Preparation method of a functionalized light-driven nanomotor adsorbent and its adsorption application

Abstract

The present invention belongs to the technical field of preparing functional materials for ion recognition, adsorption, and separation, and discloses a method for preparing a functionalized light-driven nanomotor adsorbent and its adsorption application. The present invention uses a solvent method to load gold nanoparticles (Au NPs) inside HNTs to produce a good photothermal effect. The surface is then covered with a layer of polydopamine (PDA) and dithiothreitol succinate (DMSA), thereby improving the adsorption performance of the adsorbent. Experiments have shown that Au@DHNTs-DMSA has good photothermal conversion efficiency, biocompatibility, and biosafety, and an in vitro blood lead removal rate of up to 91.25%, making it effective in treating lead poisoning.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of functional materials for ion recognition, adsorption and separation, and specifically relates to a preparation method of a functionalized light-driven nanomotor adsorbent and its adsorption application. Technical Background

[0002] Lead is a heavy metal widely used in various industrial processes. However, lead emissions from these processes can cause severe environmental pollution. Furthermore, environmental lead can easily enter the human body through the food chain and accumulate in bones, blood, and other soft tissues, causing serious damage to the nervous, renal, cardiovascular, and reproductive systems. Therefore, effectively removing lead from blood has become a major challenge in the fields of environmental protection and biomedical functional materials. Currently, hemoperfusion is one of the most commonly used methods for removing lead ions from blood. It offers the advantages of large adsorption capacity and wide adaptability. However, conventional hemoperfusion adsorbents have poor biocompatibility and low selectivity for target compounds, resulting in limited removal efficiency and application environments. Therefore, there is an urgent need to develop new hemoperfusion adsorbents with enhanced safety and biocompatibility. Halloysite nanotubes (HNTs), as natural clay minerals, are often used in drug delivery due to their low cost, large specific surface area, and good biocompatibility. Therefore, incorporating HNTs as a substrate into the preparation of novel hemoperfusion adsorbents could significantly improve their safety and biocompatibility. However, this alone is not enough. Due to the low mass transfer efficiency of the adsorbent, its adsorption efficiency is low, which prolongs the time it takes to remove blood lead. Therefore, the development of a hemoperfusion adsorbent with high adsorption efficiency remains an urgent problem to be solved.

[0003] To further enhance the adsorption performance of novel hemoperfusion adsorbents, we combined micro / nanomotor strategies to fabricate micro / nanomotor adsorbents and address the issue of rapid contact between the adsorbent and the target. Artificial micro / nanomotors, with their ability to convert various external energies into kinetic energy, are widely used in biomedical fields such as drug delivery, medical diagnostics, and chemical detoxification. External energy sources include various stimuli such as light, electric fields, magnetic fields, temperature, and fuel gradients, which can trigger motor propulsion, stopping, and direction changes. Most micro / nanomotors are propelled by decomposing substrates, but in practical applications, this often requires the addition of toxic chemical fuels such as hydrogen peroxide or hydrazine, severely limiting their biomedical applications. Near-infrared (NIR) light, an electromagnetic wave between visible and mid-infrared light, offers advantages such as high penetrability, good controllability, excellent safety, significant thermal effects, and long-range propagation. Therefore, NIR-driven photothermal motors are particularly well-suited for achieving controllable motion in complex biological environments. In summary, the present invention proposes to combine HNTs and NIR-driven photothermal motors to prepare a novel hemoperfusion adsorbent with high safety, good biocompatibility, and excellent adsorption performance. This approach has not yet been reported. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention proposes a method for preparing a functionalized light-driven nanomotor adsorbent to selectively adsorb and separate Pb(II) in order to solve the technical bottlenecks of existing nanoadsorbents, such as low adsorption performance, poor biocompatibility, and application conditions that are not suitable for biological environments.

[0005] The present invention prepares a HNT-based photothermal nanomotor adsorbent modified with dithiothiocyanate (DMSA) for removing lead ions from blood. First, gold nanoparticles are loaded onto the inner surface of HNTs by solvent evaporation. Polydopamine (PDA) and DMSA are then modified on the outer surface to produce the Au@DHNTs-DMSA nanomotor adsorbent. Near-infrared (NIR) testing demonstrates that Au@DHNTs-DMSA rapidly generates heat under NIR illumination, forming a thermal gradient on the surface and exhibiting excellent photothermal conversion efficiency. Furthermore, NIR irradiation enables the adsorbent to move, improving the mass transfer efficiency between the adsorbent and Pb(II) and raising the ambient temperature during adsorption, significantly increasing adsorption capacity. Furthermore, as a blood lead adsorbent, Au@DHNTs-DMSA exhibits excellent biocompatibility and a blood lead removal efficiency exceeding 90%. In selectivity experiments, Au@DHNTs-DMSA exhibits excellent adsorption selectivity while adsorbing Pb(II).

[0006] In order to achieve the above technical purpose, the technical solution adopted by the present invention is:

[0007] This paper proposes a method for preparing a functionalized light-driven nanomotor adsorbent (Au@DHNTs-DMSA). The selective adsorption and separation of Pb(II) ions by the Au@DHNTs-DMSA adsorbent was evaluated using a simulated Pb(II) solution. The method includes the following steps:

[0008] (1) Activation of halloysite nanotubes (HNTs)

[0009] The HNTs powder was dispersed in a hydrochloric acid solution and stirred at room temperature for a certain period of time. The acid-treated HNTs were then washed with deionized water and centrifuged. Finally, the activated HNTs were dried in a vacuum drying oven.

[0010] (2) Halloysite nanotubes loaded with gold nanoparticles (Au@HNTs)

[0011] The HNTs activated in step (1) were mixed with HAuCl4·3H2O, ethanol, toluene, oleylamine and oleic acid, ultrasonically dispersed, and heated and stirred for the first time under magnetic stirring;

[0012] Then, a certain amount of ascorbic acid (AAc) was added, and the mixture was heated and stirred for the second time. The resulting dark product was washed repeatedly with ethanol and toluene alternately for several times, and then washed with toluene several times to remove the free gold nanoparticles (Au NPS) in the solution. Finally, it was dried in a vacuum drying oven to obtain the product Au@HNTs.

[0013] (3) Preparation of Au@DHNTs-DMSA by surface modification of Au@HNTs with polydopamine and DMSA

[0014] Au@HNTs were dispersed in Tris buffer and then mixed evenly with Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA). After stirring at a certain temperature for a certain time, the reaction was centrifuged and the solid product was washed with ethanol and deionized water. Finally, it was dried in a vacuum drying oven to obtain Au@DHNTs-DMSA.

[0015] In step (1), the ratio of the HNTs powder to the hydrochloric acid solution is: 1.0 g: (5.0-15) mL, wherein the concentration of the hydrochloric acid solution is 2.0 mol / L.

[0016] In step (1), the stirring time is 24 hours.

[0017] In step (1), the acid-treated HNTs are washed with deionized water until the pH of the solution is 7.0.

[0018] In step (2), the usage ratio of the activated NHTs, HAuCl4·3H2O, ethanol, toluene, oleylamine, oleic acid and ascorbic acid (AAc) is 1.0 mg:(1.40-1.50) mg:(0.10-0.15) mL:(0.10-0.15) mL:(0.01-0.05) mL:(0.01-0.05) mL:(5.0-15) mg.

[0019] In step (2), the temperature of the first heating and stirring is 55° C. and the time is 1.0 min.

[0020] In step (2), the temperature of the second heating and stirring is 55° C. and the time is 20 min.

[0021] In step (3), the dosage ratio of the Au@HNTs to the Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) is 1.0 mg:(0.25-0.75) mL, wherein the concentrations of dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) in the Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) are both 2.0 mg / mL.

[0022] In step (3), the concentration of the Tris buffer is 10 mM, and the pH is 8.5.

[0023] In step (3), the stirring temperature is 37° C. and the stirring time is 12 h.

[0024] In steps (1), (2) and (3), the temperature of the vacuum drying oven is 50°C.

[0025] The Au@DHNTs-DMSA adsorbent prepared by the present invention is used for the selective adsorption and separation of Pb(II).

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This study has designed a blood lead adsorbent more suitable for biological environments. Au is loaded onto HNTs, and then DMSA is modified with PDA to attach to the HNTs' outer surface to create a near-infrared light-driven Au@DHNTs-DMSA nanomotor adsorbent. Due to the presence of thiol and carboxyl groups in DMSA, Au@DHNTs-DMSA exhibits extremely high selectivity. Furthermore, Au@DHNTs-DMSA exhibits excellent biocompatibility and biosafety, making it an effective treatment for lead poisoning and possessing significant research implications for biological applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1FT-IR patterns (a) and XRD patterns (b) of Au@DHNTs and Au@DHNTs-DMSA prepared in Example 1.

[0029] Figure 2 (a, b) are TEM images of Au@DHNTs (ascorbic acid mass is 150 mg) in Example 1.

[0030] (c) is the TEM image of Au@DHNTs (the mass of ascorbic acid is 75 mg) in Example 2.

[0031] (d)-(f) are TEM images of Au@DHNTs-DMSA in Example 1.

[0032] Figure 3 In Example 1, 1.0 W / cm 2 Thermal imaging of Au@DHNTs-DMSA suspensions with different concentrations under near-infrared light (808 nm) (a); temperature changes of 1.0 mg / mL Au@DHNTs-DMSA suspension under near-infrared light (808 nm) of different powers (b).

[0033] Figure 4 Schematic diagram of the Au@DHNTs-DMSA near-infrared nanomotor prepared in Example 1 (a) and the motion trajectory (b) and average speed (c) of Au@DHNTs-DMSA under near-infrared irradiation of different powers.

[0034] Figure 5 Effects of pH (a) and temperature (b) on the adsorption of Au@DHNTs-DMSA in Example 1, and Van't Hoff diagram.

[0035] Figure 6 (a) The adsorption kinetics diagram and (b) the adsorption thermodynamics diagram of Au@DHNTs-DMSA prepared in Example 1 for Pb(II).

[0036] Figure 7 2 is the adsorption capacity change curve of Au@DHNTs-DMSA prepared in Example 1 under the presence or absence of near-infrared light (NIR) irradiation.

[0037] Figure 8 (a) The selective adsorption diagram of Au@DHNTs-DMSA prepared in Example 1 and (b) the removal rate of blood lead by Au@DHNTs-DMSA under near-infrared light. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below with reference to specific embodiments and drawings.

[0039] Example 1:

[0040] (1) Activation of halloysite nanotubes (HNTs)

[0041] 5.0 g of HNTs powder was dispersed in 50 mL of hydrochloric acid solution (2.0 mol / L) and stirred at room temperature for 24 h. The acid-treated HNTs were then washed with deionized water until the solution reached a pH of 7.0. Finally, the solution was dried in a vacuum drying oven at 50°C to obtain activated HNTs.

[0042] (2) Halloysite nanotubes loaded with gold nanoparticles (Au@HNTs)

[0043] 15 mg of activated HNTs, 22 mg of HAuCl4·3H2O, 2.0 mL of ethanol, 2.0 mL of toluene, 0.5 mL of oleylamine, and 0.5 mL of oleic acid were added to a 20 mL flask and dispersed by ultrasonication. The mixture was heated to 55°C under magnetic stirring and stirred for 1.0 min. Then, 150 mg of ascorbic acid (AAc) was added to the flask and stirred at 55°C for 20 min. The color of the solution rapidly changed from light yellow to dark purple, indicating the formation of gold nanoparticles (Au NPs). The resulting dark product was washed several times with alternating ethanol and toluene, followed by repeated washing with toluene to remove free Au NPs. Finally, the product was dried in a vacuum oven to obtain Au@HNTs.

[0044] (3) Preparation of Au@DHNTs-DMSA by surface modification of Au@HNTs with polydopamine and DMSA

[0045] 100 mg of Au@HNTs was dispersed in 10 mM Tris buffer (pH 8.5) and mixed with 50 mL of Tris buffer containing 2.0 mg / mL dopamine hydrochloride (DA) and 2.0 mg / mL dimercaptosuccinic acid (DMSA). The reaction was stirred at 37°C for 12 hours, followed by centrifugation, washing the solid product with ethanol and deionized water, and finally drying in a vacuum oven at 50°C to obtain Au@DHNTs-DMSA.

[0046] Example 2:

[0047] (1) Activation of halloysite nanotubes (HNTs)

[0048] 5.0 g of HNTs powder was dispersed in 25 mL of hydrochloric acid solution (2.0 mol / L) and stirred at room temperature for 24 h. The acid-treated HNTs were then washed with deionized water until the solution reached a pH of 7.0. Finally, the HNTs were dried in a vacuum drying oven at 50°C to obtain activated NHTs.

[0049] (2) Halloysite nanotubes loaded with gold nanoparticles (Au@HNTs)

[0050] 15 mg of activated HNTs, 21 mg of HAuCl4·3H2O, 1.5 mL of ethanol, 1.5 mL of toluene, 0.15 mL of oleylamine, and 0.15 mL of oleic acid were added to a 20 mL flask and dispersed by ultrasonication. The mixture was heated to 55°C under magnetic stirring and stirred for 1.0 min. Then, 75 mg of ascorbic acid (AAc) was added to the flask and stirred at 55°C for 20 min. The color of the solution rapidly changed from light yellow to dark purple, indicating the formation of gold nanoparticles (Au NPs). The resulting dark product was washed several times with alternating ethanol and toluene, followed by several washes with toluene to remove free Au NPs. Finally, the product was dried in a vacuum oven to obtain Au@HNTs.

[0051] (3) Preparation of Au@DHNTs-DMSA by surface modification of Au@HNTs with polydopamine and DMSA

[0052] 100 mg of Au@HNTs was dispersed in 10 mM Tris buffer (pH 8.5) and mixed with 25 mL of Tris buffer containing 2.0 mg / mL dopamine hydrochloride (DA) and 2.0 mg / mL dithiothreitol succinic acid (DMSA). The reaction was stirred at 37°C for 12 hours, followed by centrifugation, washing the solid product with ethanol and deionized water, and finally drying in a vacuum oven at 50°C to obtain Au@DHNTs-DMSA.

[0053] Example 3:

[0054] (1) Activation of halloysite nanotubes (HNTs)

[0055] 5.0 g of HNTs powder was dispersed in 75 mL of hydrochloric acid solution (2.0 mol / L) and stirred at room temperature for 24 h. The acid-treated HNTs were then washed with deionized water until the solution reached a pH of 7.0. Finally, the HNTs were dried in a vacuum drying oven at 50°C to obtain activated NHTs.

[0056] (2) Halloysite nanotubes loaded with gold nanoparticles (Au@HNTs)

[0057] 15 mg of activated NHTs, 22.5 mg of HAuCl4·3H2O, 2.25 mL of ethanol, 2.25 mL of toluene, 0.75 mL of oleylamine, and 0.75 mL of oleic acid were added to a 20 mL flask and dispersed by ultrasonication. The mixture was heated to 55°C under magnetic stirring and stirred for 1.0 min. Then, 225 mg of ascorbic acid (AAc) was added to the flask and stirred at 55°C for 20 min. The color of the solution rapidly changed from light yellow to dark purple, indicating the formation of gold nanoparticles (Au NPs). The resulting dark product was washed several times with alternating ethanol and toluene, followed by several washes with toluene to remove free Au NPs. Finally, the product was dried in a vacuum oven to obtain Au@HNTs.

[0058] (3) Preparation of Au@DHNTs-DMSA by surface modification of Au@HNTs with polydopamine and DMSA

[0059] 100 mg of Au@HNTs was dispersed in 10 mM Tris buffer (pH 8.5) and mixed with 75 mL of Tris buffer containing 2.0 mg / mL dopamine hydrochloride (DA) and 2.0 mg / mL dithiothreitol succinic acid (DMSA). The reaction was stirred at 37°C for 12 hours, followed by centrifugation, washing the solid product with ethanol and deionized water, and finally drying in a vacuum oven at 50°C to obtain Au@DHNTs-DMSA.

[0060] Figure 1 (a) shows the FT-IR spectra of Au@HNTs and Au@DHNTs-DMSA. As a metal element, AuNPs has no vibration peaks in the infrared spectrum, so the spectrum of Au@HNTs is consistent with that of HNTs. In the spectrum of Au@DHNTs-DMSA, at 3630 cm -1 and 3570cm -1 The characteristic peak at 1230 cm-1 is derived from the stretching vibration of Si-OH, but the intensity of the characteristic peak is reduced due to the modification of PDA and DMSA. -1 and 1400cm -1 The two characteristic peaks at 3346 cm are caused by the stretching vibration of C=O and the bending vibration of NH in PDA, respectively. -1 The broad peak at 1631 cm is attributed to the bending vibration of NH and OH. However, the infrared spectrum has a low sensitivity to -SH, so it is difficult to observe its absorption peak. -1 The characteristic peaks can be attributed to the stretching vibration of C=O in DMSA. FTIR results show that PDA and DMSA were successfully modified on the outer surface of HNTs. Figure 1The XRD results in (b) show that the gold-specific (111), (200), (220) and (311) crystal planes exist in the spectra of Au@HNTs and Au@DHNTs-DMSA, which proves that gold nanoparticles (AuNPs) are loaded on HNTs and the AuNPs are not destroyed in the subsequent modification.

[0061] Figure 2 The morphology and nanoparticle structure of Au@HNTs and Au@DHNTs-DMSA were analyzed by transmission electron microscopy (TEM). Figure 2 As shown in (ac), different loading effects can be achieved by using different masses of ascorbic acid (AAc) to reduce gold tetrachloride when loading Au NPs. When the mass of AAc is 150 mg, the size of the Au NPs in the obtained Au@HNTs is about 10-30 nm and is evenly distributed in the tube in a chain-like arrangement ( Figure 2 (a, b)), even Au NPs are linked to each other; and when the mass of AAc is 75 mg, such as Figure 2 In (c), it was observed that only a small amount of Au NPs was loaded in the Au NPs tube, indicating that 150 mg is more conducive to the preparation of a motor adsorbent with good photosensitivity. Then, the Au@HNTs modified with PDA and DMSA maintained a hollow tubular structure, and polymer was clearly seen on the outer surface. This is because the presence of the PDA layer makes the outer surface of the Au@DHNTs-DMSA rough and uneven in thickness, as shown in Figure 2. Figure 2 (df), indicating that the surface modification was successful and the modification process did not affect the tubular structure of HNTs.

[0062] In the work, the photothermal conversion performance of Au@DHNTs-DMSA was tested by a near-infrared laser emitter and an infrared thermal imager, providing a basis for the subsequent movement and adsorption process of the motor adsorbent. Figure 3 (a) is a thermal image of Au@DHNTs-DMSA suspension at different concentrations. It can be observed that under the irradiation of near-infrared light, the Au@DHNTs-DMSA suspension system has a very obvious temperature increase phenomenon compared to pure water, and the temperature increase gradient increases with the extension of irradiation time, which shows that it has excellent photothermal properties. Figure 3 (b) shows that as the near-infrared light power increases, the temperature rises. 2 The highest temperature after 120s of illumination is 0.75W / cm 2 The high is 12.4℃.

[0063] Figure 4(a) is a schematic diagram of the near-infrared driven nanomotor. The PDA and Au NPs on the Au@DHNTs-DMSA can absorb near-infrared light, generate a temperature gradient, and drive by self-thermophoresis. Figure 4 As shown in (b), as the near-infrared light power density increases from 0.5W / m 2 Increased to 1.0W / cm 2 At the same time, the trajectory of the nanomotor is extended within the same time, indicating that regulating the infrared light intensity can achieve control of the motor speed. At the same time, near-infrared light drive makes the movement of Au@DHNTs-DMSA directional, and its movement trajectory is close to a straight line. The motor movement trajectory is analyzed through the Tracking plug-in, and the calculated average speed can be used to quantitatively compare the propulsion performance of Au@DHNTs-DMSA under different near-infrared laser power densities. Figure 4 In (c), when the power density of near-infrared light is increased from 0.5W / cm 2 Increased to 1.0W / cm 2 When the adsorption rate was 1.0W / cm2, the average motion velocity of Au@DHNTs-DMSA increased from 194.6μm / s to 327.3μm / s, indicating that effective near-infrared light driving was achieved. 2 The near-infrared light-driven motor accelerates the mass transfer rate, increases the probability of Au@DHNTs-DMSA contacting lead ions, and thus improves the adsorption performance.

[0064] Test Example 1:

[0065] 8.0 mg of the product Au@DHNTs-DMSA from step (3) of Example 1 was added to a 10 mL centrifuge tube, followed by 8.0 mL of a 50 mg / L Pb(II) solution with pH values ​​of 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0. The centrifuge tube was placed in a constant temperature water bath for 12 hours of static adsorption. After adsorption, the adsorbent was separated by centrifugation, and the supernatant was filtered using a microporous nitrocellulose membrane. The Pb(II) concentration in the filtrate was determined by ICP-OES. The above steps were repeated for three parallel experiments to calculate the equilibrium adsorption amount Q. e (mg / g). Figure 5 As shown in (a), when the solution pH increases from 1.0 to 5.0, the adsorption capacity (Q e ) gradually increases, and when the pH is 5.0-6.0, Q e The adsorption capacity gradually stabilized and reached a maximum of 46.80 mg / g. This is because a large amount of H +It competes with Pb(II) for adsorption, occupying the majority of adsorption sites on the Au@DHNTs-DMSA surface. As the pH increases, Pb(II) dominates the adsorption process. However, during the experiment, when the pH exceeds 5.0, the Pb(II) solution begins to precipitate, which will affect the evaluation of the adsorption performance of Au@DHNTs-DMSA. Therefore, the following experiments selected pH = 5.0 as the optimal adsorption condition to study the adsorption capacity of Au@DHNTs-DMSA for lead ions.

[0066] Test Example 2:

[0067] 8.0 mg of the product Au@DHNTs-DMSA from step (3) of Example 1 was added to 8.0 mL of Pb(II) solution (50 mg / L, pH = 5.0) and adsorbed at 25°C, 35°C, and 45°C for 1.0 h. The mixture was then filtered through a nitrocellulose membrane and the residual lead ion concentration in the supernatant was determined by ICP-OES. The above steps were repeated for three sets of parallel experiments to calculate the equilibrium adsorption capacity Q. e (mg / g). Figure 5 As shown in (b), when the temperature rises from 25℃ to 45℃, the adsorption capacity of Au@DHNTs-DMSA increases from 46.677mg / g to 49.734mg / g. At the same time, the adsorption thermodynamic properties of the nanomotor adsorbent were studied using thermodynamic parameters, including Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS), to determine the thermodynamic adsorption mechanism of Au@DHNTs-DMSA for Pb(Ⅱ). The Van't Hoff diagram is ln(Q e / C e ) and 1 / T ( Figure 5 (c)) was used to calculate ΔH, ΔS, and ΔG values. A ΔH > 0 indicates that the adsorption of Pb(II) by the nanomotor is endothermic, meaning that higher temperatures lead to better adsorption performance. Furthermore, a ΔG < 0 indicates that the adsorption process is reversible and spontaneous, and that increasing temperature facilitates adsorption, leading to an increase in adsorption capacity.

[0068] By studying the adsorption isotherm of the adsorbent, the adsorption characteristics of the adsorbent can be evaluated, which helps to understand the adsorption principle between the adsorbent and the target. Figure 6 As shown in (b), with the increase of the initial concentration of Pb(II), the adsorption capacity of Au@DHNTs-DMSA increased significantly and eventually reached adsorption saturation. In this work, the Langmuir and Freundlich models were used to fit and analyze the equilibrium adsorption process. At different temperatures, the fitting coefficient R1 of the Langmuir model was 2Both are higher than the Freundlich model, indicating that the Langmuir model can better describe the adsorption process, which is a monolayer adsorption and mainly depends on the chemical interaction between surface functional groups and lead ions.

[0069] Test Example 3:

[0070] 8.0 mg of the product Au@DHNTs-DMSA from step (3) of Example 1 was added to 8.0 mL of Pb(II) solution (50 mg / L, pH = 5.0) and adsorbed at 25°C for 1.0 min, 3.0 min, 5.0 min, 10 min, 15 min, 20 min, 30 min, and 40 min, respectively. The mixture was then filtered through a nitrocellulose membrane and the residual lead ion concentration in the supernatant was determined by ICP-OES. The above steps were repeated for three sets of parallel experiments to calculate Q. t (mg / g). Figure 6 (a) shows the adsorption kinetics of Pb(II) by the adsorbent (0-40 min). The adsorption process can be roughly divided into three stages. In the initial stage (about 0-5.0 min), the adsorption capacity increases rapidly. In the transition stage (5.0-20 min), the adsorption capacity growth slows down significantly. Finally, the adsorption equilibrium stage (about 20-40 min) is reached, and the active sites on the adsorbent reach saturation (Q e =46.129 mg / g). The adsorption kinetic data were fitted using pseudo-first-order kinetic model and pseudo-second-order kinetic model. The fitting coefficient R2 of the pseudo-second-order kinetic model for the adsorption process was 2 R1 of the pseudo-first-order kinetic model 2 High, Q e,c With Q e,e The results are quite close, which indicates that the pseudo-second-order kinetic model is applicable to the adsorption kinetics of Au@DHNTs-DMSA to Pb(Ⅱ), which is mainly chemical adsorption.

[0071] Test Example 4:

[0072] Use 1.0W / cm 2 The product of step (3) in Example 1, Au@DHNTs-DMSA, was driven to adsorb Pb(II) in aqueous solution (200 mg / L, pH = 5.0) by irradiation with near-infrared light of high power. The irradiation time was 0.5 min, 1.0 min, 2.0 min, 3.0 min, 4.0 min and 5.0 min. The residual Pb(II) concentration was measured by ICP-OES and the adsorption capacity (Q e , mg / g). Experimental data are as follows Figure 7As shown in the figure, the adsorption capacity increases significantly with increasing near-infrared light irradiation time. The adsorption capacity under near-infrared light irradiation at each time point is higher than that without near-infrared light irradiation. The adsorption capacity of Au@DHNTs-DMSA for Pb(II) reaches 151.769 mg / g at 5.0 min, which is 1.80 times the adsorption capacity of the nanomotor without near-infrared light irradiation (84.242 mg / g). This is because the light-driven Au@DHNTs-DMSA accelerates the adsorption rate and increases the contact probability between Pb(II), resulting in a higher adsorption capacity within a limited time. At the same time, the increase in solution temperature under near-infrared light irradiation also promotes the improvement of adsorption capacity.

[0073] Test Example 5:

[0074] 8.0 mg of the product Au@DHNTs-DMSA of step (3) in Example 1 was added to a mixed solution (8.0 mL) of K(I), Pb(II), Ca(II), Mg(II) and Na(I) with an ion concentration of 100 mg / L. The mixture was adsorbed at 25°C for 1.0 h, centrifuged, and the supernatant was passed through a membrane. The residual Pb(II) concentration was detected by ICP-OES. The above steps were repeated for three groups of parallel experiments. The adsorption capacity Q for different metal ions was calculated using the formula e (mg / g). Figure 8 As shown in (a), in a mixed solution of Ca(Ⅱ), K(Ⅰ), Mg(Ⅱ), Na(Ⅰ) and Pb(Ⅱ) (pH = 5.0, 100 mg / L), the adsorption capacity of Au@DHNTs-DMSA for Pb(Ⅱ) is 71.782 mg / g, which is consistent with the adsorption capacity of a single Pb(Ⅱ) solution, and the adsorption capacity of other ions is extremely low, indicating that Au@DHNTs-DMSA has excellent competitive adsorption capacity for Pb(II), with an adsorption efficiency of up to 70%, and has great application potential in blood lead removal.

[0075] Test Example 6:

[0076] Fresh blood was collected and added with a PBS solution containing Pb(II) ions. The blood lead concentration was adjusted to 0.1 mg / L, 0.2 mg / L, 0.3 mg / L, and 0.4 mg / L, respectively. The blood was incubated in a constant temperature water bath at 37°C for 2.0 h to obtain lead-containing blood. 2.0 mg of the product Au@DHNTs-DMSA from step (3) of Example 1 was added to 2.0 mL of fresh blood with different blood lead concentrations and irradiated with near-infrared light for 0.5 min (to prevent the solution temperature from being too high and damaging red blood cells). After adsorption was completed, the solution was centrifuged (10,000 rpm, 10 min) and the supernatant was separated. 0.5 mL of the upper layer solution was added to a Teflon reactor and then digested with a mixture of 4.5 mL of nitric acid and hydrogen peroxide (volume ratio of 7:3) at 180°C under high temperature and pressure for 2.0 h. The liquid was then transferred to a 5.0 mL volumetric flask and made up to volume with deionized water. The concentration of Pb(II) in the blood before and after adsorption was determined by ICP-OES. The above steps were carried out in three sets of parallel experiments and a blank control experiment, and the adsorption efficiency was calculated. Figure 8 (b) shows the adsorption capacity and removal rate of Au@DHNTs-DMSA in the in vitro blood lead adsorption study. With the increase of blood lead concentration, the adsorption capacity and removal rate of blood lead increased. 2 Under near-infrared light irradiation, the maximum blood lead removal rate was 91.25%, which indicated that the nanomotor effectively enhanced the blood lead removal efficiency.

[0077] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Therefore, although this specification has described the present invention in detail with reference to the above embodiments, it should be understood by those skilled in the art that the present invention may still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for preparing a functionalized light-driven nanomotor adsorbent, characterized in that: The following steps are involved: (1) Activation of halloysite nanotubes (HNTs): The HNTs powder was dispersed in a hydrochloric acid solution and stirred at room temperature for a certain period of time. The acid-treated HNTs were then washed with deionized water and centrifuged. Finally, the HNTs were dried in a vacuum drying oven to obtain activated HNTs. (2) Halloysite nanotubes loaded with gold nanoparticles Au@HNTs: The HNTs activated in step (1) were mixed with HAuCl4·3H2O, ethanol, toluene, oleylamine and oleic acid, ultrasonically dispersed, and heated and stirred for the first time under magnetic stirring; Then, a certain amount of ascorbic acid (AAc) was added, and the mixture was heated and stirred for the second time. The resulting dark product was washed repeatedly with ethanol and toluene alternately for several times, and then washed with toluene several times to remove the free gold nanoparticles (Au NPS) in the solution. Finally, it was dried in a vacuum drying oven to obtain the product Au@HNTs. (3) Au@HNTs surface modified with polydopamine and DMSA to prepare Au@DHNTs-DMSA: Au@HNTs were dispersed in Tris buffer and then mixed evenly with Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA). After stirring at a certain temperature for a certain time, the reaction was centrifuged and the solid product was washed with ethanol and deionized water. Finally, it was dried in a vacuum drying oven to obtain the functionalized light-driven nanomotor adsorbent Au@DHNTs-DMSA.

2. The preparation method according to claim 1, wherein In step (1), the ratio of the HNTs powder to the hydrochloric acid solution is: 1.0 g: (5.0-15) mL, wherein the concentration of the hydrochloric acid solution is 2.0 mol / L.

3. The preparation method according to claim 1, wherein In step (1), the stirring time is 24 hours; the acid-treated HNTs are washed with deionized water until the solution pH is 7.

0.

4. The preparation method according to claim 1, wherein In step (2), the ratio of the activated HNTs, HAuCl4·3H2O, ethanol, toluene, oleylamine, oleic acid and ascorbic acid (AAc) is 1.0 mg: (1.40-1.50) mg: (0.10-0.15) mL: (0.10-0.15) mL: (0.01-0.05) mL: (0.01-0.05) mL: (5.0-15) mg.

5. The preparation method according to claim 1, wherein In step (2), the temperature of the first heating and stirring is 55° C., and the time is 1.0 min; the temperature of the second heating and stirring is 55° C., and the time is 20 min.

6. The preparation method according to claim 1, wherein In step (3), the dosage ratio of the Au@HNTs to the Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) is 1.0 mg:(0.25-0.75) mL, wherein the concentrations of dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) in the Tris buffer containing dopamine hydrochloride (DA) and dimercaptosuccinic acid (DMSA) are both 2.0 mg / mL.

7. The preparation method according to claim 1, wherein In step (3), the concentration of the Tris buffer is 10 mM, and the pH is 8.

5.

8. The preparation method according to claim 1, wherein In step (3), the stirring temperature is 37° C. and the stirring time is 12 h.

9. The preparation method according to claim 1, wherein In steps (1), (2) and (3), the temperature of the vacuum drying oven is 50°C.

10. Use of the functionalized light-driven nanomotor adsorbent prepared by the preparation method according to any one of claims 1 to 9 for the selective adsorption and separation of Pb(II).

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