Adsorption of UO2 2+ on poly(N,N-diethylacrylamide-co-acrylic acid): effects of pH, ionic strength, initial uranyl concentration, and temperature

We prepared poly(N,N-diethylacrylamide-co-acrylic acid) (P(DEA-co-AA)) microgels which could efficiently remove UO₂ ²⁺ from aqueous solutions. In this study, the effect of adsorption parameters such as pH value, adsorbent dose, shaking time, and temperature has investigated. It is found that the pseudo-second-order model is more suitable for our experiment. The adsorption kinetic data indicated that the chemical adsorption was the swiftness processes, the adsorption equilibrium could be achieved within 30 min. And there are very good correlation coefficients of linearized equations for Langmuir isotherm model, which indicated that the sorption isotherm of the hydrogel for UO₂ ²⁺ can be fitted to the Langmuir isotherm model. The adsorption process was spontaneous (?G ⁰ < 0) and exothermic (?H ⁰ < 0). The adsorbed UO₂ ²⁺ can be desorbed effectively by 0.1 M HNO₃ and the adsorption capacity is not significantly reduced after five cycles. Present study suggests that this P(DEA-co-AA) can be used as a potential adsorbent for sorption UO₂ ²⁺ and also provide a simple, fast separation method for removal of UO₂ ²⁺ ions from aqueous solution.     

Removal of UO2 2+ from aqueous solution by plasma functionalized MWCNTs

The study was undertaken to evaluate the feasibility of functionalized multi-walled carbon nanotubes (MWCNTs) for the removal of UO₂ ²⁺ from aqueous solutions. The MWCNTs was treated by oxygen plasma and characterized by FTIR and XPS. The characterization indicates that MWCNTs is successfully functionalized of oxygen groups such as –COOH on its surface (denote as P-MWCNTs). The sorption of UO₂ ²⁺ from aqueous solution on P-MWCNTs was studied as a function of contact time, solid contents, pH, ionic strength and temperature under ambient conditions using batch experiment. Two simplified kinetic models of pseudo-first-order and pseudo-second-order were tested to determine kinetic parameters such as rate constants, equilibrium sorption capacities and related correlation coefficients for kinetic models of the sorption process. It can be seen that the UO₂ ²⁺ sorption on P-MWCNTs could be described more favorably by the pseudo-second-order model. The thermodynamic parameters (?G°, ?S°, ?H°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of UO₂ ²⁺ on P-MWCNTs were an endothermic and spontaneous processes. The results of the present study suggest that P-MWCNTs can be used beneficially in treating industrial effluents containing radioactive and heavy metal ions.     

Amin-functionalized magnetic-silica core-shell nanoparticles for removal of Hg2+ from aqueous solution

Magnetic nanoparticles with monodisperse shape and size were prepared by a simple method and covered by silica. The prepared core-shell Fe₃O₄@silica nanoparticles were functionalized by amino groups and characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. The synthesized nanoparticles were employed as an adsorbent for removal of Hg²⁺ from aqueous solutions, and the adsorption phenomena were studied from both equilibrium and kinetic point of views. The adsorption equilibriums were analyzed using different isotherm models and correlation coefficients were determined for each isotherm. The experimental data were fitted to the Langmuir–Freundlich isotherm better than other isotherms. The adsorption kinetics was tested for the pseudo-first-order, pseudo-second-order and Elovich kinetic models at different initial concentrations of the adsorbate. The pseudo-second-order kinetic model describes the kinetics of the adsorption process for amino functionalized adsorbents. The maximum adsorption occurred at pH 5.7 and the adsorption capacity for Fe₃O₄@silica-NH₂ toward Hg²⁺ was as high as 126.7 mg/g which was near four times more than unmodified silica adsorbent.     

Preconcentration of Pb2+ by iron oxide/amino-functionalized silica core–shell magnetic nanoparticles as a novel solid-phase extraction adsorbent and its determination by flame atomic absorption spectrometry

The use of iron oxide/amino-functionalized silica core–shell magnetic nanoparticles for preconcentration of Pb²⁺ followed by its consecutive atomic absorption spectrometry determination is described. Effects of various operating variables, namely, solution pH, initial Pb²⁺ concentration, contact time, adsorbent dosage, sample volume, concentration and volume of desorbing solution, and co-existing ions on solid-phase extraction (SPE) of Pb²⁺ were studied by batch equilibrium technique. The experimental adsorption data were well fitted to the Langmuir isotherm model. The Langmuir adsorption capacity and equilibrium time were found to be 100 mg g^?1 and 20 min, respectively. The adsorption data were also fitted to kinetic pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption followed pseudo-second-order model. Under the optimal SPE conditions, the enrichment factor, detection limit and relative standard deviation for determination of Pb²⁺ were found to be 211, 1 μg L^?1, and 3.7 % for 50 μg L^?1, respectively. The proposed method was successfully applied to the determination of lead in a real sample with satisfactory results.     

Chemically modified kapok fiber for fast adsorption of Pb2+, Cd2+, Cu2+ from aqueous solution

Kapok fiber, a natural hollow fiber with thin shell and large cavity, has rarely been used as adsorbent for heavy metal ions. In this paper, kapok fibers were modified with diethylenetriamine pentaacetic acid (DTPA) after hydrophilicity treatment. The adsorption behavior of the resultant kapok-DTPA influenced by pH, adsorption time and initial concentration of metal ion was investigated. The results demonstrate that adsorption equilibrium was reached within 2 min for Pb²⁺ and Cd²⁺. Adsorption kinetics showed that the adsorption rate was well fitted by pseudo-second-order rate model. The adsorption isotherms were studied, and the best fit was obtained in the Langmuir model. The maximum adsorption capacities of kapok-DTPA were 310.6 mg g^?1 for Pb²⁺, 163.7 mg g^?1 for Cd²⁺, 101.0 mg g^?1 for Cu²⁺, respectively. After eight desorption and re-adsorption loops, the lost adsorption capacities for Pb²⁺ and Cu²⁺ were less than 10 %. Because of the large specific area derived from the hollow fiber structure, kapok-DTPA exhibited much better adsorption capacity compared with many other reported adsorbents based on natural materials.     

Amine-modified maleic anhydride containing terpolymers for the adsorption of uranyl ion in aqueous solutions

Maleic anhydride–styrene–methyl methacrylate (MA–S–MM) terpolymer was prepared. It was modified by ethylenediamine (EDA) and diethylenetriamine (DETA) in order to get cross-linked polymers bearing carboxyl and amine groups. Modified polymers used as an adsorbent for the removal of UO₂ ²⁺ from water. The characterizations of structures of all the polymers were performed by Fourier transform infrared. The adsorptive features of adsorbents were then investigated for UO₂ ²⁺ in view of dependency on ion concentration, pH, temperature and kinetics. Experimentally obtained isotherms were evaluated with reference to Langmuir, Freundlich and Dubinin–Radushkevich models. The maximum monolayer adsorption capacity for UO₂ ²⁺ was found to be 1.59 and 2.43 mol kg^?1 for EDA–MA–S–MM and DETA–MA–S–MM, respectively. It can be said that the new modified polymers prepared in our laboratory have been suggested as new adsorbents for uranyl ions.     

Synthesis of Amino-Functionalized Hexagonal Mesoporous Silica for Adsorption of Pb2+

Highly ordered amino‐functionalized hexagonal mesoporous silica (HMS‐NH₂) had been synthesized successfully by co‐condensation. The resultant materials were characterized by means of XRD, TEM, FT‐IR, N₂ ad‐desorption and ²⁹Si NMR to confirm the ordered mesoporous structure and the functionalization of the amino groups. The sample was employed as a Pb²⁺ adsorbent in aqueous solutions at room temperature. Both Lagergren's first order kinetic model and Lagergren's second order kinetic model were used to describe the adsorption data. It was found that the pseudo second order model fitted the sorption kinetic data better than the pseudo first order model. According to the information analyzed from AAS, HMS‐NH₂ had a Pb²⁺ adsorption amount of over 90.7 mg·g^?1, showing a promising application for the treatment of wastewater containing Pb²⁺ ions.     

In situ synthesis of MnO<Subscript>2</Subscript>-loaded biocomposite based on microcrystalline cellulose for Pb<Superscript>2+</Superscript> removal from wastewater

We fabricated a new MnO₂-loaded biocomposite based on microcrystalline cellulose (MCC–MnO₂) by an in situ synthesis method and investigated its adsorption behavior and mechanism for Pb²⁺ removal from aqueous medium. As-prepared MCC–MnO₂ was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analyses. The effects of pH value, initial Pb²⁺ concentration, contact time, and solution temperature on the uptake of Pb²⁺ onto MCC–MnO₂ were investigated using a batch system. Adsorption equilibrium could be achieved in 3 h for various studied initial concentrations, and a pseudo-second-order model could fit the adsorption behavior well. The equilibrium data could be well described by the Langmuir isotherm model, and the maximum monolayer adsorption capacity of MCC–MnO₂ (with 7.98% MnO₂ loading) for Pb²⁺ was estimated to be 247.5 mg/g at 313 K. Thermodynamic studies indicated a spontaneous and endothermic adsorption process. X-ray photoelectron spectroscopy (XPS) was used to analyze the adsorption mechanism, revealing that the chemical speciation of Pb²⁺ on MCC–MnO₂ was similar to the compound PbO. Moreover, no variations in the valence of Mn were observed after adsorbing Pb²⁺. The regeneration study showed that the adsorption capacity retained about 89.6% of its initial value at the fifth sequential regeneration cycle, indicating that this material is an efficient and renewable hybrid adsorbent for Pb²⁺ removal.     

Adsorption of UO2 2+, Tl+, Pb2+, Ra2+ and Ac3+ onto polyacrylamide-bentonite composite

Composite of polyacrylamide-bentonite (PAA-B) was prepared by direct polymerization in a suspension of bentonite (B), the composite was then modified by phytic acid (PAA-B-Phy). The parameters related to adsorption of UO₂ ²⁺ in absence and presence of 0.01M CaCl₂ and of natural radionuclides (Tl⁺, Pb²⁺, Ra²⁺ and Ac³⁺ in a leaching solution) onto PAA-B and PAA-B-Phy, and thermodynamics of the adsorption were investigated. Adsorption isotherms were of L and H types for the adsorption of UO₂ ²⁺ onto PAA-B and PAA-B-Phy, whilst for Tl⁺, Pb²⁺, Ra²⁺ and Ac³⁺ they were of C type for both adsorbents. Langmuir equilibrium constants for the adsorption of all studied ions onto PAA-B-Phy were significantly higher than those found for PAA-B. The thermodynamic parameters indicated that adsorption reactions are spontaneous in terms of adsorption free enthalpy. The composite of PAA-B and its modification by Phy have been used for the first time in this study. It is concluded that the composites can be practically used for adsorption and applied as adsorbent of radionuclides.     

Adsorption of UO2 2+ from aqueous solution onto copolymers of styrene and maleic anhydride

The copolymers of styrene and maleic anhydride resin (PSt/MA) was synthesized by free radical polymerization and characterized by means of FTIR. It is shown that the PSt/MA copolymer has rather strong coordination ability to UO₂ ²⁺ ions by chelation with the carboxylate group, and the microstructures of the U(VI)-PSt/MA complexes can be well controlled. The influence factors on UO₂ ²⁺ ions were also investigated and described in detail, such as contact time, solid/liquid ratio, pH value, ethanol content, and initial concentration. It was found that the maximum adsorption quantity of UO₂ ²⁺ was 831 mg/g. Experiments show that PSt/MA can recover UO₂ ²⁺ ions with high adsorption selectively from a simulated industry solution containing Ca²⁺ and Mg²⁺ as impurities. The adsorption kinetic data were best described by the pseudo-second-order equation, indicating that the chemical adsorption was the rate-limiting step. And there are very good correlation coefficients of linearized equations for Langmuir model, which indicated that the sorption isotherm of the PSt/MA for UO₂ ²⁺ can be fitted to the Langmuir model. After five times of repeated tests for the hydrogel it still remained its excellent adsorption.     

Encapsulating nanosilica into polyacrylic acid and chitosan interpenetrating network hydrogel for preconcentration of uranium from aqueous solutions

Polyacrylic acid, Chitosan and nanosilica particles composite (PCNS) was prepared for enrichment of U (VI) from aqueous solutions. Adsorption tests controlled by different parameters including contact time, pH, initial concentration of UO₂²⁺ and coexistence ions were examined. FTIR, SEM and EDX studies proved the formation of composite and confirmed efficient adsorption of UO₂²⁺ by PCNS. The experimental datas fit the Langmuir and pseudo-second-order models, the R_L (0.115–0.645) indicates the adsorption of UO₂²⁺ onto PCNS are favorable. The value of q_m (451.118 mg g^?1) and adsorption–desorption experiments showed PCNS hydrogel can be reckoned as a high efficienct and sustainable material for removal of U (VI).     

Synthesis of anionic gemini surfactant-templated mesoporous silica nanoparticles and its adsorption application for Pb2+

Abstract

Amino-functionalized mesoporous silica nanoparticles (AFMSN) were prepared based on the self-assembly process of the pre-fabricated template of anionic gemini surfactant. The perfect mass ration of the reactants for the synthesis of the AFMSN with high surface area and amino loading was optimized by orthogonal experiments. Adsorption capability of the optimized product for lead ion (Pb²⁺) was investigated in detail. Specially, the effects of the amino content, solution pH, adsorbent dosage, temperature, and interference of other metal ions on the removal efficiency of Pb²⁺ were studied. It is found that these factors can greatly affect the removal efficiency of Pb²⁺ and the prepared adsorbent exhibits the high adsorption selectivity for Pb²⁺. At an optimal condition, the AFMSN adsorbent presents an excellent adsorption capacity for Pb²⁺ up to 211.42?mg/g. The adsorption kinetics study revealed that the pseudo-second-order model could well describe the Pb²⁺ adsorption process, and the adsorption isotherm was fitted well with the Langmuir model. More importantly, the AFMSN adsorbent could be recycled 8 times and a high adsorption efficiency of Pb²⁺ could still be maintained. Therefore, the prepared AFMSN adsorbent may find practical application in removing Pb²⁺ from the polluted water.     

Chemically activated Ipomoea carnea as an adsorbent for the copper sorption from synthetic solutions

An indigenously prepared zinc chloride activated Ipomoea carnea (morning glory), a low-cost and abundant adsorbent, was used for removal of Cu(II) ions from aqueous solutions in a batch adsorption system. The chemical activating agent ZnCl₂ was dissolved in deionised water and then added to the adsorbent in two different ratios 1:1 and 1:0.5 adsorbent to activating agent ratio by weight. Studies were conducted as a function of contact time, initial metal concentration, dose of adsorbent, and pH. Activated Ipomoea carnea (AIC) were characterised using scanning electron microscopy (SEM), iodine number and methylene blue number. High iodine numbers indicates development of micro pores with zinc chloride activation. Maximum adsorption was noted within pH range 6.0(±0.05). Adsorption process is fast initially and reaches equilibrium after about 4 hours. The kinetic data were analysed using pseudo-first-order and pseudo-second-order models. The pseudo-second-order kinetic model was found to agree well with the experimental data. Adsorption equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The Langmuir model represented the sorption process better than the Freundlich model. Based on the Langmuir isotherm, the monolayer adsorption capacity of Cu(II) ions was 7.855 mg?g^?1 for AIC (1:1) and 6.934 mg?g^?1 for AIC (1:0.5).     

Adsorptive features of polyacrylic acid hydrogel for UO2 2+

Polyacrylic acid hydrogel was synthesized by Free Radical polymerization and characterized by means of FTIR. The FTIR results show that the carboxylic groups in the complexes coordinated to the metal ions in the form of two dentate. The effects of contact time, solid/liquid ratio, pH value, and initial concentration on the adsorption of UO₂ ²⁺ ions onto polyacrylic acid were investigated. The adsorption of UO₂ ²⁺ ions was highly dependent on the initial pH of metal ions solution and initial metal ions concentration. The adsorption kinetic data indicated that the chemical adsorption was the swiftness processes, the adsorption equilibrium could be achieved within 15 min. And there are very good correlation coefficients of linearized equations for Freundlich model, which indicated that the sorption isotherm of the hydrogel for UO₂ ²⁺ can be fitted to the Freundlich model. It was found that the maximum adsorption quantity of UO₂ ²⁺ was 1,179 mg/g. After five times of repeated tests for the hydrogel it still remained its excellent adsorption.     

Solid-phase extraction of Cu2+ and Pb2+ from waters using new thermally treated chitosan/polyacrylamide thin films; adsorption kinetics and thermodynamics

New biologically safe thin adsorptive films were synthesised using chitosan/polyacrylamide polymer blend (Ch/PA) via thermal crosslinking technique for the separation of Cu²⁺ and Pb²⁺ from aqueous solution and natural water samples. The prepared films were characterised using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and Thermogravimetric analysis (TGA) techniques. Thermo-gravimetric analysis revealed an enhancement in the thermal stability of the prepared thin films with increasing polyacrylamide content. Kinetic and thermodynamic studies were evaluated by batch-type experiments. The obtained results indicated that the adsorption isotherms were well described by Freundlich model, and Ch/PA have adsorption capacities of 177.9 and 126.58 mg.g^?1 to Cu²⁺ and Pb²⁺, respectively. Under optimum conditions, calculated detection limits were as low as 0.018 and 0.034 μg.L^?1 for Cu²⁺ and Pb²⁺, respectively, and relative standard deviations of less than 4% for five separate experiments. Moreover, the traditional Lagergren adsorption kinetic model provided the best fitting for the kinetic data. Furthermore, the reusability studies revealed a decrease in the adsorption capacity by about 8% after three adsorption–desorption cycles. The prepared thin films were successfully applied for the separation of Cu²⁺ and Pb²⁺ from natural water samples.     

Synthesis and characterization of CDs/Al2O3 nanofibers nanocomposite for Pb2+ ions adsorption and reuse for latent fingerprint detection

This study reports a new approach of preparation of carbon dots coated on aluminum oxide nanofibers (CDs/Al₂O₃NFs) nanocomposite and reusing the spent adsorbent of lead (Pb²⁺) ions loaded adsorbent (Pb²⁺-CDs/Al₂O₃NFs) nanocomposite for latent fingerprint detection (LFP) after removing Pb²⁺ ions from aqueous solution. CDs/Al₂O₃NFs nanocomposite was prepared by using CDs and Al₂O₃NFs with adsorption processes. The prepared nanocomposite was then characterized by using UV–visible spectroscopy (UV–visible), Fourier transforms infrared spectroscopy (FTIR), Fluorescence, X-ray diffraction pattern (XRD), scanning electron microscope (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), Zeta potential, X-ray photoelectron spectroscopy (XPS). The average size of the CDs was 51.18 nm. The synthesized CDs/Al₂O₃NFs nanocomposite has proven to be a good adsorbent for Pb²⁺ ions removal from water with optimum pH 6, dosage 0. 2 g/L. The results were best described by the Freundlich Isotherm model. The adsorption capacity of CDs/Al₂O₃NFs nanocomposite showed the best removal of Pb²⁺ ions with q_m = (177. 83 mg/g), when compared to the previous reports. This adsorption followed the pseudo-second order kinetic model. ΔG and ΔH values indicated spontaneity and the endothermic nature of the adsorption process. CDs/Al₂O₃NFs nanocomposite therefore showed potential as an effective adsorbent. The data were observed from adsorption–desorption after 6 cycles which showed good adsorption stability and re- usability of CDs/Al₂O₃NFs nanocomposite. Furthermore, the spent adsorbent of Pb²⁺-CDs/Al₂O₃NFs nanocomposite has proven to be sensitive and selective for LFP detection on various porous substrates. Hence Pb²⁺-CDs/Al₂O₃NFs nanocomposite can be reused as a good fingerprint labelling agent in LFP detection so as to avoid secondary environmental pollution by disposal of the spent adsorbent.     

Adsorption characteristics of Titan yellow and Congo red on CoFe2O4 magnetic nanoparticles

This paper assesses the adsorption characteristics of Titan yellow and Congo red on CoFe₂O₄ magnetic nanoparticles. The adsorption behavior of Titan yellow and Congo red from aqueous solution onto CoFe₂O₄ magnetic nanoparticles has been determined by investigating the effects of pH, concentration of the dye, amount of adsorbent, contact time, ionic strength and temperature. Experimental results indicated that CoFe₂O₄ nanoparticles can remove more than 98 % of each dye under optimum operational conditions of a dosage of 15.0 mg CoFe₂O₄, pH 3.0, initial dye concentration of 22–140 mg L^?1, and contact times of 2.0 and 15.0 min for Congo red and Titan yellow, respectively. Langmuir and Freundlich isotherm models have been used to evaluate the ongoing adsorption kinetic equations. Regeneration of the saturated adsorbent was possible by NaCl/acetone solution as eluent. The maximum adsorption capacities were 200.0 and 212.8 mg dye per gram adsorbent for Congo red and Titan yellow, respectively. With the help of adsorption isotherm, thermodynamic parameters such as free energy, enthalpy and entropy have been calculated. On the basis of pseudo-first-order and pseudo-second-order kinetic equations, different kinetic parameters have been obtained.     

UO2 2+, Tl+, Pb2+, Ra2+, Bi3+ and Ac3+ adsorption onto polyacrylamide-zeolite composite and its modified composition by phytic acid

The adsorption of naturally occurring radionuclides (UO₂ ²⁺, Tl⁺, Pb²⁺, Ra²⁺, Bi³⁺ and Ac³⁺) onto zeolite (Z) and polyacrylamide-zeolite composite (PAA-Z) and its modified composition by phytic acid (Z-Phy and PAA-Z-Phy) were investigated. Adsorption parameters were derived from the Langmuir and Freundlich fits to adsorption isotherms of the ions studied. The adsorption isotherms were of L and H types. The adsorption capacity of Z decreased by PAA inclusion, but the Phy modification of PAA-Z increased the capacity back to that of Z. The Phy modification made the adsorption spontaneity at least ten times better than in the absence of Phy. This investigation showed that the zeolite, as one of the most abundant natural materials and commonly used adsorbent can also be used for the removal of UO₂ ²⁺ and, in the PAA-Z form, of the studied radionuclides. The usage of Z, as PAA-Z and its Phy modification provide research materials which possess adequate practicality and effectiveness in studies of adsorption. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dried Biomass of Activated Sludge for Cu2+ Adsorption: Behaviors and Mechanisms

Activated sludge was tested for its ability to remove Cu²⁺ from aqueous solution. The effects of various experimental parameters (initial pH, initial Cu²⁺ concentration, adsorbent dosage, and temperature) on Cu²⁺ adsorption were evaluated. The Langmuir isotherm model well described the adsorption of Cu²⁺ onto activated sludge. The pseudo-second-order kinetic equation was appropriate for describing the kinetic performance of the sorption. Furthermore, Webber–Morris models indicated that the sorption of Cu²⁺ was generally found to involve with the intraparticle diffusion process. Parameters of adsorption thermodynamic suggested that the interaction of Cu²⁺ adsorbed by sludge was spontaneous and exothermic. Activated sludge was characterized by Fourier transform infrared spectroscopy analysis and results showed that active groups such as –OH, –COOH, –NH₂ were involved in Cu²⁺ adsorption. Zeta potential analysis demonstrated inner-sphere adsorption for Cu²⁺ adsorption on sludge.     

Application of 1-(2-Pyridylazo)-2-naphthol Anchored SiO2 Nanoparticles for the Preconcentration of Trace Pb2+ from Different Water and Food Samples

SiO₂‐PAN nanoparticles has been synthesized by reacting silica nanoparticles with 3‐aminopropyltriethoxysilane, formaldehyde and 1‐(2‐pyridylazo)‐2‐naphthol and characterized by FT‐IR and SEM which were used as new sorbent for the preconcentration of trace amount of Pb²⁺ from various samples. Conditions of the analysis such as preconcentration factor, effect of pH, sample volume, shaking time, elution conditions and effects of interfering ions for the recovery of analyte were investigated. The adsorption capacity of the nanometer SiO₂‐PAN was found to be 168.34 μmol/g at optimum pH and the detection limit (3δ) was 0.63 µg/L. The extractant showed rapid kinetic sorption. The adsorption equilibrium of Pb²⁺ on the nanometer SiO₂‐PAN was achieved within 15 min. Adsorbed Pb²⁺ was easily eluted with 6 mL of 4 mol·L^?1 hydrochloric acid. The maximum preconcentration factor was 50. The method was applied to determine trace amounts of Pb²⁺ in different samples (water and food samples).