Search Results (31)

Pentavalent sodium antimoniate (Sb(V)) has been used for over 50 years in leishmaniasis treatment. Sb(V) is converted into trivalent antimony (Sb(III)) within macrophages acting as a prodrug by disrupting fatty acid beta-oxidation and glycolysis, impairing the energy metabolism of the parasite. Despite extensive use, the effects of antimonials on host mitochondria are not well understood. This study investigated the impact of Sb(V) and Sb(III) on mitochondria isolated from mouse hearts via differential centrifugation and lastly incubated with Sb(V) or Sb(III). Mitochondrial function was evaluated by oxygen consumption, ATP production, reactive oxygen species (ROS) generation, and transmembrane potential. Both Sb(V) and Sb(III) reduced oxygen consumption in complex I respiratory states 1, 2, and 3 at 1 µg/mL and 1 ng/mL. ROS production increased in Sb(V)-treated mitochondria. ATP production was impaired by both drugs starting at 1 ng/mL. Proton leak also increased, and significant changes in transmembrane potential were observed at both concentrations. These findings indicate that Sb(V) and Sb(III) directly compromise mitochondrial function from isolated mouse heart mitochondria by reduced ATP production and increased ROS. Full article

Complex antimony pyrochlores Bi_2.7M_0.46Ni_0.70Sb₂O_10+Δ (M = Zn, Mg) were synthesized from oxide precursors, using the solid-state reaction method. For each composition variant, the pyrochlore phase formation process was studied during solid-state synthesis in the range of 500–1050 °C. The influence of zinc and magnesium on the phase formation process was established. The interaction of oxide precursors occurs at a temperature of 600 °C and higher, resulting in the formation of bismuth stibate (Bi₃SbO₇) as a binary impurity phase. Oxide precursors, including bismuth(III) and antimony(III,V) oxides, are fixed in the samples up to 750 °C, at which point the intermediate cubic phase Bi₃M_2/3Sb_7/3O₁₁ (sp. gr. Pn-3, M = Zn, Ni) is formed in the zinc system. Interacting with transition element oxides, it is transformed into pyrochlore. An intermediate phase with the Bi_4.66Ca_1.09VO_10.5 structure (sp. gr. Pnnm) was found in the magnesium system. The unit cell parameter of pyrochlore for two samples has a minimum value at 800 °C, which is associated with the onset of high-temperature synthesis of pyrochlore. The synthesis of phase-pure pyrochlores is confirmed by high-resolution Raman spectroscopy. The data interpretation showed that the cations in Ni/Zn pyrochlore are more likely to be incorporated into bismuth positions than in Ni/Mg pyrochlore. The nickel–magnesium pyrochlore is characterized by a low-porosity microstructure, with grain sizes of up to 3 μm, according to SEM data. Zinc oxide has a sintering effect on ceramics. Therefore, the grain size in ceramics is large and varies from 2 to 7 μm. Full article

The effect of low-molecular-weight dissolved organic matter (LDOM) on antimony enrichment in groundwater remains unclear. In this study, the spectroscopic and molecular characteristics of high- and low-Sb groundwater are compared using optical spectrophotometry, ultrafiltration, and Fourier transform ion cyclotron resonance mass spectrometry. The results demonstrated that although the mean DOM concentration in LDOM groundwater (3.98 mg/L) accounted for only 69.22% of the mean DOM concentration, the proportion of Sb(V) within the total Sb varied between 80.29% and 99.56%. LDOM was characterized by higher biological and fluorescence index values, a greater H/C ratio, and reduced double-bond equivalent values compared with high-molecular-weight dissolved organic matter. High abundances of LDOM can enhance the primary enrichment of Sb(V) within the total Sb concentration via competitive adsorption and, as energy and electron acceptors for microbial communities facilitate Sb(III), oxidation within groundwater systems. This study provides new perspectives on understanding how DOM influences the migration and speciation transformation of Sb in groundwater environments. Full article

Antimony-resistant bacteria are potential natural resources for the bioremediation of mining soil pollution. A Raoultella sp. 64 strain was isolated from antimony-contaminated soil. To enhance its Sb resistance abilities, this strain was transported into space aboard the Shenzhou spacecraft for space breeding, resulting in a mutant strain, Raoultella sp. D9. The whole genomes of Raoultella sp. 64 and mutant strain Raoultella sp. D9 were sequenced, revealing the genomic information for the bacterium. Comparative genomic analysis was then carried out to identify differential functional genes. The adsorption conditions for Sb(III) were optimized and refined. Further, Fourier transform infrared spectroscopy (FTIR) was used to determine the adsorption of antimony. Results show that strain D9 exhibits a higher tolerance to Sb(III), and Sb resistance genes were identified in both Raoultella sp. 64 and D9. Analysis of the differential functional genes indicated that the increased copy number of plsX may lead to a higher lipid content in the cell membrane, thereby enhancing the cell’s resistance to heavy metals. Mutant strain D9 exhibited better biosorption capacity compared to strain 64. FTIR studies showed that key functional groups, including -OH, C-N, C-H, and C-O, are likely to have participated in Sb(III) biosorption. Further study of the differential functional genes could provide a basis for future research and the subsequent development of technologies for the remediation of Sb-contaminated sites. Full article

This study investigates the combustion characteristics of silicon-based time-delay compositions with bismuth(III) oxide (Bi₂O₃), antimony(III) oxide (Sb₂O₃), and lead(II,IV) oxide (Pb₃O₄) to identify formulations with pressure-independent burn rates. Unlike conventional pyrotechnic compositions, silicon-based mixtures offer an improved energy density and reduced sensitivity to pressure variations. The linear combustion rate of the compositions was determined for a wide range of silicon contents and for different compaction pressures. Experimental results show that burn rates range from 8 mm s⁻¹ to 195 mm s⁻¹, depending on the metal oxide type and silicon content. The highest rate (195 mm s⁻¹) was observed for Si/Pb₃O₄ at 30 wt.% silicon, while Si/Sb₂O₃ had the lowest (10 ÷ 35 mm s⁻¹). The calorimetric heat of combustion varied between 1200 J g⁻¹ and 1400 J g⁻¹, with adiabatic combustion temperatures reaching 2200 K, calculated from this heat. DTA and XRD confirmed the condensed-phase combustion, forming reduced metal phases and silicon oxides. SEM and EDS revealed a porous residue structure. This work introduces a novel approach to time-delay compositions using silicon as a primary fuel. It shows that specific silicon oxide–metal systems maintain stable combustion for different loading pressures and advance pyrotechnic formulations for safer and more efficient industrial and defense applications. Full article

Microbes have been shown to adapt to stressful or even lethal conditions through displaying genome plasticity. However, how bacteria utilize the ability of genomic plasticity to deal with high antimony (Sb) stress has remained unclear. In this study, the spontaneous mutant strain SMAs-55 of Achromobacter sp. As-55 was obtained under antimonite (Sb(III)) stress. SMAs-55 displayed significantly increased Sb(III) resistance, but it lost the ability to oxidize arsenite (As(III)) by deleting an entire gene island containing genes encoding functions involved in As(III) oxidation, arsenic (As)/Sb resistance and phosphate transport. This study suggests that genetic plasticity has played an important role in As-55 adaption to Sb(III) stress. Transcriptomic analysis found that genes encoding functions involved in capsule polysaccharide synthesis, as well as functions correlated to stress adaptation, ATP production, and metabolism were more strongly expressed in SMAs-55. In addition, a lower intracellular Sb(III) accumulation in SMAs-55 was observed. These findings indicate that reduced uptake through increased capsule biosynthesis was an effective way for SMAs-55 to adapt to an environment displaying high levels of Sb. This study helps us to better understand the evolutionary processes enabling survival of microbes and microbial community in contaminated environments. Full article

Effective wastewater treatment remains a critical challenge, especially when dealing with hazardous pollutants like antimony (Sb(III)). This study addresses this issue by using innovative nanocomposites to remove Sb(III) ions from water, while simultaneously repurposing the spent adsorbents for energy storage applications. We developed reduced graphene oxide-NiFe₂O₃-SiO₂-polyindole nanocomposites (RGO-NiFe₂O₃-SiO₂-PIn NCs) via a hydrothermal synthesis method, achieving a high removal efficiency of 91.84% for Sb(III) ions at an initial concentration of 50 mg/L at pH 8. After adsorption, the exhausted adsorbent was repurposed for energy storage, effectively minimizing secondary pollution. The Sb(III)-loaded adsorbent (RGO-NiFe₂O₃-SiO₂-PIn@SbO_x) exhibited excellent performance as an energy storage material, with a specific capacitance (C_s) of 701.36 F/g at a current density of 2 A/g and a retention rate of 80.15% after 10,000 cycles. This dual-purpose approach not only advances wastewater treatment technologies but also contributes to sustainable and economical recycling practices, particularly in the field of energy storage. Full article

Antimony (Sb) is currently a widespread element with key roles in telecommunication, sustainable energy, and military industries, among others. Its significant toxicity determines the need to realize sensors for water, air, and soil and the industrial process monitoring of Sb species. Unfortunately, no antimony sensors exist so far, and just laboratory analysis methods are in use. We aimed to contribute to the development of optical sensors for the metalloid by tailoring, for the first time, luminescent Ru(II) and Re(I) polypyridyl complexes to probe and quantify the presence of Sb(III). The molecular design of the complexes includes the multifunctional Sb-binding 2-(2,2′-bithien-5-yl)-1H-imidazo[4,5-f]-1,10-phenanthroline (btip) ligand that ensures the molecular binding of Sb(III) in organic media. The Ru(II)-btip complex is additionally endowed with one 2,2′-bipyrazine (bpz) or two 1,4,5,8-tetraazaphenanthrene (tap) ligands, namely [Ru(bpz)(btip)₂]²⁺ and [Ru(tap)₂(btip)]²⁺, that boost the excited state oxidation potential of the probe, leading to an intramolecular photoinduced electron transfer from btip to the Ru(II) core. The latter is suppressed upon interaction with Sb(III), leading to an 11-fold increase in both the luminescence intensity and lifetime of [Ru(bpz)(btip)₂]²⁺ in the presence of ca. 50 μmol L⁻¹ of SbCl₃ in organic medium. The fluorescence intensity of [Re(CO)₃(H₂O)(btip)]⁺ also increases upon interaction with Sb(III) but to a much lesser extent due to the intraligand π*→π nature of its emission compared to the Ru(II) ligand-to-metal excited state deactivation. However, the weak π*→d emission band in the red spectral region of the former is quenched by the semimetallic element. The sensing mechanisms of the Ru(II)- and Re(I)-btip probes that allow luminescence intensity (Ru, Re), ratiometric (Ru), and lifetime measurements (Ru) are compared and discussed in this initial solution sensing study. Full article

This study introduces a series of Fe/Mn-GOCS composites using high-temperature impregnation with graphene oxide and chitosan as substrates, modified by diverse manganese salts, including MnCl₂∙4H₂O, KMnO₄, and MnSO₄. Among these, FeCl₂/MnSO₄-GOCS demonstrated the highest adsorption capacity for Sb(III), peaking at 57.69 mg/g. The adsorption performance was extensively evaluated under various conditions, such as different initial concentrations, pH levels, solid–liquid ratios, and adsorption durations. It was observed that when the Fe/Mn molar ratio exceeded 4:1, there was a notable decrease in both the adsorption capacity and removal rate. Kinetic analyses using the pseudo-second-order model revealed a better fit (R² > 0.99) compared to the pseudo-first-order model, indicating that chemisorption dominated the adsorption process. Additionally, isothermal modeling highlighted the efficiency of Fe/Mn-GOCS, particularly in high-concentration environments, with the Sips model demonstrating the best fit, integrating characteristics of both Langmuir and Freundlich models. These results not only offer a robust theoretical and practical basis for efficient Sb(III) removal but also underscore the potential of multi-metal-modified adsorbents as sustainable solutions for environmental remediation. Full article

Antimony (Sb) is one of the most concerning toxic metals globally, making the study of methods for efficiently removing Sb(III) from water increasingly urgent. This study uses graphene oxide and chitosan as the matrix (GOCS), modifying them with FeCl₂ and four MnO_x to form iron–manganese oxide (FM/GC) at a Fe/Mn molar ratio of 4:1. FM/GC quaternary composite microspheres are prepared, showing that FM/GC obtained from different MnO_x exhibits significant differences in the ability to remove Sb(III) from neutral solutions. The order of Sb(III) removal effectiveness is MnSO₄ > KMnO₄ > MnCl₂ > MnO₂. The composite microspheres obtained by modifying GOCS with FeCl₂ and MnSO₄ are selected for further batch experiments and characterization tests to analyze the factors and mechanisms influencing Sb(III) removal. The results show that the adsorption capacity of Sb(III) decreases with increasing pH and solid–liquid ratio, and gradually increases with the initial concentration and reaction time. The Langmuir model fitting indicates that the maximum adsorption capacity of Sb(III) is 178.89 mg/g. The adsorption mechanism involves the oxidation of the Mn-O group, which converts Sb(III) in water into Sb(V). This is followed by ligand exchange and complex formation with O-H in FeO(OH) groups, and further interactions with C-OH, C-O, O-H, and other functional groups in GOCS. Full article

Antimony and arsenic, which have a high carcinogenicity, should be removed depending on their ionic charge in water. Therefore, we attempted to confirm the adsorption characteristics of antimony and arsenic considering ionic charge to improve removal efficiency. We used palm-based activated carbon (PAC), coal-based activated carbon (CAC), modified activated carbon (MAC), styrene-divinylbenzene copolymer (SP825), activated alumina (AA), and zeolite as adsorbents for antimony and arsenic. Negatively charged adsorbents (CAC, PAC, MAC, and zeolite) with similar zeta potentials showed better removal efficiency as the surface area increased. However, SP825, which is almost neutral, and AA, which is positively charged, exhibited a high removal efficiency (100%) for arsenic and Sb(V), which are anions, regardless of surface area. However, due to the price, coal-based activated carbon or palm-based activated carbon is considered more advantageous than using AA or SP825. Last, during the arsenic adsorption process, As(III) was oxidized to As(V) due to Fe(II) contained in activated carbon. The addition of activated carbon can improve oxidation efficiencies of As(III) before coagulation and precipitation, in which As(V) is easier to remove than As(III). Full article

The aim and the novelty of the present review article was to provide the literature with a collective study focusing on the migration and safety issues in plastic food packaging materials that have been raised in recent years and proposing the use of safer and biodegradable ones. The conventional packaging materials used for the preservation of foods may exhibit many disadvantages that are related to the migration of micromolecular chemical substances incorporated in the packaging material net to the packaged food. There are many chemical substances in the matrix of plastic packaging materials and epoxy-resins that are used in food packaging materials, varnishes, and can coatings. Many migrants have high toxicity, such as acetaldehyde, antimony, antimony (III) oxide, 2,4-di-tert-butylphenol, tris (2,4-di-tert-butylphenol) phosphate, tris(2,4-di-tert-butylphenyl) phosphite, bisphenol A, and the plasticizers di(2-ethylhexyl) phthalate), di-n-butyl phthalate, benzyl-butylphthalate, di-isononylphthalate, and di-isododecylphthalate. It is therefore necessary to take a detailed look at the migrants in conventional packaging materials (plastics) used for foods, point out the migration of certain compounds into foods and the need to reconsider their use, and establish updated protocols for the safety of consumers and the industrial production of biodegradable packaging materials (films or coatings) based on natural sources. Full article

Natural limonite, which contains mainly nano-sized iron and manganese oxides, is widely distributed worldwide. This study investigated the kinetics, thermodynamics, and the effects of pH, ion strength, and anions on the adsorption of Sb(III) via limonites sampled from Xinqiao and Yeshan (Tongling, China). Results show that adsorption equilibrium is achieved after 24 h for all experiments. Under initial Sb(III) = 200 mg/L, pH = 3.0, and temperature = 25 °C, Sb adsorption quantities for X1 (Mn-free limonite from Xinqiao), X2 (Mn-containing limonite from Xinqiao), Y1 (Mn-free limonite from Yeshan), and Y2 (Mn-containing limonite from Yeshan) are 10.92, 12.97, 27.12, and 89.34 mg/g, respectively. Manganese oxides in limonites promote Sb removal through oxidizing Sb(III) to Sb(V). The adsorption processes for all four limonites are fitted with a pseudo-second-order model. All adsorptions except for X1 fit with the Freundlich model; for X1, the Langmuir adsorption model is better. All adsorptions are spontaneous reactions (ΔG < 0). All adsorptions except for Y1 (ΔH < 0, exothermic reaction) are endothermic reactions (ΔH > 0). Antimony adsorption is independent of solution pH for Mn-free limonites but is negatively related to solution pH for Mn-containing limonites. Generally, ion strength has a weak positive effect on Sb adsorption. The effects of anions on Sb adsorption are grouped into three types: weak negative (NO₃⁻ and SO₄²⁻), negative (CO₃²⁻, SiO₄⁴⁻, and PO₄³⁻), and equivocal (humic acid). This study indicates that due to a much higher surface area, Yeshan (124.8 m²/g for X1 and 171.7 m²/g for X2) rather than Xinqiao (13.7 m²/g for Y1 and 12.8 m²/g for Y2) limonites are better materials for Sb(III) removal in an aqueous solution. The key factors for the better use of limonite as an Sb(III) treatment material include temperature, pH, ion strength, and Mn content. Full article

In this study, the iridium nanodendrites (Ir NDs) and antimony tin oxide (ATO)-supported Ir NDs (Ir ND/ATO) were prepared by a surfactant-mediated method to investigate the effect of ATO support and evaluate the electrocatalytic activity for the oxygen evolution reaction (OER). The nano-branched Ir ND structures were successfully prepared alone or supported on ATO. The Ir NDs exhibited major diffraction peaks of the fcc Ir metal, though the Ir NDs consisted of metallic Ir as well as Ir oxides. Among the Ir ND samples, Ir ND2 showed the highest mass-based OER catalytic activity (116 mA/mg at 1.8 V), while it suffered from high degradation in activity after a long-term test. On the other hand, Ir ND2/ATO had OER activity of 798 mA/mg, and this activity remained >99% after 100 cycles of LSV and the charge transfer resistance increased by less than 3 ohm. The enhanced durability of the OER mass activities of Ir ND2/ATO catalysts over Ir NDs and Ir black could be attributed to the small crystallite size of Ir and the increase in the ratio of Ir (III) to Ir (IV), improving the interactions between the Ir NDs and the ATO support. Full article

The emergence of mixed matrix membranes (MMMs) or nanocomposite membranes embedded with inorganic nanoparticles (NPs) has opened up a possibility for developing different polymeric membranes with improved physicochemical properties, mechanical properties and performance for resolving environmental and energy-effective water purification. This paper presents an overview of the effects of different hydrophilic nanomaterials, including mineral nanomaterials (e.g., silicon dioxide (SiO₂) and zeolite), metals oxide (e.g., copper oxide (CuO), zirconium dioxide (ZrO₂), zinc oxide (ZnO), antimony tin oxide (ATO), iron (III) oxide (Fe2O3) and tungsten oxide (WO_X)), two-dimensional transition (e.g., MXene), metal–organic framework (MOFs), covalent organic frameworks (COFs) and carbon-based nanomaterials (such as carbon nanotubes and graphene oxide (GO)). The influence of these nanoparticles on the surface and structural changes in the membrane is thoroughly discussed, in addition to the performance efficiency and antifouling resistance of the developed membranes. Recently, GO has shown a considerable capacity in wastewater treatment. This is due to its nanometer-sized holes, ultrathin layer and light and sturdy nature. Therefore, we discuss the effect of the addition of hydrophilic GO in neat form or hyper with other nanoparticles on the properties of different polymeric membranes. A hybrid composite of various NPs has a distinctive style and high-quality products can be designed to allow membrane technology to grow and develop. Hybrid composite NPs could be used on a large scale in the future due to their superior mechanical qualities. A summary and future prospects are offered based on the current discoveries in the field of mixed matrix membranes. This review presents the current progress of mixed matrix membranes, the challenges that affect membrane performance and recent applications for wastewater treatment systems. Full article