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Context: The heavy metal ions are the typical carcinogenic agents. Up to now, the interaction mechanism of toxic metal ions with the biomolecules such as carbohyrate have not been elucidated and reported in the detail. In this research work, the adjacent dissociation Gibbs energy (EAB) of M3+(H2O)5(R-OH) complexes depended significantly on the molecular volume of primary alcohols and the inductive effects of substituent R in primary alcohols (R = CH3, CH3CH2, CH3CH2CH2, CH3CH2CH2CH2, Cl-CH2, F-CH2) as well as the length of linear cellulose. The affinity of M3+(H2O)5 ions with the sixth water molecule in gas phase reduced in the order as follows: Fe3+ > Ru3+ > Os3+, which were determined by the EAB values and bond lengths of M–O. The water solvent made the EAB values of Fe3+(H2O)6 ions and Fe3+(H2O)5(CH3OH) ions changed completely in the case of the polarizable continuum model, while the Onsager model gave the good agreement with the gas phase model. Methods: The nature of interaction between hydrated Fe3+(H2O)5 ion and the hydroxy groups of primary alcohols were investigated using density functional theory method at the B3LYP/6–311 + G** level, the PBEPBE/6–311 + G** level. The influence of water solvent was evaluated using the Onsager model and the polarizable continuum model. The two-layer ONIOM approach and the local softness analysis were employed for the hydroxy groups of linear cellulose at the B3LYP/6–311 + G**:HF/6-31G* level. The affinity of M3+(H2O)5 ions (M = Fe, Ru, and Os) with the sixth water molecule were probed at the B3LYP/QZVPP/6–311 + G** level (QZVPP basis set for the metal atoms). [ABSTRACT FROM AUTHOR]

In-situ modification of cellulose fibers with titania nanoparticles (TiO2 NPs) (TiO2 NPs-cellulose) was carried out via the sol–gel process using titania sol and fibers of cellulose. Cellulose fibers were extracted from wheat straw, an agricultural waste material, whereas titania sol was prepared from titanium(IV) acetoximate, [Ti{ONC(CH3)2}4]. The synthesized TiO2 NPs-cellulose composite was characterized by FT-IR, SEM–EDX, and XRD analyses. The obtained results exposed that TiO2 NPs were homogeneously dispersed over the surface of cellulose fibers. A study was conducted to compare the photocatalytic activities of TiO2 NPs-cellulose composite and TiO2 NPs towards the degradation of methylene blue and methyl orange dyes under sunlight, and it was observed that the photo-degradation of methylene blue (99.99%) and methyl orange (80.73%) within 160 min is higher in the presence of TiO2 NPs-cellulose composite than TiO2 NPs. The adsorption capabilities of TiO2 NPs-cellulose composite towards Pb2+, Cd2+, and Cr3+ toxic metal ions were also examined, and it was found 44.73 mg. g−1 (89.46%), 38.82 mg. g−1 (77.65%), and 4.42 mg. g−1 (8.85%), respectively. Removal of pollutants from textile industrial effluent were also investigated using TiO2 NPs-cellulose composite under sun light. The results obtained were very promising which shows potential of TiO2 NPs-cellulose composite as an efficient photocatalyst and absorbent for real time applications. [ABSTRACT FROM AUTHOR]

Our study was conducted between January and September 2023, and aimed to evaluate the presence of toxic heavy metals in vegetables cultivated using effluent and sewage water in Jodhpur city. Eight vegetable samples were obtained from four distinct locations, and the concentrations of seven harmful heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, and Fe) were examined. The initial analysis employed ICP-MS, followed by determining the concentration of heavy metals in the vegetables through atomic absorption spectrometry (AAS). The Heavy Metal Pollution Index (HPI) was computed to assess pollution levels at each site. Comparative analysis of vegetable samples using both ICP-MS and AAS indicated elevated levels of lead, cadmium, and chromium pollution in vegetables from all four sites. Calculations further confirmed the contamination of the sites with toxic heavy metals. The order of metal concentration based on allowable limits was Fe>Cd>Cr>Pb>Ni>Zn>Cu. The overall order of observed heavy metal concentrations site-wise was site 4 > site 3 > site 2 > site 1. Many samples were obtained from local vendors near residential areas and community markets frequented by the public. This highlights a crucial issue of heavy metal toxicity exposure to the general population, emphasizing urgent government action, including essential restrictions and measures, to address this pressing problem. [ABSTRACT FROM AUTHOR]

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A high photoluminescence (PL)-based nanosensor based on graphene quantum dots (GQDs) is fabricated for the detection of toxic ions Ag+, Ce2+, Cd2+, Cu2+, Cr2+, Pb2+, Sn2+, and Fe3+, p-nitrophenol, and thioacetamide in water. The quenching of PL spectra indicates that the complex of GQDs/Fe(III) shows a high florescent quenching efficiency (~ 75%) toward the hydrophobic surface of the GQDs. The limit of detection for Fe(III) concentration 40 ± 2 nM, with high linearity and sensitivity. The change of the zeta potential value proves the attachment of Fe (III) ions to the surface of the GQDs. The GQDs/Fe(III) complexes can be utilized as a turn-OFF or turn-ON type fluorescence probe for p-nitrophenol (turn-OFF) detection with 5 ± 1 pM concentration and the sulfur (turn-ON) detection with 7.6 ± 1 pM. The proposed method is facile, sensitive and fast, which makes it ideal for nanosensors to detect water quality of rivers, ponds, or industrial wastes. [ABSTRACT FROM AUTHOR]

In electrodialysis, an ion exchange membrane removes unwanted ions from wastewater and toxic metal ions from effluents. Montmorillonite-based modified "polyethersulfone membranes" have been studied as a potential small-scale electrodialysis approach for removing ions from wastewater. The study featured several steps, including solid polymerization, electrolyte balance, and removal of each component from the water. The study used three distinct “cation-exchange membranes (CEM)" types. The selected water body was diluted 100 times before being added to the electrodialysis cell in amounts of the center, cathodic, and anodic chambers, each containing 55, 30, and 40 mL. The initial pH for the real solutions of the water body was 7.16 at 25°C. Compared to "Sulfonated poly arylene ether sulfone (S-PESOS)" (23.23%) and Nafion® (35.34%), "hexamethylenediamine (HEXCl)" stands out as the only cross-linked material with significantly high-water content. When the membrane water content is too high, the membrane may lose its mechanical strength and cannot provide enough ionic conductivity. The semi-empirical model's parameters were estimated to simulate the elimination of Na+, K+, Ca2+, and Mg2+ by three membranes. HEXCl and S-PESOS were electrodialyzed and used to treat the serial dilution from the water with cationics. The removal rate gradually rose after the electrodialysis started.

In acid soil, aluminum (Al) toxicity is one of the main factors limiting agricultural output. As is known to all, the cell wall is the first line of defense against metals that serves as a significant target of Al toxicity and also is crucial for Al detoxification. However, nothing is known about how this process is transcriptionally regulated. Here, we describe recent findings to understand the role of two kinds of transcription factors in regulating the cell wall composition and modification in response to Al stress in Arabidopsis thaliana. ANAC017 encodes a NAM, ATAF1/2, and cup-shaped cotyledon 2 (NAC) transcription factor, loss function of ANAC017 enhanced Al tolerance with the decreased Al content and xyloglucan content in the cell wall. Next, we characterized one xyloglucan endotransglucosylase/hydrolase (XTH), XTH31, which is previously reported to participate in Al stress, acted downstream of ANAC017 to regulate Al tolerance in Arabidopsis. In addition, we also identified MYB103, an R2R3-type transcription factor. MYB103 disruption caused Al sensitivity, and myb103 mutants’ xyloglucan had a high O-acetylation level. Additionally, it was discovered that TRICHOME BIREFRINGENCE-LIKE27 (TBL27), which is in charge of xyloglucan’s O-acetylation, functions downstream of MYB103 through the direct binding of the MYB103 to the promoter of the TBL27 to influence Arabidopsis’s sensitivity to Al. In summary, our research showed that two distinct molecular modules modulate Arabidopsis cell wall composition and modification to positively influence Al resistance.

In this study the porous composites, in-situ TiO2-g-C3N4 (in-situ TiO2-g-CN), was fabricated by in-situ generation of TiO2 from titanium tetra-oximate during thermal polymerisation of urea into gC3N4. For comparison, TiO2-g-C3N4 composite (TiO2-g-CN) and g-C3N4 (gCN) were also prepared by decomposition of urea in the presence and absence of TiO2 nanoparticles (NPs), respectively. The synthesised composites were characterised by FT-IR, SEM-EDX, TGA, and XRD analyses. The analyses of the samples revealed that the particle size of the composites decreases with the addition of TiO2 precursor, titanium tetra-oximate, during g-C3N4 Synthesis. A comparative study has been conducted on the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in the presence of in-situ TiO2-g-CN, TiO2-g-CN, and gCN under the solar spectrum. In the presence of in-situ TiO2-g-CN, 99.7% degradation of MB and 68.4% degradation of MO was observed within 100 min, and it is superior as compared to TiO2-g-CN and gCN. [ABSTRACT FROM AUTHOR]

In Mach–Zehnder interferometer of photonic crystal fiber based on surface Plasmon resonance (SPR), the sensing is made by fusing a Photonic Crystal Fiber between two multi-mode fibers (MMF). The PCF is then tapered down to 74.6 μm using custom-made tapering equipment, which considerably improves its ambient index sensitivity. The sensor has a sensitivity of 10 μm/RIU, a Signal-to-Noise Ratio (0.209), a figure of merit (FOM) of (90.9), and a resolution of (1 × 10−4). [ABSTRACT FROM AUTHOR]

The adsorptive performance of mesoporous silica-based materials towards inorganic (metal ions) and organic (dyes) water pollutants was investigated. Mesoporous silica materials with different particle size, surface area and pore volume were prepared and tailored with different functional groups. These materials were then characterised by solid-state techniques, namely vibrational spectroscopy, elemental analysis, scanning electron microscopy and nitrogen adsorption–desorption isotherms, allowing the successful preparation and structural modifications of the materials to be confirmed. The influence of the physicochemical properties of the adsorbents towards the removal of metal ions (Ni2+, Cu2+ and Fe3+) and organic dyes (methylene blue and methyl green) from aqueous solutions was also investigated. The results reveal that the exceptionally high surface area and suitable ζ-potential of the nanosized mesoporous silica nanoparticles (MSNPs) seem to favour the adsorptive capacity of the material for both types of water pollutants. Kinetic studies were performed for the adsorption of organic dyes by MSNPs and large-pore mesoporous silica (LPMS), suggesting that the process follows a pseudo-second-order model. The recyclability along consecutive adsorption cycles and the stability of the adsorbents after use were also investigated, showing that the material can be reused. Current results show the potentialities of novel silica-based material as a suitable adsorbent to remove pollutants from aquatic matrices with an applicability to reduce water pollution. [ABSTRACT FROM AUTHOR]

This work aimed to synthesize the aluminium oxide nanoparticles using Ixoro coccinea leaf extract. Furthermore, the synthesized Ixoro coccinea aluminium oxide nanoparticles (I–Al 2 O 3 -NPs) and nanocomposites (I–Al 2 O 3 -NC), including them as the fillers in a chitosan matrix were characterized, and I–Al 2 O 3 -NC was applied to remove the toxic metals (TMs) including Cd, Ni, and Pb from water. Optimization of different batch experimental adsorption parameters (pH, concentration of TMs, dose of I–Al 2 O 3 -NC, temperature, and time of contact) was done to check the feasibility of I–Al 2 O 3 -NC for maximum removal of TMs from water. The extreme adsorption capacities using nanocomposites for Cd, Ni, and Pb were 66.0, 60.0, and 66.4 mg g−1, respectively. The I–Al 2 O 3 -NC followed the Freundlich isotherm model for removing Cd and Ni while showing the monolayer surface coverage for the removal of Pb. For this process, the best-fitted kinetic model was the pseudo-second-order equation. The enthalpy, entropy, and free energy of metal ion adsorption, among other parameters of thermodynamics, were estimated. The process was found to be exothermic, advantageous, and spontaneous. Kinetic studies show that intra-particle diffusion is essential for eliminating TMs. In addition, I–Al 2 O 3 -NC was applied for the adsorption of TMs from surface water and determined to be effective in removing these contaminants up to an acceptable drinking water standard. Regeneration of adsorbent suggested that green synthesized I–Al 2 O 3 -NC may be an active tool for removing Cd, Ni, and Pb ions from contaminated water. [ABSTRACT FROM AUTHOR]

This review summarises the progress that has been made in silver nanoparticles (NPs) based colorimetric quantification of toxic metal ions in the water and environmental samples. Due to the anthropogenic activities, contamination of metallic ions in the ecosystem rapidly increased, inflicting serious illness to human and aquatic life. Consequently, to monitor the presence of metallic ions in the environment and waterbodies a simple and rapid assay is urgently needed. Recently, silver NPs based colorimetric assay has received tremendous interest in simple and fast determination of toxic metal ions. Localised surface plasmon resonance (LSPR) is a vital optical property of silver NPs exhibiting different colours in the visible vicinity of the electromagnetic spectrum depending on their shape, size and aggregation conditions. LSPR provides an excellent platform for the development of an ingenious, economical, visual readout assay for on-site monitoring of various analytes. Here in this study, we critically summarised the recent progress that has been made in the silver NPs based colorimetric assay for recognition of toxic metal ions. Also, the mechanism and future applications of each method were discussed. [ABSTRACT FROM AUTHOR]

Individual titanium and calcium–magnesium phosphates are widely known as effective sorbents. The sorption processes on these phosphates are based on different mechanisms. The sorption efficiency towards different cations depends on the phase composition of the sorbent. Composite materials with various ratio Ti:(Ca+Mg) have been synthesized. The sorption properties of samples obtained towards Cs+, Sr2+, Co2+, Cd2+, Zn2+, Cu2+, and Pb2+ have been studied to establish the effect of sorbent composition on metal removal. The adsorption isotherms have been analyzed using the Langmuir, Freundlich, and Redlich–Peterson models. The composition of sorbents has no effect on the level of removal of readily hydrolyzable Pb2+ and Cu2+ cations. Removal of lead occurs preferentially via the precipitation of metal phosphates and hydroxides. Copper precipitates as hydroxide in case of a high share of Ca-Mg phosphates in the composite sorbent. The removal of cesium proceeds according to the ion exchange mechanism only. For Cd2+, Co2+, Sr2+, and Zn2+ cations, the sorption efficiency on the composite materials synthesized is found to increase with the increase in titanium phosphate's share in the sample. All composite sorbents synthesized demonstrated a considerable increase in the level of purification of solutions studied compared with individual Ti and Ca-Mg phosphates due to the synergism of the components. [ABSTRACT FROM AUTHOR]

Selenium‐doped Graphite (Se‐DG) has been used for electrochemical (EC) sensing and adsorption of poisonous Hg(II) and Cd(II) ions which can produce acute toxic effects on various organs. Hence, detection and efficient removal of both the metal ions from aquatic sources are very crucial. Herein, square wave anodic stripping voltammetry (SWASV) method was applied for EC detection using Se‐DG coated glassy carbon electrode (GCE) as a working electrode. Corresponding EC responses were observed due to the interaction between the sensing surface and the analytes. Elemental Se (Se0) present in Se‐DG played a crucial role in EC sensing. The limit of detection (LoD) of Hg(II) and Cd(II) were observed to be 4.3 ppb and 1.9 ppb respectively. The limit of quantification (LoQ) were found as ppb 14.3 ppb and 6.3 ppb respectively. Batch method was carried out for adsorption of the same carcinogenic metal ions on the Se‐DG surface. Ultra‐trace concentration of the metal ions was determined in Inductively Coupled Plasma Mass Spectrometry (ICP‐MS). Maximum adsorption capacity (QM) for Hg(II) and Cd(II) were found 210.81 mg g−1 and 205.53 mg g−1 respectively from Langmuir fit. The adsorption process was spontaneous and endothermic and it could be better fitted by a pseudo‐second order rate law, suggesting a chemisorption over physisorption. X‐Ray Photoelectron spectroscopy (XPS) was performed to investigate the binding interaction of different functionalities present in Se‐DG with metal ions. [ABSTRACT FROM AUTHOR]

• A polarization exfoliation (PE) method is developed to accelerate the exfoliation of the Ti 3 AlC 2. • Double layer forces enhance the exfoliation efficiency with the etchants under the electric polarization. • The core@shell polyvinyltetrazole@MXene/Fe 3 O 4 (PVT@ MXFe) is synthesized as adsorbents. • The PVT@MXFe exhibits an excellent performance of adsorption of toxic metal ions. • The reuse of PVT@MXFe with hyperthermia by coil-wrapped tube can reduce the secondary pollution. The conventional etching method for exfoliating MXene using hydrofluoric acid solution is time-consuming and inefficient in productivity. A double layer force is generated through polarization among the heterogeneous layers of MXene due to their different dielectric properties. The exfoliated MXene by the polarization method in an acidic solution was employed to synthesize magnetic MXene (MXFe) with Fe 3 O 4 nanoparticles. MXFe was coated on polyacrylonitrile microspheres (PANs) as precursors (PAN@MXFe) by Pickering emulsion polymerization. The core@shell polyvinyltetrazole@MXFe (PVT@MXFe) was obtained as the adsorbent after subsequent cyano-tetrazole conversion of PAN@MFs for the removal of toxic metal ions. The maximum adsorption capacities of Hg(II) on the MXFe and PVT@MXFe coating 2 wt% of MXFe were 579 and 324 mg/g, respectively, indicating the high use efficiency of MXFe. At 8.5 kHz of high frequency, hyperthermia occurs on the PVT@MXFe, facilitating the desorption of the toxic metal ions from the adsorbents. Compared with reuse using an acidic solution, the PVT@MXFe can be reused repeatedly 10 times without obvious damage under the AMF. Our proposed polarization exfoliation method not only provides a novel methodology to exfoliate MXene but also develops an ideal adsorbent for universal adsorption, simple separation, stable regeneration, and low secondary pollution. [ABSTRACT FROM AUTHOR]

Industrial effluents contain many toxic heavy metal ions and they are the main source for water pollution. Different methods are adopted for the purification of infected water. Among the diverse techniques, ion exchange method using conducting polymer based ion exchange material has several advantages over than other traditional methods like adsorption. In the present work, polyaniline/Ti(IV) iodosulphosalicylate (PANI/Ti(IV) ISS) a conducting polymer based ion exchange material was synthesised by sol–gel method via the mixing of inorganic precipitate of Titanium(IV) iodosulphosalicylate (Ti(IV) ISS) into the matrix of organic conducting polymer polyaniline (PANI). The PANI/Ti(IV) ISS conducting polymer based ion exchange material was well characterised using techniques such as Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction studies (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray (EDAX), transmission electron microscopy (TEM) and thermal (TGA/DTG) analysis. The ion exchange capacity, elution behaviour, elution time and pH titration studies were also investigated. Furthermore a.c. electrical conductivity studies and impedance spectrum of this material also carried out. Some binary separations of heavy metal ions were achieved by the column packed by PANI/Ti(IV) ISS conducting polymer based ion exchange material. PANI/Ti(IV) ISS conducting polymer based ion exchange material showed an ion exchange capacity values (IEC) for Li+, Na+ and K+ which were found to be 1.98, 2.49 and 2.68 meq/g respectively. Based on the distribution coefficient values, PANI/Ti(IV) ISS conducting polymer based ion exchange material was found to be selective for the removal of Pb2+ ion, and the Kd value of 493.02 mL/g for Pb2+ ion from a mixture of toxic metal ions. Pb(II)ion from a synthetic mixture can be removed quantitatively by using PANI/Ti(IV) ISS and it is a promising candidate for ion selective electrode membrane studies. [ABSTRACT FROM AUTHOR]

The development of functional materials from food waste sources and minerals is currently of high importance. In the present work, polylactic acid (PLA)/silica composites were prepared by in situ ring-opening polymerizations of L-lactide onto the surface of pristine (Silochrom) and amine-functionalized (Silochrom-NH2) silica. The characteristics of the ring-opening polymerization onto the surface of modified and unmodified silica were identified and discussed. Fourier transform infrared spectroscopy was used to confirm the polymerization of lactide onto the silica surface, and thermogravimetric analysis determined that PLA constituted 5.9% and 7.5% of the composite mass for Silochrom/PLA and Silochrom-NH2/PLA, respectively. The sorption properties of the composites with respect to Pb(II), Co(II), and Cu(II) ions were investigated, and the effect of contact time, initial metal ion concentration, and initial pH were evaluated. Silochrom-NH2/PLA composites were found to have a higher adsorption capacity than Silochrom/PLA for all chosen ions, with the highest adsorption value occurring for Pb2+ at 1.5 mmol/g (90% removal efficiency). The composites showed the highest performance in the neutral or near-neutral pH (created by distilled water or buffer pH 6.86) during the first 15 min of phase contact. The equilibrium characteristics of adsorption were found to follow the Langmuir isotherm model rather than the Freundlich and Temkin models. Perspective applications for these PLA/silicas include remediation of industrial wastewater or leaching solutions from spent lead-acid and Li-ion batteries. [ABSTRACT FROM AUTHOR]

Glycylglycine functionalized water-dispersible gold nanoparticles (AuNPs) were prepared and characterized on the basis of ultraviolet and visible spectroscopy (UV-vis), Fourier transform infrared (FTIR), dynamic light scattering (DLS), transmission electron microscope (TEM) and energy dispersive X-ray (EDX) analysis. The AuNPs exhibited a strong SPR band at 522 nm, which after functionalization with glycylglycine, appeared at 525 nm. This SPR band of the functionalized nanoparticles is used as a tool for the detection of toxic metal ions in water. A large number of metal ions were tested, among which Hg2+, Pb2+, and Cr3+ exhibited distinct colour change, detectable with bare eye, and substantial UV-vis spectral change. TEM images and EDX analysis suggested that the colour change is due to metal-induced aggregation of the functionalized nanoparticles due to inter-particle plasmon coupling. The aggregation, which resulted in an increase in particle size, is further confirmed by DLS measurement. A mechanism of metal-induced aggregation is also proposed. The present study is an example of a simple methodology to prepare water-dispersible functionalized nanoparticle for colorimetric detection of toxic heavy metal ions such as Cr3+, Pb2+, and Hg2+ with high sensitivity. Synopsis Glycylglycine functionalized water dispersible gold nanoaprticles were prepared, characterized and its metal-ion sensing property was evaluated with the aid of spectroscopic, microscopic and energy dispersive X-ray analysis. These nanoparticles detect Hg2+, Pb2+ and Cr3+ with colour change due to inter particle plasmon coupling because of metal-induced aggregation of the nanoparticles. [ABSTRACT FROM AUTHOR]

The adsorptive performance of mesoporous silica-based materials towards inorganic (metal ions) and organic (dyes) water pollutants was investigated. Mesoporous silica materials with different particle size, surface area and pore volume were prepared and tailored with different functional groups. These materials were then characterised by solid-state techniques, namely vibrational spectroscopy, elemental analysis, scanning electron microscopy and nitrogen adsorption–desorption isotherms, allowing the successful preparation and structural modifications of the materials to be confirmed. The influence of the physicochemical properties of the adsorbents towards the removal of metal ions (Ni2+, Cu2+ and Fe3+) and organic dyes (methylene blue and methyl green) from aqueous solutions was also investigated. The results reveal that the exceptionally high surface area and suitable ζ-potential of the nanosized mesoporous silica nanoparticles (MSNPs) seem to favour the adsorptive capacity of the material for both types of water pollutants. Kinetic studies were performed for the adsorption of organic dyes by MSNPs and large-pore mesoporous silica (LPMS), suggesting that the process follows a pseudo-second-order model. The recyclability along consecutive adsorption cycles and the stability of the adsorbents after use were also investigated, showing that the material can be reused. Current results show the potentialities of novel silica-based material as a suitable adsorbent to remove pollutants from aquatic matrices with an applicability to reduce water pollution.

A copolymer of poly(BuMA–co–EDMA) modified with C-tetra(nonyl)calix[4]resorcinarene was obtained via the impregnation method. The formation of the modified copolymer was confirmed and investigated using various techniques; in this way, the presence of calix[4]resorcinarene was confirmed by FT-IR spectroscopy and by high resolution transmission electron microscopy. The modified copolymer was used for the removal of highly toxic cations (Pb2+, Hg2+, and Cd2+) from aqueous solutions. To perform the removal, we used the batch sorption technique and the effects of time of contact, pH, and volume of sample on the effective sorption were determined. The best results were observed for Pb2+ extraction, which was comparatively more efficient. Adsorption–desorption experiments revealed that the modified copolymer could be used for several cycles without significant loss of adsorption capacity. Finally, the results showed that the modified copolymer application is highly efficient for the removal of lead ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Large‐scale usage of agrochemicals in the soils found in the highland regions of Western Ghats, Kerala, India, is often equated with soil contamination and land degradation. Kerala, being the second largest cardamom producer in the world, unscrupulously uses agrochemicals in cardamom plantations, which release high levels of potentially toxic elements (PTEs) into the soils. Here, the PTEs from 25 agricultural soils were taken from high‐range mountain landscapes of southern Western Ghats, India, to evaluate the sources and levels of soil pollution. The data revealed that the soil samples from the study area were contaminated with PTEs, and their observed average concentration was in the order of Ba > Zr > V > Cr > Ni > Sr > Zn > Cu. Geochemical maps were generated to understand the hotspots in trace element contamination. Correlation matrix and factor analysis were applied to apportion the sources of PTEs. Enrichment factor and geochemical accumulation index indicated slight enrichment in all the elements analyzed. The contamination factor varied from 15.41 to 25.58, signifying a considerable degree of contamination in the area with respect to soil pollution. The pollution load index (PLI) values ranged from 0.97 to 1.99, indicating progressive deterioration of the sites. High degree of contamination and PLI values implied that not only geogenic sources, but also intensified anthropogenic activities may contribute to trace element accumulation. This work provides insights on the accumulation of PTEs in the soils, which will pose a great health risk to the local population through the consumption of various agricultural products cultivated in the area. [ABSTRACT FROM AUTHOR]

The work reported here exploits the extraordinary features of graphene nanoribbons (GNR) and well‐known conductive polypyrrole (PPy) polymer to develop a very good electrochemically active composite for sensing metal ions. A strong hydrogen bond and π‐π interaction between the two components facilitates an enhanced conductive 3D network that has been used to design and fabricate an electrochemical sensor for selective and sensitive determination of Pb2+ ions by differential pulse voltammetry (DPV). The probe has been further extended to simultaneously detect Zn2+, Cd2+, As2+, Cu2+, Pb2+, Fe2+ and Hg2+ ions. Moreover, the larger effective surface area, higher porosity and chelating groups of composite promotes better adsorption‐stripping process of Pb2+ ions, leading to a high detection limit of 0.03 nM with a sensitivity of 0.7557 μA μM−1cm−2. This study is extended to detect heavy metal ions in lake water samples, demonstrating promising applications in real time (environmental) samples, and the study shows a deviation of ≈10 %, when validated with atomic absorption spectroscopy studies. [ABSTRACT FROM AUTHOR]

[Display omitted] A rapid, cost-effective and accurate detection of heavy metal ions is crucial for human health monitoring and environmental protection. Surface-enhanced Raman spectroscopy (SERS) has become a reliable method due to its outstanding performance for the identification of contaminants. In this paper, silver phosphate microcubes (Ag 3 PO 4) were fabricated using two different precipitation methods for ultrasensitive SERS detection of heavy metal ions. The use of an organic linker (BPy) with Ag 3 PO 4 enabled the immobilization of Hg2+ and Pb2+ ions. The formation of Ag 3 PO 4 was confirmed by XRD, UV-DRS, FESEM coupled with EDX and HRTEM. The analytical enhancement factor (AEF) obtained was 1010 with a detection limit of 10-15 M indicating high sensitivity. Based on these results, the possible SERS mechanism has been proposed and discussed. Moreover, an excellent reusability of Ag 3 PO 4 substrate for at least four cycles was achieved upon the light exposure on heavy metal loaded substrate due to its superior catalytic ability for the degradation of heavy metal ions. The as-prepared substrate demonstrated remarkable stability, selectivity and SERS sensitivity towards real samples. The results conclude that Ag 3 PO 4 microcubes offer a great prospect in recyclable SERS applications. [ABSTRACT FROM AUTHOR]

The Kingdom of Saudi Arabia (KSA) is one of the rising countries in the Gulf region but always scared of water; being present in the arid desert. Among some water resources groundwater is one of the most significant ones in this country but unfortunately is being contaminated by the toxic metal ions. The present article describes the status of groundwater contamination by toxic metal ions. The meal ions analysed in the groundwater of KSA are Al, Cr, As, Cd, Ba, Co, Cu, Fe, Li, Hg, Mn, Ni, Se, Pb, V and Zn. This article describes the different groundwater resources in KSA, toxicities of the metal ions, metal ions contamination in the groundwater and sources of metal ions pollution. Besides, efforts are made to discuss the future challenges and the remediation measures; needed to protect the groundwater resources. This article will be important to the academicians, researchers, industry persons and the regulatory authorities.

In this research, an environmental friendly extraction method based on vortex-assisted liquid-phase microextraction and the solidified deep eutectic solvent (VALPME-SDES) has been developed for the determination of Pb, Cd, Cu, As, and Hg in tea prior to their analysis by graphite furnace atomic absorption spectrometry (GFAAS). A new deep eutectic solvent consisting of 1-decyl-3-methylimidazolium chloride and n-butanoic acid was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. The accuracy of the proposed procedure was also assessed by determining the concentration of the studied metal ions in a certified reference material for Green Tea (GBW 10052). [ABSTRACT FROM AUTHOR]

In present scenario, there is need to develop adsorbent based and cost-effective water purifier for removal of radiological and toxic metal ion contaminants viz. cesium, strontium and cobalt from contaminated water. In this regard, modified montmorillonite was prepared using reaction with hydrogen peroxide and potassium di-hydrogen phosphate and obtained product was characterized by different spectroscopic techniques viz. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The obtained modified montmorillonite was evaluated for removal of Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from contaminated water. Various factors which affect adsorption of metal ions on modified montmorillonite viz. contact time, initial concentration of metal ions and pH were studied. The batch method has been employed to determine adsorption capacity for metal ions in solution from 1000–10 000 μg/L, contact time 5–30 min, pH 4–10 and material quantities 50–200 mg at room temperature. The obtained adsorption data were fitted to Freundlich and Langmuir isotherm models; both models were found applicable for the metal ions adsorption on modified montmorillonite. The adsorption data were shown to follow pseudo second order reaction kinetics as per kinetic studies. The maximum adsorption capacity obtained 1.65–2.82 mg/g for Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) metal ions. The results show that modified montmorillonite have great potential to remove Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from aqueous solutions through chemisorption and physio-sorption. Modified montmorillonite can be used for removal of radiological and toxic metal ion contaminants from contaminated water. [ABSTRACT FROM AUTHOR]

Two types of macroacyclic ligands were synthesized by reacting 8-hydroxyquinoline-7-carbaldehyde with o-phenylenediamine (8H-OPD) and 4,4ʹ-diaminobenzanilide (8 H-DAB) and were characterized by certain spectroscopic techniques. The efficiency of the synthesized ligands toward the effective extraction of toxic metal ions such as Cu2+, Pb2+ and Ag+ from aqueous to organic phase was studied in two different types of organic solvents, viz., chloroform and dichloromethane. The effect of pH, solvents, concentration of ligands on the abstraction of metal ions, temperature, extraction time and the solvent ratio was investigated using an atomic absorption spectrophotometer. It has been observed that Ag+ ions have greater selectivity than other two metal ions and also the extraction efficiency was greater at 298 K. [ABSTRACT FROM AUTHOR]

The levels of some selected essential, non-essential, toxic elements and water-soluble inorganic anions (WSIAs) leached from green tea (GT) leaves infusion in boiled water at various time breaks were determined. A number of 29 GT samples were analyzed by Inductively Coupled Plasma-Mass/optical emission Spectrometry (ICP-OES/MS) and Ion chromatography (IC). The levels of studied elements and WSIAs (F−, Cl−, NO3−, PO43− and SO42−) leached from GT leaves in boiled water increased on growing infusion time. Chemical speciation (labile and complexed fractions) of P, Al, Cu, Pb and Cd in GT leaves in boiled water was estimated. At 95% confidence level (P > 0.50), the student t-test values as calculated for essential and toxic metals were smaller than the critical value indicating no significant differences between element concentrations in the tested samples. The average daily dietary intake (ADDIs) for selected elements and the average daily intake (ADI) and the chronic reference dose (RFD) for Cd (μg kg−1 BW day−1) were critically determined. Evaluation of inorganic composition allows quantification of the leaching percentage and the hazard beyond provisional acceptable average daily intake (ADI) values. Practical applications: WSIAs plays a significant role in green tea quality monitoring. Calculation and speciation of the mineral configuration and selected elements of GTs is of prime importance to evaluate the intake of hazard metals and biocomponent associated with the eating of infusions. Therefore, the levels of WSIAs leached in boiled tea infusions using IC and ICP-OES/MS were determined. However, the number of GT samples and their origins are limited. The work clearly indicated that, the differentiation and classification of tea samples from various provinces in many countries could be possible employing pattern recognition and analytical techniques. The levels of the elements K, P, Si, Fe, Cu, Al, Pb and Cd may be used as appropriate descriptors for identification of GTs origin.

A copolymer of poly(BuMA–co–EDMA) modified with C-tetra(nonyl)calix[4]resorcinarene was obtained via the impregnation method. The formation of the modified copolymer was confirmed and investigated using various techniques; in this way, the presence of calix[4]resorcinarene was confirmed by FT-IR spectroscopy and by high resolution transmission electron microscopy. The modified copolymer was used for the removal of highly toxic cations (Pb2+, Hg2+, and Cd2+) from aqueous solutions. To perform the removal, we used the batch sorption technique and the effects of time of contact, pH, and volume of sample on the effective sorption were determined. The best results were observed for Pb2+ extraction, which was comparatively more efficient. Adsorption–desorption experiments revealed that the modified copolymer could be used for several cycles without significant loss of adsorption capacity. Finally, the results showed that the modified copolymer application is highly efficient for the removal of lead ions from aqueous solutions.

In this work, the functional density theory calculations were performed to investigate the interaction mechanism (adsorption) of Cu2+, Cr3+ and Cd2+ metal ions in cellulose (CE) and cellulose acetate (AC). After the optimization of the structures at their energy minima, the following analyses were performed: molecular electrostatic potential (MEPs), reactivity indexes, frontier molecular orbitals (FMOs), structural parameters, interaction energy and QTAIM analysis. The study of MEPs, FMOs and reactivity indexes showed that it is possible to predict the site of interaction. Structural analyses have proven that the interactions occur. The calculated electron interaction energies showed that all ions interact with the matrix of CE and AC, and among them, the Cr3+ ion was the one that interacted most effectively. Finally, the QTAIM analysis allowed to characterize the nature of the interaction, in which the interactions of cellulose acetate-Cr3+ and cellulose-Cu2+ presented electrostatic character, and the other interactions were partially covalent. [ABSTRACT FROM AUTHOR]

The Kingdom of Saudi Arabia (KSA) is one of the rising countries in the Gulf region but always scared of water; being present in the arid desert. Among some water resources groundwater is one of the most significant ones in this country but unfortunately is being contaminated by the toxic metal ions. The present article describes the status of groundwater contamination by toxic metal ions. The meal ions analysed in the groundwater of KSA are Al, Cr, As, Cd, Ba, Co, Cu, Fe, Li, Hg, Mn, Ni, Se, Pb, V and Zn. This article describes the different groundwater resources in KSA, toxicities of the metal ions, metal ions contamination in the groundwater and sources of metal ions pollution. Besides, efforts are made to discuss the future challenges and the remediation measures; needed to protect the groundwater resources. This article will be important to the academicians, researchers, industry persons and the regulatory authorities. [ABSTRACT FROM AUTHOR]

Surface of Fe3O4 nanoparticles (NPs) was coated with (3‐mercaptopropyl)trimethoxysilane (MPTS) to form Fe3O4@MPTS NPs. Thus formed Fe3O4@MPTS NPs were studied for preconcentration of the representative Cd(II), Pb(II), and As(III) ions, and loading capacities toward these ions were found to be 17(±0.7), 29(±0.3), and 13(±0.5) mg g−1, respectively. As an example of safe utilization of toxic metal ions strongly bonded on magnetically retrievable NPs for catalytic applications, the Cd(II) loaded Fe3O4@MPTS NPs were successfully utilized for conducting the C−N bond formation reaction in comparable yields with that were reported in the literature but exhibited higher turnover number and turnover frequency. [ABSTRACT FROM AUTHOR]

An efficient and eco‐friendly procedure for the synthesis of highly stable silver (Ag) and gold (Au) nanoparticles (NPs) using phenylalanine conjugated cholic acid (CPhe) in aqueous medium has been developed.These NPs were prepared under natural sunlight irradiation, in which CPhe acts both as self‐reducing and capping agent. The size and shape of the NPs were optimized by changing the ratio of the concentration of CPheand Au3+ ions, pH of the solution, sunlight irradiation and reaction time.The optical properties of the nanoparticles (NPs) were studied using UV‐visible spectroscopy. Size and morphology of the NPs were analyzed using high resolution transmission electron microscopy (HR‐TEM) and dynamic light scattering techniques (DLS) techniques. The interaction of CPhe on the NPs surface were studied by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT‐IR) spectra.The synthesized Ag and Au NPs solutions were found to be highly stable for more than a year. The prepared NPs were used as probes for highly selective and sensitive detection of heavy metal ions (Hg2+, Cr6+ and Pb2+) by colorimetric in aqueous medium with a detection limit in the range ofnanomolar concentrations. [ABSTRACT FROM AUTHOR]

The harmful impact posed by toxic metals such as mercury, lead and arsenic on living organisms is well known. Although, the efforts have been made by environmental agencies to decrease the levels of these toxic metals, still there is high demand for potential materials that can bring down the levels of toxic metals in the environment. This eventually needs designing of new and efficient probes that can recognize the toxic ions from environmental samples. In this minireview, we summarize the effects caused by mercury, lead and arsenic in the environment and different types of sensors, particularly, chemical and nano-based sensors, including carbon and quantum dots used for the detection of aforementioned toxic metal ions. Further, we have predominantly focused on the reports that describes colorimetric and/or fluorescent detection methods of determination of the levels of toxic metal ions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Naked-eye sensing of Cu2+ and Hg2+ in physiological media. • Role of signaling unit in determining the stoichiometry of probe-metal ion complexes. • Estimation of toxic metal ions in natural water samples and also in presence of serum albumin. • Low-cost reusable paper strips for on-location detection purpose. Abstract Easy to synthesize probes are designed using bispicolyl moiety as the receptor unit with two different signaling moieties, anthraquinone and bisindolyl. Both the compounds show 'naked-eye' sensing of Cu2+ and Hg2+ in ∼100% aqueous medium. Not only selectivity, the compounds also show high sensitivity towards the target metal ions, as evident by their sufficiently low detection limits. The present system can detect Cu2+ as low as 0.06 ppm and Hg2+ up to 0.03 ppm from visible color change. The sensors are found equally effective in the detection of metal ions even in the protein-bound state. The impact of the signaling unit on the sensing properties of probes having same binding units has been observed and investigated. Mechanistic investigations revealed that variations in signaling unit influence the p K a of the bispicolyl nitrogens, which subsequently controls the stoichiometry of the probe-metal ion complexes as well as their luminescence property. Additionally, high specificity and good accuracy with recovery values ranging from 98.0 to 104.0% were obtained during Cu2+/Hg2+ estimation in spiked water samples. Low cost, reusable paper strips were developed for on-site detection of the metal ions which does not require the assistance of an optical instrument. [ABSTRACT FROM AUTHOR]

Abstract: An amino functionalized microcrystalline cellulose from corn stalk was prepared and its synthesis and operation conditions were optimized to remove Cu2+ from wastewater. To prepare this adsorbent, cellulose was grafted by glycidyl methacrylate in the presence of OP-10 as emulsifiers and potassium persulfate as initiators, then the grafted cellulose was aminated by diethylenetriamine. Batch experiments were performed to evaluate its adsorption capacity for Cu2+. Its adsorption process for Cu2+ was spontaneous and well fitted with pseudo-second-order kinetics and Langmuir isotherm. The maximum adsorption capacity of this modified cellulose for Cu2+ was demonstrated to be 343 mg/g at 45 °C and pH 4.5. The adsorbent showed a promising future due to its high performance in the removal of toxic Cu2+ and reusability. From the characterization results of scanning electron microscope, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, the adsorbent structure and adsorption mechanism could be inferred. The adsorption mechanism revealed that the primary and secondary amines were the main functional groups to adsorb Cu2+. The study results could provide a new route for the utilization of waste corn stalk to control water pollution caused by toxic metal ions.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract In this work, density functional theory (DFT) calculations were performed to investigate the complex formation ability of Meso-2,3-dimercaptosuccinic acid (DMSA) with metal ions (Cd2+, Hg2+ and Pb2+) in water. The binding energy values and thermodynamic parameters have been calculated. Natural bond orbital and charge decomposition analyses show an effective charge transfer from the oxygen and sulfur atoms of the DMSA to metal ions. Quantum theory of atoms in molecules analysis reveals that the covalent interactions between DMSA and Pb2+ are the driving force in complex formation, while the non-covalent interactions, mainly, electrostatic interactions play an important role in the complex formation of the DMSA with Cd2+ and Hg2+. Finally, The electronic properties such as highest occupied molecular orbital, lowest unoccupied molecular orbital energies, electronic chemical hardness, electronic chemical potential and global electrophilicity were calculated to get a better insight of molecular properties. Graphical abstract Image Highlights • Charge transfer and stability of [Cd-DMSA], [Hg-DMSA] and [Pb-DMSA] complexes were studied theoretically. • [Pb-DMSA] is the more stable complex than the other complexes. • Charge transfer occurs from the oxygen and sulfur atoms of DMSA to the metal ions. • QTAIM, ELF and LOL analyses confirm that the strongest metal-DMSA interactions are related to [Pb-DMSA] complex. [ABSTRACT FROM AUTHOR]

This article reviews the synthesis of crosslinked polyzwitterions (CPZs) (poly-carboxybetaines, -phosphonobetaines, and -sulfobetaines) having multiple pH-responsive centers as well as hydrophobic motifs. The synthesis follows the Butler cyclopolymerization protocol involving a multitude of diallylammonium salts along with crosslinkers and their copolymerization with SO 2 and maleic acid. The CPZs have been transformed into crosslinked anionic polyelectrolytes (CAPEs) under the influence of pH. CPZs/CAPEs were effectively used as sorbents to remove priority toxic metal ions and organic dyes (cationic and anionic) from their aqueous solutions and industrial wastewater. Many amphiphilic polymers incorporating a few mol% hydrophobic monomers have shown enhanced efficacies in removing organic dyes. Previous works involving expensive sorbents with limited stability led us to design stable pH-responsive resins due to the lack of labile organic motifs. The presence of pH-responsive chelating motifs thus helped to trap priority metal contaminants. While most of the previous studies involved the removal of toxic metal ions in high-concentration regimes, the studies in low-concentration regimes remain challenging. The current review deals with multipurpose pH-responsive resins with chelating motifs, positive and negative charge centers, and hydrophobes to entrap organic contaminants. Most of the resins in the current review efficiently reduced toxic metal ion concentrations in aqueous and industrial wastewater in a short time to ppb and sub-ppb levels, thereby making them safe for human health. Changing the backbone to have positive or negative charge centers has led to the sequestration of respective anionic and cationic dyes. Quite a few of the resins were found to be super adsorbents for the fast removal of dyes, with maximum adsorption capacities for methylene blue being in the range of 2109–2609 mg g−1. Future works are expected to focus on immobilizing cyclopolymers on magnetic nanoparticles. [Display omitted] • pH-responsive x-linked PEs were synthesized by Butler cyclopolymerization protocol. • Many diallylammonium salts contain polymers with residues of amino acids discussed. • Diallyl monomers, x-linkers, and copolymerization with SO 2 and maleic acid discussed. • Most resins efficiently reduced toxic metal ions, organic dyes up to sub-ppb levels. • X-linked resin finds applications in environmental remediation. [ABSTRACT FROM AUTHOR]

In acid soil, aluminum (Al) toxicity is one of the main factors limiting agricultural output. As is known to all, the cell wall is the first line of defense against metals that serves as a significant target of Al toxicity and also is crucial for Al detoxification. However, nothing is known about how this process is transcriptionally regulated. Here, we describe recent findings to understand the role of two kinds of transcription factors in regulating the cell wall composition and modification in response to Al stress in Arabidopsis thaliana. ANAC017 encodes a NAM, ATAF1/2, and cup-shaped cotyledon 2 (NAC) transcription factor, loss function of ANAC017 enhanced Al tolerance with the decreased Al content and xyloglucan content in the cell wall. Next, we characterized one xyloglucan endotransglucosylase/hydrolase (XTH), XTH31, which is previously reported to participate in Al stress, acted downstream of ANAC017 to regulate Al tolerance in Arabidopsis . In addition, we also identified MYB103, an R2R3-type transcription factor. MYB103 disruption caused Al sensitivity, and myb103 mutants' xyloglucan had a high O -acetylation level. Additionally, it was discovered that TRICHOME BIREFRINGENCE-LIKE27 (TBL27), which is in charge of xyloglucan's O -acetylation, functions downstream of MYB103 through the direct binding of the MYB103 to the promoter of the TBL27 to influence Arabidopsis's sensitivity to Al. In summary, our research showed that two distinct molecular modules modulate Arabidopsis cell wall composition and modification to positively influence Al resistance.

In-situ modification of cellulose fibers with titania nanoparticles (TiO 2 NPs) (TiO 2 NPs-cellulose) was carried out via the sol-gel process using titania sol and fibers of cellulose. Cellulose fibers were extracted from wheat straw, an agricultural waste material, whereas titania sol was prepared from titanium(IV) acetoximate, [Ti{ONC(CH 3 ) 2 } 4 ]. The synthesized TiO 2 NPs-cellulose composite was characterized by FT-IR, SEM-EDX, and XRD analyses. The obtained results exposed that TiO 2 NPs were homogeneously dispersed over the surface of cellulose fibers. A study was conducted to compare the photocatalytic activities of TiO 2 NPs-cellulose composite and TiO 2 NPs towards the degradation of methylene blue and methyl orange dyes under sunlight, and it was observed that the photo-degradation of methylene blue (99.99%) and methyl orange (80.73%) within 160 min is higher in the presence of TiO 2 NPs-cellulose composite than TiO 2 NPs. The adsorption capabilities of TiO 2 NPs-cellulose composite towards Pb 2+ , Cd 2+ , and Cr 3+ toxic metal ions were also examined, and it was found 44.73 mg. g -1 (89.46%), 38.82 mg. g -1 (77.65%), and 4.42 mg. g -1 (8.85%), respectively. Removal of pollutants from textile industrial effluent were also investigated using TiO 2 NPs-cellulose composite under sun light. The results obtained were very promising which shows potential of TiO 2 NPs-cellulose composite as an efficient photocatalyst and absorbent for real time applications., Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-023-00884-9., Competing Interests: Conflict of interestThe authors have no conflicts of interest to declare., (© The Author(s), under exclusive licence to Tehran University of Medical Sciences 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)