Search Results (1,058)

The windowpane oyster (Placuna placenta) is common in coastal areas of the Philippines, thriving in brackish waters. Its shells underpin the local craft industries. While its meat is edible, only small amounts are consumed locally, most going to waste. Utilization of this potential nutrient source is hindered by the lack of information concerning its organic and mineral content, the possible presence of heavy metal ions, and the risk of microbial pathogens. We report extensive analysis of the meat from Placuna placenta, harvested during three different seasons to account for potential variations. This comprises proximate analysis, mineral, antioxidant, and microbial analyses. While considerable seasonal variation was observed, the windowpane oyster was found to be a rich source of protein, fats, minerals, and carbohydrates, comparing well with the meats of other shellfish and land animals. Following pre-cooking (~90 °C, 25–30 min), the standard local method for food preparation, no viable E. coli or Salmonella sp. were detected. Mineral content was broadly similar to that reported in fish, although iron, zinc, and copper were more highly represented, nevertheless, heavy metals were below internationally acceptable levels, with the exception of one of three samples, which was slightly above the only current standard, FSANZ. Whether the arsenic was in the safer organic form, which is commonly the case for shellfish, or the more toxic inorganic form remains to be established. This and the variation of arsenic over time will need to be considered when developing food products. Overall, the meat of the windowpane oyster is a valuable food resource and its current (albeit low-level) use should lower any barriers to its acceptance, making it suitable for commercialization. The present data support its development for high-value food products in urban markets. Full article

The increasing demand for rapid, sensitive, and eco-friendly methods for the detection of trace heavy metals in environmental samples, attributed to their serious threats to health and the environment, has spurred considerable interest in the development of sustainable sensor materials. Toxic metal ions, namely, lead (Pb²⁺), cadmium (Cd²⁺), mercury (Hg²⁺), arsenic (As³⁺), and chromium, are potential hazards due to their non-biodegradable nature with high toxicity, even at trace levels. Acute health complications, including neurological, renal, and developmental disorders, arise upon exposure to such metal ions. To monitor and mitigate these toxic exposures, sensitive detection techniques are essential. Pre-existing conventional detection methods, such as atomic absorption spectroscopy (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), involve expensive instrumentation, skilled operators, and complex sample preparation. Electrochemical sensing, which is simple, portable, and eco-friendly, is foreseen as a potential alternative to the above conventional methods. Carbon-based nanomaterials play a crucial role in electrochemical sensors due to their high conductivity, stability, and the presence of surface functional groups. Biochar (BC), a carbon-rich product, has emerged as a promising electrode material for electrochemical sensing due to its high surface area, sustainability, tunable porosity, surface rich in functional groups, eco-friendliness, and negligible environmental footprint. Nevertheless, broad-spectrum studies on the use of biochar in electrochemical sensors remain narrow. This review focuses on the recent advancements in the development of biochar-based electrochemical sensors for the detection of toxic heavy metals such as Pb²⁺, Cd²⁺, and Hg²⁺ and the simultaneous detection of multiple ions, with special emphasis on BC synthesis routes, surface modification methodologies, electrode fabrication techniques, and electroanalytical performance. Finally, current challenges and future perspectives for integrating BC into next-generation sensor platforms are outlined. Full article

This article presents the potential use of a humic agent called ‘Superhumate’, obtained from weathered coal from the Shubarkol deposit in Kazakhstan. The experiment was conducted using model solutions and surface mine water samples from the “Degelen” site at the Semipalatinsk Test Site. The adsorption of heavy metals and toxic elements using the “Superhumate” agent was carried out under dynamic conditions using a chromatographic column. Tests were conducted at a natural pH range of 5–8 (mine waters) and with a model solution at pH 1.7. Assessing the sorption efficiency of this preparation revealed that at pH 1.7, the agent does not adsorb elements such as Cd, Cu, Pb, and Zn. Under dynamic experimental conditions, using the preparation for mine waters at natural pH levels (pH 5–8), elements such as Be, Sr, Mo, Cd, Cs, Zn, and U were efficiently adsorbed at levels of 60–95%. The sorption efficiency of Pb ions was found to be almost independent of pH. The experimental results obtained with mine water samples indicate that alkaline solutions have the highest sorption efficiency, with pH ≥ 7, which is attributed to the solubility of the agent. Full article

Lithium-ion batteries (LiBs) are utilized in numerous applications due to advancements in technology, and the recovery of end-of-life (EoL) LiBs is imperative for environmental and economic reasons. Pyrometallurgical and hydrometallurgical methods have been used in the recovery of metals such as Li, Co, and Ni in the EoL LiBs. Hydrometallurgical methods, which have been demonstrated to exhibit higher recovery efficiency and reduced energy consumption, have garnered increased attention in recent research. Inorganic acids, including HCl, HNO₃, and H₂SO₄, as well as organic acids such as acetic acid and citric acid, are employed in the hydrometallurgical recovery of these metals. It is imperative to acknowledge the environmental hazards posed by these acids. Consequently, solvometallurgical processes, which involve the use of organic solvents with minimal or no water, are gaining increasing attention as alternative or complementary techniques to conventional hydrometallurgical processes. In the context of solvent systems that have been examined for a range of solvometallurgical methods, deep eutectic solvents (DESs) have garnered particular interest due to their low toxicity, biodegradable nature, tunable properties, and efficient metal recovery potential. In this study, the leaching process of black mass containing graphite, LCO, NMC, and LMO was carried out in a short time using the ternary DES system. The ternary DES system consists of choline chloride (ChCl), glycolic acid (GLY), and ascorbic acid (AA). As a result of the leaching process of cathode powders in the black mass without any pre-enrichment process, Li, Co, Ni, and Mn elements passed into solution with an efficiency of over 95% at 60 °C and within 1 h. Moreover, the kinetics of the leaching process was investigated, and Density Functional Theory (DFT) calculations were used to explain the leaching mechanism. Full article

Industrial effluents pose a significant concern because they contain a variety of metals and metalloids that have detrimental effects on the environment. Conventional techniques are widely used in effluent treatment plants (ETPs) to remove metallic pollutants; however, they are less effective, are costly, and generate secondary toxic waste. Mycosorbent would be a sustainable and economical alternative to conventional techniques, as it offers numerous advantages. In this study, we shed light on the development of mycosorbent, which could be potentially applicable in the treatment of industrial effluent. In a competitive (i.e., multimetal system) optimisation study, mycosorbent AD2 exhibited a maximum biosorption capacity of 3.7 to 6.20 mg/g at pH 6.0, with an initial metal ion concentration of 25 mg/L, a contact time of 2 h, at 50 ± 2 °C, and a pH_PZC of 5.3. The metal-removal capacity increased up to 1.23-fold after optimisation. The thermodynamic parameters confirmed that the AD2 mycosorbent facilitated an endothermic, feasible, and spontaneous biosorption process. The FT-IR and SEM characterisation analysis confirmed the adsorption of metals on the surface of the mycosorbent from the aqueous system. This study demonstrated that mycosorbent could be an effective tool for combating metallic pollutants in various industrial effluents. Full article

The primary worldwide variables limiting plant development and agricultural output are the ever-present threat that environmental stressors such as salt (may trigger osmotic stress plus ions toxicity, which impact on growth and yield of the plants), drought (provokes water stress, resulting in lowering photosynthesis process and growth rate), heavy metals (induced toxicity, hindering physiological processes also lowering crop quantity and quality), and pathogens (induce diseases that may significantly affect plant health beside productivity). This review explores the integrated effects of these stressors on plant productivity and growth rate, emphasizing how each stressor exceptionally plays a role in physiological responses. Owing to developments in technology that outclass traditional breeding methods and genetic engineering techniques, powerful alleviation strategies are vital. New findings have demonstrated the remarkable role of nanoparticles in regulating responses to these environmental stressors. In this review, we summarize the roles and various applications of nanomaterials in regulating abiotic and biotic stress responses. This review discusses and explores the relationship between various types of nanoparticles (metal, carbon-based, and biogenic) and their impact on plant physiology. Furthermore, we assess how nanoparticle technology may play a role in practices of sustainable agriculture by reducing the amount of compounds used, providing them with a larger surface area, highly efficient mass transfer abilities, and controlled, targeted delivery of lower nutrient or pesticide amounts. A review of data from several published studies leads to the conclusion that nanoparticles may act as a synergistic effect, which can effectively increase plant stress tolerance and their nutritional role. Full article

Electrochemical sensors, particularly those based on ion transfer at the interface between two immiscible electrolyte solutions (ITIES), offer significant advantages such as high selectivity, ease of fabrication, and cost effectiveness for toxic metal ion detection. However, distinguishing between cyclic voltammograms (CVs) of analytes with closely spaced half-wave potentials, such as Cd²⁺ and Cu²⁺, remains a challenge, especially for non-expert users. In this work, we present a novel methodology that integrates advanced artificial intelligence (AI) models with ITIES-based sensing to automate and enhance metal ion detection. Our approach first employed a convolutional neural network to classify CVs as either ideal or faulty with an accuracy exceeding 95 percent. Ideal CVs were then further analyzed for metal ion identification, achieving a classification accuracy of 99.15 percent between Cd²⁺ and Cu²⁺ responses. Following classification, an artificial neural network was used to quantitatively predict metal ion concentrations, yielding low mean absolute errors of 0.0158 for Cd²⁺ and 0.0127 for Cu²⁺. This integrated AI–ITIES system not only provides a scientific methodology for differentiating analyte responses based on electrochemical signatures but also substantially lowers the expertise barrier for sensor signal interpretation. To our knowledge, this is the first report of the AI-assisted differentiation and quantification of metal ions from ITIES-based CVs, establishing a robust framework for the future development of user-friendly, automated electrochemical sensing platforms for environmental and biological applications. Full article

The detection of Fe²⁺ in environmental water sources is critical due to its biological relevance and potential toxicity at elevated levels. Herein, we report a plasmon-driven catalytic sensing nanoplatform based on p-aminothiophenol (pATP)-functionalized silver nanoparticles (AgNPs) for the selective and sensitive detection of Fe²⁺. The nanoplatform exploits the inhibition of the plasmon-driven catalytic conversion of pATP to 4,4-dimercaptoazobenzene (DMAB), monitored via surface-enhanced Raman scattering (SERS) spectroscopy. The catalytic efficiency was quantified by the intensity ratio between the formed DMAB-specific Raman band and the common aromatic ring vibration band of pATP and DMAB. This ratio decreased proportionally with increasing Fe²⁺ concentration over a range of 100 µM to 1.5 mM, with a calculated limit of detection of 39.7 µM. High selectivity was demonstrated against common metal ions, and excellent recovery rates (96.6–99.4%) were obtained in real water samples. Mechanistic insights, supported by chronopotentiometric measurements under light irradiation, revealed a competitive oxidation pathway in which Fe²⁺ preferentially consumes plasmon-generated hot holes over pATP. This mechanism clarifies the observed catalytic inhibition and supports the design of redox-responsive SERS sensors. The platform offers a rapid, low-cost, and portable solution for Fe²⁺ monitoring and holds promise for broader applications in detecting other redox-active analytes in complex environmental matrices. Full article

Heavy metal ions pose a significant threat to the environment and human health due to their high toxicity and bioaccumulation. Traditional instrumentations, although sensitive, are often complex, costly, and unsuitable for on-site rapid detection of heavy metal ions. Lateral flow assay technology has emerged as a research hotspot due to its rapid, simple, and cost-effective advantages. This review summarizes the applications of lateral flow assay technology based on nucleic acid molecules and antigen–antibody interactions in heavy metal ion detection, focusing on recognition mechanisms such as DNA probes, nucleic acid enzymes, aptamers, and antigen–antibody binding, as well as signal amplification strategies on lateral flow testing strips. By incorporating these advanced technologies, the sensitivity and specificity of lateral flow assays have been significantly improved, enabling highly sensitive detection of various heavy metal ions, including Hg²⁺, Cd²⁺, Pb²⁺, and Cr³⁺. In the future, the development of lateral flow assay technology for detection of heavy metal ions will focus on multiplex detection, optimization of signal amplification strategies, integration with portable devices, and standardization and commercialization. With continuous technological advancements, lateral flow assay technology will play an increasingly important role in environmental monitoring, food safety, and public health. Full article

The persistent contamination of aquatic environments by heavy metals, particularly Pb²⁺, Cd²⁺, and Cu^2+, poses a serious global threat due to their toxicity, persistence, and bioaccumulative behavior. In response, low-cost and eco-friendly adsorbents are being explored, among which CaCO₃-based biocomposites derived from mollusk shells have shown exceptional performance. In this study, a hybrid biocomposite composed of poly(vinyl alcohol) (PVA) and oyster shell-derived CaCO₃ was computationally investigated using Density Functional Theory (DFT) to elucidate the electronic and structural basis for its high metal-removal efficiency. Calculations were performed at the B3LYP/6-311++G(d,p), M05-2X/6-311+G(d,p), and M06-2X/6-311++G(d,p) levels using GAUSSIAN 16. Among them, B3LYP was identified as the most balanced in terms of accuracy and computational cost. The hybridization with CaCO₃ reduced the HOMO-LUMO gap by 20% and doubled the dipole moment (7.65 Debye), increasing the composite’s polarity and reactivity. Upon chelation with metal ions, the gap further dropped to as low as 0.029 eV (Cd²⁺), while the dipole moment rose to 17.06 Debye (Pb²⁺), signaling enhanced charge separation and stronger electrostatic interactions. Electrostatic potential maps revealed high nucleophilicity at carbonate oxygens and reinforced electrophilic fields around the hydrated metal centers, correlating with the affinity trend Cu²⁺ > Cd²⁺ > Pb²⁺. Fukui function analysis indicated a redistribution of reactive sites, with carbonate oxygens acting as ambiphilic centers suitable for multidentate coordination. Natural Bond Orbital (NBO) analysis confirmed the presence of highly nucleophilic lone pairs and weakened bonding orbitals, enabling flexible adsorption dynamics. Furthermore, NCI/RDG analysis highlighted attractive noncovalent interactions with Cu²⁺ and Pb²⁺, while FT-IR simulations demonstrated the formation of hydrogen bonding (O–H···O=C) and Ca²⁺···O coordination bridges between phases. Full article

In this study, kaolinite-based clay (Ka-Clay) was used as an adsorbent for the efficient removal of Pb(II), Cd(II) and Hg(II) ions from aqueous media. The selection of Pb(II), Cd(II) and Hg(II) ions for experimental studies took into account their high toxicity, while the choice of Ka-Clay, the ease of preparation and high availability of this material were the most important arguments. Ka-Clay exhibits high adsorption performance, with removal percents over 98% for Pb(II) and 93% for Cd(II), even at high concentrations of metal ions (over 150 mg/L, pH = 6.5, 4 g adsorbent/L, 21 ± 1 °C). For Hg(II) ions, the adsorption percent does not exceed 55%, and this moderate value is mainly due to the significant change in pH. The adsorption behavior was in accordance with the Langmuir model (R² > 0.95) and the pseudo-second order kinetic model (R² > 0.99), indicating an adsorption process that occurs mainly through chemical interactions at the adsorbent surface between the metal ions and the functional groups. Adsorption processes are spontaneous (ΔG = −8.66 ÷ −15.76 kJ/mol) and endothermic (ΔH = 7.09 ÷ 21.81 kJ/mol), and the adsorption mechanism is the results of elementary processes of electrostatic attraction, ion exchange and superficial complexation. The insignificant effect of other ions (Ca(II), Mg(II), Na(I), K(I)) present in real wastewater samples as well as the desorption behavior of exhausted adsorbent highlight the practical utility of this adsorbent on a large scale. The experimental results included in this study suggest that Ka-Clay can be used as a promising adsorbent for the removal of high concentrations of toxic heavy metals with low cost and high efficiency, and this can contribute to the design of a sustainable wastewater treatment method. Full article

In this study, Ni²⁺ and Cd²⁺ resistant Pseudomonas aeruginosa 18, Enterobacter ludwigii 11Uz, and Enterobacter cloacae Uz_5 strains were isolated from soils contaminated with heavy metals in the Samarkand and Kashkadarya regions (Uzbekistan), and tested to remove Ni²⁺ and Cd²⁺ ions from the environment via biosorption. The biosorption capacity of these strains was observed under in vitro conditions. The biosorption process was highly dependent on the growing conditions, with the highest biosorption rate observed after 300 min of incubation at pH 7.0, and 40 °C. The presence of functional groups such as S=O, NH₂, and COOH in the biosorbing microorganisms was confirmed by IR spectroscopy. The adsorption capacity decreased when the initial metal concentration was increased and was enhanced with higher microbial biomass. Enterobacter ludwigii 11Uz strain was found to alter the toxic oxidation state of Ni²⁺ and Cd²⁺ cations, while Pseudomonas aeruginosa 18 and Enterobacter cloacae Uz_5 strains reduced the toxicity of Ni²⁺ cations only by changing their oxidation state. It was confirmed in our studies that the three selected bacterial strains actively participated in the detoxification of Cd²⁺ through the synthesis of cysteine amino acid. Full article

Nickel’s durability and catalytic properties make it essential in the aerospace, automotive, electronics, and fuel cell technology industries. Wastewater analysis typically relies on sensitive but costly techniques such as ICP-MS, AAS, and ICP-AES, which require complex equipment and are unsuitable for on-site testing. This study introduces a novel screen-printed electrode array with 16 chemically and, optionally, electrochemically coated Au electrodes. Its electrochemical response to Ni²⁺ was tested using Na₂SO₃ and ChCl-EG deep eutectic solvents as electrolytes. Ni²⁺ solutions were prepared from NiCl₂·6H₂O, NiSO₄·6H₂O, and dry NiCl₂. In Na₂SO₃, the linear detection ranges were 20–196 mM for NiCl₂·6H₂O and 89–329 mM for NiSO₄·6H₂O. High Ni²⁺ concentrations (10–500 mM) were used to simulate industrial conditions. Two linear ranges were observed, likely due to differences in electrochemical behaviour between NiCl₂·6H₂O and NiSO₄·6H₂O, despite the identical Na₂SO₃ electrolyte. Anion effects (Cl⁻ vs. SO₄²⁻) may influence response via complexation or ion pairing. In ChCl-EG, a linear range of 0.5–10 mM (R² = 0.9995) and a detection limit of 1.6 µM were achieved. With a small electrolyte volume (100–200 µL), nickel detection in the nanomole range is possible. A key advantage is the array’s ability to analyze multiple analytes simultaneously via customizable electrode configurations. Future research will focus on nickel detection in industrial wastewater and its potential in the multiplexed analysis of toxic metals. The array also holds promise for medical diagnostics and food safety applications using thiol/Au-based capture molecules. Full article

In the wake of global energy transition and the “dual-carbon” goal, the rapid growth of electric vehicles has posed challenges for large-scale lithium-ion battery decommissioning. Retired batteries exhibit dual attributes of strategic resources (cobalt/lithium concentrations several times higher than natural ores) and environmental risks (heavy metal pollution, electrolyte toxicity). This paper systematically reviews pyrometallurgical and hydrometallurgical recovery technologies, identifying bottlenecks: high energy/lithium loss in pyrometallurgy, and corrosion/cost/solvent regeneration issues in hydrometallurgy. To address these, an integrated recycling process is proposed: low-temperature physical separation (liquid nitrogen embrittlement grinding + froth flotation) for cathode–anode separation, mild roasting to convert lithium into water-soluble compounds for efficient metal oxide separation, stepwise alkaline precipitation for high-purity lithium salts, and co-precipitation synthesis of spherical hydroxide precursors followed by segmented sintering to regenerate LiNi_1/3Co_1/3Mn_1/3O₂ cathodes with morphology/electrochemical performance comparable to virgin materials. This low-temperature, precision-controlled methodology effectively addresses the energy-intensive, pollutive, and inefficient limitations inherent in conventional recycling processes. By offering an engineered solution for sustainable large-scale recycling and high-value regeneration of spent ternary lithium ion batteries (LIBs), this approach proves pivotal in advancing circular economy development within the renewable energy sector. Full article

Salinity and heavy metal stress significantly reduce agricultural productivity in arable lands, particularly affecting crops like rice (Oryza sativa L.). This study aimed to evaluate the efficacy of heavy metal-tolerant plant growth-promoting rhizobacteria (HMT-PGPR) in mitigating the harmful effects of salt (NaCl), chromium (Cr), and combined NaCl + Cr stress on rice plants. Two pre-isolated and well-characterized heavy metal-tolerant epiphytic (Ochrobactrum pseudogrignonense strain P14) and endophytic (Arthrobacter woluwensis strain M1R2) PGPR were tested. The LSD test (p ≤ 0.05) was used to assess the statistical significance between treatment means. Stresses caused by NaCl, Cr, and their combination were found to impair plant growth and biomass accumulation through mechanisms, including osmotic stress, oxidative damage, ionic imbalance, reduced photosynthetic pigment, lowered relative water content, and compromised antioxidant defense systems. Conversely, inoculation with HMT-PGPR alleviated these adverse effects by reducing oxidative stress indicators, including malondialdehyde (MDA), hydrogen peroxide (H₂O₂) content and electrolyte leakage (EL) and enhancing plant growth, osmolyte synthesis, and enzymatic antioxidant activity under single- and dual-stress conditions. The application of HMT-PGPR notably restricted Na⁺ and Cr⁶⁺ uptake, with an endophytic A. woluwensis M1R2 demonstrating superior performance in reducing Cr⁶⁺ translocation (38%) and bioaccumulation (42%) in rice under dual stress. The findings suggest that A. woluwensis effectively mitigates combined salinity and chromium stress by maintaining ion homeostasis and improving the plant’s antioxidant defenses. Full article