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WO2021088159A1 - 一种吸附Pb和Cd的改性环糊精/介孔硅及其应用 - Google Patents

一种吸附Pb和Cd的改性环糊精/介孔硅及其应用 Download PDF

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WO2021088159A1
WO2021088159A1 PCT/CN2019/121385 CN2019121385W WO2021088159A1 WO 2021088159 A1 WO2021088159 A1 WO 2021088159A1 CN 2019121385 W CN2019121385 W CN 2019121385W WO 2021088159 A1 WO2021088159 A1 WO 2021088159A1
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modified cyclodextrin
mesoporous silica
adsorption
solution
naoh
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PCT/CN2019/121385
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English (en)
French (fr)
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王金鹏
李静
金征宇
徐学明
田耀旗
龙杰
周星
谢正军
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江南大学
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Publication of WO2021088159A1 publication Critical patent/WO2021088159A1/zh
Priority to US17/402,871 priority Critical patent/US12145866B2/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J20/28078—Pore diameter
    • B01J20/28083—Pore diameter being in the range 2-50 nm, i.e. mesopores
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/24—Naturally occurring macromolecular compounds, e.g. humic acids or their derivatives
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3071—Washing or leaching
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/286—Treatment of water, waste water, or sewage by sorption using natural organic sorbents or derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/288—Treatment of water, waste water, or sewage by sorption using composite sorbents, e.g. coated, impregnated, multi-layered
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
    • C02F1/62—Heavy metal compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/46—Materials comprising a mixture of inorganic and organic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4806—Sorbents characterised by the starting material used for their preparation the starting material being of inorganic character
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4812—Sorbents characterised by the starting material used for their preparation the starting material being of organic character
    • B01J2220/4825—Polysaccharides or cellulose materials, e.g. starch, chitin, sawdust, wood, straw, cotton
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4812—Sorbents characterised by the starting material used for their preparation the starting material being of organic character
    • B01J2220/4825—Polysaccharides or cellulose materials, e.g. starch, chitin, sawdust, wood, straw, cotton
    • B01J2220/4831—Polysaccharides or cellulose materials, e.g. starch, chitin, sawdust, wood, straw, cotton having been subjected to further processing, e.g. paper, cellulose pulp
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/285—Treatment of water, waste water, or sewage by sorption using synthetic organic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/16—Regeneration of sorbents, filters

Definitions

  • the invention relates to a modified cyclodextrin/mesoporous silicon capable of adsorbing Pb and Cd and its application, and belongs to the technical field of adsorption materials.
  • ⁇ -CD is non-toxic, easily degradable, and has a special molecular structure of "hydrophilic outer cavity and hydrophobic inner cavity".
  • hydrophilic outer cavity and hydrophobic inner cavity due to its limited cavity size, its own solubility in water and poor mechanical properties, it is used for construction Supramolecular materials are still difficult, and traditional modified cyclodextrins have problems such as complicated preparation process, large amount of reactants, relatively high cost, and low yield of intermediate products.
  • the modified cyclodextrin/mesoporous silicon adsorption material prepared by the present invention is simple and easy to obtain, can achieve rapid adsorption in a short time, has good selectivity to Pb and Cd, and has relatively important applications in wastewater treatment, etc. value.
  • the present invention provides a method for preparing a modified cyclodextrin/mesoporous silicon adsorption material that selectively adsorbs Pb and Cd.
  • the preparation steps of the invention are simple and easy to control, flexible, easy to popularize, low cost, high adsorption efficiency, recyclable and other advantages, can effectively solve the problems of heavy metal ion pollution in wastewater treatment, and are used in chemical, petroleum, food, Light industry and environmental protection also have potential applications.
  • the first object of the present invention is to provide a modified cyclodextrin/mesoporous silica.
  • the preparation method of the modified cyclodextrin/mesoporous silica is to select chloroacetic acid as the anion, and modify the cyclodextrin to pass through
  • the nucleophilic substitution method is grafted to the surface of cyclodextrin/mesoporous silica (EA-CD-Si@Si), and the anionic carboxymethyl group is modified on the surface of the material by controlling the pH of the solution to obtain modified cyclodextrin/mesoporous silica (CM-EACD@Si);
  • the cyclodextrin/mesoporous silicon (EA-CD-Si@Si) is prepared with reference to the patent publication number CN107597070A.
  • the second object of the present invention is to provide a method for preparing modified cyclodextrin/mesoporous silica.
  • the method for preparing the modified cyclodextrin/mesoporous silica is to select chloroacetic acid as the anion and change the cyclodextrin to After sex, it is grafted to the surface of cyclodextrin/mesoporous silicon (EA-CD-Si@Si) by means of nucleophilic substitution, and the surface of the material is modified by anionic carboxymethyl by controlling the pH of the solution to obtain modified cyclodextrin/ Mesoporous silicon (CM-EACD@Si); the cyclodextrin/mesoporous silicon (EA-CD-Si@Si) is prepared with reference to the patent publication number CN107597070A.
  • the preparation method specifically includes the following steps:
  • the mass ratio of EA-CD-Si@Si to NaOH in the step (1) is 0.5:1 to 2.5:1.
  • the amount of distilled water in the step (1) is 1 to 5 times the total mass of cyclodextrin/mesoporous silicon powder and NaOH particles.
  • the concentration of chloroacetic acid in the step (1) is 5%-25%, and the dosage is 0.5-2.5 times the total mass of EA-CD-Si@Si and NaOH.
  • the pH of the reaction system is adjusted to 5-9.
  • the method is specifically: the method is specifically: adding 5.0 g EA-CD-Si@Si and 4.65 g NaOH to 18.5 mL ultrapure water and stirring at room temperature, and then Add 13.5mL 16.3% chloroacetic acid solution to react at 60°C for 6h, cool, add 36% HCl, adjust the pH of the solution to 7, precipitate the product with methanol, filter, wash, vacuum dry the sample to obtain CM-EACD@Si.
  • the method is specifically: the method is specifically: dissolving 10g EA- ⁇ -CD@Si, 5g NaOH particles in 10mL distilled water, and then adding 10mL of 10% chloroacetic acid solution , React at 60°C for 10 hours, cool, add 36% HCl, adjust the pH of the solution to 6, precipitate the product with 50 mL of methanol, filter, wash, and dry in vacuum at 40°C to obtain CM-EACD@Si.
  • the third object of the present invention is to provide an application of the above-mentioned modified cyclodextrin/mesoporous silica as an adsorbent.
  • the modified cyclodextrin/mesoporous silicon adsorbent is used in sewage containing one or more metal ions among Pb, Cd, Cu and Ca.
  • the modified cyclodextrin/mesoporous silica is used to quickly and selectively remove Pb and Cd from wastewater.
  • the fourth object of the present invention is to provide a method for rapidly adsorbing Pb, which is characterized in that the above-mentioned modified cyclodextrin/mesoporous silica is used as an adsorbent to adsorb Pb in sewage.
  • the adsorption conditions are: pH is 4-6, and the adsorption time is 5min-2h.
  • the fifth object of the present invention is to provide a method for rapid and selective adsorption of Pb and Cd, which is characterized in that the above-mentioned modified cyclodextrin/mesoporous silica is used as an adsorbent to selectively adsorb Pb and Cd in sewage;
  • the conditions are: pH is 4-6, adsorption time is 5min-2h.
  • the sixth object of the present invention is to provide a method for regeneration of modified cyclodextrin/mesoporous silicon.
  • the method is to add the adsorbed CM-EACD@Si to the desorption solution for regeneration treatment.
  • the adsorbent is to add the adsorbed CM-EACD@Si to the desorption solution for regeneration treatment.
  • the desorption liquid is a nitric acid solution, a sodium ethylenediaminetetraacetate solution or a phosphoric acid solution.
  • the concentration of the desorption solution is 0.1-1.0 mol/L.
  • the treatment condition is: shaking at 100-500 rpm for 1-3 h.
  • a modified cyclodextrin/mesoporous silicon adsorption material prepared by the present invention that selectively adsorbs Pb and Cd has simple synthesis steps, cheap and easy-to-obtain raw materials, and has high specific surface area and active sites, thereby enhancing the adsorption
  • the stereoselectivity and molecular recognition performance of the material make it possible to achieve the highest removal rates of 97.8% and 81.29% when the heavy metal ions Pb and Cd are adsorbed and removed.
  • the modified cyclodextrin/mesoporous silicon adsorbent prepared by the present invention contains a large number of active sites-carboxylate ions, has strong mechanical stability, significant adsorption effect, and adsorption It has fast speed, high removal rate, reusability, low recovery cost, low production cost, easy batch and large-scale production, and the material can effectively solve problems such as heavy metal ions in industrial wastewater.
  • Figure 1 is a schematic diagram of the preparation of CM-EACD@Si.
  • Figure 2 shows the infrared spectra of EA- ⁇ -CD@Si and CM-EACD@Si.
  • Figure 3 shows the effect of pH on the adsorption of HMs on CM-EACD@Si.
  • Figure 4 shows the effect of adsorption time on the adsorption of HMs by CM-EACD@Si.
  • Figure 6 shows the removal effect under the multi-element composite system.
  • Figure 7 shows the influence of interfering ions on the removal effect.
  • Figure 8 shows the desorption repeatability of CM-EACD@Si on HMs; (a) Desorption results under three different types of desorption solutions; (b) Desorption effect on Pb 2+ three times in 0.1mol/L HNO 3 solution .
  • Qe ⁇ -CD to HMs (Pb 2+ , Cd 2+ , Cu 2+ and Ca 2+ ) removal capacity, mg; V: HMs (Pb 2+ , Cd 2+ , Cu 2+ and Ca 2 + ) Volume, mL; C 0 : HMs (Pb 2+ , Cd 2+ , Cu 2+ and Ca 2+ ) initial mass concentration, mg/L: E: removal rate, %.
  • cyclodextrin/mesoporous silicon (EA-CD-Si@Si) mentioned in the present invention is prepared with reference to the patent publication number CN107597070A.
  • a method for preparing a modified cyclodextrin/mesoporous silicon adsorbent that selectively adsorbs Pb 2+ and Cd 2+ is prepared by the following steps:
  • the modified cyclodextrin/mesoporous silicon adsorbent prepared in Example 1 has an adsorption rate of 80.6% and 67.7% for adsorbing 20 mg/L of Pb 2+ and Cd 2+ solutions.
  • a method for preparing a modified cyclodextrin/mesoporous silicon adsorbent that selectively adsorbs Pb 2+ and Cd 2+ is prepared by the following steps:
  • the modified cyclodextrin/mesoporous silicon adsorbent prepared in Example 2 has an adsorption rate of 95.6% and 80.7% for adsorbing 20 mg/L of Pb 2+ and Cd 2+ solutions.
  • a method for preparing a modified cyclodextrin/mesoporous silicon adsorbent that selectively adsorbs Pb 2+ and Cd 2+ is prepared by the following steps:
  • the modified cyclodextrin/mesoporous silicon adsorbent prepared in Example 3 of the present invention has an adsorption rate of 83.6% and 72.2% for adsorbing 20 mg/L of Pb 2+ and Cd 2+ solutions.
  • Example 4 Application of CM-EACD@Si as an adsorbent in a single metal ion system
  • CM-EACD@Si prepared in Example 2 as the adsorbent
  • Pb 2+ , Cd 2+ and Cu 2+ were selected as the typical HMs to explore the removal effect of EA- ⁇ CD-Si and CM-EACD@Si on HMs
  • the corresponding HMs concentration was measured under the atomic absorption spectrophotometer at 283.3nm, 228.8nm and 324.8nm respectively.
  • the carboxylate ion (negative charge) has a strong coordination affinity to the metal ion (positive charge), and the attractive force also makes the carboxylate ion trap M 2+ through surface complexation, thereby forming a chelate.
  • the degree of surface complexation shows an upward trend with the increase of pH.
  • the adsorption effect of Si on HMs is: Pb 2+ (92.02%)>Cd 2+ (80.29%)>>Cu 2+ (23.4%)>Ca 2+ (15.42%), that is, the effect of the entire process on the first two ions
  • the removal effect is obviously better than the latter two, and the removal effect of Ca 2+ is the weakest.
  • Figure 4 shows the adsorption capacity of CM-EACD@Si on Pb 2+ /Cd 2+ /Cu 2+ (Qt, mg /g) The relationship graph with the time of contact. It can be seen from the figure that the adsorption amount of Pb 2+ /Cd 2+ /Cu 2+ by CM-EACD@Si increases with the increase of contact time, and the overall adsorption rate is very fast, and it is fast adsorption at 0-5min. State, the equilibrium state has been achieved within 10-15 minutes.
  • HMs Compared with existing reported materials such as activated carbon/chitosan composite, ⁇ -CD/graphene oxide composite, ⁇ -CD/SiO2 composite, CM-EACD is used.
  • the time required for @Si to adsorb HMs to reach equilibrium is relatively short, mainly due to the large amount of COO-distributed on its surface, which can quickly interact with HMs (positively charged) and the unreacted hydroxyl groups in the ⁇ -CD molecule. It will quickly chelate with HMs to achieve rapid adsorption.
  • HMs Pb 2+ , Cd 2+ and Cu 2+ ) stock solution, at 25°C, respectively in 50mL 50mg/L containing 50mg EA- ⁇ -CD@Si and CM-EACD@Si
  • the HMs solution was subjected to adsorption kinetics experiment.
  • the pH was controlled by HNO 3 /NaOH. After adsorption, the supernatant was sucked and separated by filtration through a 0.22 ⁇ m pore filter membrane to determine the remaining HMs concentration.
  • Table 1 The results are shown in Figure 5 and Table 1.
  • Figure 5(a) and Table 1 show the quasi-second-order kinetic fitting diagrams of CM-EACD@Si for three HMs and the corresponding kinetic parameter results. It can be seen from the figure and table that the fitting linear correlation coefficients R 2 of the three HMs are all greater than 0.997, which is very consistent with the quasi-second-order kinetic fitting, with chemical adsorption as the dominant factor, and corresponding to the maximum adsorption of the three HMs
  • the capacities are Pb 2+ (46.4124mg/g), Cd 2+ (30.4405mg/g) and Cu 2+ (10.3672mg/g), which are close to the calculated results by fitting.
  • Figure 5(b) shows the fitting of the particle internal diffusion model.
  • the fitting means that in a uniformly mixed solution, the internal diffusion rate of the particles is the main speed control step, and if there is external resistance or chemical action, the fitting result is linear without passing through the origin.
  • the initial concentration of 50mg / L three HMs, CM-EACD @ Si qt and the t 1/2 are not a linear relationship, but is synthesized by two straight lines not passing through the origin, indicating that The whole process involves 2 steps, each of which has a different control mechanism: the first stage may be attributed to the diffusion of HMs to the outer surface of the material through the solution and the diffusion to the inner surface of the material through the boundary layer, and the second stage is attributed to the HMs and then Diffusion within the particles.
  • HMs diffuses into the internal structure of the material, the smaller the diffusion rate of the diffusion hole, the slower the diffusion rate will be. Based on this, it can be inferred that the adsorption process of CM-EACD@Si to HMs is mainly surface adsorption, and the surface adsorption rate is significantly higher than the internal diffusion rate.
  • Example 5 Application of CM-EACD@Si as an adsorbent in a composite metal ion system
  • CM-EACD@Si prepared in Example 2 as the adsorbent
  • CM-EACD@Si adsorption effects of several HMs in different mixed systems were compared.
  • Each HMs was prepared into a mixed solution with the same mass concentration (20mg/L), and the HMs concentration of the supernatant was determined after shaking for 2 hours. The result is shown in Figure 6.
  • Figure 6 shows the removal effect of CM-EACD@Si on HMs under different systems. It can be seen that the removal rate of the single-component system is 97.80% for Pb 2+ , 81.29% for Cd 2+ , and 24.00% for Cu 2+. In the binary system containing Pb 2+, the presence of Cd 2+ or Cu 2+ slightly reduces Pb 2+ adsorption (91.17% and 90.05%, respectively). However, in the same binary system, the removal rate of Cd 2+ or Cu 2+ was significantly reduced to 39.09% and 9.50%, respectively, indicating that Pb 2+ would preferentially adsorb on the surface of CM-EACD@Si, while Cd 2 + Or Cu 2+ has a weak affinity.
  • Cd 2+ and Cu 2+ are also reduced to 55.49% and 15.1%, respectively, showing the mutual competitiveness of the two ions.
  • the removal rate of Pb 2+ by CM-EACD@Si decreased slightly (88.57%), while the removal rate of Cd 2+ and Cu 2+ was lower than that of the single or binary system (only 28.69%).
  • the adsorption capacity of CM-EACD@Si in the multi-system mixed solution will be lower than that of the single system, which can be attributed to the reduced availability of binding sites.
  • metals with greater affinity can replace other metals with weaker affinity.
  • Example 6 Application of CM-EACD@Si as an adsorbent in actual sewage
  • CM-EACD@Si on Pb 2+ is weakly inhibited with the increase of K + , Na + , SO 4 2- and NO 3 - concentration, and with the increase of Ni 2+ , Mg 2+ and Ca
  • the increase of the 2+ concentration was significantly inhibited. This is mainly due to the difference in the ionic radius of the cation and the different affinity to different ions; the anion’s influence is mainly due to the fact that under acidic conditions, the functional groups on the surface of CM-EACD@Si are protonated, which will cause it to interact with the solution.
  • CM-EACD@Si The saturated CM-EACD@Si was added to three desorption solutions (0.1mol/L nitric acid, sodium ethylenediaminetetraacetate and phosphoric acid) for desorption study. After shaking at 230rpm for 2h, the HMs in the supernatant was determined. Concentration, through three cycles of adsorption-desorption process to verify its reusability.
  • CM-EACD @ Si bind the active site and HMs insufficient long maintained under acidic conditions
  • H + protonated surface of the material i.e., carboxyl (COO - regeneration) is more favorable, so that the adsorption Positively charged HMs on the surface of the material are more prone to desorption.
  • the desorption effect of Na 2 EDTA on the three HMs is: Pb 2+ >Cd 2+ >Cu 2+ , this is because the stronger ligand in Na 2 EDTA will form a stronger bond with Pb 2+ , Thus making Pb 2+ easier to desorb from CM-EACD@Si.

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Abstract

提供了一种吸附Pb和Cd的改性环糊精/介孔硅及其应用，采用表面修饰的方式，以氯乙酸为阴离子，将环糊精改性后通过亲核取代方式接枝到环糊精/介孔硅表面，制备得到改性环糊精/介孔硅吸附材料。该制备方法简便，制备的改性环糊精/介孔硅吸附材料具有强吸附性、易分离、良好生物相容性等优势，在重金属污水的去除等方面具有广泛的应用前景，继而改善人们赖以生存的水环境。

Description

一种吸附Pb和Cd的改性环糊精/介孔硅及其应用 技术领域
本发明涉及一种吸附Pb和Cd的改性环糊精/介孔硅及其应用，属于吸附材料技术领域。
背景技术
随着工业化进程的加快，工业废水中重金属离子含量越来越多，已成为不可忽视的污染问题，对人体健康和生态系统产生了不可小觑的影响，亟需解决。
β-CD无毒、易降解，且具有“外腔亲水，内腔疏水”的特殊分子结构，但由于其空腔尺寸有限，且存在自身溶于水、机械性差等局限性，用于构筑超分子材料仍比较困难，且传统改性环糊精存在制备工艺较为复杂、反应物用量大、成本相对较高、中间产物收率低等问题。
目前已有较多关于吸附材料方面的研究，但传统吸附剂存在吸附时间长、吸附速率低，吸附效果差且选择性差等问题，且大多材料存在制备繁琐、不可控，稳定性差等问题，基于此，本发明制备的改性环糊精/介孔硅吸附材料简单易得，在短时间可以实现快速吸附，对Pb和Cd具有较好的选择性，在废水处理等方面具有较为重要的应用价值。
发明内容
针对现有技术存在的上述问题，本发明提供了一种选择性吸附Pb和Cd的改性环糊精/介孔硅吸附材料的制备方法。本发明制备步骤简单易控，灵活性强，易推广，且低成本，吸附效率高，可循环利用等优势，可有效解决废水处理中的重金属离子污染等问题，且在化工、石油、食品、轻工和环境保护等领域也具有潜在的应用。
本发明的第一个目的是提供一种改性环糊精/介孔硅，所述改性环糊精/介孔硅的制备方法是选取氯乙酸为阴离子，将环糊精改性后通过亲核取代方式接枝到环糊精/介孔硅(EA-CD-Si@Si)表面，通过控制溶液pH在材料表面实现阴离子羧甲基改性，得到改性环糊精/介孔硅(CM-EACD@Si)；所述环糊精/介孔硅(EA-CD-Si@Si)是参照公开号为CN107597070A的专利制备得到的。
本发明的第二个目的是提供一种改性环糊精/介孔硅的制备方法，所述改性环糊精/介孔硅的制备方法是选取氯乙酸为阴离子，将环糊精改性后通过亲核取代方式接枝到环糊精/介孔硅(EA-CD-Si@Si)表面，通过控制溶液pH在材料表面实现阴离子羧甲基改性，得到改性环糊精/介孔硅(CM-EACD@Si)；所述环糊精/介孔硅(EA-CD-Si@Si)是参照公开号为CN107597070A的专利制备得到的。
在本发明的一种实施方式中，所述制备方法具体包括以下步骤：
(1)将EA-CD-Si@Si、NaOH颗粒溶解于蒸馏水中，再加入氯乙酸溶液，充分混匀后，使反应体系在40～80℃下反应6～18h，冷却；
(2)调节反应后的反应体系的pH，用甲醇溶液沉淀产物，过滤，洗涤，于40～60℃干燥，得到改性环糊精/介孔硅(CM-EACD@Si)。
在本发明的一种实施方式中，所述的步骤(1)中的EA-CD-Si@Si与NaOH的质量比为0.5:1～2.5:1。
在本发明的一种实施方式中，所述的步骤(1)中的蒸馏水用量为环糊精/介孔硅粉末与NaOH颗粒总质量的1～5倍。
在本发明的一种实施方式中，所述的步骤(1)中的氯乙酸浓度为5％～25％，用量为EA-CD-Si@Si与NaOH总质量的0.5～2.5倍。
在本发明的一种实施方式中，所述的步骤(2)中调节反应体系的pH为5～9。
在本发明的一种实施方式中，所述方法具体为：所述方法具体为：将5.0g EA-CD-Si@Si和4.65g NaOH加入到18.5mL超纯水中于常温下搅拌，再加入13.5mL 16.3％的氯乙酸溶液于60℃反应6h，冷却，加入36％HCl，调节溶液pH＝7，用甲醇沉淀产物，过滤，洗涤，将样品真空干燥后得到CM-EACD@Si。
在本发明的一种实施方式中，所述方法具体为：所述方法具体为：将10g EA-β-CD@Si、5g NaOH颗粒溶解于10mL蒸馏水中，再加入10mL的10％氯乙酸溶液，在60℃下反应10h，冷却，加入36％的HCl，调节溶液pH＝6，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si。
在本发明的一种实施方式中，将5g EA-β-CD@Si、2.5g NaOH颗粒溶解于10mL蒸馏水中，再加入10mL的16.3％氯乙酸溶液，在80℃下反应6h，冷却，加入36％的HCl，调节溶液pH＝7，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si。
本发明的第三个目的是提供一种上述改性环糊精/介孔硅作为吸附剂的应用。
在本发明的一种实施方式中，改性环糊精/介孔硅吸附剂用于包括Pb，Cd，Cu和Ca中的一种或多种金属离子的污水中。
在本发明的一种实施方式中，所述改性环糊精/介孔硅用于快速从废水中选择性去除Pb和Cd。
本发明的第四个目的是提供一种快速吸附Pb的方法，其特征在于，采用上述改性环糊精/介孔硅作为吸附剂吸附污水中的Pb。
在本发明的一种实施方式中，吸附条件为：pH为4～6，吸附时间为5min～2h。
本发明的第五个目的是提供一种快速选择性吸附Pb和Cd的方法，其特征在于，采用上述改性环糊精/介孔硅作为吸附剂选择性吸附污水中的Pb和Cd；吸附条件为：pH为4～6，吸附时间为5min～2h。
本发明的第六个目的是提供一种改性环糊精/介孔硅的再生方法，所述方法是将吸附后的CM-EACD@Si加入到解吸液中进行再生处理，即得再生后的吸附剂。
在本发明的一种实施方式中，所述解吸液为硝酸溶液、乙二胺四乙酸钠溶液或磷酸溶液。
在本发明的一种实施方式中，所述解吸液浓度为0.1～1.0mol/L。
在本发明的一种实施方式中，所述处理条件为：置于100-500rpm下振荡1-3h。
本发明有益的技术效果在于：
(1)本发明制备的一种选择性吸附Pb和Cd的改性环糊精/介孔硅吸附材料合成步骤简单，原料廉价易得，具有高比表面积和活性位点，从而增强了该吸附材料的立体选择性和分子识别性能，使其在对重金属离子Pb和Cd进行吸附去除时，去除率最高可分别达到97.8％和81.29％。
(2)与现有普通吸附剂相比，本发明制备的改性环糊精/介孔硅吸附材料含有大量的活性位点——羧酸根离子，机械稳定性强，吸附效果显著，且吸附速率快，去除率高，可重复使用，回收成本低，且生产成本低，易于批量化、规模化生产，且该材料可有效解决工业废水中重金属离子等问题。
附图说明
图1为CM-EACD@Si的制备示意图。
图2为EA-β-CD@Si和CM-EACD@Si的红外光谱图。
图3为pH值对CM-EACD@Si上HMs吸附的影响。
图4为吸附时间对CM-EACD@Si吸附HMs的影响。
图5中(a)准二级动力学拟合；(b)颗粒内部扩散拟合。
图6为多元复合体系下的去除效果。
图7为干扰离子对去除效果的影响。
图8为CM-EACD@Si对HMs的解吸重复性；(a)在三种不同类型解吸液下的解吸结果；(b)在0.1mol/L HNO 3溶液中对Pb 2+解吸三次的效果。
具体实施方式
下面结合附图和实施例，对本发明进行具体描述。
1、吸附量和去除率的测试方法
分别称取质量不等的10,20,40,60,80,100mg EA-β-CD@Si和CM-EACD@Si置于50mL  50mg/L的HMs(Pb 2+，Cd 2+和Cu 2+)溶液中，在30℃下恒温振荡2h，于10000rpm下离心15min后吸取上清液并在紫外分光光度计测定，Pb 2+，Cd 2+和Cu 2+分别在283.3nm，228.8nm和324.8nm处的原子吸收分光光度计下测定相应的HMs浓度。利用标准曲线及公式(2-2)和公式(2-3)计算其吸附量(Qe)和去除率(E)：
Qe＝(C 0-C e)×V/m
E(％)＝(C 0-C e)/C 0×100
式中，Qe：β-CD对HMs(Pb 2+，Cd 2+，Cu 2+和Ca 2+)去除容量，mg；V：HMs(Pb 2+，Cd 2+，Cu 2+和Ca 2+)体积，mL；C 0：HMs(Pb 2+，Cd 2+，Cu 2+和Ca 2+)初始质量浓度，mg/L：E：去除率，％。
2、本发明中提到的环糊精/介孔硅(EA-CD-Si@Si)是参照公开号为CN107597070A的专利制备得到的。
实施例1：CM-EACD@Si的制备
一种选择性吸附Pb 2+和Cd 2+的改性环糊精/介孔硅吸附材料的制备方法，通过下述步骤制得：
将环糊精/介孔硅粉末(EA-β-CD@Si 10g)、NaOH颗粒(5g)溶解于蒸馏水(10mL)中，再加入10mL的10％氯乙酸溶液，在60℃下反应10h，冷却，加入36％的HCl，调节溶液pH＝6，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si，8.89g，具体反应原理见图1。
为确定EA-β-CD@Si是否羧甲基化改性成功，采用FT-IR对EA-β-CD@Si和CM-EACD@Si的红外光谱进行表征，结果如图2所示。通过对比可以发现，位于3430cm -1处的宽峰为O-H键和N-H键的伸缩振动吸收峰，位于1000-1200cm -1波数段属于C-O键、Si-O键和C-O-C键的伸缩振动吸收峰，且强度明显增强，且位于945cm -1处的峰是β-CD中R-1,4-键的弯曲振动峰有所保留。此外，CM-EACD@Si在1718cm -1处出现了新的特征吸收峰，这主要是由于羧酸根离子中C＝O的伸缩振动吸收峰的存在，这也可以证实EA-β-CD@Si表面引入了COO -基团，即成功得到了羧甲基化改性后的材料，实现了进一步改性。
实施例1制备的改性环糊精/介孔硅吸附材料用于吸附20mg/L的Pb 2+和Cd 2+溶液的吸附率为80.6％和67.7％。
实施例2：CM-EACD@Si的制备
一种选择性吸附Pb 2+和Cd 2+的改性环糊精/介孔硅吸附材料的制备方法，通过下述步骤制得：
将环糊精/介孔硅粉末(5g)、NaOH颗粒(4.65g)溶解于蒸馏水(18.5mL)中，再加入13.5mL的16.3％氯乙酸溶液，在50℃下反应6h，冷却，加入36％的HCl，调节溶液pH＝7，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si，4.55g。
实施例2制备的改性环糊精/介孔硅吸附材料用于吸附20mg/L的Pb 2+和Cd 2+溶液的吸附率为95.6％和80.7％。
实施例3：CM-EACD@Si的制备
一种选择性吸附Pb 2+和Cd 2+的改性环糊精/介孔硅吸附材料的制备方法，通过下述步骤制得：
将环糊精/介孔硅粉末(5g)、NaOH颗粒(2.5g)溶解于蒸馏水(10mL)中，再加入10mL的16.3％氯乙酸溶液，在80℃下反应6h，冷却，加入36％的HCl，调节溶液pH＝7，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si，3.68g。
本发明实施例3制备的改性环糊精/介孔硅吸附材料用于吸附20mg/L的Pb 2+和Cd 2+溶液的吸附率为83.6％和72.2％。
实施例4：CM-EACD@Si作为吸附剂在单一金属离子体系中的应用
采用实施例2制备得到的CM-EACD@Si作为吸附剂，选择Pb 2+，Cd 2+和Cu 2+作为典型的HMs，探究EA-βCD-Si和CM-EACD@Si对HMs的去除效果，分别在283.3nm，228.8nm和324.8nm处的原子吸收分光光度计下测定相应的HMs浓度。
1、pH对去除效果的影响：
溶液pH不同会影响材料表面电荷的分布，从而导致材料与HMs的静电引力也不同。配制20mg/L的HMs(Pb 2+，Cd 2+，Cu 2+和Ca 2+)溶液，取50mL，称取20mg CM-EACD@Si置于溶液中，通过NaOH/HCl)调节pH范围为2-6，在30℃下恒温振荡2h，测定上清液的HMs浓度，结果见图3。
从图3可以看出，整体HMs吸附能力随pH值的增加而增加，且CM-EACD@Si的吸附效果高于EA-β-CD@Si，这是由于材料表面的羧基去质子化程度提高，表面电荷密度增加，HMs(带正电荷)与COO -(带负电荷)通过静电或离子相互作用而实现对HMs的去除，且在pH<6时，HMs主要是以M 2+和M(OH) +存在，吸附能力的变化主要与等电点有关。在高于等电点的pH下，羧酸根离子(负电)对金属离子(正电)具有强配位亲和力，吸引力也使羧酸根离子通过表面络合捕获M 2+，从而形成螯合物，其表面络合度随pH增加而呈现上升的趋势。而在低于零点电荷的pH下，CM-EACD@Si表面的正电荷和HMs之间存在排斥力作用，导致整体去除效果较弱，在pH＝6时为最大吸附效果，整体CM-EACD@Si对HMs的吸 附效果为：Pb 2+(92.02％)>Cd 2+(80.29％)>>Cu 2+(23.4％)>Ca 2+(15.42％)，即整个过程对前两种离子的去除效果明显优于后两者，且对Ca 2+的去除效果最弱。
2、吸附时间对去除效果的影响：
配制50mg/L的HMs(Pb 2+，Cd 2+和Cu 2+)溶液，分别取20mL，称取20mg CM-EACD@Si置于溶液中，在30℃下恒温振荡吸附1h，每隔一定时间取样，在30℃下恒温振荡2h，测定上清液的HMs浓度，结果见图4。
图4显示了在pH为5.5-6、温度为30℃、HMs溶液浓度为50mg/L的溶液中，CM-EACD@Si对Pb 2+/Cd 2+/Cu 2+吸附量(Qt,mg/g)随接触时间变化的关系图。从图中可以看出，CM-EACD@Si对Pb 2+/Cd 2+/Cu 2+的吸附量随接触时间的增加而增加，且整体吸附速率都很快，在0-5min为快速吸附状态，10-15min内已实现平衡状态，与现有报道的材料如活性炭/壳聚糖复合材料，β-CD/氧化石墨烯复合材料，β-CD/SiO2复合材料相比，使用CM-EACD@Si吸附HMs达到平衡所需的时间较短，主要是由于其表面大量分布的COO-可以很快和HMs(带正电荷)发生静电相互作用，以及β-CD分子中未反应的羟基基团会迅速和HMs发生螯合作用，从而实现快速吸附。
3、吸附动力学实验：
配制1000mg/L的HMs(Pb 2+，Cd 2+和Cu 2+)储备液，在25℃下，分别在含有50mg EA-β-CD@Si和CM-EACD@Si的50mL 50mg/L的HMs溶液进行吸附动力学实验，通过HNO 3/NaOH控制pH，吸附后吸取上清液并通过0.22μm孔径的滤膜过滤分离，以测定剩余的HMs浓度，结果见图5和表1。
表1不同HMs的准二级动力学参数
Figure PCTCN2019121385-appb-000001
图5(a)和表1显示了CM-EACD@Si对三种HMs的准二级动力学拟合图和对应的动力学参数结果。由图和表可以看出，三种HMs的拟合线性相关系数R 2均大于0.997，即非常符合准二级动力学拟合，以化学吸附为主导影响因素，且对应三种HMs的最大吸附容量分别为Pb 2+(46.4124mg/g)、Cd 2+(30.4405mg/g)和Cu 2+(10.3672mg/g)，与通过拟合的计算结果接近。
如图5(b)为对颗粒内部扩散模型拟合。该拟合是指在混合均匀的溶液中，颗粒内部扩散速率是主要的控速步骤，且如果存在外部阻力或化学作用时，拟合结果为不通过原点的线 性。由图可以看出，对于初始浓度为50mg/L的三种HMs，CM-EACD@Si的qt与t 1/ 2均不成线性关系，而是由两条直线合成，也不经过原点，这说明整个过程涉及2个步骤，每个步骤有不同的控制机理：第一阶段可能归因于HMs通过溶液扩散到材料外表面和通过边界层扩散到材料内表面，第二阶段则归因于HMs继而在颗粒内扩散。一般来说，由于HMs扩散到材料的内部结构中，扩散孔的扩散速度越小，扩散速率会慢慢降低。基于此，可推断CM-EACD@Si对HMs的吸附过程主要是表面吸附，且其表面吸附速率明显高于内部扩散速率。
实施例5：CM-EACD@Si作为吸附剂在复合金属离子体系中的应用
为了检验某种HMs在多金属溶液中相互作用的竞争效应，比较了CM-EACD@Si对单一体系，二元体系和三元体系中HMs的去除效率。
采用实施例2制备得到的CM-EACD@Si作为吸附剂，为了探究CM-EACD@Si对HMs吸附的同时受其他干扰离子的影响情况，比较了几种HMs在不同混合体系下的吸附效果，每种HMs以相同质量浓度(20mg/L)配成混合溶液，振荡2h后测定上清液的HMs浓度，结果见图6。
如图6所示为不同体系下CM-EACD@Si对HMs的去除效果。可以看出，单组分体系的去除率分别为Pb 2+为97.80％，Cd 2+为81.29％，Cu 2+为24.00％。在含Pb 2+存在的二元体系中，Cd 2+或Cu 2+的存在使Pb 2+吸附略微降低(分别为91.17％和90.05％)。然而，在相同的二元体系中，Cd 2+或Cu 2+的去除率分别显著降低至39.09％和9.50％，这表明Pb 2+会优先吸附在CM-EACD@Si的表面，而Cd 2+或Cu 2+的亲和性较弱。在二元体系(Cd 2+、Cu 2+)中，Cd 2+和Cu 2+也分别降低至55.49％和15.1％，显示出两种离子的相互竞争力。在三元混合体系中，CM-EACD@Si对Pb 2+的去除率略有下降(88.57％)，而Cd 2+和Cu 2+的去除率低于单一或二元体系(仅仅为28.69％和7.30％)，即CM-EACD@Si在多体系混合溶液中的吸附能力比单体系的吸附能力会有所降低，这可归因于结合位点的可用性降低的缘故。在多体系溶液中，具有更大亲和力的金属可以取代较弱亲和力的其他金属。经过多种对比发现，三种HMs去除率排序为：Pb 2+>Cd 2+>Cu 2+，即使是在三元复合体系中CM-EACD@Si对Pb 2+仍有超过80％的去除效果。
实施例6：CM-EACD@Si作为吸附剂在实际污水中的应用
考虑到实际污水中不只存在某几种HMs，也存在诸如电解质、有机物等污染物会影响其吸附行为，在水溶液中会发生一定的竞争性吸附行为，因此，有必要研究共存阴离子和阳离子的竞争效应。选择一系列不同浓度(20mg/L和50mg/L)的Ni 2+、Mg 2+、Ca 2+、Na +、K +、 SO 4 2-和NO 3 -，加入到50mL的不同浓度(20mg/L和50mg/L)的Pb 2+溶液中，振荡2h后测定上清液的HMs浓度。
向含Pb 2+溶液中分别加入含一种离子或多种离子的混合体系溶液后，考察多种干扰离子对Pb 2+去除效果的影响，如图7所示。由图7可以看出，当Pb 2+与其他多种离子混合时，CM-EACD@Si对Pb 2+的吸附效果受到了不同程度的抑制作用，尤其是Ni 2+、SO 4 2-和NO 3 -对吸附效果的影响较为显著。此外，CM-EACD@Si对Pb 2+的去除效果随K +、Na +、SO 4 2-和NO 3 -浓度的增加而受到微弱的抑制作用，而随Ni 2+、Mg 2+和Ca 2+浓度的增加，受到较为明显的抑制作用。这主要是由于阳离子的离子半径的不同以及对不同离子的亲和力不同而造成的；而阴离子的影响主要是在酸性条件下，CM-EACD@Si表面的功能基团易于质子化，从而会与溶液中存在的SO 4 2-和NO 3 -结合，而CM-EACD@Si表面的活性位点是一定的，这会使CM-EACD@Si对SO 4 2-和NO 3 -的去除与对Pb 2+的去除产生竞争作用，使得部分活性位点被其他阴离子占据从而抑制其对Pb 2+的吸附作用。
实施例7：再生性与可重复性
将吸附饱和的CM-EACD@Si加入到三种解吸液(0.1mol/L硝酸，乙二胺四乙酸钠和磷酸)中进行解吸研究，置于230rpm下振荡2h后，测定上清液中HMs浓度，通过对吸附-解吸过程进行三次循环验证其可重复使用性。
从经济角度出发，可再生性与稳定性是吸附材料的两大关注点。针对HMs的可重复性，本研究选择了三种类型解吸液(0.1mol/L的HNO 3溶液、H 3PO 4溶液和Na 2EDTA溶液)进行考察，在三种不同类型解吸液下的解吸结果如图8(a)。可以发现，HNO 3和Na 2EDTA溶液对Pb 2+解吸效果较好(84.51％和80.75％)，而H 3PO 4对Cd 2+和Cu 2+的解吸效果更好(55.48％和66.89％)，表明：CM-EACD@Si的活性位点和HMs的结合不足以在酸性条件下长久的维持，H +使材料表面质子化，即对羧基(COO -)的再生更有利，从而使得吸附在材料表面的带正电荷的HMs更易发生解吸。此外，Na 2EDTA对三种HMs的解吸效果为：Pb 2+>Cd 2+>Cu 2+，这是因为Na 2EDTA中更强的配位体将与Pb 2+形成更强的键合，从而使得Pb 2+更易从CM-EACD@Si中解吸。此外，也探究了在0.1mol/L HNO 3溶液中对Pb 2+解吸三次的效果，如图8(b)。可以看出解吸三次后CM-EACD@Si对Pb 2+的去除率仍可达到71％左右，这主要是因为当pH该结果揭示了CM-EACD@Si在实际应用中的稳定性和回收性。
虽然本发明已以较佳实施例公开如上，但其并非用以限定本发明，任何熟悉此技术的人，在不脱离本发明的精神和范围内，都可做各种的改动与修饰，因此本发明的保护范围应该以权利要求书所界定的为准。

Claims (20)

  1. 一种快速选择性吸附Pb和Cd的方法，其特征在于，采用改性环糊精/介孔硅作为吸附剂选择性吸附污水中的Pb和Cd；吸附条件为：pH为4～6，吸附时间为5min～2h，所述改性环糊精/介孔硅的制备方法具体包括以下步骤：
    (1)将EA-CD-Si@Si、NaOH溶解于蒸馏水中，再加入氯乙酸溶液，充分混匀后，使反应体系在40～80℃下反应6～18h，冷却；EA-CD-Si@Si与NaOH的质量比为0.5:1～2.5:1；氯乙酸浓度为5％～25％，用量为EA-CD-Si@Si与NaOH总质量的0.5～2.5倍；
    (2)调节步骤(1)反应后反应体系的pH，用甲醇溶液沉淀产物，过滤，洗涤，于40～60℃干燥，得到改性环糊精/介孔硅；调节反应体系的pH为5～9。
  2. 一种改性环糊精/介孔硅，其特征在于，所述改性环糊精/介孔硅的制备方法是：采用阴离子对EA-CD-Si@Si进行阴离子羧甲基改性，得到改性环糊精/介孔硅；所述阴离子为氯乙酸。
  3. 根据权利要求2所述的改性环糊精/介孔硅，其特征在于，所述制备方法具体包括以下步骤：
    (1)将EA-CD-Si@Si、NaOH溶解于蒸馏水中，再加入氯乙酸溶液，充分混匀后，使反应体系在40～80℃下反应6～18h，冷却；
    (2)调节步骤(1)反应后反应体系的pH，用甲醇溶液沉淀产物，过滤，洗涤，于40～60℃干燥，得到改性环糊精/介孔硅。
  4. 根据权利要求3所述的改性环糊精/介孔硅，其特征在于，所述的步骤(1)中的EA-CD-Si@Si与NaOH的质量比为0.5:1～2.5:1。
  5. 根据权利要求3或4所述的改性环糊精/介孔硅，其特征在于，所述的步骤(1)中的蒸馏水用量为EA-CD-Si@Si与NaOH总质量的1～5倍。
  6. 根据权利要求3-5任一所述的改性环糊精/介孔硅，其特征在于，所述的步骤(1)中的氯乙酸浓度为5％～25％，用量为EA-CD-Si@Si与NaOH总质量的0.5～2.5倍。
  7. 根据权利要求3-6任一所述的改性环糊精/介孔硅，其特征在于，所述的步骤(2)中调节反应体系的pH为5～9。
  8. 根据权利要求3-7任一所述的改性环糊精/介孔硅，其特征在于，所述方法具体为：将5.0g EA-CD-Si@Si和4.65g NaOH加入到18.5mL超纯水中于常温下搅拌，再加入13.5mL16.3％的氯乙酸溶液于60℃反应6h，冷却，加入36％HCl，调节溶液pH＝7，用甲醇沉淀产物，过滤，洗涤，将样品真空干燥后得到CM-EACD@Si。
  9. 根据权利要求3-7任一所述的改性环糊精/介孔硅，其特征在于，所述方法具体为：将10g EA-β-CD@Si、5g NaOH颗粒溶解于10mL蒸馏水中，再加入10mL的10％氯乙酸溶液， 在60℃下反应10h，冷却，加入36％的HCl，调节溶液pH＝6，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si。
  10. 根据权利要求3-7任一所述的改性环糊精/介孔硅，其特征在于，所述方法具体为：将5g EA-β-CD@Si、2.5g NaOH颗粒溶解于10mL蒸馏水中，再加入10mL的16.3％氯乙酸溶液，在80℃下反应6h，冷却，加入36％的HCl，调节溶液pH＝7，用50mL甲醇沉淀产物，过滤，洗涤，于40℃真空干燥，得到CM-EACD@Si。
  11. 权利要求1-10任一所述的改性环糊精/介孔硅作为吸附剂的应用。
  12. 根据权利要求11所述的应用，其特征在于，改性环糊精/介孔硅吸附剂用于包括Pb，Cd，Cu和Ca中的一种或多种金属离子的污水中。
  13. 根据权利要求12所述的应用，其特征在于，所述改性环糊精/介孔硅用于快速从废水中选择性去除Pb和Cd。
  14. 一种快速吸附Pb的方法，其特征在于，采用权利要求1-10任一所述的改性环糊精/介孔硅作为吸附剂吸附污水中的Pb。
  15. 根据权利要求14所述的应用，其特征在于，吸附条件为：pH为4～6，吸附时间为5min～2h。
  16. 一种快速选择性吸附Pb和Cd的方法，其特征在于，采用权利要求1-10任一所述的改性环糊精/介孔硅作为吸附剂选择性吸附污水中的Pb和Cd；吸附条件为：pH为4～6，吸附时间为5min～2h。
  17. 一种权利要求1-10任一所述的改性环糊精/介孔硅的再生方法，其特征在于，所述方法是将吸附后的改性环糊精/介孔硅加入到解吸液中进行再生处理，即得再生后的改性环糊精/介孔硅。
  18. 根据权利要求17所述的再生方法，其特征在于，所述解吸液为硝酸溶液、乙二胺四乙酸钠溶液或磷酸溶液。
  19. 根据权利要求18所述的再生方法，其特征在于，所述解吸液浓度为0.1～1.0mol/L。
  20. 根据权利要求17所述的再生方法，其特征在于，所述处理条件为：置于100-500rpm下振荡1-3h。
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