A method for strengthening nanometer silica gel adsorption of lead ions by using anion surfactant

Abstract

The application relates to a method for strengthening nanometer silica gel adsorption of lead ions by using an anionic surfactant, which is used for efficiently removing lead ions in a neutral or weak alkaline environment. The method comprises the following steps: adjusting the pH of a lead ion-containing solution to 7-9; obtaining a standby solution; then adding acid-modified silica gel and an anionic surfactant into the standby solution; stirring and adsorbing, and then adopting a flotation process; realizing solid-liquid separation, and obtaining a lead-removed solution. By controlling the corresponding amount relationship of the standby solution, the acid-modified silica gel and the anionic surfactant, efficient adsorption of lead ions is realized, and efficient removal of lead ions is realized by using the flotation process. The method is simple in process, low in cost, suitable for industrial production, and has a wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of chemical adsorption technology, and more specifically to a method for removing lead ions by using anionic surfactants to enhance the adsorption performance of nano-silica gel in a neutral or weakly alkaline environment. Background Technology

[0002] Heavy metal ions such as lead, cadmium, and mercury are non-biodegradable and accumulate in organisms. Even at low concentrations, they are toxic and carcinogenic, posing a threat to the environment and public health. Heavy metal pollutants enter water bodies through human activities such as industry and mining, and these pollutants are difficult for water bodies to eliminate through their own purification capacity alone. Among many heavy metal pollutants, lead ions are emitted in particularly large quantities, with a wide range of harmful effects and strong toxicity. Lead ions not only have strong chronic neurotoxicity and hepatotoxicity to humans, but also exhibit persistent degradation and bioaccumulation, posing a profound threat to human health. When the lead concentration in water exceeds 0.1 mg / L, the self-purification capacity of natural water bodies is inhibited. Currently, various methods have been developed for the removal of lead ions from water bodies, including chemical precipitation, oxidation-reduction, cation exchange, adsorption, membrane separation, and biological treatment. Among these, adsorption has become an important method for lead ion treatment due to its advantages such as simple operation, relatively low cost, good treatment effect, and ease of combination with other methods. In recent years, surfactants have become increasingly popular due to their unique solubilizing, flow-increasing, cost-effective, high adsorption capacity, and good selectivity properties, and have been widely used for the adsorption of heavy metal ions in wastewater.

[0003] A search revealed few reports on techniques for enhancing lead ion adsorption using anionic surfactants on nano-silica gel. In particular, there are few reports on techniques for using acid-modified silica gel combined with appropriate amounts of sodium dodecylbenzenesulfonate and sodium oleate to enhance lead ion adsorption. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention addresses the issue of efficiently removing lead ions by adding an appropriate amount of anionic surfactant in conjunction with acid-modified silica gel, which combines with lead ions to form a colloid, thereby enhancing the adsorption performance of the silica gel.

[0005] This invention discloses a method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants, comprising the following steps:

[0006] Step 1

[0007] Adjust the pH of the lead ion-containing solution to 7-9; obtain the standby solution.

[0008] Step Two

[0009] Then, acid-modified silica gel and anionic surfactant are added to the standby solution; the mixture is stirred for adsorption, and then a flotation process is used to achieve solid-liquid separation, resulting in a lead-free solution.

[0010] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel; the concentration of lead ions in the standby solution is 1-5 mg / L.

[0011] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants. The acid-modified silica gel is prepared by the following steps: 1g of silica gel is mixed with 10-30ml of hydrochloric acid with a concentration of 1-4mol / L. The silica gel is added to the hydrochloric acid, stirred, and soaked for at least 6 hours. The solid and liquid are then separated, and the solid is washed with distilled water until the washing liquid is neutral. The solid is then placed in a drying oven to dry and cool, thus obtaining the acid-modified silica gel.

[0012] In industrial applications, nano-silica gel is soaked in hydrochloric acid overnight, washed with distilled water until it becomes neutral, then dried in a drying oven, cooled, and ready for use.

[0013] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel; the temperature of the drying oven is 100-120°C.

[0014] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel; 0.3-1.5g of acid-modified silica gel and 20-150ml of anionic surfactant are added to 1L of standby solution; acid-modified silica gel and anionic surfactant are added to the standby solution.

[0015] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants; 0.5-1.5g of acid-modified silica gel and 20-30ml of anionic surfactant are added to 1L of standby solution; acid-modified silica gel and anionic surfactant are added to the standby solution.

[0016] As a further preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants; 0.8-1.1g of acid-modified silica gel and 20-30ml of anionic surfactant are added to 1L of standby solution; acid-modified silica gel and anionic surfactant are added to the standby solution.

[0017] Preferably, this invention provides a method for enhancing the adsorption of lead ions on nano-silica gel using anionic surfactants; the anionic surfactant is selected from at least one of sodium oleate, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate. More preferably, the mass ratio of sodium dodecyl sulfate to oleic acid is 1:1 to 1:1.5. These anionic surfactants form colloids with lead, adsorbing onto the silica gel surface, thus enhancing the adsorption performance of the nano-silica gel and providing a certain foaming ability, thereby improving the flotation effect.

[0018] Preferably, this invention provides a method for enhancing the adsorption of lead ions by using an anionic surfactant; the anionic surfactant is composed of sodium oleate and sodium dodecyl sulfate. After optimization, the adsorption performance and efficiency of the nano-silica gel are further improved, and the flotation effect is also enhanced.

[0019] Preferably, the silica gel has a particle size of 5–40 nm and a specific surface area of ​​600–700 m². 2 / g, pore volume is 0.4~0.5L / g.

[0020] As a preferred option, the concentration of the anionic surfactant is 0.3 g / L to 1.2 g / L.

[0021] Preferably, this invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel; the stirring and adsorption time is 30–45 min. In industrial applications, ultrasound can be used as an auxiliary method, with the preferred ultrasound frequency being 45–55 kHz.

[0022] As a preferred embodiment, the present invention provides a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel; the flotation process is an air flotation process; during air flotation, the stirring speed is controlled at 1700-1900 rpm / min and the flotation is carried out in the flotation machine for 5-10 minutes.

[0023] This invention discloses a method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel. When treating an aqueous solution with a lead ion concentration of 0.8–1.2 mg / L, 92% or more of the lead can be removed within 60 minutes. After optimization, when treating an aqueous solution with a lead ion concentration of 0.8–1.2 mg / L, 96% or more of the lead can be removed within 50 minutes.

[0024] This invention discloses a method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants. The clarified solution after flotation is used as the treatment target. The anionic surfactant and acid-modified silica gel are added in a ratio of 1.0–1.2 ml of 0.3 g / L anionic surfactant and 8–10 mg of acid-modified silica gel particles per 40 ml of the treatment target. The solution is ultrasonically stirred for 35–45 min to adsorb the lead ions. After adsorption, the solution is subjected to air flotation at a stirring speed of 1700–1800 r / min.-1 The lead-adsorbed silica nanoparticles are floated in the flotation machine for 5-7 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

[0025] This invention discloses a method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants. After the initial lead removal, acid-modified silica gel and anionic surfactant are added to the solution. The solution is stirred for adsorption, followed by flotation to achieve solid-liquid separation, thereby reducing the lead ion concentration in the solution to below 0.1 mg / L.

[0026] The silicone material of this invention can be reused.

[0027] Compared with existing technologies, the advantages of this invention are as follows: the synthesis process of anionic surfactants is simple and their performance is stable. After adding anionic surfactants under neutral or alkaline conditions, acid-modified silica gel exhibits excellent adsorption performance for lead ions in solution, with short adsorption time and large adsorption capacity. Furthermore, by utilizing flotation to separate particulate solids, and again leveraging the foaming ability of the colloid formed by the anionic surfactant and lead ions, rapid separation of ionic lead from liquids (including water) is achieved. This invention enriches lead-adsorbed nano-silica gel particles in a foam layer via air flotation, separating them from the liquid phase, thus achieving the separation and removal of lead from solution. Experiments show that the anionic surfactant has the best adsorption efficiency for lead ions in a neutral or alkaline environment with a pH of 7-9. When its concentration is 0.3 g / L-1.2 g / L, the adsorption efficiency is high, with a single adsorption rate exceeding 90%. This means that under appropriate environmental conditions, efficient removal of lead ions can be achieved through two adsorption processes, resulting in a residual lead ion concentration below 0.01 mg / L, meeting drinking water standards.

[0028] Its process is simple, low-cost, and has broad application prospects, making it suitable for industrial production and promising for industrial applications. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Example 1

[0033] Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 1 mg / L.

[0034] Activated silica nanoparticles are prepared via the following process:

[0035] Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washings are neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​655m². 2 / g, pore volume is 0.43L / g. The concentration of hydrochloric acid used is 3mol / L.

[0036] Add 1 ml of 0.4 g / L sodium oleate anionic surfactant to 40 ml of the prepared 1 mg / L lead ion solution, adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles, and sonicate for 30 min (ultrasound frequency 50 kHz). After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 8 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be up to 95%.

[0037] Example 2

[0038] Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 2 mg / L.

[0039] Activated silica nanoparticles are prepared via the following process:

[0040] Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. Separate the solid and liquid. Wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​630m². 2 / g, pore volume is 0.45L / g. The concentration of hydrochloric acid used is 3mol / L.

[0041] Add 1.2 ml of 0.6 g / L sodium dodecylbenzenesulfonate anionic surfactant to 40 ml of the prepared 1 mg / L lead ion solution. Adjust the pH of the solution to 7.5 with HCl / NaOH, then add 35 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 35 min (ultrasonic frequency 50 kHz). After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 5 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be up to 93%.

[0042] Example 3

[0043] Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 2 mg / L.

[0044] Activated silica nanoparticles are prepared via the following process:

[0045] Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​650m². 2 / g, pore volume is 0.45L / g. The concentration of hydrochloric acid used is 3mol / L.

[0046] Add 0.8 ml of 0.4 g / L sodium dodecyl sulfate anionic surfactant to 40 ml of the prepared 1 mg / L lead ion solution. Adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles. Sonicate the solution for 40 min (50 kHz). After adsorption, use air flotation at a stirring speed of 1700 r / min. -1The lead-adsorbed silica nanoparticles were floated in a flotation machine for 6 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be up to 94%.

[0047] Example 4

[0048] Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 3 mg / L.

[0049] Activated silica nanoparticles are prepared via the following process:

[0050] Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​660m². 2 / g, pore volume is 0.45L / g. The concentration of hydrochloric acid used is 3mol / L.

[0051] Add 40 ml of the prepared 1 mg / L lead ion solution to 1.2 ml of 0.3 g / L anionic surfactant sodium dodecylbenzenesulfonate and sodium oleate (the mass ratio of sodium dodecylbenzenesulfonate to sodium oleate is 1:1). Adjust the pH of the solution to 7 with HCl / NaOH, then add 35 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 40 min (ultrasound frequency 50 kHz). After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 6 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be up to 96%.

[0052] The clarified solution after flotation was used as the treatment target. 0.3 g / L sodium dodecylbenzenesulfonate and 1.2 ml sodium oleate (mass ratio of sodium dodecylbenzenesulfonate to sodium oleate was 1:1) were added to the treatment target. The pH of the solution was adjusted to 7 with HCl / NaOH, and then 10 mg of activated silica nanoparticles were added. The mixture was ultrasonically stirred for 40 min (ultrasound frequency was 50 kHz). After adsorption, the solution was subjected to air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 6 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 99.95%.

[0053] Example 5

[0054] Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 3 mg / L.

[0055] Activated silica nanoparticles are prepared via the following process:

[0056] Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​660m². 2 / g, pore volume is 0.40L / g. The concentration of hydrochloric acid used is 3mol / L.

[0057] Add 0.3 g / L sodium dodecylbenzenesulfonate and 1.0 ml sodium oleate (mass ratio of sodium dodecylbenzenesulfonate to sodium oleate is 1:1.5) to 40 ml of the prepared 1 mg / L lead ion solution. Adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 40 min (ultrasound frequency 50 kHz). After adsorption, use air flotation at a stirring speed of 1800 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 6 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be up to 97%.

[0058] The clarified solution after flotation was used as the treatment target. 0.3 g / L of anionic surfactant sodium dodecylbenzenesulfonate and 1.0 ml of sodium oleate (mass ratio of sodium dodecylbenzenesulfonate to sodium oleate was 1:1.5) were added to the treatment target. The pH of the solution was adjusted to 7 with HCl / NaOH, and then 8 mg of activated silica nanoparticles were added. The mixture was ultrasonically stirred for 40 min (ultrasound frequency was 50 kHz). After adsorption, the solution was subjected to air flotation at a stirring speed of 1800 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 6 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 99.97%.

[0059] Comparative Example 1

[0060] Take 300 ml of the 1 mg / L lead ion solution prepared above, except that 1.0 ml of 0.4 g / L anionic surfactant sodium oleate is added; adjust the pH of the solution to 7.5 with HCl / NaOH, then add 40 mg of unactivated silica nanoparticles, and sonicate for 35 min (ultrasound frequency of 50 kHz). After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 5 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 60%.

[0061] Comparative Example 2

[0062] The nano-silica gel was activated using the method described in Example 1. 300 ml of the prepared 1 mg / L lead ion solution was mixed with 2.5 ml of 0.4 g / L sodium oleate anionic surfactant. The pH of the solution was adjusted to 7.5 using HCl / NaOH. Then, 40 mg of activated nano-silica gel particles were added, and the mixture was ultrasonically stirred for 35 min (ultrasound frequency 50 kHz). After adsorption, the mixture was subjected to air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 5 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 75%.

[0063] Comparative Example 3

[0064] The nano-silica gel was activated using the method described in Example 1. 40 ml of the prepared 1 mg / L lead ion solution (without anionic surfactant) was added, and the pH was adjusted to 7.5 with HCl / NaOH. Then, 40 mg of activated nano-silica gel particles were added, and the mixture was ultrasonically stirred for 35 min (ultrasound frequency 50 kHz). After adsorption, the mixture was subjected to air flotation at a stirring speed of 1700 r / min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 5 minutes, thus enriching them in the foam layer and separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 47%.

[0065] Comparative Example 4

[0066] The nano-silica gel was activated using the method described in Example 1. 40 ml of the previously prepared 1 mg / L lead ion solution was added, except that 0.8 ml of the 1.5 g / L anionic surfactant sodium oleate was added. The pH of the solution was adjusted to 7.5 using HCl / NaOH, and then 40 mg of activated nano-silica gel particles were added. The mixture was ultrasonically stirred for 35 min (ultrasound frequency 50 kHz). After adsorption, the mixture was subjected to air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 5 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 67%.

[0067] Comparative Example 5

[0068] The nano-silica gel was activated using the method described in Example 1. 40 ml of the previously prepared 1 mg / L lead ion solution was added, except that 1.0 ml of 0.1 g / L anionic surfactant sodium oleate was added. The pH of the solution was adjusted to 7.5 using HCl / NaOH, and then 40 mg of activated nano-silica gel particles were added. The mixture was ultrasonically stirred for 35 min (ultrasound frequency 50 kHz). After adsorption, the mixture was subjected to air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in a flotation machine for 5 minutes, enriching them in the foam layer and thus separating them from the liquid phase. The concentration of lead ions in the solution was determined by atomic absorption spectrometry (AAS), and the removal rate was calculated to be 73%.

[0069] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel, characterized in that: Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 1 mg / L. Activated silica nanoparticles are prepared via the following process: Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​655m². 2 / g, pore volume is 0.43L / g, and the concentration of hydrochloric acid used is 3mol / L; Add 1 ml of 0.4 g / L sodium oleate anionic surfactant to 40 ml of the prepared 1 mg / L lead ion solution. Adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 30 min at a frequency of 50 kHz. After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 8 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

2. A method for enhancing the adsorption of lead ions by nano-silica gel using anionic surfactants, characterized in that: Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 2 mg / L. Activated silica nanoparticles are prepared via the following process: Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​630m². 2 / g, pore volume is 0.45L / g, and the concentration of hydrochloric acid used is 3mol / L; Add 1.2 ml of 0.6 g / L sodium dodecylbenzenesulfonate anionic surfactant to 40 ml of the prepared 2 mg / L lead ion solution. Adjust the pH of the solution to 7.5 with HCl / NaOH, then add 35 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 35 min at a frequency of 50 kHz. After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 5 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

3. A method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel, characterized in that: Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 2 mg / L. Activated silica nanoparticles are prepared via the following process: Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​650m². 2 / g, pore volume is 0.45L / g, and the concentration of hydrochloric acid used is 3mol / L; Add 0.8 ml of 0.4 g / L sodium dodecyl sulfate anionic surfactant to 40 ml of the prepared 2 mg / L lead ion solution. Adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 40 min at a frequency of 50 kHz. After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 6 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

4. A method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel, characterized in that: Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 3 mg / L. Activated silica nanoparticles are prepared via the following process: Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. After solid-liquid separation, wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​660m². 2 / g, pore volume is 0.45L / g, and the concentration of hydrochloric acid used is 3mol / L; Add 1.2 ml of 0.3 g / L anionic surfactant (composed of sodium dodecylbenzenesulfonate and sodium oleate in a 1:1 mass ratio) to 40 ml of the prepared 3 mg / L lead ion solution. Adjust the pH of the solution to 7 with HCl / NaOH, then add 35 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 40 min at a frequency of 50 kHz. After adsorption, use air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 6 minutes, thus enriching them in the foam layer and separating them from the liquid phase. The clarified solution after flotation was used as the treatment target. 1.2 ml of a 0.3 g / L anionic surfactant (composed of sodium dodecylbenzenesulfonate and sodium oleate in a 1:1 mass ratio) was added to the treatment target. The pH of the solution was adjusted to 7 with HCl / NaOH. Then, 10 mg of activated silica nanoparticles were added, and the mixture was ultrasonically stirred for 40 min at a frequency of 50 kHz. After adsorption, the solution was subjected to air flotation at a stirring speed of 1700 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 6 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

5. A method for enhancing the adsorption of lead ions by using anionic surfactants on nano-silica gel, characterized in that: Lead nitrate was added to deionized water to prepare an initial solution with a lead ion concentration of 0.1 g / L; the initial solution was then diluted with deionized water to obtain a lead ion solution with a concentration of 3 mg / L. Activated silica nanoparticles are prepared via the following process: Prepare silica gel and hydrochloric acid by mixing 1g of silica gel with 20ml of hydrochloric acid. Add the prepared silica gel to the prepared hydrochloric acid, stir, and soak for 12 hours. Then, separate the solid and liquid. Wash the solid with distilled water until the washing solution is neutral. Then, dry the solid in a drying oven and cool it to obtain acid-modified silica gel. The silica gel has a particle size of 5-40nm and a specific surface area of ​​660m². 2 / g, pore volume is 0.40L / g, and the concentration of hydrochloric acid used is 3mol / L; Add 1.0 ml of 0.3 g / L anionic surfactant to 40 ml of the prepared 3 mg / L lead ion solution. The anionic surfactant is composed of sodium dodecylbenzenesulfonate and sodium oleate in a mass ratio of 1:1.

5. Adjust the pH of the solution to 7 with HCl / NaOH, then add 40 mg of activated silica nanoparticles. Adsorb the solution by ultrasonic stirring for 40 min at a frequency of 50 kHz. After adsorption, use air flotation at a stirring speed of 1800 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 6 minutes, thus enriching them in the foam layer and separating them from the liquid phase. The clarified solution after flotation was used as the treatment target. 1.0 ml of a 0.3 g / L anionic surfactant (composed of sodium dodecylbenzenesulfonate and sodium oleate in a mass ratio of 1:1.5) was added to the treatment target. The pH of the solution was adjusted to 7 with HCl / NaOH, followed by the addition of 8 mg of activated silica nanoparticles. The mixture was ultrasonically stirred and adsorbed for 40 min at a frequency of 50 kHz. After adsorption, the solution was subjected to air flotation at a stirring speed of 1800 r·min. -1 The lead-adsorbed silica nanoparticles were floated in the flotation machine for 6 minutes, thus enriching them in the foam layer and separating them from the liquid phase.

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