Method for removing bisphenol a in water by visible light combined with humic acid activated periodic acid

Abstract

The present application relates to a kind of visible light combined humic acid activation periodate removal bisphenol A in water method, comprising the following steps: respectively, appropriate amount of humic acid and periodate are sequentially added in the wastewater containing bisphenol A pollution, after being fully stirred and mixed, visible light is irradiated for a period of time, bisphenol A degradation can be realized.The method of the present application utilizes the excited state humic acid formed under the irradiation of visible light to accelerate the electron transfer between humic acid and periodate, thereby efficiently activating periodate to form active substance for bisphenol A degradation, the pH range is wider, solves the defects that most advanced oxidation technologies need to be carried out under acidic conditions;In addition, since visible light and humic acid are ubiquitous in nature, the method of the present application also has the advantages of simple operation, low cost and no secondary pollution, etc., which can provide a new perspective for the field of organic wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for removing bisphenol A from water by combining visible light with humic acid activation of periodate. Background Technology

[0002] With the development of industrial production technology, the environmental pollution caused by the large-scale use and disposal of industrial products is becoming increasingly serious. Bisphenol A (BPA), as a raw material in the organic chemical industry, is widely present in the human living environment. However, BPA is considered an endocrine disruptor, readily soluble in water but difficult to hydrolyze. Furthermore, BPA has potential toxicity and can affect the reproductive, endocrine, and nervous systems of organisms through the food chain, causing adverse effects on humans and other organisms. The stability and biodegradability of BPA result in its high detection rate in various environmental matrices. Therefore, developing an efficient and low-cost BPA remediation method is of great significance.

[0003] In recent years, advanced oxidation processes (AOPs) based on periodate (PI) have been widely used for the degradation of emerging organic pollutants due to their chemical stability and strong oxidizing power (+1.60V). PI activation can generate various reactive substances, such as singlet oxygen (…). 1 O2), superoxide radical anion (O2) •- ), hydroxyl radicals (•OH), and iodate radicals (•IO3, •IO4). Various activation methods for PI have been proposed, such as ultraviolet irradiation (UV), ultrasound, alkaline conditions (pH>8), freezing, hydroxylamine, and metal ions (Mn). 2+ and Fe 3+ Activation. Most research on PI activation focuses on introducing transition metal catalysts or using ultraviolet light for photocatalytic activation. However, these methods mostly have limitations, such as unsatisfactory activation performance, high energy consumption, and potential secondary pollution, limiting their practical environmental applications. While ultraviolet light activation of PI has been studied, it only accounts for 5% of the solar spectrum, while visible light (VL) accounts for 44% and has a more moderate and stable energy level. Therefore, fully developing VL-based photochemical activation is crucial for light-driven advanced oxidation technologies. PI cannot be effectively activated by VL irradiation alone, making it difficult to use for the degradation of organic pollutants; therefore, photocatalysts are often required. Studies have shown that photocatalysts such as TiO2 can effectively activate PI under VL irradiation, but their complex preparation methods and cumbersome separation processes make them unsuitable for practical water treatment. Therefore, developing a visible light-assisted metal-free catalyst for PI activation is of great significance.

[0004] Humic acid (HA), a colored, soluble organic compound, is ubiquitous in the natural environment and plays a vital role in both abiotic and biotic reactions. HA can complex with pollutants through its active functional groups such as carboxyl, hydroxyl, and phenolic groups, ultimately influencing their migration and transformation. Furthermore, as a photosensitizer, HA can be excited to a triplet state (3HA*) under light conditions, generating various reactive free radicals. 1 O2, O2 •- •OH) and hydrated electrons (e aq BPA directly or indirectly affects the degradation of pollutants. HA activated by VL may activate PI to form reactive oxygen species (ROS) to degrade organic pollutants. Therefore, this invention provides a method for VL combined with HA to activate PI, which is expected to remove BPA from polluted water bodies. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for removing bisphenol A from water using visible light combined with humic acid activation of periodate. This method is simple to operate, does not require expensive catalysts, and does not generate secondary pollution, thus expanding the field of advanced oxidation technologies driven by visible light.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for removing bisphenol A from water using visible light combined with humic acid activation of periodate, comprising the following steps:

[0008] Step S1: Adjust the pH of the bisphenol A-containing wastewater to 7;

[0009] Step S2: Humic acid and periodate are added sequentially to the wastewater in step S1 to obtain a mixed solution;

[0010] Step S3: The mixture obtained in step S2 is treated under simulated visible light irradiation and stirring conditions to obtain wastewater in which bisphenol A has been removed.

[0011] Specifically, the periodate mentioned in step S2 is potassium periodate.

[0012] Specifically, the concentration of humic acid mentioned in step S2 is 0.5–5 mg / L in the wastewater.

[0013] Specifically, the concentration of potassium periodate in step S2 is 0.1–3 mM in the wastewater.

[0014] Specifically, the wavelength of visible light mentioned in step S3 is 400–760 nm.

[0015] Specifically, the visible light irradiation time mentioned in step S3 is 5 to 80 minutes.

[0016] Specifically, the stirring speed in step S3 is 100-300 r / min.

[0017] The advantages of this invention compared to the prior art are as follows:

[0018] 1. The method of this invention has a mild reaction, stable effect and high removal rate: it uses visible light as an aid and utilizes humic acid to activate periodate, resulting in a good oxidation effect. Bisphenol A in wastewater can be completely removed after 80 minutes of treatment.

[0019] 2. The method of this invention does not produce secondary pollution: By using photochemical degradation, a small amount of humic acid and periodate are added to the polluted water. Humic acid is a substance naturally present in the water and will not have a toxic effect on the water. Therefore, it will not cause secondary pollution and is an environmentally friendly method for treating polluted water.

[0020] 3. The method of the present invention is simple to operate and has no safety hazards: Compared with ultraviolet light, visible light has a higher proportion in the solar spectrum and is greener and cleaner, providing a new perspective for light-driven advanced oxidation technology.

[0021] 4. The method of this invention can be carried out at room temperature, which solves the defect of existing advanced oxidation technologies that require acidic conditions to oxidize pollutants. It has a wide pH range of applicability. In addition, since visible light and humic acid are ubiquitous in the natural environment, it has advantages such as being environmentally friendly and inexpensive, and is expected to be applied to large-scale water pollution treatment. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The graphs show the degradation curves of BPA in water by different reaction systems of this invention.

[0024] Figure 2 A schematic diagram illustrating the contribution of different reactive oxygen species in the degradation of BPA according to the present invention;

[0025] Figure 3 This is a graph showing the degradation curves of BPA in water by HA of different particle sizes according to the present invention.

[0026] Figure 4 This is a graph showing the degradation curves of BPA in different types of water bodies using the VL / HA / PI system of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a method for removing bisphenol A from water using visible light combined with humic acid activation of periodate, comprising the following steps:

[0029] Step S1: Adjust the pH of the bisphenol A-containing wastewater to 7;

[0030] Step S2: Humic acid and periodate are added sequentially to the wastewater in step S1 to obtain a mixed solution;

[0031] Step S3: The mixture obtained in step S2 is treated under simulated visible light irradiation and stirring conditions to obtain wastewater in which bisphenol A has been removed.

[0032] Specifically, the periodate mentioned in step S2 is potassium periodate.

[0033] Specifically, the concentration of humic acid mentioned in step S2 is 0.5–5 mg / L in the wastewater.

[0034] Specifically, the concentration of potassium periodate in step S2 is 0.1–3 mM in the wastewater.

[0035] Specifically, the wavelength of visible light mentioned in step S3 is 400–760 nm.

[0036] Specifically, the visible light irradiation time mentioned in step S3 is 5 to 80 minutes.

[0037] Specifically, the stirring speed in step S3 is 100-300 r / min. Example 1

[0038] This embodiment utilizes visible light-assisted complexation of iron ions to activate periodate and remove bisphenol A from water, which is achieved through the following steps:

[0039] BPA solution was added to a quartz tube to ensure an initial concentration (C0) of 20 μM. The initial pH was adjusted to 7.0 with 1 M NaOH solution to obtain the BPA-containing water to be treated. With a total system volume of 40 mL, HA and PI were added sequentially to the BPA-containing water to concentrations of 2 mg / L and 1 mM, respectively. The mixture was thoroughly mixed using a magnetic stirrer to obtain a homogeneous system. This homogeneous system was then subjected to photocatalytic reaction under xenon lamp simulating visible light irradiation, with the system maintained at a constant temperature of 25 °C through a circulating water system. During the reaction, samples were taken at fixed reaction time points of 0, 5, 10, 20, 40, 60, and 80 minutes to detect the BPA degradation within 80 minutes.

[0040] As a comparative example of Example 1, the process of Example 1 was repeated, except that HA and PI were not added, and only BPA-containing water was treated with simulated visible light. The degradation results were as follows. Figure 1 As shown.

[0041] As another comparative example of Example 1, the process of Example 1 was repeated, except that HA was not added and the mixture was placed in the dark. The degradation results were as follows. Figure 1 As shown.

[0042] As another comparative example of Example 1, the process of Example 1 was repeated, except that HA was not added, and the degradation results were as follows. Figure 1 As shown.

[0043] As another comparative example of Example 1, the process of Example 1 was repeated, except that the mixture was placed in darkness instead of under xenon lamp irradiation to simulate visible light. The degradation results were as follows: Figure 1 As shown.

[0044] from Figure 1 The results show that when VL is used alone to treat BPA-containing water samples, the degradation of BPA is negligible. This rules out the possibility of direct photodegradation of BPA under VL. In the presence of PI alone, BPA also shows almost no degradation, indicating that the oxidation capacity of PI itself is insufficient to degrade BPA. In the VL / PI system, the removal rate of BPA within 80 minutes is approximately 11.97%, indicating that VL cannot activate PI alone. Furthermore, the degradation efficiency of BPA in the HA / PI system within 80 minutes is only 2.0%, indicating that HA has a weak activation ability for PMS under light-free conditions. It is noteworthy that the combination of visible light, HA, and PI has an excellent degradation effect on BPA in aqueous solution; BPA is completely degraded within 80 minutes, indicating a significant synergistic effect between HA and PI on BPA degradation under visible light. This can be attributed to HA forming an excited state under visible light irradiation and ejecting electrons (e−) to activate PI, thereby accelerating the generation of reactive oxygen species and the degradation of BPA. Example 2

[0045] In this embodiment, the effect of the molar ratio of HA and PI on the degradation rate of BPA was investigated.

[0046] Referring to Example 1, the only difference was changing the concentration of PI in the mixture to 0.5, 1, 2, 3, and 5 mM. After 80 minutes, the degradation rates of BPA were 96.32%, 100.00%, 100.00%, 100.00%, and 100.00%, respectively. Example 3

[0047] Referring to Example 2, the only difference was changing the concentration of HA to 0.5, 1, 2, 3, and 5 mg / L. After 80 minutes, the BPA degradation rates reached 67.04%, 91.32%, 100.00%, 100.00%, and 100.00%, respectively. Example 4

[0048] Under conditions of temperature (25±1℃), BPA, HA, and PI were added to the water sample to ensure their initial concentrations (C0) were 20 μM, 2 mg / L, and 1 mM, respectively. While maintaining a total system volume of 40 mL, quenchers of different active substances were added, including histidine at 5 mM (corresponding to ROS of [missing information]). 1 O2O2 •- ), Nitroblue tetrazolium 0.1mM (corresponding to ROS O2) •- ), tert-butanol 10 mM (corresponding to ROS 0.06 HO•), phenol 10 mM (corresponding to ROS 0.06 HO•, IO3• and IO4•). Figure 2 As shown, the ROS of the VL / HA / PI system has 1 O2, HO•, IO3• and IO4•. Example 5

[0049] In this embodiment, the effect of different HA particle sizes on the degradation rate of BPA was investigated.

[0050] Referring to Example 1, the only difference is that the particle size of HA in the mixture is changed so that the particle size of HA is >100kD, 10-100kD, 1-10kD, and <1kD.

[0051] Step 1: First, prepare the HA stock solution in deionized water.

[0052] Step 2: Filter the HA stock solution through a 0.45μm cellulose acetate membrane.

[0053] Step 3: Use a relative molecular mass (pore size cutoff) of 100×10 3 10×10 3 and 1×103 (PES membrane, 5×10) -3 m 2 The HA filtered in step 2 is separated by an ultrafiltration membrane, and the process is carried out under a constant pressure of 0.1 MPa.

[0054] BPA removal rate results are as follows: Figure 3 As shown, the results indicate that the VL / HA>100kD / PI system exhibits the best degradation effect on BPA, with a degradation rate of 87.02%. The degradation rates of BPA in the VL / HA10-100kD / PI, VL / HA1-10kD / PI, and VL / HA<1kD / PI systems are 62.95%, 69.64%, and 46.44%, respectively. This may be because HA>100kD contains more aromatic hydrocarbon components than HA of other particle sizes, thus enhancing the electron-donating ability of HA and promoting BPA degradation. Example 6

[0055] Various actual water bodies contain large amounts of Cl. - SO4 2- NO3 - HCO3 - This embodiment uses BPA-containing wastewater with a pH of 7 as the reaction matrix. By adding different solutions to change the concentration of each ion, the effects of each major component on the degradation of BPA in the VL / HA / PI system are determined based on data.

[0056] Under conditions of temperature (25±1℃), BPA, HA, and PI were added to the water sample to ensure their initial concentrations C0 were 20 μM, 2 mg / L, and 1 mM, respectively. With a total system volume of 40 mL, different doses of NaCl solution, Na2SO4 solution, NaNO3 solution, and NaHCO3 solution were added to maintain the concentration range of each ion from 1 to 10 mM. The concentration C of BPA in the system was measured at different reaction times to determine the degradation of BPA within 60 minutes. The results are shown in Table 1 below.

[0057] Table 1. Effects of different ions on the reaction system

[0058] Concentration (mM) <![CDATA[Removal rate % (Cl - )]]> <![CDATA[Removal rate % (SO4 2- )]]> <![CDATA[Removal rate % (NO3 - )]]> <![CDATA[Removal rate % (HCO3 - )]] 1 100.00 98.54 100.00 71.01 5 100.00 98.86 99.26 63.41 10 100.00 99.40 100.00 60.73

[0059] As shown in Table 1 above: Cl - SO4 2- and NO3 - The presence of HCO3 had no significant effect on the degradation of BPA in the system. - It has an inhibitory effect on the degradation of BPA. This may be due to HCO3. - The addition of HCO3 will increase the pH of the system. -It will eliminate free radicals in the reaction system, thereby inhibiting the degradation of BPA. Example 7

[0060] BPA solution was added to tap water to ensure an initial concentration (C0) of 20 μM, resulting in BPA-containing water to be treated. With a total system volume of 40 mL, HA and PI were added sequentially to the BPA-containing natural water, achieving concentrations of 2 mg / L and 1 mM, respectively. The mixture was thoroughly mixed using a magnetic stirrer to obtain a homogeneous system. This homogeneous system was then subjected to photocatalytic reaction under xenon lamp irradiation simulating visible light, with the system maintained at a constant temperature of 25°C via a circulating water system. During the reaction, samples were taken at fixed reaction time points of 0, 5, 10, 20, 40, 60, and 80 minutes to detect the BPA degradation within 80 minutes. The results are shown below. Figure 4 As shown. Example 8

[0061] Repeat Example 6, except that lake water (Poyang Lake) was used instead of tap water, and the results are as follows. Figure 4 As shown. Example 9

[0062] Example 6 was repeated, except that river water (Le'an River) was used instead of tap water. The result was as follows. Figure 4 As shown. Example 10

[0063] Example 6 was repeated, except that domestic wastewater was used instead of tap water, and the results were as follows. Figure 4 As shown.

[0064] like Figure 4 As shown, the VL / HA / PI system constructed in this invention can be effectively applied to the pollution treatment of various actual water bodies, further demonstrating that the VL / HA / PI system has good application prospects.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for removing bisphenol A from water using visible light combined with humic acid activation of periodate, characterized in that, Includes the following steps: Step S1: Adjust the pH of the bisphenol A-containing wastewater to 7; Step S2: Humic acid and periodate are added sequentially to the wastewater in step S1 to obtain a mixed solution; Step S3: The mixture obtained in step S2 is treated under simulated visible light irradiation and stirring conditions to obtain wastewater in which bisphenol A has been removed. The method is performed at room temperature; The periodate mentioned in step S2 is potassium periodate; The concentration of humic acid mentioned in step S2 in the wastewater is 2-5 mg / L; The concentration of potassium periodate mentioned in step S2 is 1-3 mM in the wastewater; The visible light irradiation time mentioned in step S3 is 80 minutes.

2. The method for removing bisphenol A from water by combining visible light with humic acid activation of periodate according to claim 1, characterized in that, The wavelength of the visible light mentioned in step S3 is 400–760 nm.

3. The method for removing bisphenol A from water by combining visible light with humic acid activation of periodate as described in claim 1, characterized in that, The stirring speed in step S3 is 100-300 r / min.

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