Synthesis of CuInS2 Quantum Dots Modified with Alanine for Sensitive and Selective Detection of Pb2+ and Cysteine.

In this study, a novel fluorescent probe based on CuInS2 quantum dots modified with alanine (Ala-CuInS2 QDs) was developed for the detection of lead ions and cysteine (Pb2+ and Cys). Ala-CuInS2 QDs were synthesized through a one-step hydrothermal method exhibiting uniform size, good stability and water solubility. The QDs were then utilized as an "on-off-on" fluorescence sensor to detect Pb2+ and Cys in the ranges of 0-20 µM and 0-55 µM respectively, with detection limits of 0.29 µM and 0.66 µM. The mechanism of fluorescence quenching and recovery processes was also explored. Furthermore, Ala-CuInS2 QDs have been successfully applied to detect Pb2+ in tap and river water and detect cysteine in serum.

Biochar-supported magnesium oxide as high-efficient lead adsorbent with economical use of magnesium precursor.

With unique porous structure inherited from lignocellulose, biochar was an appropriate carrier for small-size MgO materials, which could simplify the synthetic process and better solve agglomeration and separation problems during adsorption. Biochar-supported MgO was prepared with impregnation method. Under different synthesis conditions, the obtained MgO presented diverse properties, and moderate pyrolysis condition was conducive to the improvement of Mg conversion rate. The Pb(II) capacity was highly correlated with Mg content, rather than the specific surface area. Reducing the pyrolysis temperature or increasing the usage of supporter could improve adsorption efficiency when using Mg content-normalized capacity as the criterion. The better release ability of Mg, contribute by the higher extent of hydration and better spread of MgO, were the critical factors. The maximal Mg content-normalized capacity could reach 0.932 mmol·mmol-Mg-1 with the mass ratio of biochar/MgCl2·6H2O = 4:1 at the pyrolysis temperature of 600 °C. Considering the ultimate utilization efficiency of Mg in precursor, the optimum Mg consumption-normalized capacity was 0.744 mmol·mmol-Mg-1 with the mass ratio of biochar/MgCl2·6H2O = 1:1 at 600 °C.

Self-powered DNA nanomachines for fluorescence detection of lead.

A versatile DNA nanomachine detection system has been developed via the combination of DNAzyme with catalytic hairpin assembly (CHA) technology for achieving accurate and sensitive detection of lead ions (Pb2+). In the presence of target Pb2+, capture DNA nanomachine formed by AuNP and DNAzyme recognized and reacted with Pb2+, which yielded an "active" DNAzyme, that induced the cleavage of substrate strand, and then released the initiator DNA (TT) for CHA. With the help of the initiator DNA TT, self-powered CHA was activated to achieve the signal amplification reaction in the detection of DNA nanomachine. Meanwhile, the initiator DNA TT was released and hybridized with the other H1 strand to initiate another CHA, replacement, and turnovers, producing enhanced fluorescence signal of fluorophore FAM (excitation 490 nm/emission 520 nm) for sensitive determination of Pb2+. Under the optimized conditions, the DNA nanomachine detection system revealed high selectivity toward Pb2+ in the concentration range 50-600 pM, with the limit of detection (LOD) of 31 pM. Recovery tests demonstrated that the DNA nanomachine detection system has excellent detection capability in real samples. Therefore, the proposed strategy can be extended and act as a basic platform for highly accurate and sensitive detection of various heavy metal ions.

Enhancement of Xanthate Adsorption on Cerussite Surfaces by Pb(II) Activation and Its Effect on Floatability.

Cerussite is a lead oxide mineral resource that is typically enriched through sulfidization flotation. The surface sulfidation degree and the high solubility of cerussite strongly affect the flotation ability of cerussite. In the current work, lead ions were used to pretreat cerussite to intensify its sulfidization flotation. The sulfidization mechanism regulating the lead ions pretreatment on cerussite was investigated by the micro-flotation test, ToF-SIMS, zeta potential measurement, adsorption test, and XPS. The results from the micro-flotation test demonstrated that the floatability of cerussite could be improved by adding an appropriate amount of lead ions. Compared with the treatment involving only Na2S, the maximum recovery increased by 17.57%. Adsorption experiments showed that lead modification improved the stability of xanthate products on the surface of cerussite. According to the measurement of zeta potential and the results of ToF-SIMS, the addition of lead ion Pb pretreatment increased the number of active Pb sites adsorbed by xanthate, thereby improving the formation of hydrophobic Pb-dilute precipitate. Therefore, the interaction between lead ions and the surface of cerussite enhances the strength and stability of the hydrophobic layer, resulting in enhanced hydrophobicity of cerussite.

Biosorption of lead ions from aqueous solution by Clostridium tyrobutyricum immobilized in macroporous Ca-alginate-lignin beads.

AIMS: The adsorption of lead ions from aqueous solution by macroporous Ca-alginate-lignin (MCAL) beads immobilized with Clostridium tyrobutyricum and free strains was evaluated. METHODS AND RESULTS: The effects of different factors including pH, adsorption time, adsorbent dosage and initial concentration of lead ions were explored. Different characterization methods were used to evaluate the adsorption process of lead ions. Meanwhile, the adsorption kinetics models and adsorption isotherm models were applied. The fitting results showed that the adsorption behaviour of C. tyrobutyricum immobilized in MCAL beads and free strains was better described by the pseudo-second-order kinetic model and the adsorption process followed the Langmuir isotherm model. The maximum biosorption of lead ions by C. tyrobutyricum immobilized in MCAL beads and free strains was 144.9 and 106.4 mg/g respectively. CONCLUSIONS: The C. tyrobutyricum immobilized in MCAL beads proved to be practicable and had better adsorption effects on lead ions compared with the free strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper demonstrated a new insight and strategy for the effective treatment of lead ions from aqueous solutions by the novel function of C. tyrobutyricum.

Removal of lead ions from wastewater using lanthanum sulfide nanoparticle decorated over magnetic graphene oxide.

In this study, the new lanthanum sulfide nanoparticle (La2S3) was synthesized and incorporated onto magnetic graphene oxide (MGO) sheets surface to produce potential adsorbent (MGO@LaS) for efficient removal of lead ions (Pb2+) from wastewater. The synthesized MGO@LaS adsorbent was characterized using Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The effective parameters on the adsorption process including solution pH (~5), adsorbent dosage (20 mg), contact time (40 min), initial Pb2+ concentration and temperature were studied. The removal efficiency was obtained >95% for lead ions at pH 5 with 20 mg adsorbent. To validate the adsorption rate and mechanism, the kinetic and thermodynamic models were studied based on experimental data. The Langmuir isotherm model was best fitted to initial equilibrium concentration with a maximum adsorption capacity of 123.46 mg/g. This indicated a monolayer adsorption pattern for Pb2+ ions over MGO@LaS. The pseudo-second-order as the kinetic model was best fitted to describe the adsorption rate due to high R2 > 0.999 as compared first-order. A thermodynamic model suggested a chemisorption and physisorption adsorption mechanism for Pb2+ ions uptake into MGO@LaS at different temperatures; ΔG° < -5.99 kJ mol-1 at 20 °C and ΔG° -18.2 kJ mol-1 at 45 °C. The obtained results showed that the novel nanocomposite (MGO@LaS) can be used as an alternative adsorbent in wastewater treatment.

Development of a Toxic Lead Ionic Sensor Using Carboxyl-Functionalized MWCNTs in Real Water Sample Analyses.

Functional multiwall carbon nanotubes (f-MWCNTs) are of significant interest due to their dispersion ability in the aqueous phase and potential application in environmental, nanotechnology, and biological fields. Herein, we functionalized MWCNTs by a simple acid treatment under ultra-sonification, which represented a terminal or side-functional improvement for the fabrication of a toxic lead ion sensor. The f-MWCNTs were characterized in detail by XRD, Raman, XPS, BET, UV/vis, FTIR, and FESEM-coupled XEDS techniques. The analytical performance of the f-MWCNTs was studied for the selective detection of toxic lead ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of the f-MWCNTs was evaluated using several metal ions such as Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Pb2+, and Zn2+ ions. Lastly, the newly designed ionic sensor was successfully employed to selectively detect lead ions in several environmental water samples with reasonable results. This approach introduced a new technique for the selective detection of heavy metal ions using functional carbon nanotubes with ICP-OES for the safety of environmental and healthcare fields on a broad scale.

Defect-enhanced electrochemical property of h-BN for Pb2+ detection.

A new strategy has been developed for the determination of trace lead ions (Pb2+) based on hexagonal boron nitride (h-BN) laden with point defect. The defect-laden boron nitride (D-BN) was synthesized by a thermal polymerization route, in which melamine borate was used as a precursor. The defect microstructure was confirmed by photoluminescence (PL) and x-ray diffraction (XRD) techniques. As compared with h-BN, the D-BN-modified glassy carbon electrode (GCE) showed an enhanced electrochemical response towards Pb2+ peaking at - 0.551 V (vs. SCE), which was evidenced by linear sweep anodic stripping voltammetry (LSASV) results. The point defect plays a pivotal role in the electrocatalytic reaction process, which can mediate the electronic structure and surface properties of h-BN. Accordingly, the sensor presented a low detection limit of 0.15 µg/L towards Pb2+ and a wide linear response concentration range from 0.5 to 400 µg/L (correlation coefficient = 0.995). In view of its superior selectivity, stability, and reproducibility, the proposed method was applied for Pb2+ determination in real samples and exhibited satisfactory results. This work provides insight for the construction of electrochemical sensor with high-performance by engineering defects of modifying materials. Defect-loaden h-BN exhibited enhanced electrocatalytic redox reaction towards lead ions and thus a novel Pb2+ sensor with high performances was constructed.

Highly Sensitive and Selective Fluorescence "Turn-On" Detection of Pb (II) Based on Fe3O4@Au-FITC Nanocomposite.

New nanocomposites, Fe3O4@Au-FITC, were prepared and explored to develop a fluorescent detection of Pb2+. The Fe3O4@AuNPs-FITC nanocomposites could be etched by Pb2+ in the presence of Na2S2O3, leading to fluorescence recovery of FITC quenched by Fe3O4@Au nanocomposites. With the increase of Pb2+ concentration, the fluorescence recovery of Fe3O4@AuNPs-FITC increased gradually. Under optimized conditions, a detection limit of 5.2 nmol/L of Pb2+ with a linear range of 0.02-2.0 µmol/L were obtained. The assay demonstrated negligible response to common metal ions. Recoveries of 98.2-106.4% were obtained when this fluorescent method was applied in detecting Pb2+ spiked in a lake-water sample. The above results demonstrated the high potential of ion-induced nanomaterial etching in developing robust fluorescent assays.

A highly sensitive DNAzyme-based SERS biosensor for quantitative detection of lead ions in human serum.

Lead ions (Pb2+), one form of the toxic heavy metal, have drawn significant attention due to their harmful effects on human health and the environment. Although many analytical techniques have been developed over the past few decades, the development of a sensitive, selective, and rapid method to detect Pb2+ remains a challenge. In this work, we developed a sensitive surface-enhanced Raman scattering (SERS) biosensor for highly sensitive detection of Pb2+ by using DNAzyme-modified Fe3O4@Au@Ag nanoparticles (Fe3O4@Au@Ag NPs). Firstly, the thiolated 5'-Cy3 DNA probe was modified on the surface of Fe3O4@Au@Ag NPs, which hybridized with the Pb2+-specific DNAzyme to form a SERS biosensor, and the Cy3 labels were used to detect Pb2+. In the presence of Pb2+, the DNAzyme cleaves the Cy3-labeled DNA probe, leading to the release of Cy3-labeled DNA probe from the Fe3O4@Au@Ag NPs. Therefore, the Raman intensity of the Cy3 labels decreases. The proposed biosensor exhibited excellent linearity in the range from 0.01 to 1.0 nM, with a limit of detection for Pb2+ of 5 pM. It features superior selectivity to Pb2+ over other interfering metal ions and good application in the determination of Pb2+ in tap water and human serum samples. The SERS biosensor provides a novel' simple and sensitive method for detection of Pb2+ and sheds new light on the design and synthesis of analogous SERS biosensors for the detection of other heavy metal ions.

A novel electrochemiluminescence biosensor based on the self-ECL emission of conjugated polymer dots for lead ion detection.

The poly[(9,9-dioctylfuorenyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1',3}-thiadiazole)] (PFBT) was carboxyl-functionalized to prepare polymer dots (C-PFBT Pdots), which served as a self-ECL emitter for producing an extraordinary ECL signal without any exogenous coreactants. The C-PFBT Pdots-modified electrode captured the substrate DNA and further hybridized with a ferrocene (Fc)-labeled DNA. The ECL emission of C-PFBT Pdots was quenched by Fc (a signal off state). After the DNAzyme was added, the DNAzyme-substrate hybrids were formed through hybridizing between DNAzyme and substrate and the Fc-labeled DNA was released. In the presence of target Pb2+, the DNAzyme-substrate hybrids could be specifically recognized and cleaved to release the DNAzyme and Pb2+. Ultimately, the released DNAzyme would further hybridize with the substrate for producing the DNAzyme-substrate hybrids and then were cleaved by the released Pb2+. As a result, the DNA walking machine was generated and the substantial Fc was away from C-PFBT Pdots to obtain a signal on state. Such a strategy achieved a sensitive detection of Pb2+ and the detection limit was as low as 0.17 pM. Moreover, making this ECL biosensor for an intracellular Pb2+ detecting, a convincing performance was achieved. The self-ECL emitter C-PFBT Pdots combining with the quencher Fc provided a new strategy and platform for constructing a coreactant-free ECL assay.

Adsorption of lead (â ¡) from aqueous solution by modified Auricularia matrix waste: A fixed-bed column study.

In this study, Auricularia Matrix Waste (AMW) was modified by sodium hydroxide and immobilized into granular adsorbent with sodium alginate to remove lead ions from aqueous solution through a fixed-bed column. The results of Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FTIR) illuminated that immobilization greatly changed the structure, elements, polarity and functional groups of the adsorbent. Amino, hydroxyl, carboxyl groups on the adsorbent actively participated lead(II) adsorption and cation exchange also played an important role in adsorption process. The effects of bed length, flow rate and lead ions concentration determined the breakthrough characteristics and remarkably impacted lead(II) adsorption. The maximum adsorption capacity of lead(II) was 151.7 mg/g, when the influent bed, bed height and initial concentration were 15 mL/min, 25 mL/min and 150 mg/L, respectively. Thomas model was more suitable than the Bohart-Adams model to describe the performance of lead(II) adsorption onto IMAMW.

A Simple, Cost-Effective Sensor for Detecting Lead Ions in Water Using Under-Potential Deposited Bismuth Sub-Layer with Differential Pulse Voltammetry (DPV).

This research has developed a simple to use, cost effective sensor system for the detection of lead ions in tap water. An under-potential deposited bismuth sub-layer on a thin gold film based electrochemical sensor was designed, manufactured, and evaluated. Differential pulse voltammetry (DPV) measurement technique was employed in this detection. Tap water from the Cleveland, OH, USA regional water district was the test medium. Concentrations of lead ion in the range of 8 × 10-7 M to 5 × 10-4 M were evaluated, showing a good sensitivity over this concentration range. The calibration curve for the DPV measurements of lead ions in tap water showed excellent reproducibility with R² value of 0.970. This DPV detection system required 3-6 min to complete the detection measurement. A longer measurement time of 6 min was used for the lower lead ion concentration. The selectivity of this lead ion sensor was very good, and Fe III, Cu II, Ni II, and Mg II at a concentration level of 5 × 10-4 M did not interfere with the lead ion measurement.

Ion sensors based on novel fiber organic electrochemical transistors for lead ion detection.

Fiber organic electrochemical transistors (FECTs) based on polypyrrole and nanofibers have been prepared for the first time. FECTs exhibited excellent electrical performances, on/off ratios up to 10(4) and low applied voltages below 2 V. The ion sensitivity behavior of the fiber organic electrochemical transistors was investigated. It exhibited that the transfer curve of FECTs shifted to lower gate voltage with increasing cations concentration, the sensitivity reached to 446 µA/dec in the 10(-5)-10(-2) M Pb(2+) concentration range. The ion selective properties of the FECTs have also been systematically studied for the detection of potassium, calcium, aluminum, and lead ions. The devices with different cations showed great difference in response curves. It was suitable for selectively monitoring Pb(2+) with respect to other cations. The results indicated FECTs were very effective for electrochemical sensing of lead ion, which opened a promising perspective for wearable electronics in healthcare and biological application. Graphical Abstract The schematic diagram of fiber organic electrochemical transistors based on polypyrrole and nanofibers for ion sensing.

Protective effect of chitosan-modified rice porous starch loaded catechin on HT-29 cells exposed to lead ion.

To explore how chitosan-modified rice porous starch-loaded catechin (CT@RPS/CS) protects HT-29 cells exposed to lead ions. METHOD: The HT-29 cells were treated differently based on their grouping. The effect of CT@RPS/CS on lead-induced toxicity was evaluated using cell proliferation, apoptosis, oxidative stress index, and cytokine tests. RESULTS: CT@RPS/CS did not affect the activity, cell apoptosis, oxidative stress level, and related cytokines of HT-29 cells. After exposure to lead, CT@RPS/CS has the potential to enhance cellular activity, minimize apoptosis, and decrease the level of oxidative stress. DISCUSSION: CT@RPS/CS not only has no toxicity to cells but also adsorbs lead ions, which protects cells.

Designing of a cellulose-based ion-imprinted biosorbent for selective removal of lead (II) from aqueous solutions.

Developing an effective adsorbent for Pb2+ removal from wastewater has huge economic and environmental implications. Adsorbents made from cellulosic materials that have been modified with certain chelators could be used to get rid of metal cations from aqueous solutions. However, their selectivity for specific metals remains very low. Here, we describe the synthesis of 4-(2-pyridyl)thiosemicarbazide (PTC) hydrazidine-functionalized cellulose (Pb-PTC-CE), a polymer imprinted with Pb2+ ions that may be used to remove Pb2+ ions from wastewater. Owing to its potent -NH2 functionalization, PTC hydrazidine not only served as an efficient chelator to effectively supply coordinating sites and construct hierarchical porous structures on Pb-PTC-CE, but it also made it possible for cross-linking to occur through the glyoxal cross-linker. The abundant chelators, along with the hierarchical porous construction of the developed Pb-PTC-CE with PTC functionality, result in a greater sorption capacity of 336 mg/g and a short sorption period of 40 min for Pb2+. Additionally, Pb-PTC-CE exhibits highly selective Pb2+ uptake compared to competing ions. This study proposes a feasible methodology for the development of high-quality materials for Pb2+ remediation by combining the advantages of active ligand functionality with ion-imprinting techniques in a straightforward way.

Fabrication of thiosemicarbazide-modified biochar/carrageenan composite beads based on Eichhornia crassipes for effective removal of Pb (II) from aqueous medium.

Several biomasses have been applied as environmentally friendly substitutes to produce biochar, which can be utilized to remediate effluents that contain inorganic chemicals. This study applied water hyacinth (Eichhornia crassipes) as a foundation source for the assembly of thiosemicarbazide-modified biochar (BC), which then was modified with potassium carrageenan (KC). Thiosemicarbazide-modified biochar (BC), potassium carrageenan (KC), and thiosemicarbazide-modified biochar/carrageenan composite beads (BKC) were described by several physicochemical methods. The adsorption of Pb (II) onto the three solid adsorbents was investigated under various experimental conditions. The BKC composite beads revealed a surface area of 687.43 m2/g and a mesoporous structure. The best adsorption conditions were found to be 25 min as an equilibrium time, 1.2 g/L of adsorbent dose, and a solution pH of 5 at a temperature of 15 °C. The pseudo-second-order, Elovich kinetic models, Langmuir, and Temkin isotherms were well familiar to the experimental data, inferring that the progression was physical monolayer adsorption onto the homogenous surface. The highest capacity of Pb (II) adsorption onto BKC was 460.45 mg/g at 15 °C. Thermodynamic measurements proved that adsorption was a spontaneous process and endothermic in the case of BC and BKC while exothermic for KC. Furthermore, BKC showed high reusability conditions.

Fabrication and characterization of Araucaria gum/calcium alginate composite beads for batch and column adsorption of lead ions.

In this work, we developed five solid adsorbents such as calcium alginate beads (CG), Araucaria gum (AR) extracted from Araucaria heterophylla tree by chemical precipitation procedures, and Araucaria gum/calcium alginate composite beads (CR21, CR12, and CR11) prepared with different calcium alginate: Araucaria gum ratios (2:1, 1:2, and 1:1, respectively). The synthesized solid adsorbents were characterized utilizing TGA, XRD, nitrogen adsorption/desorption analysis, ATR-FTIR, pHPZC, swelling ratio, SEM, and TEM. Through the batch and column adsorption strategies, we evaluated the effect of adsorbent dose, pH, initial Pb (II) concentration, shaking time, bed height, and flow rate. The data of batch technique indicated that CR11 demonstrated a maximum batch adsorption capacity of 149.95 mg/g at 25 °C. Lead ions adsorption was well fitted by pseudo-second order and Elovich according to kinetic studies, in addition to Langmuir and Temkin models based on adsorption isotherm studies onto all the samples. Thermodynamic investigation showed that Pb (II) adsorption process is an endothermic, physical, and spontaneous process. The highest column adsorption capacity (161.1 mg/g) was achieved by CR11 at a bed height of 3 cm, flow rate of 10 mL/min, and initial Pb+2 concentration of 225 mg/L with 68 min as breakthrough time and 180 min as exhaustion time. Yoon-Nelson and Thomas models applied well the breakthrough curves of Pb (II) column adsorption. The maximum column adsorption capacity was decreased by 11.4 % after four column adsorption/desorption processes. Our results revealed that CR11 had an excellent adsorption capacity, fast kinetics, and good selectivity, emphasizing its potential for its applications in water treatment.

Adsorption of Pb(II) by UV-aged microplastics and cotransport in homogeneous and heterogeneous porous media.

To investigate the adsorption effects of aged microplastics (MPs) on Pb(II) and their co-transport properties in homogeneous (quartz sand) and heterogeneous (quartz sand with apple branches biochar) porous media, we explored the co-transport of UV-irradiated aged MPs and coexisting Pb(II) along with their interaction mechanisms. The UV aging process increased the binding sites and electronegativity of the aged MPs' surface, enhancing its adsorption capacity for Pb(II). Aged MPs significantly improved Pb(II) transport through homogeneous media, while Pb(II) hindered the transport of aged MPs by reducing electrostatic repulsion between these particles and the quartz sand. When biochar, with its loose and porous structure, was used as a porous medium, it effectively inhibited the transport capacity of both contaminants. In addition, since the aged MPs cannot penetrate the column, a portion of Pb(II) adsorbed by the aged MPs will be co-deposited with the aged MPs, hindering Pb(II) transport to a greater extent. The transport experiments were simulated and interpreted using two-point kinetic modeling and the DLVO theory. The study results elucidate disparities in the capacity of MPs and aged MPs to transport Pb(II), underscoring the potential of biochar application as an effective strategy to impede the dispersion of composite environmental pollutants.

Structural analysis of lignite-derived humic acid and its microscopic interactions with heavy metal ions in aqueous solution.

Understanding heavy metal environmental behavior with humic acid (HA) is critical. There is currently a lack of information on the control of its structure organization on its reactivity to metals. The difference in HA structures under non-homogeneous conditions is critical for revealing its micro-interaction with heavy metals. The heterogeneity of HA was reduced using the fractionation method in this study, the chemical properties of HA fractions were analyzed using py-GC/MS, and the structural units of HA were proposed. Pb2+ was used as a probe to investigate the difference in the adsorption capacity of HA fractions. The microscopic interaction of structures with heavy metal was investigated and validated by structural units. The results show that as molecular weight increased, the oxygen content and the number of aliphatic chains decreased, but the opposite was true for aromatic and heterocyclic rings. The adsorption capacity for Pb2+ was as follows: HA-1 > HA-2 > HA-3. According to the linear analysis of the influencing factors of maximum adsorption capacity and possibility factors, the adsorption capacity was positively correlated with the contents of acid groups, carboxyl groups, phenolic hydroxyl groups, and the number of aliphatic chains. The phenolic hydroxyl group and the aliphatic-chain structure have the greatest impact. Therefore, structural differences and the number of active sites play an important role in adsorption. The binding energy of HA structural units to Pb2+ was calculated. It was found that the chain structure is easier to bind to heavy metals than aromatic rings, and the affinity of-COOH to Pb2+ is greater than that of -OH. These findings can help improve the adsorbent design.