may also trigger kidney disease and allergic reactions in humans. Therefore, removing these pollutants from water bodies is a primary task in water environmental protection.

[0003] To address this problem, physical, chemical, and biological technologies have been employed to remove harmful dyes from industrial wastewater. While physical methods (such as membrane separation and adsorption) are effective, they suffer from drawbacks such as high operating costs and low treatment capacity. Chemical methods (such as photocatalysis and oxidation), while offering high decolorization efficiency and low cost and gradually replacing physical methods, are prone to generating secondary pollution, limiting their large-scale application. Therefore, researchers have turned to efficient, environmentally friendly, low-cost, and readily available biological treatment methods. In recent years, the adsorption or biotransformation of reactive dyes and heavy metals by microorganisms such as bacteria, fungi, and algae has become a research hotspot. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes a method for removing dyes from water.

[0005] The present invention proposes a method for removing dye from water, which includes adding an aqueous dye solution to a Haematococcus pluvialis culture medium to obtain a mixed solution, and then culturing it to obtain the final product.

[0006] Preferably, the dye is selected from one or more of methylene blue, chrome blue SE, chrome black T, basic yellow, and methyl orange.

[0007] Preferably, the concentration of the dye in the mixed solution is 0.5~10 mg / L.

[0008] Preferably, the dye aqueous solution can also be a dye aqueous solution filtered through a sterile filter membrane.

[0009] Preferably, the Haematococcus pluvialis species numbered FACHB-712 is purchased from the Freshwater Algae Culture Collection of the Chinese Academy of Sciences.

[0010] Preferably, the number of Haematococcus pluvialis cells in the Haematococcus pluvialis culture medium is 1×10⁻⁶. 6 ~2×10 7 cells / mL.

[0011] Preferably, the method for preparing the Haematococcus pluvialis culture medium includes the following steps: culturing Haematococcus pluvialis on BBM medium under a light intensity of 30-60 μmol photons / m². -2 s -1 The cycle is 12 hours during the day and 12 hours at night, and the culture temperature is 25±1℃.

[0012] More preferably, the BBM culture medium comprises: NaNO3, NaCl, K2HPO4, KH2PO4, H3BO3, EDTA, Co(NO3)2·6H2O, CuSO4·5H2O, MnCl2·4H2O, ZnSO4·7H2O, MoO3, MgSO4·7H2O, CaCl2·2H2O, FeSO4·7H2O, and water.

[0013] Preferably, the concentration of dye in the mixed solution is detected during the culture process.

[0014] Detecting the concentration of dye in a mixed solution helps determine the extent of dye removal from the water.

[0015] Preferably, the number of Haematococcus pluvialis cells in the mixed solution is detected during the culture process.

[0016] Detecting the number of Haematococcus pluvialis cells helps determine the cell proliferation rate of Haematococcus pluvialis.

[0017] Preferably, the culture process further includes detecting the absorption values ​​of carotenoids and chlorophyll in the mixed solution of Haematococcus pluvialis.

[0018] The changes in the absorption values ​​of carotenoids (470nm) and chlorophyll (685nm) within Haematococcus pluvialis cells can more accurately reflect the changes in pigment content within algal cells; thus, the effects of dyes on the growth of Haematococcus pluvialis can be determined.

[0019] Preferably, the cultivation conditions include: a cultivation temperature of 24~30℃; a cultivation light intensity of 1000~3000 lux; and a cultivation light-dark ratio of 10~14h:10~14h.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention utilizes Haematococcus pluvialis to remove dyes from water. The dyes act as photosensitizers, inducing oxidative stress and triggering the algae to transform from vegetative cells into red cysts. The transformed algal cells then accumulate carotenoids, significantly improving dye removal efficiency. This provides a rapid and efficient novel screening strategy for quickly identifying potential microalgae for removing recalcitrant dyes from wastewater. Detailed Implementation

[0022] The technical solution of the present invention will be described in detail through specific embodiments.

[0023] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0024] Example 1

[0025] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 6 A mixed solution of methylene blue was added to the culture medium of the single-celled green alga Haematococcus pluvialis with a concentration of 0.5 mg / L. The mixture was then cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0026] Example 2

[0027] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 6 A mixed solution of methylene blue was added to the culture medium of the single-celled green alga Haematococcus pluvialis with a concentration of 1 mg / L. The solution was then cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0028] Example 3

[0029] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 6 A mixed solution of methylene blue was added to the culture medium of the single-celled green alga Haematococcus pluvialis with a concentration of 5 mg / L. The mixture was then cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0030] Example 4

[0031] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 6 A mixed solution of methylene blue was added to the culture medium of the single-celled green alga Haematococcus pluvialis with a concentration of 10 mg / L. The mixture was then incubated in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0032] Example 5

[0033] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 7 A mixed solution of Chrome Blue SE was added to the culture medium of single-celled green algae Haematococcus pluvialis at a concentration of 1 mg / L. The solution was then cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0034] Example 6

[0035] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 7 A mixed solution of Eriochrome Black T was added to the culture medium of single-celled green algae Haematococcus pluvialis at a concentration of 1 mg / L. The solution was then cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light / dark cycle, with manual shaking 2-3 times daily for 24 days.

[0036] Example 7

[0037] A method for removing dye from water includes adding dye to a solution with a concentration of 1.5 × 10⁻⁶. 6 A mixed solution of Basic Yellow 11 was obtained by adding Basic Yellow 11 aqueous solution to the culture medium of single-celled green algae Haematococcus pluvialis at a concentration of 5 mg / L. The solution was cultured in a light incubator at 2000 lux, 25±0.5℃, and a 12h / 12h light-dark cycle, with manual shaking 2-3 times a day for 24 days.

[0038] The method for preparing the culture medium for the single-celled green algae Haematococcus pluvialis includes the following steps: culturing the single-celled green algae Haematococcus pluvialis on BBM medium under a light intensity of 50 μmol photons / m². -2 s -1The cycle is 12 hours during the day and 12 hours at night, and the culture temperature is 25±1℃. Specifically, the BBM medium contains: 0.25 g / L NaNO3, 0.025 g / L NaCl, 0.075 g / L K2HPO4, 0.175 g / L KH2PO4, 0.1865 g / L H3BO3, 0.05 g / L EDTA, 0.00049 g / L Co(NO3)2·6H2O, 0.00157 g / L CuSO4·5H2O, 0.00144 g / L MnCl2·4H2O, 0.00882 g / L ZnSO4·7H2O, 0.00071 g / L MoO3, 0.075 g / L MgSO4·7H2O, 0.025 g / L CaCl2·2H2O, 0.005 g / L FeSO4·7H2O, with the remainder being water. Sterilize at 121℃ with high-pressure steam for 30 minutes, then set aside.

[0039] Determination of the methylene blue (MB) standard curve: Prepare methylene blue solutions with concentration gradients of 0 mg / L, 0.5 mg / L, 1 mg / L, 5 mg / L, and 10 mg / L. Preheat the UV spectrophotometer for 20 minutes beforehand. After preheating, open the application program, select absorbance measurement as the instrument method, and set the measurement value to 665 nm. Clean and dry the cuvettes, then fill them with ultrapure water to 2 / 3 full as blanks. Place two cuvettes filled with ultrapure water into the sample chamber, ensuring the light path passes through the transparent surface. Close the caps and scan the baseline from 300 to 800 nm. Set the measurement value to 665 nm again and zero the instrument. Pour out the water from the cuvette in the test position, leaving the other cuvette as a control. Measure the standard solutions in ascending order of concentration. After the measurements, plot the standard curve based on the obtained values, clean the cuvettes with 95% alcohol, and then air dry. The only difference between the determination of the standard curve for Chrome Blue (SE) and the MB standard curve is that the measurement value is set at 528 nm. The only difference between the determination of the standard curve for Chrome Black (T) and the MB standard curve is that the measurement value is set at 616 nm. The only difference between the determination of the standard curve for Basic Yellow 11 (BY11) and the MB standard curve is that the measurement value is set at 422 nm. Determination of dye content in the supernatant: Following the same steps as the standard curve determination described above, the supernatant was measured and its values ​​recorded every two days. The dye concentration in the supernatant was calculated using the standard curve, and the dye removal rate was calculated using the following formula: RE(%) = (C0-C) / C0×100%; where RE is the removal rate, C0 is the initial dye concentration, and C is the dye concentration after a period of co-cultivation. The test results are shown in Table 1.

[0040] Table 1

[0041]

[0042] As shown in Table 1, the method for removing dyes from water provided by this invention achieves a dye removal rate of over 80% within 24 days. Within the methylene blue (MB) concentration range of 0.5 to 5 mg / L, the removal efficiency of methylene blue increases with increasing co-cultivation time. However, when the initial methylene blue concentration reaches 10 mg / L, the removal efficiency (81.6%) increases sharply; however, the dye removal efficiency remains at this level and does not further increase with increasing co-cultivation time. Furthermore, when the initial methylene blue concentration is 5 mg / L and reaches equilibrium within 12 days, the maximum removal rate is 97.2%, which is significantly higher than the removal rates of the other three experimental groups. In addition, Example 5 of this invention removes Chrome Blue (SE) with a removal efficiency of 90.7%; Example 6 removes Chrome Black (T) with a removal efficiency of 90.5%; and Example 7 removes Basic Yellow 11 (BY11) with a removal efficiency of 98.8%.

[0043] The absorbance values ​​of carotenoids (470 nm) and chlorophyll (685 nm) in Haematococcus pluvialis after 24 days of culture were measured, and the ratio of carotenoid to chlorophyll absorbance was calculated. The results are shown in Table 2.

[0044] Table 2

[0045]

[0046] Table 2 shows that different Haematococcus pluvialis culture media exhibit significant differences in intracellular pigments. This invention, by analyzing changes in the intracellular uptake values ​​of carotenoids (470 nm) and chlorophyll (685 nm), more accurately reflects the changes in pigment content within algal cells. Lower concentrations of MB (0.5–5 mg / L) significantly increased the accumulation of carotenoids in Haematococcus pluvialis cells; however, when the MB concentration was further increased to 10 mg / L, this ratio decreased significantly, indicating that higher concentrations of MB significantly inhibited the synthesis of carotenoids in Haematococcus pluvialis cells. 1 mg / L Chrome Blue SE, 1 mg / L Chrome Black T, and 5 mg / L Basic Yellow 11 also significantly increased the accumulation of carotenoids in Haematococcus pluvialis cells.

[0047] The number of Haematococcus pluvialis cells in the mixed solution cultured for 24 days was tested, and the results are shown in Table 3. The specific test method is as follows: Take 1 mL of algal solution into a 1.5 mL centrifuge tube for microscopic counting; check the counting chamber. If the blood coverslip is dirty, wipe it clean with lens paper. If the counting plate is dirty, rinse the bottle, wipe it gently with a cotton ball soaked in 95% alcohol, and then dry it with lens paper. Microscopic counting of Haematococcus pluvialis: Secure the coverslip tightly against the raised platform of the counting plate, shake 1 mL of algal solution in a centrifuge tube (to remove air bubbles), pipette the algal solution, and gently touch the V-groove at a 45° angle to the edge of the counting plate and coverslip to fill the counting cell using capillary action (to prevent overflow / insufficiency); let stand for 1-2 minutes to allow cells to settle, locate the counting cell network under a 10x microscope, and count under a 40x microscope, counting the cells in the four corners plus the central square. For cells on the lines, count the cells above the lines, not below; count the cells on the left, not right. Calculate using the formula "cell count / ml = 50000A′B (A′ is the total number of cells in 5 central squares, B is the dilution factor, undiluted B = 1)". Count the upper chamber first, then the lower chamber, and take the average of the two chambers as the final concentration. If the difference is too large, recount. Complete the algal count in this manner.

[0048] Table 3

[0049]

[0050] As shown in Table 3, under low-dose dye treatment conditions, Haematococcus pluvialis can eliminate the effects of the dye on algal cells through adsorption and reduction. However, when the dye dose reaches 5-10 mg / L, it damages microalgal cells by inhibiting photosynthesis, disrupting metabolism, and affecting cell physiology, ultimately resulting in a significant inhibition of Haematococcus pluvialis cell growth rate.

[0051] In summary, the method for removing dyes from water provided by this invention effectively removes dyes from water through biological methods, which helps improve the ecological environment and promotes the restoration of degraded aquatic ecosystems.

[0052] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for removing dye from water, characterized in that, This involves adding an aqueous dye solution to a Haematococcus pluvialis culture medium to obtain a mixed solution, which is then cultured to obtain the final product.

2. The method according to claim 1, characterized in that, The dye is selected from one or more of methylene blue, chrome blue SE, chrome black T, basic yellow, and methyl orange.

3. The method according to claim 1 or 2, characterized in that, The concentration of the dye in the mixed solution is 0.5~10 mg / L.

4. The method according to claim 1, characterized in that, The species number of Haematococcus pluvialis mentioned is FACHB-712.

5. The method according to claim 1, characterized in that, The Haematococcus pluvialis culture medium contained 1 × 10⁻⁶ cells of Haematococcus pluvialis. 6 ~2×10 7 cells / mL.

6. The method according to claim 1, characterized in that, The method for preparing the Haematococcus pluvialis culture medium includes the following steps: culturing Haematococcus pluvialis on BBM medium under a light intensity of 30-60 μmol photons / m². -2 s -1 The cycle is 12 hours during the day and 12 hours at night, and the culture temperature is 25±1℃.

7. The method according to claim 6, characterized in that, The BBM culture medium includes: NaNO3, NaCl, K2HPO4, KH2PO4, H3BO3, EDTA, Co(NO3)2·6H2O, CuSO4·5H2O, MnCl2·4H2O, ZnSO4·7H2O, MoO3, MgSO4·7H2O, CaCl2·2H2O, FeSO4·7H2O, and water.

8. The method according to claim 1, characterized in that, The cultivation conditions include: a cultivation temperature of 24~30℃; a cultivation light intensity of 1000~3000 lux; and a cultivation light-dark ratio of 10~14h:10~14h.

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