A method for strengthening nanomaterial adsorption of inorganic pollutants by microbubbles

Abstract

The application discloses a method for strengthening adsorption of inorganic pollutants by nanomaterials by using microbubbles, which comprises the following steps: firstly, using a microbubble generating device to aerate a solution containing inorganic pollutants for 10-30 min; then, adding nanomaterials into the solution; after 24-48 h, taking out the nanomaterials to obtain nanomaterials adsorbing inorganic pollutants. The adsorption method can significantly improve the selective removal effect of nanomaterials on pollutants by introducing the microbubble technology, so that the removal amount of pollutants is increased by 0.2-5 times, and the problem that the removal effect of different inorganic pollutants is affected by pH and competitive ions, resulting in poor removal rate, can be avoided, and the pH range for using the nanoadsorption material is widened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inorganic pollutants removal, and particularly relates to a method for removing inorganic pollutants by using micro-bubbles to reinforce nanomaterials. BACKGROUND

[0002] Adsorption is one of the most widely used water treatment technologies at present, which has the advantages of low cost, convenient operation and stable effect. Among them, the adsorbent can remove inorganic anions in water through physical adsorption, chemical adsorption and ion exchange. After saturation, the adsorbent can be desorbed and regenerated for recycling, thereby reducing the cost; and adsorption usually adopts a fixed bed form, which has low equipment investment, simple operation, stable and reliable treatment effect.

[0003] The rapid development of nanotechnology provides a new opportunity for further innovation of deep water treatment technology. Compared with traditional adsorbents, nanomaterials have higher specific surface area and selectivity, and the utilization rate of active sites is high. Therefore, nanomaterials have good removal effect on pollutants, and can effectively remove pollutants even at low concentration. For example, Fe / Zr / Mn / La / Ce metal oxide nanoparticles can realize specific adsorption and removal of inorganic pollutants such as arsenate, phosphate and fluoride through inner coordination.

[0004] However, nanomaterials have good removal effect on arsenate under neutral conditions, but the removal effect is poor under acidic or alkaline conditions (Chem. Eng. J, 2014, 248, 290-296); when competitive ions exist, nanomaterials have higher removal rate of phosphate under acidic conditions (J. Hazard. Mater., 2015, 284, 35-42); under acidic conditions, nanomaterials have excellent removal effect on fluoride ions, but the defluorination performance significantly decreases under medium alkaline conditions (Environ. Sci. Technol. 2013, 47, 16, 9347-9354). In actual application, it is difficult to obtain acid or base to adjust the pH of the solution by using inorganic acid and base, and the operation is complicated, and it is easy to cause waste of chemical reagents.

[0005] That is, the removal effect of nanomaterials on inorganic pollutants is greatly affected by pH. Based on this, there is an urgent need for a new adsorption method for inorganic pollutants, which can widen the application range of nanomaterials and not be limited by the influence of pH. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a method for removing inorganic pollutants by using micro-bubbles to reinforce nanomaterials, which can increase the removal amount of inorganic anion pollutants by 0.2-5 times, and effectively widen the use pH range of the adsorbent.

[0007] Technical solution: The application utilizes micro-bubble to strengthen the adsorption of inorganic anion pollutants by nanomaterials, including the following steps:

[0008] (1) The micro-bubble generating device is used to aerate the solution containing inorganic pollutants for 10-30 min;

[0009] (2) The nanomaterials are added to the solution of step (1) and reacted for 24-48 h, and then taken out to obtain the nanomaterials adsorbing inorganic pollutants.

[0010] The micro-bubbles are different from the traditional bubbles, which have the characteristics of high mass transfer efficiency, stable existence in water, high specific surface area, negative surface charge and free radicals generated when broken. The application introduces the micro-bubbles into the solution, which are enriched on the surface of the nanomaterials through electrostatic or hydrophobic effects, promotes the proton transfer to the surface of the nanomaterials, and further promotes the protonation of the nanomaterials, increases the adsorption sites on the surface of the nanomaterials, and accelerates the kinetics of the adsorption of inorganic pollutants on the nanomaterials, thereby improving the adsorption performance of the nanomaterials.

[0011] Further, in step (1) of the adsorption method, the size of the micro-bubbles generated by the micro-bubble generating device is 100-500 nm, and the concentration of the micro-bubbles is 3×10 6 -9×10 8 / mL, that is, there are 3×10 6 -9×10 8 bubbles in 1 mL of solution.

[0012] Further, in step (1) of the adsorption method, the gas for aeration is air, nitrogen, carbon dioxide or oxygen.

[0013] Further, in step (1) of the adsorption method, the inorganic pollutants are arsenate, phosphate or fluoride.

[0014] Further, in step (1) of the adsorption method, the pH value of the inorganic pollutant solution is 3-11, and the concentration of the competitive ion chloride is 0-1 g / L.

[0015] Further, in step (2) of the adsorption method, the nanomaterials are nanometer iron oxide, nanometer manganese oxide, nanometer zirconium oxide, nanometer lanthanum oxide or nanometer cerium oxide, and the size of the nanomaterials is 20-100 nm.

[0016] Beneficial effects: Compared with the prior art, the significant advantages of the present application are that the adsorption method can significantly improve the selective removal effect of nanomaterials on pollutants by introducing microbubble technology, so that the removal amount of pollutants is increased by 0.2-5 times, and the problem that the removal effect of different inorganic pollutants is affected by pH and competitive ions to cause poor removal rate is avoided, and the use pH range of the adsorption material is widened. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Optical microscope picture of the nanobubbles prepared in Example 1 of the present application;

[0018] Figure 2 Transmission electron microscope (TEM) picture of the nanomaterial used in Example 1 of the present application. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be further described in detail below in combination with the drawings and examples.

[0020] It should be noted that the raw materials and devices used in the present application can be purchased from the market. It should be noted that the microbubbles generated by the microbubble generator of the present application have a size of 100-500 nm, and the microbubble concentration is 3x10 6 -9x10 8 / mL, that is, there are 3x10 6 -9x10 8 bubbles in 1 mL of solution. The nanomaterial used in the present application has a size of 20-100 nm.

[0021] Example 1

[0022] This example uses air microbubbles to strengthen the removal of phosphate by nanometer iron oxide in water treatment method, which specifically includes the following steps:

[0023] (1) Prepare a target solution with pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, respectively, and phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0024] (2) Use air as the aeration gas, and aerate the solution of step (1) through the microbubble generator for 10 min, and the generated microbubble water is as shown in the following table: Figure 1

[0025] (3) Add 0.005 g of nanometer iron oxide to 50 mL of the solution described in step (1) and react for 24 h, and the TEM structure of the nanomaterial is as shown in the following table, and the nanomaterial for adsorbing inorganic anion pollutants is obtained. Figure 2

[0026] ​​The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-iron oxide to phosphate is 22.3, 21.1, 20.2, 20.0, 18.0, 15.3, 13.0, 11.5, 9.5 mg / g respectively.

[0027] Comparative Example 1

[0028] The basic steps are the same as those in Example 1, except that the target solution is not subjected to aeration treatment, i.e., step (2) in Example 1 is cancelled.

[0029] The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-iron oxide to phosphate is 22.3, 21.1, 20.2, 20.0, 18.0, 15.3, 13.0, 11.5, 9.5 mg / g respectively.

[0030] It can be seen that when the aeration treatment is not used, the adsorption amount of nano-iron oxide to inorganic contaminant solution at pH values of 3 and 4 can reach 15 mg / g, and after the pH value is greater than 4, the adsorption amount is obviously reduced; when the aeration treatment is used, the adsorption amount of nano-iron oxide at pH values of less than 8 can still almost reach the adsorption amount at pH value of 4 when the aeration treatment is not used, effectively expanding the pH range for use of the nano-material.

[0031] Example 2

[0032] This example uses nitrogen micro-bubbles to strengthen the removal of phosphate by nano-iron oxide in water treatment method, which specifically includes the following steps:

[0033] (1) preparing a target solution with pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, a phosphate concentration of 10 mg / L, and a chloride ion concentration of 1 g / L;

[0034] (2) using nitrogen as the aeration gas, the solution in step (1) is aerated through a micro-bubble generator for 20 min;

[0035] (3) adding 0.005 g of nano-iron oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain a nano-material adsorbing inorganic anion contaminants.

[0036] The experimental results show that in the nitrogen-containing micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-iron oxide on phosphate is 23.8, 23.1, 22.3, 21.6, 21.0, 19.9, 17.8, 15.2, 13.1 mg / g, respectively.

[0037] Example 3

[0038] The embodiment utilizes carbon dioxide micro-bubbles to strengthen the nano-iron oxide to remove phosphate water treatment method, specifically comprising the following steps:

[0039] (1) preparing the target solution with pH value of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0040] (2) using carbon dioxide gas as aeration gas, the solution in step (1) is aerated through the micro-bubble generator for 30 min;

[0041] (3) adding 0.005 g of nano-iron oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain the nano-material adsorbing inorganic anion pollutants.

[0042] The experimental results show that in the carbon dioxide-containing micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-iron oxide on phosphate is 22.5, 22.0, 21.8, 21.1, 20.3, 18.6, 15.8, 13.2, 10.1 mg / g, respectively.

[0043] Example 4

[0044] The embodiment utilizes oxygen micro-bubbles to strengthen the nano-iron oxide to remove phosphate water treatment method, specifically comprising the following steps:

[0045] (1) preparing the target solution with pH value of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0046] (2) using oxygen as aeration gas, the solution in step (1) is aerated through the micro-bubble generator for 20 min;

[0047] (3) adding 0.005 g of nano-iron oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain the nano-material adsorbing inorganic anion pollutants.

[0048] The experimental results show that in the air micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano iron oxide to phosphate is 21.9, 21.1, 20.6, 20.1, 19.3, 18.1, 16.2, 14.2, 11.1 mg / g respectively.

[0049] Example 5

[0050] The embodiment utilizes the air micro-bubble to strengthen the nano iron oxide to remove arsenate water treatment method, and specifically includes the following steps:

[0051] (1) preparing the target solution with the pH value of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 respectively, the arsenate concentration of 10 mg / L, and the chloride ion concentration of 1 g / L;

[0052] (2) using air as the aeration gas, aerating the solution in step (1) through the micro-bubble generator for 15 min;

[0053] (3) adding 0.005 g of nano iron oxide into 50 mL of the solution in step (1) to react for 48 h, and obtaining the nano material adsorbing inorganic anion pollutants.

[0054] The experimental results show that in the air micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano iron oxide to arsenate is 8.9, 11.2, 15.6, 18.3, 19.3, 18.1, 16.2, 14.2, 11.1 mg / g respectively.

[0055] Comparative Example 2

[0056] The basic steps are the same as those in example 5, and the difference lies in that the target solution is not subjected to aeration treatment, that is, the step (2) in example 5 is cancelled.

[0057] The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano iron oxide to arsenate is 5.6, 8.3, 10.0, 13.9, 15.1, 12.2, 10.1, 8.2, 6.0 mg / g respectively.

[0058] Therefore, by using the micro-bubble in the present application for aeration, not only the adsorption amount is improved, but also the pH range of adsorption is widened, and when the pH value is 11, almost the adsorption amount of pH value 8 when the micro-bubble is not used can be obtained.

[0059] Example 6

[0060] The embodiment utilizes air micro-bubbles to strengthen the water treatment method of removing fluoride by nano-iron oxide, and specifically comprises the following steps:

[0061] (1) preparing a target solution with pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 respectively, fluoride concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0062] (2) using air as the aeration gas, aerating the solution in step (1) through a micro-bubble generator for 10 min;

[0063] (3) adding 0.005 g of nano-iron oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain a nano-material that adsorbs inorganic anion pollutants.

[0064] The experimental results show that in the air micro-bubble-containing solution, when the pH values are 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, and 11.0, the adsorption amounts of fluoride by the nano-iron oxide are 23.2 mg / g, 23.0 mg / g, 21.0 mg / g, 20.2 mg / g, 20.5 mg / g, 17.2 mg / g, 15.3 mg / g, 10.9 mg / g, and 10.0 mg / g respectively.

[0065] Comparative Example 3

[0066] The basic steps are the same as those in Example 6, except that the target solution is not subjected to aeration treatment, i.e., step (2) in Example 6 is cancelled.

[0067] The experimental results show that when the pH values are 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, and 11.0, the adsorption amounts of fluoride by the nano-iron oxide are 18.3 mg / g, 16.0 mg / g, 12.9 mg / g, 6.4 mg / g, 6.0 mg / g, 5.3 mg / g, 4.4 mg / g, 3.2 mg / g, and 2.8 mg / g respectively.

[0068] Therefore, by using the micro-bubbles of the present application for aeration, not only is the adsorption amount increased, but also the pH range for adsorption is widened, and at pH values of 10 and 11, almost the same adsorption amount as that at pH 5 without using micro-bubbles can be obtained.

[0069] Example 7

[0070] The embodiment utilizes air micro-bubbles to strengthen the water treatment method of removing fluoride by nano-iron oxide, and specifically comprises the following steps:

[0071] (1) Preparation of target solution with pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 respectively, phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0072] (2) Aeration of the solution in step (1) through a micro-bubble generator for 20 min using air as the aeration gas;

[0073] (3) Addition of 0.005 g of nano-manganese oxide to 50 mL of the solution in step (1) for reaction for 24 h to obtain a nano-material for adsorbing inorganic anion pollutants.

[0074] The experimental results show that in the air micro-bubble solution, when the pH values are 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, and 11.0, the adsorption amounts of phosphate by nano-manganese oxide are 20.3, 19.6, 18.9, 18.2, 16.1, 13.2, 11.4, 9.5, and 7.5 mg / g respectively.

[0075] Comparative Example 4

[0076] The basic steps are the same as those in Example 7, except that the target solution is not subjected to aeration treatment, i.e., step (2) in Example 7 is cancelled.

[0077] The experimental results show that when the pH values are 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, and 11.0, the adsorption amounts of phosphate by nano-manganese oxide are 7.5, 7.3, 6.9, 6.4, 6.0, 5.6, 5.1, 4.5, and 4.0 mg / g respectively.

[0078] Example 8

[0079] This example utilizes air micro-bubbles to strengthen the removal of phosphate by nano-zirconium oxide, and the water treatment method specifically comprises the following steps:

[0080] (1) Preparation of target solution with pH values of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0 respectively, phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0081] (2) Aeration of the solution in step (1) through a micro-bubble generator for 20 min using air as the aeration gas;

[0082] (3) Addition of 0.005 g of nano-zirconium oxide to 50 mL of the solution in step (1) for reaction for 24 h to obtain a nano-material for adsorbing inorganic anion pollutants.

[0083] The experimental results show that in the air micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-zirconium oxide to phosphate is 23.3, 22.7, 21.8, 21.1, 19.1, 16.4, 14.3, 12.5, 10.5 mg / g respectively.

[0084] Comparative Example 5

[0085] The basic steps are the same as those in Example 8, except that the target solution is not subjected to aeration treatment, i.e. step (2) in Example 8 is cancelled.

[0086] The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-zirconium oxide to phosphate is 10.6, 10.3, 9.9, 9.4, 9.0, 8.5, 8.0, 7.5, 7.0 mg / g respectively.

[0087] Example 9

[0088] This example uses air micro-bubbles to strengthen the nano-lanthanum oxide to remove phosphate water treatment method, which specifically comprises the following steps:

[0089] (1) preparing a target solution with pH value of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, phosphate concentration of 10 mg / L and chloride ion concentration of 1 g / L;

[0090] (2) using air as the aeration gas, the solution in step (1) is aerated through a micro-bubble generator for 20 min;

[0091] (3) adding 0.005 g of nano-lanthanum oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain a nano-material adsorbing inorganic anion pollutants.

[0092] The experimental results show that in the air micro-bubble solution, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano-lanthanum oxide to phosphate is 21.3, 20.4, 19.5, 19.2, 17.6, 14.3, 12.4, 10.5, 8.3 mg / g respectively.

[0093] Comparative Example 6

[0094] The basic steps are the same as those in Example 9, except that the target solution is not subjected to aeration treatment, i.e. step (2) in Example 9 is cancelled.

[0095] The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano lanthanum oxide to phosphate is 9.2, 7.9, 7.3, 6.8, 6.6, 6.2, 5.6, 5.0, 4.5 mg / g respectively.

[0096] Example 10

[0097] This example uses air micro-bubbles to strengthen the removal of phosphate by nano cerium oxide in water treatment method, which specifically includes the following steps:

[0098] (1) preparing a target solution with pH value of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, phosphate concentration of 10 mg / L, and chloride ion concentration of 1 g / L;

[0099] (2) using air as aeration gas, aerating the solution in step (1) through a micro-bubble generator for 15 min;

[0100] (3) adding 0.005 g of nano cerium oxide to 50 mL of the solution in step (1) and reacting for 24 h to obtain a nano material for adsorbing inorganic anion pollutants.

[0101] The experimental results show that in the solution containing air micro-bubbles, when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano cerium oxide to phosphate is 12.3, 11.6, 10.9, 10.6, 10.3, 7.5, 6.4, 5.2, 4.3 mg / g respectively.

[0102] Comparative Example 7

[0103] The basic steps are the same as those in Example 10, except that the target solution is not subjected to aeration treatment, i.e. step (2) in Example 10 is cancelled.

[0104] The experimental results show that when the pH value is 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, the adsorption amount of nano cerium oxide to phosphate is 5.5, 5.3, 4.8, 4.5, 4.1, 3.6, 3.2, 2.5, 2.0 mg / g respectively.

Claims

1. A method for enhancing adsorption of inorganic pollutants by nanomaterials using microbubbles, characterized in that, The method comprises the following steps: (1) using a micro-bubble generating device to aerate a solution containing inorganic pollutants for 10-30 minutes; the inorganic pollutants are arsenate, phosphate or fluoride; the pH value of the inorganic pollutant solution is 3-11, and the concentration of the competitive ion chloride is 0-1 g / L; (2) adding a nano material to the solution of step (1) and reacting for 24-48 hours to obtain a nano material adsorbing inorganic pollutants. 2.The method of claim 1, wherein the microbubbles are generated by a method comprising: In step (1), the microbubbles generated by the microbubble generating device have a size of 100-500 nm and a concentration of 3 x 10 6 -9 x 10 8 / mL. ​ 3.The method of claim 1, wherein the microbubbles are generated by a method comprising: In step (1), the gas for aeration is air, nitrogen, carbon dioxide or oxygen. ​ 4.The method of claim 1, wherein the microbubbles are generated by a method comprising: generating a gas flow; and generating a liquid flow; and mixing the gas flow and the liquid flow to generate the microbubbles. In step (2), the nano material is nano iron oxide, nano manganese oxide, nano zirconium oxide, nano lanthanum oxide or nano cerium oxide, and the size of the nano material is 20-100 nm.

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