Adsorption Process Of Pb Research Articles

Preparation of Polymeric Aluminum Chloride-Loaded Porous Carbon and Evaluation of Its Pb2+ Immobilization Mechanisms in Soil

In recent years, the remediation of heavy metal-contaminated soils has attracted great attention worldwide. Previous research on the removal of toxic heavy metals from wastewater effluents through adsorption by typical solid wastes (e.g., fly ash and coal gangue) has mainly focused on the control of wastewater pollutants. In this study, a coal gangue (CG) by-product from Hancheng City was used as a raw material to prepare polymeric aluminum chloride-loaded coal gangue-based porous carbon (PAC-CGPC) by hydrothermal synthesis. This material was subsequently employed to assess its performance in mitigating Pb2+ in soils. In addition, the effects of the pore structure of the prepared material on the adsorption rates, adsorption mechanisms, and plant root uptakes of soil Pb2+ were investigated in this study. The raw CG and prepared PAC-CGPC materials exhibited specific surface areas of 1.8997 and 152.7892 m2/g, respectively. The results of adsorption kinetics and isotherms indicate that the adsorption of Pb2+ based on PAC-CGPC mainly follows a pseudo-second-order kinetic model, suggesting that chemisorption may be the dominant process. In addition, the adsorption isotherm results showed that the Freundlich model explained better the adsorption process of Pb2+, suggests that the adsorption sites of lead ions on APC-CGPC are not uniformly distributed and tend to be enriched in APC, and also shows the ion exchange between aluminum and lead ions. The thermodynamic model fitting results demonstrated the occurrence of spontaneous and exothermic PAC-CGPC-based adsorption of Pb2+, involving ion exchange and surface complexation. The effects of the PAC-CGPC addition on soybean plants were further explored through pot experiments. The results revealed substantial decreases in the Pb2+ contents in the soybean organs (roots, stems, and leaves) following the addition of the PAC-CGPC material at a dose of 3% compared with the control and raw CG groups. Furthermore, the addition of the PAC-CGPC material at a dose of 3% effectively reduced the bioavailable Pb2+ content in the soil by 82.11 and enhanced soybean growth by 15.3%. These findings demonstrated the inhibition effect of the PAC-CGPC material on the translocation of Pb2+ in the soybean seedlings. The modified CG adsorbent has highly pore structure and good hydrophilicity, making it prone to migration in unsaturated soils and, consequently, enhancing Pb2+ immobilization. This research provides theoretical support for the development of CG-based materials capable of immobilizing soil pollutants.

Molybdenum disulfide anchored peanut shell biochar composite for efficient adsorption of Pb2+: Performance and mechanism

Heavy metal lead (Pb2+) contamination in water poses a serious threat to human health, and developing some effective strategies for the removal of Pb2+ is urgent. Herein, molybdenum disulfide (MoS2) anchored peanut shell biochar (BC) composite adsorbents were successfully prepared by hydrothermal method and applied for the adsorption of Pb2+. Among these composites, the MoS2/BC-3 composite displayed the best adsorption performance with the adsorption capacity of 232 mg·g−1 at 30 °C. The adsorption procedure followed the pseudo-secondary kinetics and Freundlich adsorption model, indicating that the adsorption process of Pb2+ over MoS2/BC-3 composite was chemical and multilayer adsorption. Moreover, Pb2+ was spontaneously adsorbed by MoS2/BC-3, and the adsorption capacity increased with the enhance of temperature. The main mechanisms involved in the adsorption of Pb2+ by MoS2/BC-3 composite were found to include electrostatic interaction and complexation interaction. In addition, the MoS2/BC-3 composite had a good stability, and the Pb2+ removal rate could still reach more than 80 % after 6 cycles of adsorption experiments. Meanwhile, the adsorbent demonstrated a strong ability to absorb common heavy metals including copper and cadmium, further confirming that the MoS2/BC-3 composite had a potential value.

Adsorption of Pb(II) in water by modified chitosan-based microspheres and the study of mechanism

In this study, a fresh three-dimensional microsphere adsorbent (CATP@SA3) was successfully synthesized by Attapulgite (ATP) and combining Chitosan (CS), incorporating them into a Sodium alginate (SA) solution, and crosslinking them in a CaCl2 solution. Multiple analyses, including XRD, TGA, FTIR, XPS, SEM-EDS, and BET were utilized to comprehensively characterize the structural makeup of CATP@SA3. These analyses revealed the presence of beneficial functional groups like hydroxyl, amino, and carboxyl groups that enhance the adsorption efficiency in adsorption procedures. CATP@SA3 was evaluated by studying different factors, including material ratio, contact time, dosage, solution pH, Pb(II) concentration, temperature, ionic strength, and aqueous environment. Three adsorption models, including kinetic, isotherm, and thermodynamic, were fitted to the experimental data. The findings demonstrated that the maximum Pb(II) adsorption capacity of CATP@SA3 was 1081.36 mg/g, with a removal rate that exceeded 70 % even after 5 cycles of use. Furthermore, correlation adsorption models revealed that the adsorption process of Pb(II) with CATP@SA3 was driven by a chemical predominantly reaction.

Typical MOFs-derived nanoporous carbon: Insight into structures, properties and Pb(II) adsorption mechanism

A series of nanoporous carbon (NC) materials were synthesized by direct carbonization of traditional metal organic frameworks (MOFs) including copper-based (HKUST-1), nickel-based (Ni-MOF), zinc-based (ZIF-8), zirconium-based (UiO-66) and iron-based (Fe-BTC) for the removal of Pb(II) from simulated waste water. The physical and chemical characteristics before and after adsorption were thoroughly investigated by Fourier transforms infrared spectroscopy (FTIR), X-Ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption analyses. The adsorption kinetics and isothermal thermodynamic properties and the effects of five central different cations on the removal of Pb(II) were compared. The adsorption kinetics were well described by the quasi-second-order model and the adsorption isotherm consistent with the Langmuir equation. The adsorption process of Pb (II) is feasible, spontaneous, endothermic and reusable on the five nanoporous carbons. Among them, Fe-BTC-NC showed the best adsorption performance for Pb (II), and the maximum adsorption capacity was 479.93 mg/g. This work highlights the applications of MOFs derived nanocarbon in heavy metal contaminated water treatment and offers a facile method for the design of novel nanocarbon materials.

Efficient Removal of Pb(II) Ion Using Tio2/Zno/Sio2 Nanocomposite from Aqueous Solutions Via Adsorption-Photocatalysis Process

This research aims to investigate the usage of a TiO2/ZnO/SiO2 (TZS) composite prepared via a 24-h hydrothermal process at 180° C to remove Pb(II) through adsorption-photocatalysis. Pb(II) exposure has known health risks, making this study significant. The research explores the impact of pH, the nanocomposite quantity, and contact time in the process. Adsorption-photocatalysis was carried out in the dark for 60 min, followed by irradiation with a 160-watt mercury lamp. The adsorption process of Pb(II) ion removal adhered to the pseudo-second-order model regarding kinetics, while the adsorption isotherm corresponded to the Freundlich isotherm. Additionally, the assessment of photocatalysis kinetics showed that the removal of Pb(II) ions followed a pseudo-first-order model, resulting in a 99.58% elimination of Pb(II) ions. Post-adsorption-photocatalytic treatment, a yellowish precipitate was observed. The XRD pattern result of the yellowish precipitate confirmed the presence of PbO as the formed Pb phase. The study concludes that the TiO2/ZnO/SiO2 nanocomposite as adsorbent-photocatalyst is a highly effective, efficient, and promising method to remove Pb(II) contamination from aqueous solutions.

Fe3O4@SiO2 Magnetic Nanoparticles Modified with Cysteine: a New Adsorbent for Environmentally Friendly Adsorption/Desorption of Pb(II) ions

In recent years, nanoparticles have become the focus of scientific research because of their wide potential application value. Iron oxides show incredible magnetic saturation, stability, and intuitive properties on the surface, making them ideal for a variety of uses. In this paper, nanometer iron oxide particles are synthesized by co-deposition method, and silica is further used to avoid agglomeration. Functional synthesis of cysteine nanoparticles (FNMs-Cys).The optimum synthesis conditions and adsorption conditions were determined by orthogonal experiments. In addition, the anti-interference and regeneration cycle performance of FNMs-Cys are discussed. The samples were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), N2 adsorption and desorption automatic specific surface and porosity analyzer (BET), thermogravimetric analysis (TG) and hysteresis loop test (VSM). The adsorption process of Pb2+ by FNMs-Cys accords with quasi-second-order kinetics and Langmuir isothermal adsorption model, which shows that the adsorption is mainly through chemical adsorption of monolayer, In the Langmuir model, the maximum single-layer adsorption capacity of FNMs-Cys for Pb2+ reached 174.85 mg/g. After five cycles of adsorption-desorption regeneration, FNMs-Cys still showed good stability and recyclability. At present, it is of forward-looking significance to study the removal effect of Pb2+ in water by using amino acid modified mesoporous magnetic silica materials in laboratory.

Adsorption of PO43−, Cd(II), Pb(II), Cu(II), As(III), and As(V) using the La-based and modified La-based metal–organic framework materials

Metal–organic framework (MOF) materials are novel adsorption materials for water treatment. In this study, La-MOF ({[La2(H2DHTPA)3(H2O)7]·4H2O}n, H4DHTPA denotes 2,5-dihydroxyterephthalic acid) was synthesized by a hydrothermal method. The material had a strong water stability, but its adsorption performance was weak and its processability was poor. K-La-MOF, with good processability, was obtained using a potassium permanganate oxidation modification method to modify the La-MOF. The results showed that the maximum adsorption capacity (qmax) of the La-MOF for PO43− was 72.19 mg/g, and the adsorption was monolayer chemical adsorption. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that P was adsorbed on the surface of the La-MOF material in the form of HPO42−. The adsorption properties of the K-La-MOF were also investigated. The results showed that the maximum adsorption capacities of the K-La-MOF for PO43−, Cd(II), Pb(II), Cu(II), As(III), and As(V) were 87.56, 37.08, 992.99, 190.51, 42.20, and 131.66 mg/g, respectively. The adsorption of PO43−, Cd(II), Cu(II), and As(III) by the K-La-MOF was determined to be monolayer chemisorption by fitting adsorption isotherm and kinetics models. The adsorption process of Pb(II) by the K-La-MOF involved both single-molecular-layer and lateral-multi-molecular-layer chemisorption. In contrast, the adsorption of As(V) by the K-La-MOF occurred through both monolayer chemical adsorption and pore physical adsorption. XRD and XPS analyses showed that P, Cd(II), Pb(II), Cu(II), As(III), and As(V) were adsorbed on the K-La-MOF in the forms of PO43−, CdO, PbO and Pb(OH)2, CuO, K3AsO4, and K4As2O7, respectively.

A novel self-assembled ZIF-67 hollow prisms for high-efficient simultaneous removal of ciprofloxacin and lead

Due to the wide variety of pollutants in wastewater, therefore, how to efficiently and effectively remove mixed pollutants is of great importance for environmental remediation. In this study, ZIF-67 hollow prisms self-assembled by nanoparticles were prepared. The nanoparticles possess a regular distributed pore structure, which mixed with the self-assembled hierarchical structure can provide more binding sites. This special self-assembly structure endows ZIF-67 hollow prisms to have a large specific surface area (1221 m2/g), and to exhibit excellent efficiency in removing a variety of pharmaceuticals. For simultaneous removal of ciprofloxacin and Pb(II) mixed pollutants, the adsorption process of Pb(II) is ultra-fast (<2 min), and the average amount removed efficiently was 100 %. The maximum adsorption capacities of ciprofloxacin (CIP) and Pb(II) were 1586.14 and 2488.14 mg g−1, respectively. The XPS results indicated that Pb(II) may be mixed with Co-OH to form Co-O-Pb during the adsorption process. As well, metal ions are easily complexed with antibiotics, which makes the adsorption performance of CIP and Pb remarkable. This study explored the adsorption capacity by porous materials with self-assembled structures, and provided a novel strategy for the efficient removal of antibiotic/heavy metal complex pollutants from the environment.

A novel magnetic Ti-MOF/chitosan composite for efficient adsorption of Pb(II) from aqueous solutions: Synthesis and investigation

In this investigation, a composite material comprising Ti-MOF and chitosan, denoted as BD-MOF(Ti)@CS/Fe3O4, was successfully designed for the efficient adsorption of Pb(II) from aqueous solutions. A comprehensive array of characterization techniques, including SEM, XRD, BET, FT-IR, and XPS, were meticulously employed to scrutinize the structural attributes and morphological features of the Pb(II) adsorbent. Notably, the material exhibits adaptability to a broad pH range, with adsorption efficiency reaching 99 % between pH 3 and 6. Kinetic studies reveal that the adsorption process of Pb(II) by BD-MOF(Ti)@CS/Fe3O4 adheres closely to a pseudo-second-order kinetic model. Impressively, within a short duration of 40 min, the adsorption efficiency can reach 85 %. Furthermore, the adsorption isotherm aligns with the Hill isotherm model, signifying cooperative adsorption. This observation underscores the synergistic interplay among the functional groups on the surface of BD-MOF(Ti)@CS/Fe3O4 in capturing Pb(II). As per the Hill model, the theoretical maximum capacity was an impressive 944.9 mg/g. Thermodynamic assessments suggested that the adsorption process was spontaneous, entropy increasing and exothermic. Even in the presence of various interfering ions, BD-MOF(Ti)@CS/Fe3O4 exhibited robust adsorption performance, thereby affirming its utility in complex environments. Moreover, the material demonstrates noteworthy reusability, sustaining effective Pb(II) removal across five consecutive cycles in aqueous solutions.

Effects of magnesium hydroxide morphology on Pb(ii) removal from aqueous solutions.

In this study, magnesium hydroxide (MH) particles with distinct morphologies were obtained through direct precipitation and subsequent hydrothermal treatment with various magnesium salts. The synthesized products were systematically characterized and utilized for the removal of Pb(ii) ions from aqueous solutions. The adsorption process of Pb(ii) by two different MH structures, namely flower globular magnesium hydroxide (FGMH) and hexagonal plate magnesium hydroxide (HPMH), adhered to the Langmuir isotherm and pseudo-second-order model. FGMH exhibited higher Pb(ii) removal capacity (2612 mg g-1) than HPMH (1431 mg g-1), attributable to the unique three-dimensional layered structures of FGMH that provide a larger surface area and abundant active sites. Additionally, metallic Pb was obtained by recycling the adsorbed Pb(ii) through acid dissolution-electrolysis. Furthermore, Pb(ii) removal mechanisms were investigated by analyzing adsorption kinetics and isotherms, and the adsorbed products were characterized. Based on the findings, the removal process occurs in two key stages. First, Pb(ii) ions bind with OH- ions on the surface upon diffusing to the MH surface, resulting in Pb(OH)2 deposits in situ. Concurrently, Mg(ii) ions diffuse into the solution, substituting Pb(ii) ions in the MH lattice. Second, the resultant Pb(OH)2, which is unstable, reacts with CO2 dissolved in water to yield Pb3(CO3)2(OH)2. Therefore, owing to its outstanding Pb(ii) adsorption performance and simple preparation method, FGMH is a promising solution for Pb(ii) pollution.

Effect of oxidative torrefaction on the pyrolysis of Clitocybe maxima stipe: Pyrolysis behaviour, and products' properties

In this study, oxidative torrefaction (OT) was used as the pretreatment process for the pyrolysis of Clitocybe maxima stipe (CMS) which is one kind of typical mushroom wastes, in order to evaluate the influence of OT on pyrolysis behaviour of torrefied CMS and products’ properties. The experimental results demonstrated that OT enhanced the degree of aromatization, and improved the thermal stability of the torrefied CMS compared with inert torrefaction (IT). The biochar (T9-P700) obtained by OT (9% oxygen) coupled pyrolysis (700 °C) had the improved pore structure with the highest specific surface area of 661.61 m2/g, while the obtained liquid products were less acidic with an increased formation of N-containing compounds (up to 19.15%) and phenolic compounds (8.08%). Furthermore, T9-P700 had a higher adsorption efficiency and adsorption capacity (147.31 mg/g) for Pb(Ⅱ). C-O, CO, -COOH, and -OH on the obtained biochar participated in the adsorption process of Pb(Ⅱ), attributing to the adsorption mechanism interpreted as physical adsorption, precipitation, and functional group complexation. Higher oxygen concentrations increased the severity of torrefaction, which facilitated a better pore structure in the CMS biochar generated during the subsequent pyrolysis process and the generation of liquid products with better qualities. Therefore, OT coupled pyrolysis may be an effective way to improve the quality of pyrolysis products.

The effect and spectral response mechanism of dissolved organic matter (DOM) in Pb(II) adsorption onto biochar

This study investigated the interaction of biochar-derived dissolved organic matter (DOM) and metal pollutant Pb(II) during adsorption. Research data showed that the adsorption capacity of biochar and residual biochar (after removal of DOM) was 277.62 and 204.47 mg g−1, respectively, indicating that DOM played a significant role in enhancing the adsorption efficiency of Pb(II). The results indicated that the adsorption process of Pb(II) on biochar and residual biochar followed the pseudo-second-order kinetic equation (R2 > 0.99), and the adsorption isotherm was much closer Freundlich model. A combination of three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence, Fourier transform infrared spectroscopy (FT-IR), and two-dimensional correlation spectroscopy (2D-COS) was employed to investigate the interaction between DOM and Pb(II). 3D-EEM indicated the presence of four major components of DOM, namely two protein-like substances, one humic acid-like substance, and one fulvic acid-like substance. The synchronous fluorescence revealed a gradual quenching of the fluorescence of the DOM sample with an increase in Pb(II) concentration, indicating a static quenching mechanism between DOM and Pb(II). FTIR-2D-COS analysis showed a specific sequence of DOM binding with Pb(II) is as follows: 1500 > 1010 > 880 > 1390 > 1260 cm−1. This findings have significant implications for the role of DOM in environmental science and have potential applications in various fields.

Adsorption of heavy metals and antibacterial activity of silicon-doped chitosan composite microspheres loaded with ZIF-8

A bifunctional composite microsphere adsorbent with high adsorption and antimicrobial activity was synthesized by combining zeolite imidazolate framework (ZIF-8) chitosan microspheres doped with silica (CS/DS) prepared by electrospraying method for removing heavy metal ions Pb2+ and Cu2+. The samples were characterized by chemical, morphological, thermal behavior, specific surface area and pore size analysis. Compared with chitosan microspheres and CS/DS, CS/DS@ZIF-8 has good crystallinity, high specific surface area, multi-pore size distribution, better thermal stability and more active groups. The adsorption process of Pb2+ and Cu2+ on CS/DS@ZIF-8 conformed to the Langmuir model and Pseudo 2nd kinetics model, of which the maximum adsorption capacities were 340.94 mg/g and 308.27 mg/g, respectively, which were better than those of CS and CS/DS microsphere adsorbents. At the same time, the composite microspheres have excellent antibacterial properties and have application potential in solving practical wastewater treatment. It is worth mentioning that CS/DS@ZIF-8 maintains 81.3 % and 72.9 % adsorption rates for Pb2+ and Cu2+ after five cycles. This study aims to help design new bifunctional adsorbents with the ability to remove chemical and biological pollutants to promote practical application scenarios.

Effective elimination of hexavalent chromium and lead from solution by the modified biochar with MgMn2O4 nanoparticles: adsorption performance and mechanism.

Heavy metal pollution is one of the environmental problems that need to be solved urgently. The adsorption method is thought as the most effective and economical treatment technology. Nature biochar usually showed unsatisfactory adsorption capacity due to its relatively small adsorption capacity and slow adsorption rate. The metal of Mn has been widely applied in the modification of biochar, which could effectively improve the adsorption capacity of biochar. However, leaching of Mn2+ on the adsorbent materials would appear during the adsorption process. And it would increase the risk of secondary pollution. The multifunctional binary modified biochar could improve the adsorption capacity of environmental pollutant removal. In addition, it could also act as a metal support carrier, reducing the risk of secondary pollution. A novel effective biochar loaded by Mg-Mn binary oxide nanoparticles (MgMn2O4@Biochar) was prepared and applied for the Cr(VI) and Pb(II) removal in aqueous solution. The characteristic of MgMn2O4@Biochar was analyzed by SEM, TEM, FTIR, and XRD. The irregular and somewhat flaky shaped particles of different shape and sizes clustered on the surface of MgMn2O4@Biochar appeared. Abundant functional groups of O-H, -C-OH, C-O, and C-OOH could be observed on the surface of MgMn2O4@Biochar. The elements of Mg and Mn elements besides of C, O, and Si elements were presented on the surface of MgMn2O4@Biochar. The wt% of C, O, Mg, Mn, and Si were 42.82%, 48.99%, 2.83%, 4.44%, and 0.93%, respectively. The operational parameters had an important influence on adsorption capacity of Cr(VI) and Pb(II) removal. The results showed that the adsorption capacity of MgMn2O4@Biochar for Cr(VI) and Pb(II) would reach 33.5 mg/g and 536 mg/g, respectively, within 360 min. Additionally, the adsorption processes of Cr(VI) and Pb(II) in solution could be described with pseudo-second-order. For Cr(VI), the Langmuir model was suitable to the adsorption process. However, the adsorption process of Pb(II) in solution could be described with Freundlich model. Furthermore, it could be concluded that the possible mechanism of Cr(VI) and Pb(II) removal by MgMn2O4@Biochar was physical adsorption, surface complexation reaction, and electrostatic adsorption.

Preparation of Coal Gangue-Based Porous Ceramics and Its Application on Pb2+ Cycling Adsorption

The presence of lead in wastewater poses a significant threat to human health. To address this issue, coal gangue-based porous ceramics (CGPC) were developed to remove Pb2+ in wastewater. Coal gangue (CG) waste from Lvliang City, Shanxi province in China was used as raw material, and porosity was introduced through the addition of a pore-forming agent and an extrusion molding process. Properties of CGPC were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) to explore its adsorption mechanism. The researchers examined the impact of pH, dosage of adsorbent, initial concentration, duration of adsorption, and temperature on the adsorption efficiency of CGPC. The CGPC of best performance had a porosity of 32.91% and compressive strength of 20.5 MPa prepared at 800 °C under nitrogen atmosphere with 10 wt% Na2CO3 pore-forming agent and 8 wt% CaO-MnO2 combined fluxing agent. The removal rate of Pb2+ in simulated lead-containing wastewater with a concentration of 200 mg/L reached 99.63%, and the maximum adsorption capacity was 32.15 mg/g. The adsorption process of Pb2+ by CGPC involves chemical adsorption and ion exchange. After being regenerated for seven cycles with 1 mol/L NaOH as the desorption agent, the removal rate of Pb2+ by CGPC still had 72%.

Adsorption Characteristics of Heavy Metals Pb2+ and Zn2+ by Magnetic Biochar Obtained from Modified AMD Sludge.

Acid mine drainage (AMD) sludge can be used to prepare adsorbent materials for the removal of heavy metals in water, which is an effective means for its resource utilization. Magnetic modified biochar (MMB), which can be recovered by magnetic separation, was prepared from sludge generated from the carbonate rock neutralization treatment of AMD and rice straw agricultural waste. Unmodified biochar (UMB) was obtained from rice straw and chemically modified and treated by ultraviolet radiation to produce MMB. The Pb2+ and Zn2+ adsorption capacities of UMB and MMB were investigated. Simultaneously, the materials were characterized by SEM, FTIR, BET, and ZETA. The results showed that the specific surface area (130.89 m2·g-1) and pore volume (0.22 m2·g-1) of MMB were significantly increased compared to those of UMB (9.10 m2·g-1 and 0.05 m2·g-1, respectively). FTIR images showed that MMB was successfully loaded with Fe3O4. The adsorption process of Pb2+ and Zn2+ onto MMB was consistent with the Langmuir adsorption isotherm and second-order kinetic models, with maximum adsorption capacities of 329.65 mg·g-1 and 103.67 mg·g-1, respectively. In a binary system of Pb2+ and Zn2+, MMB preferentially binds Pb2+. The adsorption efficiencies of MMB reached >80% for Pb2+ and Zn2+.

Synthesis and characterization of a novel N-rich porous organic polymer and its application as an efficient porous adsorbent for the removal of Pb(II) and Cd(II) ions from aqueous solutions.

In this study, a novel N-rich triazine-based porous organic polymer (NR-POP) was synthesized via Schiff-base condensation. The structure of the synthesized porous polymer was identified using FT-IR, XRD, SEM, EDS, TEM, TGA, and BET analyses. The adsorption efficiency of this polymer was investigated for the removal of lead and cadmium ions pollutants. The adsorption processes of Pb(II) and Cd(II) metal ions by this polymer adsorbent were exothermic and matched by the Langmuir isotherm with a high correlation coefficient (R2 = 0.9904, 0.9778), the maximum adsorption capacity (833.33, 178.57mgg-1), and the pseudo-second-order kinetic model. Furthermore, NR-POP showed an excellent adsorption selectivity for Pb(II) compared to Cd(II).

Breeding, Biosorption Characteristics, and Mechanism of a Lead-Resistant Strain.

To effectively carry out the bioremediation of a Pb2+ polluted environment, a lead-tolerant strain named D1 was screened from the activated sludge of a factory in Hefei, and its lead removal in a solution with Pb2+ concentration of 200 mg/L could reach 91% under optimal culture conditions. Morphological observation and 16S rRNA gene sequencing were used to identify D1 accurately, and its cultural characteristics and lead removal mechanism were also preliminarily studied. The results showed that the D1 strain was preliminarily identified as the Sphingobacterium mizutaii strain. The experiments conducted via orthogonal test showed that the optimal conditions for the growth of strain D1 were pH 7, inoculum volume 6%, 35 °C, and rotational speed 150 r/min. According to the results of scanning electron microscopy and energy spectrum analysis before and after the D1 exposure to lead, it is believed that the lead removal mechanism of D1 is surface adsorption. The Fourier transform infrared spectroscopy (FTIR) results revealed that multiple functional groups on the surface of the bacterial cells are involved in the Pb adsorption process. In conclusion, the D1 strain has excellent application prospects in the bioremediation of lead-contaminated environments.

Constructing ZIF-8-decorated montmorillonite composite with charge neutralization effect and pore structure optimization for enhanced Pb2+ capture from water

A zeolitic imidazole framework-8/montmorillonite (ZIF-8/MMT) composite was synthesized by a simple method through in-situ growth of ZIF-8 on MMT for efficient Pb2+ capture from water. The adsorption process of Pb2+ by ZIF-8/MMT composite followed the Langmuir model and the maximum adsorption could reach up to 336.89 mg/g, which was much better than that of the monocomponent of ZIF-8 (117.78 mg/g) or MMT (85.20 mg/g). Kinetics result suggested that Pb2+ adsorption by ZIF-8/MMT was a pseudo-second-order dynamic process, indicating a chemisorption process dominates. Ion exchange, electrostatic attraction and hydroxyl complexation were main pathways for Pb2+ removal by ZIF-8/MMT composite. The enhanced performance of ZIF-8/MMT composite should be attributed to following points. Firstly, the lamellar structure of MMT was in favor of ZIF-8 nanoparticles grow and disperse uniformly on the surface, thus avoiding the aggregation. Secondly, the positive charge on ZIF-8 was neutralized by the negative charge on the surface of MMT, and thus the adsorption capacity of ZIF-8 for Pb2+ is effectively released. Thirdly, the combination of MMT and ZIF-8 optimized the pore structure, which was favorable for Pb2+ adsorption and diffusion. Therefore, the synthesized ZIF-8/MMT composites is a prospective candidate for Pb2+ removal from wastewater.

Efficient removal of lead(II) ions in water using functionalized poly(styrene) oligomers

In this research, chemically functionalized polystyrene oligomers with acrylamide monomers were applied as alternative adsorbent towards Pb(II) from aqueous solutions. Adsorption process of Pb(II) was optimized using the 2*' fractional factorial design with replicates at the central point supplemented with the central composite design where the percentage adsorption was chosen as the response variable. This variable was simultancously optimized using the desirability functions approach to select the best conditions for the adsorption process. The experimental data reveal that after the optimization, the maximal response was exhibited at 38 °C, pH 5.80, initial adsorbate concentration (36.40 mg L™, and adsorbent dosage (10.77 mg) with the desirability function of 0.9260. Theoretical values and experimental data determined by the central composite design showed a high correlation with a R? value of 0.9810. Under these optimal conditions, the theoretical value for the removal of Pb(II) was 93.12%, while that experimental assay gives a maximum value of 91.23%. Likewise, the analysis of surface charge distribution, the structural and morphological characteristics confirmed the successful chemical modification of poly(styrene) oligomers.