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Lead (Pb(II)) is a pervasive heavy metal toxin with many well-established negative effects on human health. Lead toxicity arises from cumulative, repeated environmental exposures. Thus, prophylactic strategies to protect against the bioaccumulation of lead could reduce lead-associated human pathologies. Here we show that DNA and RNA aptamers protect C. elegans from toxic phenotypes caused by lead. Reproductive toxicity, as measured by brood size assays, is prevented by co-feeding of animals with DNA or RNA aptamers. Similarly, lead-induced neurotoxicity, measured by behavioral assays, are also normalized by aptamer feeding. Further, cultured human HEK293 and primary murine osteoblasts are protected from lead toxicity by transfection with DNA aptamers. The osteogenic development, which is decreased by lead exposure, is maintained by prior transfection of lead-binding DNA aptamers. Aptamers may be an effective strategy for the protection of human health in the face of increasing environmental toxicants. • Lead toxicity remains a pervasive public health problem, with limited interventions available. • Aptamers are short single-stranded nucleic acids that bind targets including proteins, small molecules, and ions. • Lead-binding aptamers applied to C. elegans protect the animals from lead-induced reproductive toxicity and neurotoxicity. • Upon transfection, DNA aptamers protect primary osteoblasts from lead toxicity. • The study represents the first demonstration of the use of an aptamer as a prophylactic to an environmental pollutant. [ABSTRACT FROM AUTHOR]

Defective NH 2 -UiO-66 adsorbent (named as NH 2 -UiO-66-SD) was successfully fabricated via post-synthesis method with the aid of both sodium carbonate anhydrous (Na 2 CO 3) and diethylenetriaminepentaacetic acid (DTPA), in which the defective structure was confirmed by various characterizations. The as-obtained defective NH 2 -UiO-66-SD exhibited outstanding Pb(II) sorption capacity (172.21 ​mg ​g−1) and rapid diffusion rate (29.87 ​mg ​g−1 min−0.5) at room temperature with optimal pH being 5.47. The Pb(II) sorption behavior was conformed to pseudo-second-order kinetics and Langmuir model, demonstrating that the chemical sorption of the monolayer played a dominant model. As well, the thermodynamic parameters like standard Gibbs free energy change Δ G o (−31.21 ​kJ ​mol−1), standard enthalpy change Δ H o (12.79 ​kJ−1 ​mol−1) and standard entropy change Δ S o (146.73 ​J ​mol−1 ​K−1) revealed that the Pb(II) sorption process of NH 2 -UiO-66-SD was spontaneous, endothermic and disordered. Furthermore, the NH 2 -UiO-66-SD exhibited desirable desorption and recirculation performances (removal efficiencies >85 ​% in 5 runs) with ideal stability. Moreover, the Pb(II) sorption mechanism of NH 2 -UiO-66-SD mainly included the electrostatic attractions and coordinative interactions. Overall, this work offered an intriguing method of fabricating defective NH 2 -UiO-66 adsorbent, which vastly enhanced adsorption efficiency for toxic metal ions elimination from wastewater. [Display omitted] • Defective NH 2 -UiO-66 was successfully fabricated via Na 2 CO 3 and DTPA. • Exceptional Pb(II) adsorption capacity (172.21 ​mg ​g−1) was achieved. • The type of defect included missing linkers and missing Zr–O clusters. • The possible adsorption mechanism for NH 2 -UiO-66-SD toward Pb(II) were proposed. [ABSTRACT FROM AUTHOR]

• BW has strong acid resistance (pH ≥ 1). • BW selectively separates lead from complex heavy metal solutions. • The selective immobilization is due to its specific composite structure. The development of bio-adsorbents with highly selective immobilization properties for specific heavy metals is a great challenge, but has important application value. Biogenic whewellite (BW) with high selectivity for Pb(II) was synthesized by mineral microbial transformation. The selective immobilization properties and mechanism of BW for Pb(II) were analyzed by combining mineral characterization technology and batch adsorption research methods. The results indicated that BW can efficiently and selectively immobilize Pb(II) in single or composite heavy metal adsorption solutions, and the immobilized Pb(II) is difficult to desorb. BW undergoes monolayer adsorption on Pb(II), Q max ≈ 1073.17 mg/g. The immobilization of Pb(II) by BW is a physico-chemical adsorption process with spontaneous heat absorption and an accompanying increase in entropy. In addition, the sequestration of Pb(II) by BW remains around 756.99 mg/g even at pH = 1. The excellent selective immobilization properties of BW for Pb(II) are closely related to its smaller K sp , electrostatic repulsion effect, organic-inorganic composite structure, acid resistance and the formation of Pb(II) oxalate. This study provides beneficial information about the recycling of lead in acidic lead-containing wastewater and composite heavy metal contaminated water bodies. [Display omitted] [ABSTRACT FROM AUTHOR]

Currently, the escalation of water pollution due to heavy metals has reached a critical point, posing a significant threat to human existence. Lead and its compounds, among these metals, exhibit notable stability, making them resistant to metabolic breakdown and degradation. However, the persistence of lead in water can endanger human well-being by infiltrating the food chain, leading to various ailments, including cancer. The adsorption approach has gained considerable prominence in the realm of heavy metal treatment methodologies, owing to its broad applicability, pronounced selectivity, and the potential for renewing and reusing adsorbents. Metal-organic frameworks (MOFs), characterized by their porous structure, have emerged as a premier choice for adsorbing heavy metal ions, thanks to their substantial specific surface area, robust stability, and minimal density. This comprehensive review aims to encapsulate and delve into the adsorption parameters, kinetics, and mechanisms inherent in the utilization of highly efficient and recyclable MOF composites for Pb(II) adsorption in water. This effort seeks to provide a foundational guide for prospective research endeavors and practical implementations. [Display omitted] • Preparation and characterization of MOFs composites. • Advantages of MOFs materials in adsorbing Pb(II). • Conditions for adsorption of Pb(II) by MOFs materials. • Adsorption mechanism and kinetics of Pb adsorption by MOFs materials. • Future development demand for MOF composites. [ABSTRACT FROM AUTHOR]

This paper presents the utilization of sodium alginate (SA) as a raw material to construct a double network structure through the incorporation of chitosan (CS) and the electrostatic polymerization of SA. Subsequently, by employing polyvinyl alcohol (PVA) as a functional material, a modified SA/CS/PVA composite hydrogel (SCPH) was prepared via the Ca(II) ion exchange method. The hydrogel exhibited a flocculent form, thereby greatly enhancing the removal of Pb(II). The adsorption process of Pb(II) by the SCPH reached equilibrium within 30 min, achieving a remarkable removal rate of 97.45% and a maximum adsorption capacity of 147.93 mg/g (298 K). A series of characterization analyses have been employed to investigate the structure and adsorption mechanism of hydrogels, and the adsorption mechanism involves ion exchange, electrostatic attraction, as well as the complexation of hydroxyl and carboxyl groups. Batch adsorption experiments were conducted at different temperatures and pH levels, and the kinetics and isotherms were investigated. The Langmuir isotherm and pseudo-second-order kinetic model were found to best fit the experimental data, suggesting the feasibility of using the SCPH as an efficient adsorbent for Pb(II) removal. Moreover, the dual network structure constructed by SA and CS significantly enhances the adsorption performance of SCPH. At the same time, PVA strengthens the mechanical strength of SCPH, which is favorable for recycling. As a low-cost and efficient adsorbent, SCPH can be widely used in water treatment. [ABSTRACT FROM AUTHOR]

The efficient elimination of lead (II) and methyl blue from aqueous media was a critical problem for humans. The removal of dyes and heavy metals, especially methylene blue and lead, from wastewater is essential for human health and the environment, and utilizing a suitable adsorbent to attain this goal is highly desirable. In the present study first time, chitosan biopolymer was functionalized using Two Dimensional Metal-Organic Frameworks (Ni 3 (HITP) 2) and MXene for efficient, rapid, and selective removal of lead (II) and Methyl blue. To obtain an adsorbent (Ni 3 (HITP) 2 /MXene/CS), 1 g of chitosan (biopolymer) and Metal-Organic Frameworks were added in MXene dark-colored suspension and ultrasonically dispersed for 25 min. The batch sorption was carried out, and sorption behavior was analyzed. Batch sorption procedures were conducted to explore the sorption of Pb2+ and MB by Ni 3 (HITP) 2 /MXene/CS composite in 25 mL of aqueous solutions. The adsorbent utilized in the present experiments was 10 mg. The effect of the initial concentration of Pb2+ and MB was explored in the range of 10–400 mg L−1. Composite (Ni 3 (HITP) 2 /MXene/CS) had excellent sorption performance in the range of pH= 3–6 for lead (II) and pH= 2–9 for methyl blue. The maximum adsorption capacity for lead (II) was 448.93 mg g− 1 at 298 K, 400.59 mg g− 1 at 308 K, and 305.80 mg g− 1 at 318 K. In contrast, the maximum sorption capability for methyl blue was 424.99 mg g− 1 at 298 K, 354.03 mg g− 1 at 308 K, and 251.78 mg g− 1 at 318 K. The sorption of lead (II) and methyl blue on Ni 3 (HITP) 2 /MXene/CS composite conformed to pseudo-second-order kinetic and Langmuir model. These outcomes verified that Ni 3 (HITP) 2 /MXene/CS composite was selectivity efficient, and quick removal of Methylene blue and lead from wastewater, which is of practical importance. [Display omitted] • MXene and CS introduced OH-, F-, NH, and S in the MOFs that increased the uptake of Pb2+, and MB. • The prepared composite was characterized by SEM, RAMAN, XRD, EDX, XPS, and TEM. • After five reusability experiments, the sorption capacities were still high. [ABSTRACT FROM AUTHOR]

In this work, magnesium-modified rice straw biochar (MgBC) was prepared by chemical impregnation, and the effects of proportion, initial pH, contact time, temperature and initial concentration on the removal of Cd(II) and Pb(II) by MgBC were investigated. Additionally, scanning electron microscopy, Brunauer–Emmett–Teller, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used for the characterisation of MgBC. The results shown that MgBC surface contained massive Mg-particles and possessed more abundant O-containing groups. Batch adsorption experiments shown that the optimum adsorption efficiency of Cd(II) and Pb(II) by MgBC was achieved at ratio of 1:2 and initial pH of 6.0. The pseudo-second-order kinetic model and the Langmuir isothermal model could better describe the removal of Cd(II) and Pb(II) by MgBC. The maximum adsorption capacity of Cd(II) and Pb(II) by MgBC was 92.68 and 128.06 mg/g at pH 6.0, 35°C and initial concentrations of 10~100 mg/L, respectively. FTIR and XRD analysis shown that the removal mechanism of Cd(II) and Pb(II) by MgBC involved complexation, ions exchange, co-precipitation and electrostatic interaction. After 4 adsorption–desorption experiment, the removal efficiency of Cd(II) and Pb(II) by MgBC remained above 80%. This results indicated that MgBC had great potential for the treatment of wastewater containing Cd(II) and Pb(II). [ABSTRACT FROM AUTHOR]

One of the important carbon materials, graphene oxide (GO), has several oxygen-containing functional groups in the form of epoxy, hydroxyl, and carboxyl on its basal plane and its edges. Due to its unique structure, it has attracted increasing interest in multidisciplinary studies of physical and chemical attributes. GO-based compounds in particular are potential for environmental uses in energy and clean-up. In the present work, GO was functionalized with ethylenediaminetetraacetic acid (EDTA) to remove lead ions from water. The as-prepared and EDTA functionalized GO were applied as adsorbents to remove Pb(II) from groundwater in Western El-Mina area, mid Upper Egypt. The adsorption of lead under effects of contact time, temperature and pH has been investigated. It is concluded that the maximum adsorption capacity of pure GO for the lead was about 246 mg/g while that of GO-EDTA was about 360 mg/g. It is indicated that pH~6 and temperature ~40°C are the best conditions for Pb(II) removal from water. The adsorption experimental data was evaluated through elucidating the adsorption kinetic using pseudo-first-order and pseudo-second-order. It is revealed that the pseudo-second-order model is the best representing adsorption kinetics model for both GO and GO-EDTA. Additionally, the equilibrium adsorption isotherm has been studied using the Langmuir and Freundlich isotherms models. The adsorption equilibrium isotherms data followed the Langmuir model better than the Freundlich model. The present work indicated that the prepared materials (GO and GO-EDTA) are efficient adsorbents for lead removal. [ABSTRACT FROM AUTHOR]

This study aims to investigate the simultaneous removal of Methylene Blue (MB), Direct Blue 71 (DB71), and Pb(II) ions, which are frequently found together at high concentrations in different industrial wastewaters, such as textile, paper, leather, paint, and plastic manufacturing wastewaters. The simultaneous removal of Pb(II) ions with MB and DB71 from binary mixtures was investigated by the adsorption method. Magnetic halloysite nanotubes-alginate (MHNTs-ALG) hybrid beads were used to remove these components from the binary adsorption media. For this purpose, a magnetic property was gained to halloysite nanotubes using the “co-precipitation method”. Magnetic halloysite nanotubes (MHNTs) were composited with alginate (ALG) biopolymers through the “extrusion dripping method”. The adsorption capacities and efficiency of these synthesized MHNTs-ALG hybrid beads were investigated according to their anionic and cationic pollutant content in binary mixtures, and the synergistic and antagonistic effects of these components on each other were investigated by comparing them according to single systems. The compatibility with the multi-component Langmuir adsorption model for binary systems was examined using equilibrium adsorption data, and the values of the constants showing the adsorption capacity and affinity were calculated. In binary mixtures of Pb(II)-MB, the maximum amounts of Pb(II) and MB adsorbed per unit adsorbent weight calculated from the multi-component Langmuir model were 248.46 mg/g (qPb,m) and 946.92 mg/g (qMB,m), respectively. The maximum adsorption capacities of Pb(II) and Direct Blue 71 from binary systems were determined as 203.14 mg/g (qPb,m) and 118.96 mg/g (qDB71,m), respectively. The co-presence of Pb(II) and MB was concluded to create a synergistic effect compared to the adsorption of Pb(II) ions alone and an antagonistic effect compared to the adsorption of MB alone. The co-presence of Pb(II) and DB71 was observed to form a synergistic effect compared to the individual presence of Pb(II) ions and an antagonisticsynergistic mixed effect compared to the individual presence of DB71. [ABSTRACT FROM AUTHOR]

A novel method for detecting Cd(II) and Pb(II) in water using composite ion-imprinted membranes (Cd@Pb-IIM/Ag@MOF@CHI) was developed. Pre-polymerization ratios were optimized via computer simulations and applied on Ag@MOF@CHI-modified electrodes using infrared light initiation. Characterization of the membranes through SEM and electrochemical methods revealed detailed morphology and composition. The sensor showed a dynamic linear response for Cd(II) and Pb(II) concentrations ranging from 1.1 × 10−9 to 1.2 × 10−6 mol L−1, with a detection limit of 1.0 × 10−10 mol L−1. In samples with various non-target ions, the sensor exhibited high selectivity, attributed to the optimal coordination ratio (Cd(II): Pb(II): PAR = 1:1:3). Successful tests were conducted in tap, lake, and river water, highlighting its potential for environmental monitoring. [Display omitted] • A dual-template electrochemical molecularly imprinted sensor guided by DFT theory was proposed. • Ag@MOF nanoparticles and CHI played an amplifying role in obtaining dual signals. • Cd@Pb-IIM catalyzed selective Cd@Pb oxidation with a sensitive detection limit of 1.0 × 10−10 mol L−1. • Molecular modeling determined the imprinting binding sites and confirmed that the binding mode with metal ions is 1:3. [ABSTRACT FROM AUTHOR]

[Display omitted] • MgO and Fe 3 O 4 were innovatively combined for decorating biochar. • MgO@MBC possessed excellent magnetism with easy separation. • Multiple adsorption mechanisms of Pb(II)/phosphate on MgO@MBC were explored. • MgO@MBC had an excellent uptake capacity of Pb(II)/phosphate with 556.62/303.08 mg/g. • MgO@MBC with outstanding adaptability is hopeful for treating actual wastewater. Herein, magnesium oxide (MgO) and ferroferric oxide (Fe 3 O 4) functionalized biochar (MgO@MBC) was synthetized through one-step pyrolysis method, which was used to decontaminate lead (Pb) and phosphate in contaminated water. Characterization results exhibited that MgO and Fe 3 O 4 particles were successfully loaded on MgO@MBC, and the magnetism of MgO@MBC was in favor of recycling materials. Experimental results showed that MgO@MBC possessed outstanding adsorption performance with 556.62/303.08 mg/g for Pb(II)/phosphate. Furthermore, MgO@MBC had excellent anti-interference performance under the coexistence of various ions, and superior reusability with over 82 % adsorption efficiency for Pb(II)/phosphate after four regeneration cycles. It demonstrated that the high-efficiency capacity of Pb(II) adsorbed on MgO@MBC was attributable to complexation, electrostatic attraction, precipitation, and pore-filling, while the efficient uptake of phosphate was due to precipitation, pore-filling, and ligand exchange. Based on the above analysis, MgO@MBC was believed to be an outstanding adsorbent for remediating Pb(II)/phosphate wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • High percentage grafting of GMA on to PP non-woven fabric using gamma radiation induced simultaneous graft polymerisation. • Optimization of the polydentate amine functionalisation of PGMA grafted PP fabric. • Sorption and kinetics behaviour of aqueous Pb2+ with the DETA functionalised PGMA grafted PP adsorbent. • Point of zero charge, effect of pH and reusability of the adsorbent towards the sorption process. • Cost effective scaling up potential for real world application. Comprehensive optimization of the functionalization of polypropylene (PP) non-woven fabric through gamma irradiation-induced graft polymerization of glycidyl methacrylate (GMA), results in a material having high grafting yield. The technique, utilizing a mutual irradiation method, produced poly-GMA (PGMA) grafted PP fabric with a remarkable grafting yield of 125 % in a 1:1 acetone–water mixture, subjected to 25 kGy of total dose at a dose rate of 5 kGyh−1. The enhancement of the amination process utilizing PGMA-grafted PP was investigated with polyamines. Under the optimized conditions, the diethylene triamine (DETA) functionalized variant was identified as an effective adsorbent for aqueous Pb2+ ions. The optimized adsorbent exhibited a high saturation capacity of approximately 230 mgg−1 for Pb2+ ions, demonstrating rapid kinetics at near-neutral pH and 25 °C. This low cost innovative material holds significant promise for effective lead removal from drinking water and industrial wastewater, offering a sustainable economical solution for environmental remediation. [ABSTRACT FROM AUTHOR]

• Modulation of crystal surface growth. • Enhancing the active phase of MoS 2 and the ratio of S vacancy. • Alkaline earth metal-doped MoS 2 -based materials as selective adsorbents. • Sr-MoS 2 with a high partition coefficient K d of Pb2+ (31.34 L g - 1 ). It was a challenge to prepare an adsorbent with excellent selectivity for target heavy metals, especially when treating real wastewater contaminated with various heavy metals. In the present study, MoS 2 with a specific binding capacity for Pb, was selected as the substrate material. And alkaline earth metal doped SM(Sr-MoS 2) adsorbent was synthesized via a simple one-step hydrothermal method. The morphology and structure of SM were characterized and the results confirmed that Sr was successfully anchored to MoS 2. In addition, it indicated that Sr played a role in expanding the MoS 2 spacing, increasing the ratio of 1 T phrases, and modifying the crystal growth (such as the growth direction and growth rate). Therefore, it suggested that SM had a high selectivity factor (171.26) and partition coefficient K d (31.34 L g - 1 ). More importantly, SM maintained good adsorption performance (∼90 % removal) after six adsorption–desorption cycles, using NaOH or Na 2 -EDTA as desorbent. Therefore, this work provided a new idea for the preparation of selective adsorbents based on MoS 2 , which was expected to be used for the remediation of Pb2+-contaminated wastewater. [ABSTRACT FROM AUTHOR]

In this study, the chitosan-grafted tetracarboxylic functionalized magnetic nanoparticle (Fe 3 O 4 @TCA@CS) was synthesized via in situ co-precipitation process and amidation reaction to improve efficiency of adsorption process and obtain cost-effective adsorbents for removal of toxic Pb(II) metal from aqueous environment. The Fe 3 O 4 @TCA@CS nanocomposite was analyzed by FTIR, TEM-EDX, TGA, XRD, BET, and Zeta potential. The performance of Fe 3 O 4 @TCA@CS for Pb(II) ions adsorption was achieved as a function of pH, dose, contact time, initial Pb(II) concentration, and temperature. The influence of coexisting ions such as Na+, Ca2+, Mg2+, and Cd2+on removal efficiency of Pb(II) was also investigated. The results revealed that the coexisting ions had little influence on Pb(II) removal efficiency. The pseudo-first-order and Freundlich models were better to describe the adsorption of Pb(II) onto Fe 3 O 4 @TCA@CS and the maximum adsorption capacity of Pb(II) was 204.92 mg/g at pH:5.5; adsorbent dose: 0.015 g; and temperature: 298 K. Thermodynamic studies revealed that the Pb(II) adsorption onto Fe 3 O 4 @TCA@CS was an exothermic process. In conclusion, the study provides a new, simple, low-cost, and effective chitosan-based magnetic nanocomposite as a promising adsorbent with excellent adsorption capacity, magnetic separation, and reusability for Pb(II) removal from an aqueous environment. • Chitosan grafted tetracarboxylic functionalized magnetite NP was synthesized. • Fe 3 O 4 @TCA@CS possessed excellent adsorption capacity (204.92 mg/g) for Pb(II). • Fe 3 O 4 @TCA@CS nanocomposite exhibits high stability under acidic medium. • Electrostatic attraction was the main adsorption mechanism of Pb(II). • In 3rd cycles, the removal efficiency of Fe 3 O 4 @TCA@CS still reached at 79.5 %. [ABSTRACT FROM AUTHOR]

The study aimed at firstly preparing two eco-friendly biomaterials of PFeS&PEB and PFeS&WAB from peanut shells biochar (PEB) and walnut shells biochar (WAB) by loading with ferrous sulfide powder (Powder-FeS) to evaluate the ability to remove Pb(II) from sewage. FeS was immobilized to the surfaces biochar through functional groups such as –OH, –COOH and C–O. The results of batch experiments showed that PFeS&PEB had the maximum adsorption capacity (98.039 mg·g–1) when pH = 5 and the dosage was 0.75 g·L–1. The adsorption data were adequately simulated with adsorption kinetics and isothermal thermodynamic analysis, suggesting that the adsorption of Pb(II) by PFeS&PEB and PFeS&WAB was mainly monolayer chemisorption, and the adsorption process was spontaneous endothermic. The removal of Pb(II) was achieved by the association of complexation, redox, ion exchange, electrostatic attraction and physical adsorption. Reusability studies showed that PFeS&PEB and PFeS&WAB had good stability over four consecutive cycles. Hence, the cost-effective materials of PFeS&PEB and PFeS&WAB can be used as effective bio)adsorbent for the removal Pb(II) from wastewater. [ABSTRACT FROM AUTHOR]

An O -hydroxyphenyl thiourea-modified chitosan (OTCS) with excellent Pb(II) adsorption performance and selectivity was prepared as an adsorbent. The structure and morphology of the adsorbent were systematically investigated by SEM, BET, FTIR, EDX, zeta-potential measurements, XPS and XRD. The impacts of the initial Pb(II) concentration, reaction time, temperature, pH value, and coexisting ions were explored. At pH 7 and 303 K, the maximal adsorption capacity of OTCS for Pb(II) was 208.33 mg/g, which was greater than those of other adsorbing materials reported in the literature. The metal ion adsorption kinetics and isotherm models were found to obey pseudo-second-order kinetics and the Langmuir isothermal model, indicating that the adsorption process was monolayer chemisorption. The adsorption process could proceed spontaneously, and the thermodynamic results revealed that the adsorption mechanism was an endothermic reaction. The ion exchange and chelation between the sulfur, nitrogen and oxygen groups on the adsorbent and lead ions endowed the material with excellent adsorption properties. Significantly, OTCS showed excellent selectivity toward Pb(II). Therefore, the adsorbent OTCS is expected to promote the wider application of chitosan in the adsorption of Pb(II). [ABSTRACT FROM AUTHOR]

This paper focuses on the potential application of Erwinin sp. in environmental purification. The Pb(II) biosorption was studied by batch method under different external environment (pH value, biosorption time, Erwinin sp. dosage, Pb(II) concentration and temperature). Batch experiments showed that Erwinin sp. could rapidly reach the biosorption equilibrium (90 min) of high capacity of Pb(II) biosorption (71.73 mg/g, T = 303 K) by Langmuir model. The interaction mechanism between Pb(II) and Erwinin sp. was investigated by TEM, XPS and FT-IR. Results of FT-IR and XPS showed that Erwinin sp. were rich in functional groups, which was the main reason for the effective Pb(II) removal. The Pb(II) biosorption was also studied by kinetic model and thermodynamic model. Pb(II) biosorption conforms to pseudo-second-order mode and is a spontaneous endothermic process. According to the above results, Erwinin sp. is a potential biosorbent for the treatment of lead pollution due to its wide source of biosorption materials, large biosorption capacity and high treatment efficiency. [ABSTRACT FROM AUTHOR]

Heavy metal such as lead (Pb(II)) is non-biodegradable and bio accumulative that posture a threat to our health when it presents in huge amount in our bloodstream. It comes from mostly chemical industrial processes into wastewater. In this study, we reported the adsorption of Pb(II) onto palm leaves from an aqueous solutions. The characterization results illustrated that the palm leaves have a mesoporous structure with a pore volume of 0.017 cm³/g. The successful removal of Pb(II) ions by palm leaves was confirmed by using Fourier transform infrared and scanning electron microscopy analysis. The influence of contact time, mass of palm leaves, initial concentration of Pb(II) in aqueous solution, temperature and pH on the removal of Pb(II) was explored. Kinetic study represented that Pb(II) adsorption fitted to pseudo-second-order model with a correlation factor (R²) of 1. The equilibrium outcomes showed that the experimental data followed to Langmuir isotherm with an R² of 0.990 and a maximum adsorption capacity of 57.4 mg/g. Adsorption thermodynamics investigation showed that Pb(II) adsorption onto palm leaves was an endothermic, feasible and spontaneous. The palm leaves demonstrated a removal efficiency of more than 59% of Pb(II) after 5 consecutive adsorption/desorption cycles. Hence, the palm leaves could be employed as an excellent candidate for Pb(II) adsorption from aqueous solutions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The dispersion of CoFe 2 O 4 was improved by the CMC interface modification. • The q e of CoFe 2 O 4 -CMC0.5 with particle size of 10.5 nm was 119.3 mg/g. • Adsorption mechanism included intermolecular interaction and coordination. The heavy metal Pb(II) is highly toxic, and it is very important for its separation and collection to improve water quality. To alleviate the phenomenon of agglomeration and inactivation, the highly dispersible composite materials (CoFe 2 O 4 -CMC) were prepared by modifying super-paramagnetic CoFe 2 O 4 using carboxymethyl cellulose (CMC) in this paper. The adsorption capacity of CoFe 2 O 4 -CMC0.5 for Pb(II) was 119.3 mg/g. Dynamic fitting results showed that the adsorption process included physical adsorption of intermolecular force and chemical adsorption of coordination; The results of thermodynamic study showed that the adsorption process was endothermic. Compared with CoFe 2 O 4 , the addition of CMC improved the dispersibility and adsorption performance, providing a new idea for environmental water quality remediation. [ABSTRACT FROM AUTHOR]

In this study, a fresh three-dimensional microsphere adsorbent (CATP@SA 3) was successfully synthesized by Attapulgite (ATP) and combining Chitosan (CS), incorporating them into a Sodium alginate (SA) solution, and crosslinking them in a CaCl 2 solution. Multiple analyses, including XRD, TGA, FTIR, XPS, SEM-EDS, and BET were utilized to comprehensively characterize the structural makeup of CATP@SA 3. These analyses revealed the presence of beneficial functional groups like hydroxyl, amino, and carboxyl groups that enhance the adsorption efficiency in adsorption procedures. CATP@SA 3 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@SA 3 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@SA 3 was driven by a chemical predominantly reaction. [Display omitted] • CATP@SA 3 was prepared by a simple method and had a high adsorption capacity for Pb(II) in water. • The process of adsorption of Pb(II) was dominated by a chemical reaction and was spontaneously heat-absorbing. • CATP@SA 3 can be reused successfully in repeated adsorption-desorption cycles. • Materials were characterized through a variety of tests, including XRD, TGA, BET, SEM and FT-IR. [ABSTRACT FROM AUTHOR]

• Bioreduction of graphene oxide (GO) induced the release of Pb(II) from GO-Pb(II). • Pb(II)-extracellular polymer substance complex dispersed in water even at pH>7.0. • Oxidative debris (OD) in GO was stripped when pH>7.0 and dispersed stably in water. • Some released Pb(II) and the PO 4 3− from bacterial metabolism formed a precipitate. In this study, Pb(II) was used as a target heavy metal pollutant, and the metabolism of Shewanella putrefaciens (S. putrefaciens) was applied to achieve reducing conditions to study the effect of microbial reduction on lead that was preadsorbed on graphene oxide (GO) surfaces. The results showed that GO was transformed to its reduced form (r-GO) by bacteria, and this process induced the release of Pb(II) adsorbed on the GO surfaces. After 72 hr of exposure in an S. putrefaciens system, 5.76% of the total adsorbed Pb(II) was stably dispersed in solution in the form of a Pb(II)-extracellular polymer substance (EPS) complex, while another portion of Pb(II) released from GO-Pb(II) was observed as lead phosphate hydroxide (Pb 10 (PO 4) 6 (OH) 2) precipitates or adsorbed species on the surface of the cell. Additionally, increasing pH induced the stripping of oxidative debris (OD) and elevated the content of dispersible Pb(II) in aqueous solution under the conditions of S. putrefaciens metabolism. These research results provide valuable information regarding the migration of heavy metals adsorbed on GO under reducing conditions due to microbial metabolism. [Display omitted] [ABSTRACT FROM AUTHOR]

Pb(II) pollution threatens human health and environmental safety, and suitable adsorption materials are important for Pb(II) removal. In this study, the adsorption characteristics of Pb(II) onto natural kaolinite and bentonite in the Dalian and Heishan areas (China) were investigated, and the effects of the solid-to-liquid ratio, pH, temperature, and reaction time on the adsorption performance of Pb(II) were analyzed. The results showed that the adsorption capacity of kaolinite decreases as the solid-to-liquid ratio increases, whereas the adsorption capacity of bentonite first increases to a maximum and then decreases. The processes by which kaolinite and bentonite adsorb Pb(II) are both rapid, in which adsorption equilibrium is reached within 120 min, and the pseudo-second-order kinetic model provides the best fit to the experimental results. The Langmuir model provides the best simulation of the isothermal adsorption characteristics of Pb(II) onto kaolinite and bentonite. The adsorption of Pb(II) onto kaolinite is a spontaneous, exothermic, and entropy-decreasing process, where a lower temperature is beneficial for adsorption. However, the adsorption of Pb(II) onto bentonite is a spontaneous, endothermic, and entropy-increasing process, where high temperature is beneficial for adsorption. The results indicate that both natural kaolinite and bentonite can be used as effective adsorbents for Pb(II) removal. [ABSTRACT FROM AUTHOR]

Lead (Pb) is widely distributed in nature and has important industrial applications, while being highly toxic. In this study, the Pb(II) biosorption and immobilization behavior of Penicillium polonicum was investigated through surface morphology observation and multiple experimental analysis. In addition, the molecular mechanism of Pb(II) immobilization was further explored through proteomics. The analysis of the removal ability of P. polonicum to Pb(II) has found that P. polonicum could remove Pb(II) up to 95% (initial 4 mM Pb(II)) in 12 d. Scanning Electron Microscope (SEM) revealed a large amount of Pb(II) adsorbed on the cell wall. Raman and Energy Disperse Spectroscopy (EDS) revealed the formation of large amounts of PbC 2 O 4 minerals extracellularly. Field Emission High–resolution Transmission Electron Microscopy (FE–TEM) found that [Pb 5 (PO 4) 3 Cl] formed on the cell surface and inside the cells. The iTRAQ technique was used to analyze the characteristics of the changes of proteins during the action between Pb(II) and P. polonicum , which further revealed the mechanism of P. polonicum against Pb(II) and biomineralization. It was found that differential proteins in terms of redox, ion binding, metabolic process and ribosome synthesis were predominant in the GO analysis. Together with some of the characterization experiments above, the mechanisms mentioned above was well explained. The up-regulated expression of related proteins involved in respiratory metabolic pathways, antioxidant stress, and degradation of intracellular hazardous substances in the P. polonicum intracellularly such as succinate dehydrogenase, ATPase and cytochrome c oxidase, could explain the high tolerance of P. polonicum to Pb(II). The up regulation of OAH was responsible for extracellular PbC 2 O 4 production. The up regulation of proteins such as TXN and GFA promoted Pb-glutathione (Pb–GSH) complex formation. This study explores the mechanism of Pb removal by fungi from the proteomic level, and provides new ideas and ways for Pb biogeochemical research. [Display omitted] • Penicillium polonicum can remove Pb(II) up to 95% (4 mM Pb(II)) in 12 d. • P. polonicum remove Pb(II) by four main mechanisms. • ITRAQ was used to explore differential proteins' expressions within fungi. • Explain the mechanism of oxalic acid formation in fungi for the first time. • Explain the mechanism of high tolerance to lead by P. polonicum. [ABSTRACT FROM AUTHOR]

A modified magnetic nano-biocomposite based on zeolite (CoFe2O4@CMC@HZSM-5) was synthesized and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, vibrating sample magnetometer, and Brunauer-Emmett-Teller tests. CoFe2O4@CMC@HZSM-5 was applied as an adsorbent for the efficient removal of Pb(II). Then, the applicability of the nano-biocomposite adsorbent was investigated for the lead removal. To determine the relationship between effective parameters on lead adsorption, the response surface methodology was applied. Maximum removal efficiency by CoFe2O4@CMC@ HZSM-5 under optimal conditions with a contact time of 300 min, pH = 5, Pb(II) concentration of 400 mg/L, and 0.4 g of the adsorbent (reactor volume = 200 mL) was 96% for synthetic and 75% for real samples, respectively. The adsorption of Pb(II) by CoFe2O4@CMC@HZSM-5 followed the Langmuir isotherm and pseudo-second-order kinetic models. According to the negative ΔH° values, the adsorption of Pb(II) onto CoFe2O4@CMC@HZSM-5 was exothermic and thermodynamics studies indicated that was not possible and spontaneous in nature. The magnetic nano-biocomposite adsorbent had good reusability and attained a high removal efficiency of 91% for Pb(II) after six consecutive adsorption cycles, thus can be recommended as a coefficient adsorbent for the removal of Pb(II) from contaminated water. [ABSTRACT FROM AUTHOR]

• MoO 3 nanobelts and MoS 2 nanoarrays were proposed to remove metal ions and MB. • MoS 2 nanoarrays were constructed from MoO 3 nanobelts as a precursor. • The theoretical removal capacity of Pb(II) and MB on MoO 3 NBs was 684.93 and 1408 mg/g. • The theoretical removal capacity of Au(III) and MB on MoS 2 NAs was 1280.2 and 768 mg/g. • The removal of Pb(II) and Au(III) on the both adsorbents was spontaneous and endothermic. Toxic heavy metal ions, valuable noble metal ions and organic dyes are significant concerns in wastewater treatment. In this work, MoO 3 nanobelts (MoO 3 NBs) prepared by solvothermal method and MoS 2 nanoarrays (MoS 2 NAs) constructed using MoO 3 NBs precursor were proposed to effectively remove heavy/noble metal ions and organic dyes, such as Pb(II), Au(III) and Methylene Blue (MB). The two adsorbents exhibited the excellent adsorption capacity towards Pb(II), Au(III) and MB. The maximum removal capacity of Pb(II) and MB on MoO 3 NBs was 684.93 mg/g and 1408 mg/g, respectively, whereas that of Au(III) and MB on MoS 2 NAs was 1280.2 mg/g and 768 mg/g, respectively. Furthermore, the thermodynamic parameters were calculated from the temperature-dependent curves, suggesting that the removal of Pb(II) and Au(III) on both adsorbents was spontaneous and endothermic. The new adsorbents introduced here were high adsorption activity, ease of fabrication, high scalability, good chemical stability, great repeatability and abundant and cheap supply, which were highly attractive for wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Kinds of heavy metals often coexist in the actual contaminated wastewater, their competitive adsorption behavior could affect the adsorption capacity of adsorbents. In this paper, the sewage sludgebased humic acid (S-HA) was extracted from the excess sludge of a sewage treatment plant, the mutual effects and inner mechanisms of Cd(II) and Pb(II) adsorption in aqueous solution on S-HA were studied by single-metal and binary-metals systems. The results showed that the adsorption process for S-HA of Cd(II) and Pb(II) were fitted well by Langmuir and Freundlich adsorption models, the pseudo-second-order kinetic model can well fit the adsorption process of Cd(II) and Pb(II) by S-HA. In binary-metals system, Cd(II) and Pb(II) had competitive adsorption and the competitive ability of Pb(II) was stronger than Cd(II), which determined mainly by the electronegativity, hydrated ionic radius and charge to radius ratio. In binary-metals system, the Cd(II) adsorption on S-HA was inhibited, while the uptake of Pb(II) was not affected significantly. The adsorption capacities of Cd(II) and Pb(II) on S-HA increased with the increasing pH in binary-metal systems. When Cd(II) and Pb(II) coexisted, the adsorption capacities of two heavy metal ions were decreased compared with the single-metal adsorption system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introduce 3D printed porous/chitosan/ZIF-67 as strategically adsorbent. • Role 3D printed porous/chitosan/ZIF-67 in interaction with heavy metals. • Interesting and effective removal of Pb(Ⅱ), Cd(Ⅱ), and Cu(Ⅱ) from wastewaters samples. To solve the complex separation and recovery after adsorption of contaminants by the powdery materials, 3D printed metal–organic composite frameworks of chitosan/ZIF-67 were prepared to remove lead ions (5.47 mg/g) via adsorption from contaminated wastewater. The materials developed were characterized by SEM, XRD, FT-IR, and XRS techniques. Adsorption of lead ions followed both pseudo-second-order kinetic model and Langmuir isothermal models. Adsorption was spontaneous and endothermic as explained in terms of surface complexation, hydrogen bond, and ion exchange between the adsorbate and adsorbents. The methods used can be considered for practical applications to address water contamination at the polluted industrial sites. The 3D printing technology of large-scale models provides scientific basis and data support for large-scale remediation of contaminated water samples in industrial sectors. [ABSTRACT FROM AUTHOR]

The emergence of microplastics (MPs) and their coexistence with heavy metal contaminants pose potential risks to the safety of the subsurface environment and public health. Therefore, it is crucial to explore the co-transport of MPs (polypropylene (PP), polyethylene (PE), polystyrene (PS), polymethyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE)) with the heavy metal Pb(II) under the surfactant (sodium dodecyl benzene sulfonate (SDBS) and cetyltrimethylammonium bromide (CTAB)). In this study, column experiments were performed to investigate the co-transport of MPs and Pb(II) under surfactants. The co-transport mechanism of MPs with Pb(II) under surfactant was revealed by MPs stability and batch adsorption experiments. Experimental results showed that the presence of Pb(II) did not influence the mobility of MPs under CTAB and SDBS; however, MPs can affect the mobility of Pb(II). Specifically, under CTAB, the MPs increased the recovery rate of Pb(II) from 86% to 87.55%–97.55%. However, under SDBS, the high mobility of PS, PE, and PP inhibited the transport of Pb(II), and the recoveries of Pb(II) decreased from 79% to 57.53%–70.96%. The low mobility of PTFE and PMMA slightly promoted the transport of Pb(II). This could be attributed to two reasons. One aspect is the adsorption rate of Pb(II) by MPs, which plays a pivotal role in influencing the transport tendency of Pb(II) with MPs. Another aspect is the MPs stability, as greater stability enhances their dispersity and accelerates the adsorption rate of Pb(II), thereby facilitating the co-transport of Pb(II) with MPs. This study could provide valuable insights for assessing the transport and environmental impact of MPs and heavy metals in the presence of surfactants. [Display omitted] • Mobility of Pb in surfactant was affected by MPs stability and adsorption rate. • MPs stability followed the order of PP > PE > PS > PMMA > PTFE under CTAB or SDBS. • The different of MPs stability resulted in different transport of Pb(Ⅱ). • Mobile MPs under surfactant provided a unique transport pathway for adsorbed Pb(II). • An index δ was defined to describe the transport capacity of MPs carrying metal ions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mg doping greatly increases the action sites of monometallic-centered MIL-101(Fe). • Construction of bis-MIL composite MOM tunes the structure and enhances the properties. • The maximum sorption capacity of MOM towards Pb(II) is 320.941 mg·g−1. • MOM has good resistance to salt interferences and regeneration performance. MIL-101(Fe) has received more and more attention in wastewater treatment, and how to further improve its stability and sorption capacity has become a research focus. In this study, metal Mg was used to dope MIL-101(Fe) to construct Mg@MIL-101(Fe) with bimetallic sites, which was then mixed with NH 2 -MIL-125(Ti) to successfully fabricate Mg@MIL-101(Fe)/NH 2 -MIL-125(Ti) (MOM) bis-MIL composites. MOM not only contains a large number of sorption sites but also exhibits excellent stability and reusability, realizing efficient sorption of Pb(II) from aqueous solution. In addition, the sorption performance and mechanism of Pb(II) on MOM were investigated by the characterizations of SEM, BET, TG, XRD, FTIR and XPS, as well as the kinetic and thermodynamic analyses. The sorption of Pb(II) on MOM is in accordance with the Langmuir isothermal model and pseudo-second-order kinetic model. The maximum sorption capacity of Pb(II) on MOM derived from the Langmuir model fitting is 320.941 mg·g−1. The sorption of Pb(II) on MOM is strongly affected by pH, but not by ionic strength, which indicates that MOM has good resistance to salt interferences. The strong complexation of carboxyl, hydroxyl and amino functional groups with Pb(II) is the main sorption mechanism of Pb(II) on MOM, and electrostatic interaction and ion exchange also contribute to the sorption. In conclusion, MOM has strong practical application prospects in the treatment of Pb(II)-containing wastewater. [ABSTRACT FROM AUTHOR]

In the present study, magnetic montmorillonite (MMT/Fe3O4) was prepared using chemical precipitation for adsorption of Pb(II) and was characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray diffraction and Fourier-transform infrared spectroscopy (FTIR). The results showed that Fe3O4 uniformly occurred on MMT. The maximum adsorption capacity of Pb(II) by MMT/Fe3O4 was obtained to be 36.76 mg/g, which was higher than the Fe3O4 and MMT alone. The removal efficiency of Pb(II) was strongly dependent on the operating factors, where the maximum efficiency occurred at pH of 5, adsorbent dose of 0.4 g/L, Pb(II) concentration of 30 mg/L, stirring rate of 300 rpm, and contact time of 120 min. The adsorption data followed the Langmuir isotherm, and the kinetic results showed that the chemisorption process is the dominant mechanism for Pb(II) removal. The results of the FTIR analysis explained that the Al–OH and Fe–O functional groups have high participation in pollutant adsorption. The column study emphasized that MMT/Fe3O4 nanocomposite has excellent efficiency in the treatment of real wastewater containing Pb(II). In addition, excellent magnetic separation and regeneration performance indicated the applicability of adsorbent for the treatment of synthetic and real solutions. [ABSTRACT FROM AUTHOR]

Mining is the most common activity that introduces heavy metal ions into aquatic ecosystems, especially in low income-developing nations where governments are implementing stricter regulations for industrial wastewater. In this context, this work is focused on the application of xanthate-modified alginates for the removal of Pb(II) and Ni(II) from aqueous solutions. In order to confirm the presence of xanthate groups alongside alginate chains, characterization by second-derivative FT-IR was carried out and significance evidence attributed to xanthate groups was found at around 1062–1079 cm−1, 829–845 cm−1 and 620–602 cm−1. In addition to this, thermogravimetric analysis and differential scanning calorimetry were employed to explore thermal properties of modified alginates. According to these results, enthalpy changes (∆H) characteristic of dehydration and collapse of biopolymeric structure were estimated as +11.41 J/g and −6.83 J/g, respectively. Furthermore, the presence of S element was confirmed by EDS mapping technique, whereas FESEM image showed a cracked and homogeneous surface distribution. On the other hand, the effect of important parameters such as pH, dosage, initial concentration as well as Langmuir and Freundlich isotherm were deeply discussed. Finally, rheological measurements were performed aiming to investigate the gel-like viscoelastic features associated to nickel xanthate compound. [Display omitted] • Suitable xanthate-modified alginates were prepared for Pb(II) and Ni(II) removal. • The presence of xanthate group was deeply studied by second derivative FT-IR. • Nickel xanthate compound behaves as gel-like viscoelastic material. • Enthalpy change values were calculated by using thermal methods. [ABSTRACT FROM AUTHOR]

Rock wool (RW) is an inorganic fiber material with chemical stability and fire retardancy also available in low cost. RW is widely used in building exterior wall insulation and interior sound insulation and accounts for an increasing proportion of demolition waste from buildings. Iron oxide can efficiently remove pollutants from aqueous solution. In our research, Fe3O4 nanoparticles were deposited on acid-modified waste rock wool (ARW) with the coprecipitation method, and a novel adsorbent for lead was generated. Sorbent materials were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction, and adsorption parameters under different reaction conditions (pH, concentration, contact time, and sorbent dosage) were investigated. The results indicate that the new adsorbent adsorbs lead more efficiently than Fe3O4 alone, because the incorporation of rock wool reduces the agglomeration effect. The adsorption of lead into Fe3O4 deposited acid-modified waste rock wool fiber (ARWF) obeys pseudo-second-order kinetics and Langmuir models. Batch adsorption experiments show that the ARWF can efficiently remove lead from water with a maximum adsorption capacity of 123.15 mg/g and can adsorb 99.45% of lead in 30 min when pH is 4-8. ARWF was also demonstrated to have good potential for regeneration and reuse after four consecutive cycles. These results suggest that waste rock wool loaded with Fe3O4 nanoparticles is a promising material for water treatment. [ABSTRACT FROM AUTHOR]

In the study, the peanut shell was selected as original biochar and modified by adding montmorillonite to obtain modified biochar (B@M). The adsorbent was characterized by scanning electron microscopy, Brunauer-Emmett-Teller, Fourier-transform infrared spectroscopy and X-ray diffraction. The adsorption kinetics study of Pb(II) on B@M showed that the adsorption process of Pb(II) was according to the pseudo-second-order model and Langmuir adsorption model. The maximum adsorption capacity of B@M (61.5 mg g-1) was significantly higher than that of the biochar (35.5 mg g-1) and montmorillonite (54.4 mg g-1) and the reproducibility study indicated that B@M had good reproducibility. When the B@M was added to the microcosms of constructed wetlands (MCW), it showed that with the increase of the amount of B@M, the removal rate of lead in water increased significantly, which was 31.3%, 48.3% and 86.1%, respectively and can reduce the stress of Pb(II) in plants of MCW. Therefore, B@M can be used as a new substrate material and heavy metal Pb(II) adsorbent for constructed wetlands. [ABSTRACT FROM AUTHOR]

A chitosan-based adsorbents (CS-Ninhydrin) was prepared by grafting ninhydrin for Pb(II) ions adsorption. SEM-EDS, XRD and FTIR analysis were used to characterize the synthesized CS-Ninhydrin. The static adsorption experiments showed that CS-Ninhydrin had a good removal rate for Pb(II) ions in a wide range of pH 3 to 7, quickly reached equilibrium (120 min) and had a higher adsorption capacity (196 mg/g). Pseudo second-order and Langmuir models showed that the adsorption process of Pb(II) by CS-Ninhydrin was a single-layer chemical adsorption. Temperature experiments showed that the reaction was a spontaneous exothermic process. In the wastewater experiment, CS-Ninhydrin showed an excellent selectivity to Pb(II) ions. The reusability of CS-Ninhydrin was perfect after five adsorption-desorption cycles. The main adsorption mechanism was the chelating and electrostatic action between N and O groups in CS-Ninhydrin and Pb(II) ions. Therefore, the new adsorbent CS-Ninhydrin was expected to promote the wide application of chitosan in Pb(II) adsorption. [Display omitted] • A novel ninhydrin-functionalized chitosan adsorbent was synthesized. • The adsorbent has a maximum adsorption capacity of 196 mg/g Pb(II) ions. • The adsorbent has excellent talent selectivity and reusability. • The adsorption mechanism is electrostatic action and chelation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A adsorbent was prepared by modified pomelo peel with 5-mercapto-1,2,4-triazole. • The adsorption capacity of the adsorbent for Pb(II) reached 420 mg/g. • The adsorbent shows high reusability and selectivity for Pb(II). • Adsorption mechanism was chelation and Ion exchange. • The adsorbent separated successfully Pb(II) from the wastewater. A novel biochar adsorbent (GP-AMT) is prepared by functionalizing biochar derived from pomelo peel to eliminate Pb (II) from water. GP-AMT was characterized by FTIR, SEM, BET, TGA and XPS. GP-AMT has a large specific area and is multiaperture. The adsorption performance was studied. At the pH = 5, the maximum uptake amount of Pb(II) on GP-AMT reached 420 mg/g. The sorption behavior of GP-AMT obeys with Langmuir and pseudo second-order formula, which shows that the adsorbing property of GP-AMT is uniform chemical sorption. Thermodynamic studies attested that the sorption was an irreversible endothermic course. GP-AMT demonstrated excellent selectivity and reproducibility. After 5 cycles, it still has an excellent sorption property. XPS and zeta potential analysis revealed that the adsorbing nature of GP-AMT for heavy metal ions was coordination and ion exchange. In conclusion, surface modification of biochar can significantly improve its sorption capacity, selectivity and regenerative ability for Pb(II), and reduce the pomelo peel waste pollution. [ABSTRACT FROM AUTHOR]

Al-doped xonotlite (Al-CSH) was prepared from SiO2, Ca(OH)2, and NaAlO2 via the ultrasonic chemical method and doping technique for the removal of lead-containing simulated wastewater. The Al-CSH was analyzed by Brunauer–Emmett–Teller, scanning electron microscopy, and X-ray diffraction. The influence of solution pH, adsorption amount, contact time, initial concentration, and temperature were studied. The results showed that optimum adsorption conditions were found to be initial pH of 5.5, Al-CSH dosage of 0.06 g, initial Pb(II) ion concentration of 200 mg/L and contact time of 60 min. The adsorption capacity and removal rate of Al-CSH for Pb(II) ions was found to be 318.48 mg/g and 95.55% at optimum conditions. The adsorption isotherms followed the Langmuir isotherm model well. The adsorption processes were well fitted by the pseudo-second-order kinetic model. Thermodynamic studies indicated that the adsorption of Pb(II) by Al-CSH is spontaneous and endothermic. Mechanism studies revealed that Al-CSH removes lead ions from aqueous solution by ion exchange, surface precipitation, dissolution-precipitation, and electrostatic interactions. The results suggest that Al-CSH has the potential for use as an effective and low-cost sorbent for removing lead ions. [ABSTRACT FROM AUTHOR]

This study utilized Aloji clay modification for Pb(II) adsorption from an aqueous solution via batch adsorption process. The clays were characterized by X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller (BET). The raw clay and acid-activated clay have BET surface areas of 138.7 and 172.0 m2/g, respectively. The adsorption parameters: adsorbent time, dosage, temperature, pH, and initial concentration were all investigated. Out of the three isotherm models investigated, the Freundlich model gave the best fit to the experimental data. The result of kinetic and thermodynamic studies revealed that the adsorption process obeyed pseudo-second-order, spontaneous, endothermic, and physical progression. The adsorption of Pb(II) onto activated Aloji clay, when compared with other natural adsorbents from literature, gave the highest monolayer adsorption capacity. [ABSTRACT FROM AUTHOR]

• A novel Pb(II) coordination polymer [Pb(FDPTH)(phen)] (1 ; FDPTH =4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) with 3D network structure was obtained. • The FDPTH ligands derived from the hydrothermal in situ acylation reactions. • Compound 1 is a potential visible light catalyst. • The mechanism of photocatalytic reaction was deeply studied. A new coordination polymer photocatalyst, [Pb(FDPTH)(phen)] (1 ; FDPTH 4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) was synthesized for the frist time. The FDPTH ligand was obtained by the in situ acylation reactions between 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDCA) and N 2 H 4 ·H 2 O for the first time. X-ray single-crystal diffraction analysis showed that FDPTH ligands have a μ 4 -bridging mode in compound 1 , which linking Pb(II) centers to create a 3D network structure. Hirshfeld surface analysis was used to investigate the crystal packing and interactions of compound 1. The catalytic activity of compound 1 for methylene blue (MB) was tested under visible light. The degradation for MB followed a pseudo-first-order kinetic pattern and remained efficient after repeated experimental runs. The active species in catalytic process were discovered by radical trapping experiments. The band gap of compound 1 was determined via UV-vis absorbance spectra and Mott-Schottky plot, and a photocatalytic mechanism was proposed for the degradation process. [Display omitted] A new coordination polymer photocatalyst, [Pb(FDPTH)(phen)] (1 ; FDPTH =4,4′ hexafluoroisoprorylidene-diphthalhydrazidate, phen = 1,10-phenanthroline) was synthesized for the frist time. The FDPTH ligand was obtained by the in situ acylation reactions between 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDCA) and N 2 H 4 ·H 2 O for the first time. X-ray single-crystal diffraction analysis showed that FDPTH ligands have a μ 4 -bridging mode in compound 1 , which linking Pb(II) centers to create a 3D network structure. Hirshfeld surface analysis was used to investigate the crystal packing and interactions of compound 1. The catalytic activity of compound 1 for methylene blue (MB) was tested under visible light. The degradation for MB followed a pseudo-first-order kinetic pattern and remained efficient after repeated experimental runs. The active species in catalytic process were discovered by radical trapping experiments. The band gap of compound 1 was determined via UV-vis absorbance spectra and Mott-Schottky plot, and a photocatalytic mechanism was proposed for the degradation process. [ABSTRACT FROM AUTHOR]

The surface functional groups of hydrochar are crucial to its surface properties, and their contents are strongly positively correlated with the adsorption performance. In this study, acrylate-functionalized hydrochar (AHC) with varying contents of O-containing functional groups (OFGs) was synthesized via hydrothermal carbonization (HTC) of bamboo, acrylic acid and an initiator, and then deprotonated with NaOH. The AHCs were analyzed by various characterization techniques. During HTC, the higher amount of acrylic acid added led to higher carbon, oxygen and carboxyl contents, and to the larger specific surface area and pore volume of AHC. The adsorption kinetics, isotherms, thermodynamic, ionic strength and pH effects of Pb(II) on AHC were studied. Adsorption isotherms and kinetics obeyed Langmuir and pseudo-second-order models, respectively, indicating adsorption is monolayer chemical process. The adsorptive ability was well linearly related to the OFG contents of AHC. When acrylic acid was added to 25 mL during HTC, the adsorbing ability of AHC over Pb(II) reached 193.90 mg g−1. Hence, direct HTC of acrylic acid, biomass and an initiator can prepare hydrochar with controllable OFG contents, which is a prospective adsorbent for treating metal cations. [Display omitted] • Efficient hydrochar was prepared by coupled HTC and free radical polymerization. • AHC25 has abundant OFGs and a high specific surface area. • The sorption capacity for Pb(II) is linearly related to the OFG contents of hydrochar. • The inner-surface complexation was the main mechanism for Pb(II) removal by AHC25. • AHC25 exhibited high sorption capacity towards Pb(II) (193.90 mg g−1). [ABSTRACT FROM AUTHOR]

The excessive content of lead (Pb(II)) and Staphylococcus aureus (S.aureus) seriously harms the quality of aquatic products. In this paper, a highly sensitive electrochemiluminescence (ECL) biosensor was constructed using the synergistic effect of Au NPs@Nickel-Cobalt-Metal-organic frameworks (Au@Ni-Co-MOFs) and double potential resolution function of urchin-like Au@luminol and Cadmium sulfide quantum dots (CdS QDs) for synchronous detection of Pb(II) and S.aureus in aquatic products. Au@Ni-Co-MOFs as the base material, its cube structure can improve the surface active area and sensitivity of the sensor, providing more catalytic active sites for the two functional probes. Urchin-like Au@luminol binding aptamer DNA2 specifically recognizes Pb(II), CdS QDs binding aptamer DNA3 specifically recognizes S.aureus, which collaboratively catalyzed hydrogen peroxide reduction to produce two electrochemiluminescence signals. The shared hairpin structure DNA1 binds stably to Au@Ni-Co-MOFs via the Au-S bond, and the two functional probes are complementary paired with the DNA1 respectively to ensure the specificity of the aptamer. According to the ECL intensity changes of different potentials signal sources, the synchronous detection of Pb(II) and S.aureus with different concentrations is realized. The sensor realizes the detection of two targets in aquatic products and provides a new strategy for the simultaneous detection of multiple targets. [Display omitted] • A double potential biosensor was developed for detection of Pb(Ⅱ) and S.aureus. • Au@Ni-Co-MOFs was firstly used to catalytic enhancement electrochemiluminescence signal. • The biosensor successfully realized the simultaneous detection of two targets. [ABSTRACT FROM AUTHOR]

KMnO 4 -modified biochar (KM/biochar) derived from cotton stem is prepared with different cotton stem/KMnO 4 ratios for Pb(II) removal from wastewater. The characterization analysis indicates that KM/biochar has abundant surface functional groups and large surface area, contributing to Pb(II) removal. Pb(II) adsorption on KM/biochar can be accurately analyzed using the Pseudo-second order and Hill model. The maximum Pb(II) adsorption capacity of KM/biochar is 144.49 mg/g at pH of 5. Pb(II) adsorption on KM/biochar is spontaneous based on thermodynamics analysis with the enthalpy value of the 8.54 kJ/mol. Coexisted ions such as Na+, K+, Ca2+ and Mg2+ have slightly influenced on Pb(II) adsorption process. The regeneration experiment analysis indicates that KM/biochar shows excellent Pb(II) adsorption capacity after three cycles. The existence of CO2 can contribute to Pb(II) removal from wastewater. Pb(II) adsorption mechanism includes precipitation, cation exchange, electrostatic attraction and π-π interaction. These above analysis results indicate that the waste cotton stem can be converted into the high-efficient KM/biochar for Pb(II) removal from wastewater. [ABSTRACT FROM AUTHOR]

For the high-value utilization of wood, a novel non-cytotoxic bifunctional wood (NBW) was synthesized in this study for simultaneous adsorption and detection of Pb(II). Adsorption experiments showcased the remarkable maximum adsorption capacity of NBW, measuring 211.6 mg/g. The adsorption isotherm followed the Langmuir model, and concurrently, adsorption kinetics adhered to the pseudo-second-order model. Critically, NBW exhibited exceptional reusability, maintaining 81.0% of its initial adsorption capacity even after undergoing six consecutive adsorption/desorption cycles. Additionally, it demonstrated notable temporal stability, preserving more than 84.2% of its initial adsorption capacity after a fifteen-week storage period. Furthermore, NBW was used for selective and sensitive detection of Pb(II), yielding a low limit of detection of 0.13 μg/L. The fluorescence quenching of NBW resulted from both the internal filtering effect and dynamic quenching. Importantly, the cost analysis demonstrated that the expense of removing Pb(II) per gram using NBW was only CNY 0.50, significantly lower than the cost associated with activated carbon, totaling CNY 2.11. This study lays the groundwork for the development of a long-term stable, reusable, cost-effective, and multifunctional adsorbent. [Display omitted] ● A novel non-cytotoxic bifunctional wood (NBW) was synthesized. ● NBW simultaneously has efficient adsorption and sensitive detection abilities. ● Maximum adsorption capacity of the NBW for Pb(II) ion was 211.6 mg/g. ● NBW had sensitive detection ability with low detection limit of 0.13 μg/L. [ABSTRACT FROM AUTHOR]