Search Results (264)

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

Animal venoms are complex biochemical secretions rich in highly potent and selective bioactive molecules, including peptides, enzymes, and small organic compounds. Once associated primarily with toxicity, these venoms are now recognized as a promising source of therapeutic agents for a wide range of medical conditions. This review provides a comprehensive analysis of the pharmacological potential of venom-derived compounds, highlighting their mechanisms of action, such as ion channel modulation, receptor targeting, and enzyme inhibition. Successful venom-derived drugs like captopril and ziconotide exemplify the translational potential of this biological arsenal. We discuss therapeutic applications in cardiovascular diseases, chronic pain, cancer, thrombosis, and infectious diseases, as well as emerging peptide candidates in clinical development. Technological advancements in omics, structural biology, and synthetic peptide engineering have significantly enhanced the discovery and optimization of venom-based therapeutics. Despite challenges related to stability, immunogenicity, and ecological sustainability, the integration of AI-driven drug discovery and personalized medicine is expected to accelerate progress in this field. By synthesizing current findings and future directions, this review underscores the transformative potential of animal venoms in modern pharmacotherapy and drug development. We also discuss current therapeutic limitations and how venom-derived compounds may address unmet needs in specific disorders. Full article

Arsenic contamination in water poses a significant global health risk, necessitating efficient and sustainable remediation strategies. Arsenic contamination affects groundwater in at least 106 countries, potentially exposing over 200 million people to elevated levels, primarily through contaminated drinking water. Among the most affected regions, Bangladesh remains a critical case study, where widespread reliance on shallow tubewells has resulted in one of the largest mass poisonings in history. Bio-based nanomaterials have emerged as promising solutions due to their eco-friendly nature, cost-effectiveness, and high adsorption capabilities. These nanomaterials offer a sustainable approach to arsenic remediation, utilizing materials like biochar, modified biopolymers, and bio-based aerogels, which can effectively adsorb arsenic and other pollutants. The use of environmentally friendly nanostructures provides a potential option for improving the efficiency and sustainability of arsenic remediation from groundwater. This review explores the mechanisms underlying arsenic remediation using such nanomaterials, including adsorption, filtration/membrane technology, photocatalysis, redox reactions, complexation, ion exchange, and coagulation–flocculation. Despite their potential, challenges such as scalability, stability, and regeneration hinder widespread application. We discuss recent advancements in material design, surface modifications, and hybrid systems that enhance performance. Finally, future perspectives are highlighted, including the integration of these bio-derived systems with smart sensing technologies, sustainable water-treatment frameworks, smart design, and life-cycle integration strategies, particularly for use in resource-constrained regions like Bangladesh and other globally impacted areas. Full article

This study investigates the potential of biochars derived from agricultural waste biomass for the removal of heavy metal ions from aqueous solutions. Biochars were produced via slow pyrolysis at 793 K using almond shells (AS), walnut shells (WS), pistachio shells (PS), and rice husks (RH) as feedstocks. The physicochemical properties and adsorption performance of the resulting materials were evaluated with respect to Cd(II), Mn(II), Co(II), Ni(II), Zn(II), total Iron (Fe_tot), total Arsenic (As_tot), and total Chromium (Cr_tot) in model solutions. Surface morphology, porosity, and surface chemistry of the biochars were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K (for specific surface area and pore structure), Fourier-transform infrared spectroscopy (FTIR), and determination of the point of zero charge (pH_pzc). Based on their textural properties, biochars derived from WS, PS, and AS were classified as predominantly microporous, while RH-derived biochar exhibited mesoporous characteristics. The highest Brunauer–Emmett–Teller (S_BET) surface area was recorded for PS biochar, while RH biochar showed the lowest. The pistachio shell biochar exhibited the highest specific surface area (440 m²/g), while the rice husk biochar was predominantly mesoporous. Batch adsorption experiments were conducted at 25 °C, with an adsorbent dose of 3 g/L and a contact time of 24 h. The experiments in multicomponent systems revealed removal efficiencies exceeding 87% for all tested metals, with maximum values reaching 99.9% for Cd(II) and 97.5% for Fe_tot. The study highlights strong correlations between physicochemical properties and sorption performance, demonstrating the suitability of these biochars as low-cost sorbents for complex water treatment applications. Full article

This article presents the single-crystal structure of the complex salt sodium dithiocuprate(I) dodecahydrate Na₃CuS₂·12(H₂O), i.e., [Na₃(H₂O)₁₂][CuS₂], which forms in the high-sulfide concentrations of the alkaline solutions used for arsenic separation from copper concentrates. It features a linear hydrogen-bonded dithiocuprate(I) anion, a novelty in crystallographically characterized thiocuprates. During the study of the alkaline sulfide leaching of Chilean copper concentrates, an analytical investigation of the solution led to the detection of this complex. This study aimed to understand the chemical behavior of the leaching solution by identifying existing ions, which facilitated the discovery of the complex using single-crystal analysis. The newly discovered complex was also synthesized from a modeling solution based on the leaching solution recipe for arsenic removal, allowing for further crystal characterization through Raman and XRD analysis. By estimating the sodium sulfide threshold concentration that enhanced the formation of the copper disulfide complex, this study defined the upper technical threshold limit of sulfide concentration for the economic development of alkaline sulfide leaching to remove arsenic. Full article

Environmental pollution remains one of the most pressing challenges facing modern society, with the removal of toxic substances from water sources being of particular concern. In this study, a composite material was synthesized by combining Cu-Al layered double hydroxides (CuAl-LDHs) with modified silica particles, aiming to develop an efficient and environmentally friendly adsorbent for the removal of phosphate and arsenate ions from water. CuAl-LDH, with a Cu²⁺/Al³⁺ molar ratio of 2:1, was synthesized using the co-precipitation method in the presence of modified silica maintaining an LDH/SiO₂ mass ratio of 2:1. The silica particles were functionalized with 3-glycidyloxypropyltrimethoxysilane (GLYMO) followed by modification with polyethyleneimine (PEI) to enhance their adsorption properties. X-ray diffraction (XRD) confirmed the successful deposition of CuAl-LDH on the silica surface, while scanning electron microscopy (SEM) revealed the porous structure of the silica and the uniform deposition of LDH. Adsorption experiments were performed to evaluate the removal efficiency of phosphate and arsenate ions under varying conditions. Equilibrium adsorption capacities, based on the Langmuir isotherm model, were determined to be 44.6 mg·g⁻¹ for phosphate (PO₄³⁻) and 32.3 mg·g⁻¹ for arsenate (As(V)) at 25 °C. The sorption behavior was better described by the Freundlich isotherm model, which yielded K_F values of 15.4 L·mg⁻¹ for phosphate and 13.9 L·mg⁻¹ for arsenate. Both batch and kinetic experiments confirmed the high adsorption efficiency of the composite, demonstrating its potential as a promising material for water treatment applications. Full article

IR-780 is a heptamethine cyanine dye that exhibits strong absorbance in the near-infrared region. Herein, we report IR-780 dye as a dual sensor for chromogenic cyanide detection and azide’s fluorogenic sensing in acetonitrile. Cyanide and hydroxide cause instant, dramatic color changes in the dye solution from green to yellow and dramatic spectral changes in the UV-Vis spectrum. The interaction of cyanide and hydroxide with the dye caused a dramatic decrease in the intensity of the strong absorption band at 780 nm and a concomitant band appearance at 435 nm. Other monovalent ions, including fluoride, chloride, bromide, iodide, dihydrogen phosphate, thiocyanate, acetate, and dihydrogen arsenate, caused no significant color or spectral changes. UV-Vis studies showed that the IR-780 dye is sensitive and selective to both ions. The detection limits for cyanide and azide are 0.39 µM and 0.50 µM, respectively. Interestingly, the IR-780 dye exhibited strong fluorescence at 535nm upon interaction with azide, while its initial emission at 809 nm was quenched. Both UV-Vis and fluorescence spectroscopy accomplished the detection of cyanide and azide using IR-780. Furthermore, the sensor’s effectiveness in fluorescence imaging of intracellular CN⁻ ions is demonstrated in live HeLa cells. Full article

Ensuring food security is essential for achieving sustainable global development, requiring a balance between sufficient food production and maintaining its safety and nutritional value. However, this objective faces considerable challenges due to the infiltration of toxic metal species into the food supply. Heavy metals and metalloids, depending on their molecular form and daily dose, exhibit varying degrees of toxicity, making the precise identification of their species essential for assessing their impact on human health and the environment. This study focuses on identifying the primary anthropogenic sources and dissemination pathways of heavy metal pollutants, with an emphasis on their speciation and bioavailability. It examines how toxic metal species, such as Pb²⁺, Cd²⁺, Hg²⁺, and various arsenic species (AsIII and AsV), infiltrate ecosystems, bioaccumulate within the food chain, and ultimately compromise food safety and nutritional value. Furthermore, the research explores the physiological and biochemical disruptions caused by these toxic metal species, including the displacement of essential ions from enzymatic active sites and transport proteins due to competitive binding by pollutants, oxidative stress induced by reactive oxygen species generation, and cellular dysfunction affecting metabolic pathways and signaling cascades, all of which contribute to both chronic and acute health conditions. By providing a detailed analysis of exposure routes and toxicological processes, this paper highlights the far-reaching consequences of heavy metal contamination on public health and agricultural sustainability. Special attention is given to the need for precise terminology, as the toxicity of metals is inherently linked to their daily dose and chemical species rather than their elemental form. Finally, this study advocates for integrated, multidisciplinary strategies aimed at mitigating these risks, enhancing ecosystem stability, and ensuring long-term food security in the face of environmental challenges. Full article

Groundwater is one of the most critical drinking water resources on Earth, and its safety significantly impacts the ecological environment and human health. This study focuses on the pollution characteristics, sources, and health risks of potentially toxic elements (PTEs) in the groundwater of the Dongting Lake basin in China. It highlights the concentration distribution and pollution causes of common toxic elements such as manganese (Mn), copper (Cu), zinc (Zn), arsenic (As), mercury (Hg), iron (Fe), chloride ions (Cl⁻), and fluoride ions (F⁻). The results indicate that the Mn concentration reached 28.6 times the background value, followed by Cu at 16.7 times. The groundwater pollution level in the study area reached a severe contamination level, with Zn classified as severely polluted and Mn categorized as moderately to heavily polluted. Approximately 47.05% of the study area was severely contaminated by PTEs. The study further reveals that the primary sources of pollution are anthropogenic activities, including agricultural fertilization, industrial discharges, and urbanization processes, which have significantly elevated PTE concentrations in groundwater. Additionally, natural geochemical processes contribute substantially to the high concentrations of specific elements in certain areas. Health risk assessments indicate that long-term exposure to PTEs in groundwater may pose various potential threats to human health, particularly in terms of carcinogenic and non-carcinogenic risks. Children are identified as the most vulnerable group. This research provides a systematic scientific basis for the management of groundwater pollution in the Dongting Lake basin, emphasizing that the current pollution levels pose serious threats to regional ecosystems and public health. The findings not only offer guidance for groundwater management in the Dongting Lake basin but also serve as a valuable reference for groundwater pollution management in similar regions. Full article

Arsenic is a highly toxic element, and excessive levels can affect human health. Composites possess a larger specific surface area and better adsorption performance than single-MOF materials. In this paper, a simple novel nanocomposite (MnFe₂O₄@Fe-UiO-67) was synthesized by the one-pot method for the removal of arsenic from industrial wastewater. The synthesis and adsorption mechanism of the adsorbent were analyzed by a series of characterizations. The results showed that the adsorption behavior of MnFe₂O₄@Fe-UiO-67 was consistent with the pseudo-secondary kinetics and Langmuir isotherm model, i.e., it is a monomolecular layer chemisorption. Characterization by Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) showed that the active site formed a strong coordination bond (As-O bond) with As ions to achieve efficient adsorption. At 298 K and pH = 10, the arsenic removal rate can reach 98.43%, and the adsorption capacity is 600.25 mg/g, which is more than most of the existing reported adsorbents. Through thermodynamic analysis, it is found that the adsorption of As ions by the adsorbent is a spontaneous exothermic process. It can exhibit excellent adsorption performance at room temperature without the need for additional energy consumption. This adsorbent has great development prospects in the treatment of wastewater. Full article

Based on the characteristics and effective components of steel slag and desulfurization gypsum, a new type of permeable reactive material was prepared by combining steel slag and desulfurization gypsum, and a simulation experiment of arsenic- and antimony-contaminated groundwater remediation was carried out. A combination of X-ray fluorescent, BGRIMM Process Mineralogy Analyzing System (BPMA), ICP-MS, and SEM-EDS detection and analysis methods was used to investigate the effects of steel slag particle size, desulfurization gypsum particle size, steel slag and desulfurization gypsum ratio, and steel slag-desulfurization gypsum mixed test block particle size on the performance of the permeable reactive wall to remove arsenic and antimony. The results show that a permeable reactive wall composed of steel slag (−4.75 + 1.18 mm) and desulfurization gypsum (−13.2 + 9.5 mm) in a 4:1 ratio achieved removal rates of 91.85% for As and 90.58% for Sb, reducing their concentrations below the drinking water standard. The purpose of using steel slag and desulfurization gypsum to intercept heavy metals and toxic ions in surface runoff was achieved. Arsenic was adsorbed, physically encapsulated, and lattice solidified by C-S-H gel. This research provides a cost-effective and environmentally friendly solution for the storage of steel slag and desulfurization gypsum while addressing heavy metal pollution in groundwater. Full article

Removing arsenic from industrial wastewater remains a crucial task. To protect public health and safety and address environmental pollution, there is an urgent need for a material that can efficiently remove arsenic from wastewater. In this study, a simple and highly efficient adsorbent, namely, a Co/Mn bimetallic-based organic framework (CoMn-MOF-74) adsorbent, was prepared by a hydrothermal synthesis method. Experimental results demonstrate that CoMn-MOF-74 exhibits excellent adsorption capacity for arsenic ions in wastewater. It was found that the optimal Co/Mn molar ratio of the adsorbent is 1:1. The CoMn-MOF-74 adsorbent compensates for the deficiencies in the adsorption performance of Co-MOF-74 and Mn-MOF-74, increasing the adsorption rate and the highest adsorption capacity. The maximum adsorption rate of CoMn-MOF-74 is 93.4%, and the highest adsorption capacity is 531 mg/g. Fitting CoMn-MOF-74 according to two categories of models, specifically, the adsorption isotherm and adsorption kinetics models, indicated that CoMn-MOF-74 adheres to the Langmuir model and pseudo-second-order kinetic model. The adsorption process is mainly chemical adsorption and monolayer adsorption. Analysis by XPS revealed that metal–oxygen groups and hydroxyl groups play important roles in the adsorption process. In conclusion, the CoMn-MOF-74 adsorbent shows excellent prospects in the field of arsenic adsorption from wastewater and is a promising arsenic-removing adsorbent. Full article

Herein, targeting arsenic-containing acidic wastewater generated from washing arsenic-containing flue gas with concentrated sulfuric acid, the arsenic removal efficiency using H₂S was investigated. The effects of H₂S concentration, the gas flow rate, H₂SO₄ concentration, temperature, and Cl⁻/F⁻ ions on arsenic removal were studied. Results indicate that H₂S concentration is the primary factor. Arsenic was precipitated as amorphous As₂S₃, reducing residual arsenic to 0.28 mg/L. Cl⁻ enhanced arsenic removal, yielding a residual concentration of 0.68 mg/L, while F⁻ exhibited a dual effect: the inhibition at low concentrations and promotion at high concentrations. At 100 g/L F⁻, the residual arsenic was 29.59 mg/L. These effects are attributed to Cl⁻/F⁻ altering the surface electrochemical properties of As₂S₃ particles. Additionally, both ions improved As₂S₃ hydrophobicity. This study provides insights for purifying arsenic-containing sulfuric acid. Full article

Soil acidification activates most of the cationic heavy metals in soil and thus enhances their accumulation in crops, posing an accentuated threat to human health, while there is limited knowledge regarding the accumulation of metalloid arsenic (As) in crops, which is influenced by acidification due to its opposite behavior in soil. In this study, the acidification processes of neutral purple soil together with the accompanied changes in soil properties and As fractionation were examined through a column-leaching experiment. Subsequently, growth and As accumulation in pakchoi (Brassica campestris L.) were investigated under various combinations of soil pH and As pollution levels in a pot experiment. This allowed us to elucidate the mechanisms of As accumulation in pakchoi under the co-stresses of soil acidification and As pollution. The results indicated that soil acidification followed a two-phase process, initially rapid and later slow, with a turning point at a pH of 4.7–4.8. Below this critical pH, the leaching rates of base ions and As accelerated significantly and the decomposition of primary minerals began, primarily from chlorite to green/mesospheric minerals, resulting in a substantial increase in the content of amorphous iron oxide. Meantime, soil As was transformed from highly labile forms, such as non-specifically and specifically adsorbed forms, to less active ones like amorphous hydrous oxide-bound and residual forms, resulting in decreased As availability. In this context, As pollution remarkably delayed the growth of pakchoi, while the influence of acidification on growth only occurred when the soil was acidified to a pH lower than 6, as demonstrated by a substantial biomass reduction at higher As levels and a 41.8% biomass decrease at pH 4.6. Moreover, soil acidification exacerbated the inhibitory effect of As on pakchoi growth. The As contents in the edible parts of pakchoi dramatically increased with the increase in the soil As level, and soil acidification did not mitigate As accumulation in plants via the suppression of soil As availability but rather greatly increased it due to the bioconcentration effect caused by As toxicity. In conclusion, significant interactions existed between soil acidification and As pollution in terms of soil properties and As transformation, leading to comprehensive effects on growth and As accumulation in crops. Full article