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Environmental pollution detection is a serious concern for both developed and developing countries. Though many existing methods are there to detect the environmental effluents and each of them have their own merits, but still they have some limitations such as requirement of highly sophisticated instruments which are quite expensive and time consuming etc. As a substitution for the current issue, optical sensing techniques made up of metal-organic frameworks have been introduced, which attract the researchers' eyes by their excellent performance and quick response and have been found to have an impressively diverse range of applications. Optical sensors of various luminescent materials are widely designed and deployed to detect environmental effluents like toxic heavy metal ions, organic molecules, dyes, bacteria, etc. This review highlights the current achievements made by the optical sensors derived by using various metal-organic frameworks to detect the different types of environmental pollutants, which will be beneficial for academics and industrialists. [ABSTRACT FROM AUTHOR]

This study introduces a new electrochemical sensor for bisphenol A (BPA) and metal ions utilizing a microsphere dual‐ligand Ni‐based MOFs modified carbon paste. The MOFs (Ni‐bipy‐btc) synthesized from dual‐ligands were prepared via a hydrothermal method and characterized using X‐ray diffraction (XRD), scanning electron microscope (SEM), FT‐IR spectrometer, X‐ray photoelectron spectrum (XPS), and specific surface area test (BET) analysis. The resulting MOFs exhibited promising performance as electrode materials for electrochemical sensors targeting the detection of BPA and heavy metal ions (Pb2+ and Cu2+). The linear range of the MOFs (Ni‐bipy‐btc)/CPE electrode for BPA detection ranged from 0.2 to 150 μM, with a detection limit of 0.045 μM, demonstrating robust immunity and stability. Additionally, the limit of detection for the MOFs (Ni‐bipy‐btc)/CPE electrode was found to be 4.3 and 9.5 nM for Pb2+ and Cu2+ ions, respectively, showcasing excellent stability and reproducibility. This study presents a straightforward approach for the highly sensitive electrochemical detection of BPA and heavy metal ions using a simple hydrothermal reaction method. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Extractive Metallurgy) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Designing inexpensive and efficient absorbent materials derived from waste is still challenging but of great significance to environmental safety and resource protection. Herein, the modified Hummers' waste liquid was used as a precursor reactant to synthesize the three types of manganese oxides via a chemical precipitation method. The components, microstructure, and adsorption capacities of the manganese oxides for heavy metal ions were investigated in detail. The results show the manganese oxides have porous structures and different crystal phases as manganese dioxide (I-MO), manganese oxide hydroxide (II-MO), and trimanganese tetraoxide (III-MO), respectively. Compared with II-MO and III-MO, I-MO has a specific surface area and pore volume of 142.27 m2·g−1 and 0.622 cm3·g−1, respectively. The experiments reveal that Ι-MO exhibits better adsorption performance of heavy metal ions than II-MO and III-MO. At 298 K, the maximum adsorption amounts of Pb2+, Cd2+, and Cu2+ on the Ι-MO are 304.15, 175.37, and 74.48 mg·g−1, respectively. The experimental findings closely match both the pseudo-second-order model and the Langmuir model. Moreover, I-MO exhibits a satisfactory adsorption capacity for heavy metal ions even after six repetitive cycles. All of these show that I-MO is a cost-effective adsorbent for heavy metal ions elimination in water. [ABSTRACT FROM AUTHOR]

Heavy metal ions in industrial wastewater pose significant environmental and ecological threats. In this work, a hydrogel featuring a double network structure was synthesized via radical polymerization and cross-linking of β-cyclodextrin (CD) and carboxymethylcellulose (CMC) with acrylic acid (AA). The hydrogel's functional groups and microstructure were characterized using Fourier transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Mechanical properties were evaluated through rheological and compression tests. The study examined the impact of initial metal ion concentration, adsorbent-ion contact time, and solution pH on adsorption capacity. The maximum adsorption capacities of the functionalized CD/CMC-PAA-MBA hydrogel for Cu2+, Pb2+, and Cd2+ ions were 158.12, 393.56, and 290.12 mg/g, respectively. Notably, the hydrogel exhibited the highest selectivity for Pb2+ in mixed solutions. The adsorption kinetics of the metal ions were modeled using the pseudo-second-order rate equation and the Langmuir adsorption isotherm. [ABSTRACT FROM AUTHOR]

To evaluate the co-migration potential between heavy metal ions and road runoff colloids, the influence of contact time, temperature, initial concentration of metal ions, pH, humic acid (HA), and polymetallic coexistence on the binding capacity of heavy metals onto runoff colloids were investigated. The adsorption of heavy metals by runoff colloids was extremely rapid, approximately 80% of the equilibrium adsorption capacity was achieved in the first 30 min. The binding capacity exhibited an increasing trend with the initial concentration of metal ions increasing, and the maximum adsorption capacities of Pb(II), Cu(II), and Cd(II) achieved 159.13, 56.06, and 78.35 mg/g at 298 K, respectively. The adsorption capacity of Cu(II) and Cd(II) by runoff colloids increased with temperature increasing, while it displayed a converse trend for Pb(II). Neutral pH facilitated the combination of metal ions and runoff colloids. The presence of humic acid increased the binding capacity of Pb(II), Cu(II), and Cd(II) onto runoff colloids by 72.19, 63.31, and 13.83mg/g, respectively. Compared to the monometallic systems, the binding capacity of Pb(II), Cu(II), and Cd(II) by runoff colloids decreased by 18.44%, 22.35%, and 56.06% in polymetallic systems, respectively. Pb(II) bounded with colloids in the road runoff should be controlled preferentially to avoid their migrations to aquatic environments. [ABSTRACT FROM AUTHOR]

A magnetic mesoporous silica, Fe3O4@SiO2@KCC-1 (MMS), was prepared using a hydrothermal method and subsequently modified by post-grafting to synthesize Fe3O4@SiO2@KCC-1-SH (MMS-SH). The synthesized mesoporous materials were characterized using various techniques, including X-ray diffraction (XRD), vibrating sample magnetometry (VSM), field emission scanning electron microscopy (FE-SEM), X-ray energy diffraction spectroscopy (EDS) analysis and mapping, nitrogen adsorption/desorption measurement, Thermal gravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. Their removal capacity for heavy metal ions was determined with flame atomic absorption spectroscopy (AAS). Due to their large surface area, these adsorbents were used for the removal of Cu(II), Ni(II), Cd(II), Hg(II), and Pb(II) ions. The unmodified MMS exhibited removal capacities of 24.10, 28.54, 21.71, 32.5, and 30.06 mg/g for Cu(II), Ni(II), Cd(II), Hg(II), and Pb(II) ions, respectively. The removal of heavy metal ions by MMS followed a pseudo-first-order kinetic model and fit well with the Langmuir model. However, modifying the surface of the MMS with thiol groups significantly increased the removal capacity for all mentioned metal ions to 36.21, 32.83, 27.34, 48.75, and 41.40 mg/g, respectively. The removal of heavy metal ions by MMS-SH followed a pseudo-second-order kinetic model and fit well with the Temkin model. The antibacterial assays showed that the synthesized mesoporous materials were generally more effective against both planktonic Escherichia coli (gram-negative bacterium) and its ability to form biofilm compared to Staphylococcus aureus (gram-positive bacterium). [ABSTRACT FROM AUTHOR]

Nowadays, the problem of heavy metal pollution is becoming more and more serious, in order to deal with heavy metal ion pollution in wastewater mostly use filtration and adsorption means. In this article, hair-derived carbon materials were prepared from hair by phosphoric acid activation and high temperature carbonization. The adsorption performance of hair activated carbon (AC) was also investigated at different activation temperatures, different adsorption times and temperatures, and initial concentrations of Fe3+ and Cu2+. The results showed that the hair AC obtained at 250 °C activation temperature when the adsorption time of 180 min and the adsorption temperature of 25 °C have good adsorption performance for heavy metal ions Fe3+ and Cu2+ reached 70.57% and 91.11%. The results of the study showed that hair AC can be used as an adsorbent to improve the water quality of heavy metal wastewater. [ABSTRACT FROM AUTHOR]

Porous materials are excellent candidates for water remediation in environmental issues. However, it is still a key challenge to design efficient adsorbents for rapid water purification from various heavy metal ions‐contaminated wastewater in one step. Here, two robust nitrogen‐rich covalent organic frameworks (COFs) bearing terpyridine units on the pore walls by a "bottom‐up" strategy are reported. Benefitting from the strong chelation interaction between the terpyridine units and various heavy metal ions, these two terpyridine COFs show excellent removal efficiency and capability for Pb2+, Hg2+, Cu2+, Ag+, Cd2+, Ni2+, and Cr3+ from water. These COFs are shown to remove such heavy metal ions with >90% of contents at one time after the aqueous metal ions mixture is passed through the COF filter. The nitrogen‐rich features of the COFs also endow them with the capability of capturing iodine vapors, offering the terpyridine COFs the potential for environmental remediation applications. [ABSTRACT FROM AUTHOR]

The rapid progress of urbanization and industrialization has led to the accumulation of large amounts of metal ions in the environment. These metal ions are adsorbed onto the negatively charged surfaces of clay particles, altering the total surface charge, double-layer thickness, and chemical bonds between the particles, which in turn affects the interactions between them. This causes changes in the microstructure, such as particle rearrangement and pore morphology adjustments, ultimately altering the mechanical behavior of the soil and reducing its stability. This study explores the effects of four common metal ions, including monovalent alkali metal ions (Na+, K+) and divalent heavy metal ions (Pb2+, Zn2+), with a focus on how ion valence and concentration impact the soil's microstructure and mechanical properties. Microstructural tests show that metal ion incorporation reduces particle size, increases clay content, and transforms the structure from layered to honeycomb-like. Small pores decrease while large pores dominate, reducing the specific surface area and pore volume, while the average pore size increases. Although cation exchange capacity decreases, cation adsorption density per unit surface area increases. Monovalent ions primarily disperse the soil structure, while divalent ions induce coagulation. Macro-mechanical tests reveal that metal ion contamination reduces porosity under loading, with compressibility rises as the ion concentration increases. Soils contaminated with alkali metal ions shows higher compression coefficients at all loads, while heavy metal ions cause higher compression under lower loads. Shear strength, the internal friction angle, and cohesion in metal-ion-contaminated clay decrease compared to uncontaminated field-state clay, with greater declines at higher ion concentrations. The Micropore Morphology Index and hydro-pore structural parameter effectively characterize both micro- and macrostructural properties, establishing a quantitative relationship between HPSP and the engineering properties of metal-ion-contaminated clay. [ABSTRACT FROM AUTHOR]

Heavy metals are commonly found in a wide range of environmental settings metals, but the potential toxicity associated with heavy metal exposure represents a major threat to global public health. It is thus vital that approaches to efficiently, reliably, and effectively detecting heavy metals in a range of sample types be established. Carbon nanomaterials offer many advantageous properties that make them well-suited to the design of sensitive, selective, easy-to-operate electrochemical biosensors ideal for detecting heavy metal ions. The present review offers an overview of recent progress in the development of carbon nanomaterial-based electrochemical sensors used to detect heavy metals. In addition to providing a detailed discussion of certain carbon nanomaterials such as carbon nanotubes, graphene, carbon fibers, carbon quantum dots, carbon nanospheres, mesoporous carbon, and Graphdiyne, we survey the challenges and future directions for this field. Overall, the studies discussed herein suggest that the further development of carbon nanomaterial-modified electrochemical sensors will support the integration of increasingly advanced sensor platforms to aid in detecting heavy metals in foods, environmental samples, and other settings, thereby benefitting human health and society as a whole. [ABSTRACT FROM AUTHOR]

Extracellular polymeric substances (EPS) are the giant polymers composed of polysaccharides, proteins, nucleic and humic acid with remarkable applications. This study was aimed to evaluate the binding efficacies of two EPS extracted from cyanobacterial strains (Microsystis aeruginosa and Microsystis ichthyoblabe) with four heavy metal ions (lead, cadmium, copper, and zinc) using excitation-emission matrix (EEM) spectroscopy with the main focus on the fluorescence properties of protein present in each EPS. Characterization of EPS showed that they were composed of > 90% of organic contents with higher carbohydrates (59.54 and 60.72%) than proteins (26.49% and 30.2%) and lower humic acid contents (8.29% and 6.96%). The amino acids profile revealed tryptophan at maximum (6.28% in EPS-A and 4.26% in EPS-I) followed by tyrosine (5.05% in EPS-A and 3.47% in EPS-I), glutamic acid (4.14% in EPS-A and 2.74% in EPS-I), leucine (3.92% in EPS-A and 2.82% in EPS-I) and phenylalanine (3.14% in EPS-A and 1.97% in EPS-I). The percentages of amino acids recorded were higher in EPS-A than EPS-I. A fluorescence peak at 280/350 nm (Ex/Em) was identified in the fluorescence spectrum for each EPS using EEM spectroscopy. Quenching experiments showed gradual decrease in EPS fluorescence intensity with increased metal concentration due to EPS-metal association. The Stern–Volmer plot displayed static quenching mechanism of metals in deactivating EPS fluorophores. Pb(II) and Cd(II) displayed superior quenching at 50 mg/L whereas Zn(II) and Cu(II) indicated lower quenching at 100 mg/L. The binding potencies of EPS from cyanobacteria with metal ions is a potential green biotechnological approach for toxic metals remediation from aqueous medium. [ABSTRACT FROM AUTHOR]

In this study, magnetic material was synthesized using iron salts, then silicon-specific material was used to gain porosity, straight-chain polyacrylamide (PAM) was modified to give the surface functional properties, and the final product synthesized Fe3O4/SiO2/PAM nanocomposite material. Heavy metal (Pb and Cd) removal studies were carried out with the synthesized composite material, considering the central composite design and response surface methodology (CCD-RSM) optimization model. The effects of various parameters, for example, the initial concentration, pH, adsorbent dose, temperature and contact time, were investigated as a part of this study. To optimize these parameters, the CCD-RSM model was applied to design the experiments. Analysis of variance (ANOVA) was applied to evaluate statistical parameters and investigate interactions of variables. In the designed experimental set, the amount of adsorbent (30 mg), pH 7.0 value, temperature (40 °C), initial concentration of Pb (80 mg/L) and Cd (20 mg/L) and 90 min contact time were determined as the optimum conditions. The high coefficient of determination of both metals showed good agreement between experimental results and predicted values (R2 0.99; 0.95). TEM, SEM, XRD, FTIR, BET and Zeta potential analyses were performed to characterize the structure and morphology of the adsorbent. In Pb2+ and Cd2+ heavy metal removal studies, maximum adsorption capacities were determined as 66.54 and 13.22 mg/g, respectively. Additionally, adsorption isotherms, adsorption kinetics and thermodynamic modeling studies were conducted. Features such as large surface area and high adsorption capacity of the synthesized nanoparticles were observed. In this study, Fe3O4/SiO2/PAM demonstrated its potential as an effective adsorbent for the removal of heavy metal ions present in simulated wastewater samples. In particular, we can say that the material has a strong selectivity, as well as a high affinity for Pb(II) ions. [ABSTRACT FROM AUTHOR]

We propose here a fabrication of an electrochemical sensor to detect heavy metal ions based on a glass carbon electrode (GCE) modified with a composite system consisting of graphene, chitosan, and Fe3O4 nanoparticles (GrCF) by using square wave voltammetry (SWV) measurements. The GrCF composite was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectroscopy. GrCF consists of thin and smooth sheets stacked in overlapping layers to form porous structures. In the GrCF composite, graphene acts as a substrate with a high electrochemical activity and a good electrical conductivity, Fe3O4 nanoparticles are uniformly distributed on the graphene thanks to chitosan as a binder, the functional groups of chitosan (− OH, − NH2) have the ability to form complexes with heavy metal ions, and the excellent adsorption capacity of Fe3O4 nanoparticles has enhanced the electrochemical reactions. The GrCF/GCE can detect Pb2+ ions with a linear range from 4 to 16 μM, a low detection limit of 3.57 μM, and a sensitivity of 8.623 μA μM−1. Furthermore, the repeatability of the measurements are reliable with a standard deviation (SD) of 0.15 μA and a relative standard deviation (RSD%) of 4.16%. Additionally, Pb2+ was detected in the real sample at potentials of − 0.50 V/ − 0.52 V with calculated recovery values for two measurements of 89.02% and 89.43%. The electrode modification method based on the GrCF composite promises outstanding advantages in the field of electrochemical sensors for detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xi'an Jiaotong University is the property of Editorial Office of Journal of Xi'an Jiaotong University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phase pure sodium trititanate (Na2Ti3O7) and hexatitanate (Na2Ti6O13) nanorods were controllably synthesized using sodium carbonate and titanic acid as sodium and titanium precursors by calcination at 850 °C for 12 h. The adsorption properties of trititanate and hexatitanate nanorods for the removal of heavy metal ions, Ni2+ and Pb2+ from simulated wastewaters at pH of 3‒7 and 20‒65 °C were investigated. The adsorption of Ni2+ and Pb2+ ions on sodium trititanate and hexatitanate nanorods are through ion exchange and electrostatic adsorption. The adsorption of Ni2+ and Pb2+ ions could be well fitted by the pseudo-second order adsorption kinetics and Langmuir adsorption isotherm. Based on the Langmuir adsorption isotherm, the adsorption capacities of naked sodium trititanate nanorods for Ni2+ and Pb2+ from simulated wastewaters at 20 °C and pH 7 are 104.17 and 89.85 mg∙g‒1 while the adsorption capacities of naked sodium hexatitanate nanorods are 95.69 and 76.69 mg∙g‒1, respectively. Sodium trititanate nanorods exhibit higher adsorption capacities for heavy metal ions from wastewaters than sodium hexatitanate nanorods because the former has richer Na+ ions for ion exchange with heavy metal ions than the latter. The adsorption processes of Ni2+ and Pb2+ on sodium trititanate and hexatitanate nanorods are spontaneous. The phase pure sodium titanate nanorods may have practical application for the removal and enrichment of metal ions from wastewaters. [ABSTRACT FROM AUTHOR]

The use of mixed microalgae offers an effective solution for the management of contamination risks in cultivation while enhancing economic viability. In this study, mixed microalgae were used for the first time for the removal of copper (Cu) and nickel (Ni) from aqueous solutions. The characteristics of the adsorbents were examined thoroughly, and the adsorption process was assessed using isotherms, kinetics, and thermodynamics. Particle size, concentration, contact time, temperature, and pH were among the variables assessed. The findings demonstrated that, at an initial concentration of 100 mg L–1 and a pH of 6, the maximum adsorption of Cu with a particle size of 1 mm (90.20%) took place in 60 min. The highest adsorption rate (78.25%) was found for Ni. Microalgae performed best over 180 min at room temperature and at pH values that promoted metal dissolution. The removal percentages of wet and dried microalgae were comparable, and the wet adsorbent was more economical. It was feasible to remove both metals at the same time. Up to three cycles of adsorbent reuse were possible, with sodium hydroxide treatment offering superior removal to hydrochloric acid. Thermodynamic analysis demonstrated that this process, which results in a disordered state, is exothermic and spontaneous. [ABSTRACT FROM AUTHOR]

In this work higher Cu2+ removal efficiency was achieved by graphene oxide GO-based electrode with the constant magnetic field (CMF)-assisted electrodeposition system. The GO was initially synthesized by the electrochemical exfoliation method in the electrolyte containing custom-made surfactant. The as-prepared GO solution was then spray coated on the pre-heated stainless steel-cathode before annealed at 400°C for 1 hour. GO-based electrode with CMF-assisted electrodeposition system was successful removed 89.1% of Cu2+ from aqueous solutions as compared to the electrode without GO of only 75.5% of Cu2+ removal within a fixed 3 hours' time. The efficient of Cu2+ removal by GO-based electrode was believed due to the high specific surface area of GO that increases the accommodation of the active species (Cu2+) at the electrode surfaces. In the meantime, it was found that the presence of CMF of 23 Gauss parallel to cathode surfaces enhances the convection and mass transport of Cu2+ charged species to the electrode as compared to the absence of the CMF on an electrodeposition system. This phenomenon was due to the Magneto-Hydrodynamics (MHD) effect of CMF which is based on the Lorentz force that increases the Cu2+ deposition efficiency by reducing the diffusion layer thus increasing the ions transfer into the electrical double layer. The electrodes before and after Cu2+ deposition was examined by electron microscopy, energy dispersive x-ray, and Raman spectroscopy, and the concentration of remaining Cu2+ in the solution was analyzed using atomic absorption spectroscopy. From the analysis done shows that the GO-based electrode with CMF-assisted electrodeposition system pave a new and pragmatic route for efficient removal of heavy metal ions. [ABSTRACT FROM AUTHOR]

Through the manipulation of electrospinning solution properties, we tuned the morphology and porosity of electrospun titanium dioxide (TiO2) nanofibers. Using a modified glassy carbon electrode (GCE) with TiO2 nanofibers and Ag-coated carbon nanofibers (AgCNFs) with nafion as a binder, heavy metal ions (HMIs) have been detected with nanomolar detection limits using square wave anodic stripping voltammetry (SWASV). It has been determined how the Cd2+ current signal responds to changes in deposition potential, deposition time, buffer solution pH, and drop-cast volume. The estimated sensitivity of Cd2+ is 49.98 µA µM−1 and the limit of detection (LOD) is found to be 12.75 nM by the three-sigma (3σ) method. The TiO2/AgCNF/nafion/GCE electrode can simultaneously detect Cd2+, Pb2+, Cu2+, and Hg2+ ions without mutual interference. The sensitivities toward Cd2+, Pb2+, Cu2+, and Hg2+ are 39.59, 42.75, 15.67, and 10.52 µA µM−1, respectively. The LOD toward Cd2+, Pb2+, Cu2+, and Hg2+ are 40.14, 31.69, 93.31, and 208.26 nM, respectively. These quantities fall far short of the WHO's recommended guideline values. This combination of very porous TiO2 nanofiber with AgCNF leads to an innovative sensor platform that has very low LOD compared to the previous sensors that have been reported. [ABSTRACT FROM AUTHOR]

This work reports the amine and mercapto bi-functionalized mesoporous silica MCM-41 for heavy metal ions removal from aqueous solutions. XRD, FTIR and N2 adsorption–desorption analyses confirmed that a series of bi-functionalized mesoporous silica MCM-41 with huge specific surface area were successfully obtained. In aqueous solution, the adsorption performance were evaluated by the adsorption of Zn(II), Cu(II), Cr(III) and Pb(II). The obtained results indicate that synthesis process has no significant influence on the structure and the existence of functional group resulted in outstanding adsorption capacity. The methodology of pre-hydrolysis was one effective treatment for grafting useful functional group on to mesoporous silica. The adsorption reactions for the adsorption of heavy metal ions by bi-functionalized silica-based mesoporous materials were spontaneous adsorption processes over the range of experimental temperatures. The adsorption isotherm is consistent with the Freundlich adsorption isotherms model. The Freundlich parameters KF and n indicated favorable adsorption. The adsorption kinetics of heavy metalions over these bi-functionalized mesoporous silica could be well described by pseudo-second-order models. Therefore, this bi-functionalized mesoporous material has promise for the removal and recovery of heavy metal ions from water. [ABSTRACT FROM AUTHOR]

We present a novel miniaturized, gear-shaped, fuel-free actuator capable of autonomously propelling itself in an aquatic environment to absorb heavy metals, such as copper ions. While hydrogel-based absorbents are promising solutions for cationic pollutant remediation, their stationary nature limits their effectiveness in areas where contaminants are unevenly distributed. To address this, we developed a bio-inspired soft actuator that mimics natural propulsion mechanisms. The Marangoni effect, driven by its inherent chemical properties, demonstrated a self-propelled motion without requiring external fuel. The proof-of-concept actuator generated a plane motion lasting up to 2 h and swept over an area approximately 400 times bigger than its size. By harnessing the chemical and optical properties of the hydrogel, we efficiently removed and quantitatively analyzed copper ions through a colorimetric method. This innovative integration of self-propelled movement and efficient copper ion absorption underscores its potential for advancing miniaturized devices in environmental remediation, paving the way for more active and efficient pollutant removal systems in challenging aquatic environments. [ABSTRACT FROM AUTHOR]

The impact of various modification methods on enhancing the adsorption performance of coal gangue (CG) for hazardous heavy metals has not been thoroughly investigated. In this study, three CG samples were first modified by calcination, followed by acid washing, alkali washing, and hydrothermal treatment, to obtain modified CG samples. The adsorption performance was assessed based on the adsorption capacities for Cd2⁺ and Pb2⁺ (i.e., qe,Cd and qe,Pb), and the kinetics of the adsorption processes were analyzed using kinetic equations. XRD, SEM-EDX, FTIR, and N2 adsorption–desorption isotherms were used to elucidate the adsorption mechanisms. Results indicated that qe,Cd and qe,Pb of raw CG samples were approximately 10 and 25 mg/g, respectively, with only slight changes observed after calcination, acid washing, and alkali washing. In contrast, hydrothermal treatment yielded NaP and NaA zeolites, which significantly enhanced qe,Cd and qe,Pb to values of 48.5–72.7 and 214.9–247.5 mg/g, respectively. The hydrothermally treated CG samples primarily adsorbed Cd2⁺ and Pb2⁺ through ion exchange with Na⁺ within the zeolite structure, facilitating the entry of these ions into the zeolite's pore channels. The adsorption processes were effectively described by the pseudo-second-order kinetic model. By optimizing the conditions of hydrothermal modification, the adsorption performance of CG samples is anticipated to further improve due to the creation of additional adsorption sites. [ABSTRACT FROM AUTHOR]

Herein, the cost-effective utilization of biosorption for toxic pollutant removal was investigated, with a specific emphasis on enhancing mushroom-based biosorbents for the decontamination of heavy metals-polluted aqueous environments. Firstly, Oyster mushrooms (Pleurotus ostreatus) collected from Bajaur, Khyber Pakhtunkhwa, Pakistan, underwent thorough cleaning, followed by air-drying for 2–3 weeks to produce a fine powder. The obtained powder was subjected to thermal modification through heating at 400°C/1 h, and a portion of it was additionally modified using potassium hydroxide (KOH). This process resulted in three distinct materials: untreated dried mushroom (AM), thermally modified mushroom (TMM), and chemically modified mushroom (CMM), and their chemical compositions were assessed using Fourier Transform Infrared (FTIR) spectroscopy. Subsequently, the resulting materials were employed as bioadsorbents for the elimination of toxic Fe(III) ions from aqueous media. Various experimental variables, including solution pH, temperature, contact time, pollutant concentration, and adsorbent amount were varied to investigate their impact on adsorption. Analysis using an atomic absorption spectrophotometer (AAS) demonstrated exceptional Fe(III) removal capacities of mushrooms, achieving a removal extent of 29.99 mg/g at 303 K, pH 6.0, and an adsorbent dosage of 0.1 g/L, resulting in a remarkable 99.97% removal efficiency. The type of adsorbent significantly affected the extent of adsorption. Furthermore, thermodynamic analysis revealed that adsorption was spontaneous and exothermic. The adsorption data were evaluated using Langmuir, Freundlich, and Temkin isotherms, with the pseudo-second-order reaction kinetics providing the best fit, suggesting that chemisorption predominates the surface adsorption of Fe(III). This study highlights the potential of mushroom-based biosorbents as eco-friendly and effective materials for purifying water contaminated with toxic pollutants. [ABSTRACT FROM AUTHOR]

In this study, electrospinning was used to connect carbon nanofibers (CNFs) with multiple metals. Then, through high-temperature graphitization technology, uniformly sized high-entropy alloy nanoparticles (HEA NPs) were successfully synthesized in situ on CNFs. An electrochemical sensor for the simultaneous and sensitive detection of three heavy metal ions was fabricated based on FeCoNiCrCe/CNFs. In 0.1 mol/L acetic acid-sodium acetate buffer solution at pH 5, at deposition voltage and time of −1.3 V and 300 s, respectively, the limits of detection (LOD) of the electrochemical sensor were 0.06, 0.005 and 0.005 μmol/L (signal-to-noise ratio = 3) for Cd2+, Pb2+, and Cu2+, respectively. The excellent performance was considered to be attributed to the good conductivity and catalytic activity provided by HEA NPs and the higher specific surface area of CNFs exposing more active sites, which were synergistically conducive to the adsorption and desorption of heavy metal ions, thereby promoting the redox reaction and charge transfer of heavy metal ions. The FeCoNiCrCe/CNFs/GCE electrochemical sensor prepared in this study has promising application prospects in the detection of heavy metal ions in vegetables and fruits.

Growing volumes of textile waste and heavy metal pollution of water are emerging environmental challenges. In an attempt to tackle these issues, a non-woven sorbent based on jute fibers was fabricated by recycling the textile waste from the carpet industry. The influence of contact time, concentration, pH and temperature on the sorption of lead and copper ions from aqueous solutions was studied. In order to enhance the sorption capacity of the non-woven material, in situ synthesis of polyaniline (PANI) in the presence of TiO2 nanostructures was performed. The contribution of TiO2 nanoparticles and TiO2 nanotubes to the uniformity of PANI coating and overall sorption behavior was compared. Electrokinetic measurements indicated increased swelling of modified fibers. FTIR and Raman spectroscopy revealed the formation of the emeraldine base form of PANI. FESEM confirmed the creation of the uniform nanocomposite coating over jute fibers. The modification with PANI/TiO2 nanocomposite resulted in a more than 3-fold greater sorption capacity of the material for lead ions, and a 2-fold greater absorption capacity for copper ions independently of applied TiO2 nanostructure. The participation of both TiO2 nanostructures in PANI synthesis resulted in excellent cover of jute fibers, but the form of TiO2 had a negligible effect on metal ion uptake. [ABSTRACT FROM AUTHOR]

The environmental toxicity caused by heavy metal ions is always taken seriously. Capacitive deionization (CDI), as an emerging and effective treatment method, is widely studied. Among them, the rational design and development of efficient electrodes based on high theoretical capacitance, high conductivity, and high stability have great prospects for CDI applications. In this study, a series of 2D titanium carbide oxide flakes (2D TCOs) are synthesized using a cation‐giving modulation strategy, and the interlayer spacing of materials is successfully controlled by confining cations (tetraalkylammonium hydroxides, TAAH) with different radii between layers. Interestingly, these TCOs exhibit widely varying electrochemical properties due to their different interlayer spacings. Among them, titanium carbide oxide flakes‐tetrapropylammonium hydroxide (TCOs‐TPAH) with the maximum interlayer spacing exhibits the best performance in sodium ion embedding and de‐embedding, with a capacity of 53.11 mg g−1. In addition, the capacitive removal efficiency of heavy metal ions (Fe3+, Cr3+, Cu2+, Cd2+, Co2+, Ni2+, and Pb2+) can reach over 97% within 2 h. This work presents a simple and creative strategy for the bottom‐up synthesis of oversized 2D nanomaterials, thus supporting the further development of high‐performance 2D materials in the fields of environmental and energy applications. [ABSTRACT FROM AUTHOR]

Permeable concrete has been limited to light traffic grade pavement because of insufficient strength and durability. An innovative high strength pervious concrete with straight holes is prepared based on C80 self-compacting concrete. The rainstorm intensity level is taken as the environmental factor variable to discuss the adsorption capacity of such pervious concrete on heavy metal ions (copper, zinc). The purification effect of each component of concrete to copper and zinc ions is studied and the adsorption mechanism is analyzed. The results show that the innovative pervious concrete has excellent mechanical properties ( The compressive strength is 94. 8 MPa and the flexural strength is 8. 4 MPa) and water permeability (permeability coefficient is 0. 81 mm / s), the removal rate of copper and zinc ions decreases with the increase of rainstorm levels. The removal rate of copper and zinc ions can still reach 22. 5% and 17. 5% under the extremely heavy rainstorm, indicating that innovative pervious concrete possesses good water purification capacity. The results show that the hydration products of cementitious materials are the main adsorbents of heavy metal ions. The removal effect of powder hydrated cementitious materials on Zn2+ is better than that of Cu2+, while the removal effect of block hydrated cementitious materials and steel fibers is more obvious. [ABSTRACT FROM AUTHOR]

In this paper, a highly sensitive fiber-optic sensor was proposed for the detection of Cu2+ traces in aqueous solution which has a nonnegligible impact on human health. Based on the principle of SPR, a uniform chitosan (CS) material was coated on a multimode fiber-single mode fiber-multimode fiber (MSM) structure with silver layer by glutaraldehyde (GLA) and graphene oxide modification. The amino and hydroxyl groups in the material have a recognition function for Cu2+, which can chelate with Cu2+ and change the ambient layer refractive index of the sensor leading to a shift in the SPR spectrum. Trace Cu2+ can be detected by monitoring the shift in the resonance wavelength of the SPR spectrum. The results illustrate that within the range of 0.1 ~ 1 mg/L Cu2+ concentration, as the Cu2+ concentration increasing, the SPR spectrum undergoes a red shift and the maximum detection sensitivity of Cu2+ ions achieves 49.466 nm/(mg/L), with a good linearity of 0.996. The temperature experimental results indicate that the sensor has good stability at room temperature (25 ~ 35 °C). The stability and repeatability characteristics of the system are also investigated. The good performance provides a new method in trace Cu2+ in-situ detection. [ABSTRACT FROM AUTHOR]

In order to remove Pb(II), Ni(II) and Mn(II) from aqueous solution, a lignin-based composite hydrogel (LS-g-P(AA-co-AM)/OMMT) was synthesized by free radical polymerization using sodium lignosulfonate (LS) and organic montmorillonite (OMMT) as raw materials. The obtained hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that the LS-g-P(AA-co-AM)/OMMT contains abundant C and O containing surface groups, which were favorable for the adsorption of Pb(II), Ni(II), Mn(II). The effects of adsorbent dosage, solution pH, temperature, initial concentration and time on hydrogel adsorption of Pb(II), Ni(II) and Mn(II) were investigated. The maximum adsorption amounts were 575.5, 326.67 and 282.82 mg/g, respectively. The adsorption process of heavy metal ions conforms to the pseudo-second-order kinetics and Langmuir model, which indicates that the adsorption of Pb(II), Ni(II) and Mn(II) by LS-g-P(AA-co-AM)/OMMT is a monolayer adsorption process dominated by chemical adsorption. The main adsorption mechanisms are ion exchange and coordination complexation. Conclusively, the prepared biomass adsorbent was proved as promising adsorbents for the removal of heavy metals. [ABSTRACT FROM AUTHOR]

Heavy metal pollution has become an increasingly prominent problem. Consequently, adsorbents with high heavy metal removal efficiency using a convenient synthesis method have to be developed urgently. The magnesium carbonate hydroxide microsheets modified activated carbon fiber (MCH@ACF) was prepared by a facile in situ hydrothermal method. The results of the characteristic of MCH@ACF indicated that a large amount of magnesium carbonate hydroxide porous microsheets is densely arranged on the surface of ACF. The Mn2+, Cu2+, Pb2+, and Cr2O72− ions adsorption kinetics of the MCH@ACF could be fitted with the pseudo-second-order model, and the results indicate the fast adsorption rate. The Mn2+, Cu2+, and Pb2+ ions adsorption on the MCH@ACF follow the Langmuir model, while the Cr2O72− adsorption on the MCH@ACF follows the Freundlich model. The theoretical adsorption capacity of the Mn2+, Cu2+, Pb2+, and Cr2O72− ions on the MCH@ACF is 558.6 mg/g, 1591.7 mg/g, 1802.8 mg/g, and 125.7 mg/g, respectively. The heavy metal ions removal performance of MCH@ACF under different pH conditions has been studied. Furthermore, the adsorption mechanism could be ascribed to the binding of heavy metal ions with carbonate or hydroxyl group. The results indicated that the MCH@ACF can be used as the potential suitable candidate for heavy metal removal. [ABSTRACT FROM AUTHOR]

As an ideal transition metal oxide, Co3O4 is a P-type semiconductor with excellent electrical conductivity, non-toxicity and low cost. This work reports the successful construction of Co3O4 materials derived from metal-organic frameworks (MOFs) using a surfactant micelle template-solvothermal method. The modified electrodes are investigated for their ability to electrochemically detect Pb2+ and Cu2+ in aqueous environments. By adjusting the mass ratios of alkaline modifiers, the morphological microstructures of Co3O4-X exhibit a transition from distinctive microspheres composed of fiber stacks to rods. The results indicate that Co3O4-1(NH4F/CO(NH2)2 = 1:0) has a distinctive microsphere structure composed of stacked fibers, unlike the other two materials. Co3O4-1/GCE is used as the active material of the modified electrode, it shows the largest peak response currents to Pb2+ and Cu2+, and efficiently detects Pb2+ and Cu2+ in the aqueous environment individually and simultaneously. The linear response range of Co3O4-1/GCE for the simultaneous detection of Pb2+ and Cu2+ is 0.5–1.5 μM, with the limits of detection (LOD, S/N = 3) are 9.77 nM and 14.97 nM, respectively. The material exhibits a favorable electrochemical response, via a distinctive Co3O4-1 microsphere structure composed of stacked fibers. This structure enhances the number of active adsorption sites on the material, thereby facilitating the adsorption of heavy metal ions (HMIs). The presence of oxygen vacancies (OV) can also facilitate the adsorption of ions. The Co3O4-1/GCE electrode also exhibits excellent anti-interference ability, stability, and repeatability. This is of great practical significance for detecting Pb2+ and Cu2+ in real water samples and provides a new approach for developing high-performance metal oxide electrochemical sensors derived from MOFs. [ABSTRACT FROM AUTHOR]

Environmental pollution significantly challenges human health, ecosystems, and the planet's sustainability. Widespread air, water, and soil contamination from various pollutants requires effective and sustainable solutions to reduce or eliminate pollution and its impacts. In this work, we designed novel magnesium oxide and graphene oxide (MgO@GO) composite free-standing membranes for nanofiltration. The membranes were characterized with the help of Fourier-transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Further, free-standing MgO@GO composite membranes with different thicknesses were used to measure the water permeance. 410 nm-thick membranes showed high water permeance up to 480 ± 5 Lm−2 h−1 bar−1. Further, the rejection efficiency of the membrane was measured against NaCl, CaCl2, Pb(NO3)2, CdCl2, and amoxicillin. The MgO@GO membrane (410 ± 10 nm) showed 100% rejection for amoxicillin and 99% for Pb(NO3)2, respectively. Additionally, the membranes were stable under acidic and neutral conditions for approximately ∼80 days and may used on an industrial scale to ensure water is clean and free from harmful substances. [ABSTRACT FROM AUTHOR]

The adsorption of weighty metal particles from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Heavy metal ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, design ability, and stability have been proposed. In this review, a carbon-based adsorbent, named M-NC, and graphene oxide were created for the particular evacuation of weighty metal particles. To increase the potential for Heavy Metals (HM) immobilization, sulfide-modified biochar was created via a process called synchronous carbon layer epitome. A hypothetical physicochemical and thermodynamic examination of the adsorption of weighty metals Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was done with factual material science fundaments. The biochar with large surface areas is utilized to eliminate weighty metal particles, quite possibly the most significant heavy metal pollutants, from aqueous solutions. The limit of the adsorbent for eliminating weighty metal ions was concentrated on utilizing Langmuir adsorption isotherm under ultrasound-helped conditions. The Mesoporous Silica Nanoparticles (MNCs) can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous measurable physical science adsorption typically was utilized to describe and analyze the experimental heavy metal removal isotherms at 30°C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The experimental results were investigated in terms of Langmuir and pseudo-2nd-order kinetic equations, Freundlich and isotherm models. The outcome of pH, initial heavy metal ion concentration, contact time, and adsorbent dosage regarding the adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the hydrogel was examined. This study contributes to the advancement of information in the ground of environmentally friendly heavy metal removal techniques, specifically focusing on the usage of biomass-based adsorbents. These findings have the potential to address the need for effective solutions in water purification and environmental cleanup efforts. [ABSTRACT FROM AUTHOR]

In the ever-increasing blind race of industrialization and urbanization environmental contamination by toxic heavy metal ions is becoming a serious issue for both scientists and masses. Hence, the objective of this paper was to evaluate the utilization of base (BMOD) and acid (AMOD) modified rice husk-corncobs composite for the removal of chromium (VI) Ion in simulated tannery wastewater using appropriate standard techniques. SEM-EDX, XRD and FTIR characterizations revealed the elemental composition, crystallographic structures and the chemical bonds respectively. The results of the sorption kinetic study showed that the data fitted well with the pseudo-second order model for both acid modified (AMOD) and base modified (BMOD) biosorbent with a maximum adsorption of 28.46 mg/g and 39.66 mg/g respectively. The results of the sorption isotherm study showed that they both fitted Freundlich isotherm model. From the results obtained, rice husk and corn cob were effective biosorbent for the removal of Cr (VI) ion from tannery effluent. [ABSTRACT FROM AUTHOR]

A novel class of hydrogels, rich in a variety of functional groups capable of interacting/complexing with metal ions was successfully synthesized. This was achieved by using acryloyl derivatives of natural α-amino acids, specifically ornithine and cystine. The δ-amino group of ornithine was modified with an acryloyl group to facilitate its attachment to the polymer chain. Additionally, N,N'-bisacryloylcystine, derived from cystine, was employed as the cross-linker. The hydrogel was obtained through a process of free radical polymerization. This hydrogel, composed only from derivatives of natural amino acids, has proven to be a competitive sorbent and has been effectively used to remove heavy metal pollutants, mainly lead, copper, and silver ions, from aqueous media. The maximum sorption capacities were ca. 155 mg·g−1, 90 mg·g−1, and 215 mg·g−1, respectively for Pb(II), Cu(II), and Ag(I). The material was characterized by effective regeneration, maintaining the sorption capacity at around 80%, 85%, and 90% for Cu(II), Ag(I), and Pb(II), respectively, even after five cycles. The properties of sorption materials, such as sorption kinetics and the effect of pH on sorption, as well as the influence of the concentration of the examined metal ions on the swelling ratio and morphology of the gel, were investigated. The EDS technique was employed to investigate the composition and element distribution in the dry gel samples. Additionally, IR spectroscopy was used to identify the functional groups responsible for binding the studied metal ions, providing insights into their specific interactions with the hydrogel. [ABSTRACT FROM AUTHOR]

Water pollution caused by heavy metal ions (HMI) and dyes is a global issue challenging current solutions. Membrane filtration shows promise, yet faces limitations like fouling and low flux. This study proposes a new membrane by incorporating graphene oxide zinc oxide (GO‐ZnO) nanocomposites into a polyethersulfone (PES) matrix to overcome these challenges. The synthesized membrane exhibits strong antimicrobial activity, crucial for water treatment, and high efficiency in removing HMIs (Cu2+ and Ni2+) and dyes (BB9 and EBT) from water samples and industrial wastewater. Characterization via FTIR and FESEM confirms its chemical composition and morphology, while contact angle measurements assess its hydrophilicity. Mechanical strength tests ensure durability. Overall, the membrane demonstrates exceptional antimicrobial activity, pollutant removal efficiency, and mechanical robustness, highlighting the potential of integrating GO‐ZnO nanoparticles into PES membranes for water treatment. Highlights: Synthesis of innovative PES membrane embedded with GO‐ZnO for durable and fast energy‐saving filtration.Thorough Membrane Characterization and its various applications with mechanisms.Efficient Heavy Metal and Dye Removal, Inherent Antibacterial Prowess. [ABSTRACT FROM AUTHOR]

As an ideal transition metal oxide, Co3O4 is a P-type semiconductor with excellent electrical conductivity, non-toxicity and low cost. This work reports the successful construction of Co3O4 materials derived from metal-organic frameworks (MOFs) using a surfactant micelle template-solvothermal method. The modified electrodes are investigated for their ability to electrochemically detect Pb2+ and Cu2+ in aqueous environments. By adjusting the mass ratios of alkaline modifiers, the morphological microstructures of Co3O4-X exhibit a transition from distinctive microspheres composed of fiber stacks to rods. The results indicate that Co3O4-1(NH4F/CO(NH2)2 = 1:0) has a distinctive microsphere structure composed of stacked fibers, unlike the other two materials. Co3O4-1/GCE is used as the active material of the modified electrode, it shows the largest peak response currents to Pb2+ and Cu2+, and efficiently detects Pb2+ and Cu2+ in the aqueous environment individually and simultaneously. The linear response range of Co3O4-1/GCE for the simultaneous detection of Pb2+ and Cu2+ is 0.5–1.5 μM, with the limits of detection (LOD, S/N = 3) are 9.77 nM and 14.97 nM, respectively. The material exhibits a favorable electrochemical response, via a distinctive Co3O4-1 microsphere structure composed of stacked fibers. This structure enhances the number of active adsorption sites on the material, thereby facilitating the adsorption of heavy metal ions (HMIs). The presence of oxygen vacancies (OV) can also facilitate the adsorption of ions. The Co3O4-1/GCE electrode also exhibits excellent anti-interference ability, stability, and repeatability. This is of great practical significance for detecting Pb2+ and Cu2+ in real water samples and provides a new approach for developing high-performance metal oxide electrochemical sensors derived from MOFs. [ABSTRACT FROM AUTHOR]

In water samples from industrial regions, the presence of highly toxic and nonbiodegradable heavy metal ions (HMI) poses a significant threat to environmental quality. While analytical methods based on mercury electrodes are widely recognized for their high performance in the sensitive and selective quantification of various metal contaminants, the development of environmentally friendly strategies for the voltammetric determination of HMI remains a formidable challenge. In this study, we propose a material utilizing small-size chitosan (CTS) cobalt ferrite core–shell nanoparticles (CoFe2O4@CTS) as an electrode modifier for the simultaneous voltammetric determination of Pb-(II) and Cd-(II). The magnetic nanoparticles were synthesized using the solvothermal method and characterized using various techniques to explore their crystalline structure, magnetic properties, and chemical composition. The resulting electrochemical sensor, CoFe2O4@CTS/GCE, was generated through a one-step modification of a glassy carbon electrode (GCE). Utilizing differential pulse adsorptive stripping voltammetry (DPAdSV), our proposed sensor exhibited high sensitivity, with low limits of detection (LOD) values of 0.04 and 0.31 μg L–1 (Ed = −1.0 V; td = 90 s) for lead and cadmium, respectively. The exceptional sensitivity observed is indicative of interactions between HMI and CTS amine groups, leading to the effective preconcentration of the analytes. Furthermore, our sensor demonstrated excellent selectivity with an interference response below 8.93% for Pb-(II) and 20% for Cd-(II). Accuracy was evaluated using SRM 1643e (NIST). The application of green analytical chemistry (GAC) metrics resulted in a score of 0.91, highlighting the environmentally conscious aspects of our methodology. [ABSTRACT FROM AUTHOR]

Copper is a toxic water contaminant; its quantification below the maximum contaminant level (MCL) of 1.3 ppm by a sensitive, field-deployable sensor becomes critical. Here, the cobalt-doped zeolitic-imidazolate framework (Co/ZIF-8) nanomaterial was developed as a novel, highly selective, sensitive, and stable chemoreceptor as an alternative to ZIF-8 for Cu-(II) ion detection. A dip-type optical absorption Cu-(II) ion sensor was realized by an in situ deposition of Co/ZIF-8 nanoparticles over a highly sensitive U-bent fiber optic sensor (FOS) probe with a remarkable high evanescent wave-based absorption (EWA) sensitivity. The Co/ZIF-8 coated FOS works on the principle of attenuation of the light passing through the FOS by the Co/ZIF-8 nanoparticles due to EWA at 400 nm wavelength upon interaction with Cu-(II) ions and increases proportional to the Cu-(II) ions concentrations. The interaction of Cu-(II) ions with Co/ZIF-8 nanoparticles was extensively characterized with the help of UV–visible absorption, scanning electron microscopy and EDAX analysis, X-ray diffraction, and FTIR absorption spectral analysis. Cu-(II) ions were found to replace Zn-(II) in the Co/ZIF-8, forming Cu-imidazole complexes over and off the nanoparticles, leaving the surface rich with Co- and Cu-imidazole complexes and thereby altering the optical and morphological properties of the Co/ZIF-8. The sensor demonstrated an excellent dynamic range of 0.05–100 ppm with an experimental LoD of 50 ppb using a simple LED-photodetector-based setup, selectivity for Cu-(II) against 12 other potential interfering metal ions, and a shelf life of at least 3 months. The facile and scalable Co/ZIF-8 deposition process, simpler instrumentation, excellent sensor parameters, and good recovery rates with field water samples make this strategy highly promising for on-site environmental monitoring. [ABSTRACT FROM AUTHOR]

Removing heavy metal (loid) s (HMs) from contaminated soil in a nonselective, highly efficient, and energy‐free manner is a major global challenge. Herein, this work synthesizes and assembles a biomimetic materials system (BMS) consisting of an artificial plant, a hemispherical glass cover, and a reflective plate, capable of non‐selective and highly efficient remediation of soil contaminated by various HM ions under sunlight. Specifically, a water cycle is driven to establish between the soil, artificial plant, and atmosphere by solar energy in the BMS, which induced water‐soluble HM ions to enrich and precipitate at the top edge of the artificial plant. The formed HM precipitate is easily removed, contributing to the extremely strong recyclability of BMS. This system has significant advantages in terms of soil properties, contamination characteristics, energy consumption, processing time, and removal amount over other representative remediation methods, demonstrating its great potential for practical application in the remediation of various HM‐contaminated soils. [ABSTRACT FROM AUTHOR]

With increasing industrialization, the pollution of water resources by heavy metal ions has become an increasingly serious problem. In this study, dopamine-modified silk fibroin powder was used for the adsorption of heavy metal ions in water. A series of tests, including L value, visible light absorption, X-ray photoelectron spectroscopy, scanning electron microscopy, and particle size analysis, were performed on the modified silk fibroin powder. The results showed that the adsorption of heavy metal ions was most effective at pH = 6, and the adsorption effects of Cu2+, Cd2+, and Ni2+ were 115.8, 60, and 60 mg/g, respectively. The adsorption of Cu2+ by the modified silk fibroin powder conformed to Langmuir-type adsorption isotherm model and pseudo-second-order kinetic model. This study provides new insight for the application of natural silk fibroin powder for the adsorption of heavy metal ions in water. [ABSTRACT FROM AUTHOR]

Referring to the oil and industrial development, contamination of water streams and soil by heavy metals becomes severe issue. Biochar has consider as cheap and ecofriendly adsorbent for heavy metal ions removal. As well as, the development and modification of biochar has been a center point of many researches. In this study it has been suggested to develop novel biochar from Peganum harmala seed precursor and evaluate the heavy metal ions adsorption performance. Chemical activation process was adopted to prepare biochar with different concentrations (20%, 30%, and 40%) of phosphoric acid followed by pyrolysis in a laboratory horizontally tube furnace underneath an N2 blanket at 600 ℃ for 3 hours. The physical and chemical properties of biochar have been assessed using Energy Dispersive X-ray Spectroscopy, X-ray diffraction, Scanning Electron Microscopy, pore structure, and Fouriertransform analysis. The prepared biochar was investigated to absorb three different heavy metal ions Fe(III), Ni(II) and Pb(II) from an aqueous solution under varied conditions. Heavy metal concentration (20-100 ppm), adsorbent dosage (0.25-0.75) g/L, contact duration (0-560 min), and solution pH (2-9) were examined. The results show that the largest BET surface area (691.58 m²/g) was achieved with activation conversation of 40% H3PO4 and 600 ℃ for 3 hours, compared to other samples. The maximum adsorption capacities were 113.4096, 112.3355, 180.3478 mg/g for Fe(III), Ni(II) and Pb(II) respectively. Finally, Freundlich isotherm model shows better describe the adsorption equilibrium data, while adsorption kinetic data shows the pseudo-first-order model fits more with Fe(III) ions which shows that chemisorption was controlled in the adsorption process, additionally the pseudo-first-order model fits more with Pb(II) and Ni(II) ions this mean the physisorption has been controlled in the adsorption process. [ABSTRACT FROM AUTHOR]

This study addresses the urgent issue of water pollution caused by iron (Fe) and manganese (Mn) ions. It introduces an innovative approach using graphene oxide (GO) and GO-decorated polyethersulphone (PES) membranes to efficiently remove these ions from contaminated water. The process involves integrating GO into PES membranes to enhance their adsorption capacity. Characterization techniques, including scanning electron microscopy, Fourier-transform infrared, and contact angle measurements, were used to assess structural and surface properties. The modified membranes demonstrated significantly improved adsorption compared to pristine PES. Notably, they achieved over 94% removal of Mn2+ and 93.6% of Fe2+ in the first filtration cycle for water with an initial concentration of 100 ppm. Continuous filtration for up to five cycles maintained removal rates above 60%. This research advances water purification materials, offering a promising solution for heavy metal ion removal. GO-decorated PES membranes may find application in large-scale water treatment, addressing environmental and public health concerns. [ABSTRACT FROM AUTHOR]

Thiophene, a heterocyclic compound characterized by a five-membered ring comprising four carbon atoms and one sulfur atom, has garnered significant attention in recent research due to its versatile applications in medicinal and chemosensing fields. Thiophene derivatives formed complexes with various transition metals. These complexes exhibit promising anti-inflammatory, anticancer, antibacterial, antifungal and other biological properties. Certainly, the complexation phenomenon involving thiophene derivatives can be effectively used for the recognition of various cations. Thiophene-based compounds can act as selective ligands, forming stable complexes with specific heavy metal ions. This property has significant implications for environmental monitoring, industrial safety, and public health, as the presence of heavy metal ions beyond permissible levels can lead to detrimental effects. This paper explored the versatile applications of thiophene derivatives, investigating their chemosensing potential for the determination of various metal ions covering the period from 2018 to 2024. Thiophene derivatives serve as versatile ligands for metal ions and exhibit fluorescence and colorimetric changes for selective detection of metal ions. Additionally, this study also explores the anticancer efficacy demonstrated by metal complexes derived from thiophene, with a specific emphasis on those formed with platinum-group metals (Ir(III), Ru(II), Ru(III), Rh, Os(II), Os(IV), Pd(II), Pt(II)). [ABSTRACT FROM AUTHOR]

Presently, the main cause of pollution of natural water resources is heavy metal ions. The removal of metal ions such as nickel (Ni2+) and cadmium (Cd2+) has been given considerable attention due to their health and environmental risks. In this regard, for wastewater treatment containing heavy metal ions, graphene oxide (GO) nanocomposites with metal oxide nanoparticles (NPs) attained significant importance. In this study, graphene oxide stacked with copper oxide nanocomposites (GO/CuO-NCs) were synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and atomic force microscopy (AFM) analytical procedures. The prepared GO/CuO-NCs were applied for the removal of Ni2+ and Cd2+ ions from a binary metal ion system in batch and continuous experiments. The obtained results revealed that GO/CuO-NCs exhibited the highest removal efficiencies of Ni2+ (89.60% ± 2.12%) and Cd2+ (97.10% ± 1.91%) at the optimum values of pH: 8, dose: 0.25 g, contact time: 60 min, and at 50 ppm initial metal ion concentration in a batch study. However, 4mL/min flow rate, 50 ppm initial concentration, and 2 cm bed height were proved to be the suitable conditions for metal ion adsorption in the column study. The kinetic adsorption data exhibited the best fitting with the pseudo- second-order model. The adsorption isotherm provided the best-fitting data in the Langmuir isotherm model. This study suggested that the GO/CuO nanocomposites have proved to be efficient adsorbents for Ni2+ and Cd2+ ions from a binary metal system. [ABSTRACT FROM AUTHOR]

The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions. [ABSTRACT FROM AUTHOR]

The simultaneous adsorption of Cu(II) and dyes (MB and MO) on LDH@GO-SH was investigated in single, MB–Cu, and MO–Cu binary systems. The coexistence of dye enhanced the adsorption of Cu(II) by LDH@GO-SH, while the presence of Cu(II) differently affected the adsorption of MB and MO. The adsorption capacity of MO remarkably increased due to the presence of Cu(II). The presence of Cu(II) had a negative effect on MB adsorption for lower MB initial concentration systems (2–10 mg·L−1), while it had a positive effect for higher MB concentration systems (25 mg·L−1 and 50 mg·L−1). The adsorption of Cu(II) in binary systems was satisfactorily fitted by a Langmuir model and pseudo-first-order kinetic model. Surface complex interaction was supposed to be a potential mechanism for the enhancement of Cu(II) adsorption in both MB–Cu and MO–Cu binary systems. The electrostatic interactions between MO and Cu(II) were another reason for the enhancement of Cu(II) adsorption in the MO–Cu binary system. LDH@GO-SH maintained a high adsorption capacity after three adsorption–desorption cycles, indicating that it can be repeatedly used for the treatment of heavy-metal-ion-containing wastewater. [ABSTRACT FROM AUTHOR]

Background. Heavy and toxic metals pose a threat to human health. Over the last century, with the growth of industrial activity, many water resources have been polluted with heavy and toxic metals. At the same time, the number of scientific studies has increased exponentially. Purpose. The aim of this paper is to interpret the data of Scopus scientific database and to study the works of scientists who have conducted research in this field using VOS-Viewer software. Methodology. The research was carried out bibliometric analysis to evaluate research trends and proposed methods for the removal of heavy metals from aqueous media. Using VOS-Viewer software, 500 articles with the highest citations were selected. Originality. For the first time, the most cited studies on removal of heavy metals from aquatic environments for the period from 2000 to 2023 were reviewed. Findings. According to bibliometric analysis, the number of articles increased by 1500 % between 2000 and 2023. The results showed that China, India, USA and Iran published the most cited articles on this topic. Using the VOS-Viewer programme, 500 articles with the highest citations were selected. China occupies the first place by a large margin. [ABSTRACT FROM AUTHOR]

With the rapid development of industry, the discharge of heavy metal-containing wastewater poses a significant threat to aquatic and terrestrial environments as well as human health. This paper provides a brief introduction to the basic principles of ion-imprinted polymer preparation and focuses on the interaction between template ions and functional monomers. We summarized the current research status on typical heavy metal ions, such as Cu(II), Ni(II), Cd(II), Hg(II), Pb(II), and Cr(VI), as well as metalloid metal ions of the As and Sb classes. Furthermore, it discusses recent advances in multi-ion-imprinted polymers. Finally, the paper addresses the challenges faced by ion-imprinted technology and explores its prospects for application. [ABSTRACT FROM AUTHOR]

The colorimetric detection of metal ions has witnessed a surge in advancements, with nanostructured fibers emerging as a powerful platform for environmental monitoring and remediation applications. These fibers offer several advantages, including a high surface area, enhanced sensitivity and selectivity, non-intrusive analysis, rapid response times, robustness under harsh conditions, and user-friendly handling. This unique combination makes them particularly suitable for visible eye detection of metal ions in remote or challenging environments. This review provides a concise overview of recent developments in nanostructured fibers, and their cutting-edge fabrication methods, for the colorimetric-based detection of various heavy metal ions in real-time samples. By exploiting the unique properties of these fibers, colorimetric detection offers a promising and cost-effective approach for heavy metal ion determination. This review delves into the design principles, functionalization strategies, and detection mechanisms employed in these innovative sensors. We highlight the potential of nanostructured fibers as a well-established and efficient platform for the colorimetric detection of heavy metals, paving the way for more sustainable and accessible environmental monitoring solutions. [ABSTRACT FROM AUTHOR]