Common Ions Research Articles

Research on Discriminant Model of Water Inrush Source By Principal Component-cluster Analysis in Jiaozuo Mining Area

This paper takes Jiaozuo Mining Area as the research object, based on the analysis of the hydrogeological conditions of the mining area, expounds the characteristics of coal strata, aquifers and groundwater recharge, runoff and discharge in the mining area; analyses the water inrush sources and water diversion channels in the mining area, analyses the routine water chemical data of each aquifer in the mining area, draws the piper three-line diagram and confirms it. To determine the hydrochemical type of groundwater in aquifer, six common water chemical ions are used as discriminant factors, a discriminant model of water inrush source is established by combining principal component analysis and cluster analysis, and the principal component of conventional water chemical ions is extracted as cluster variable to discriminate Water Inrush Source in Jiaozuo Mining Area. In order to prove the rationality and validity of the model, another group of inrush sources in Jiaozuo Mining Area is discussed. The water sample data are discriminated and the results obtained by cluster analysis are compared to verify the accuracy of the model. The results show that the model is feasible. To sum up, the identification model of inrush water source by principal component-cluster analysis can accurately and effectively identify the source of inrush water in Jiaozuo Mining Area.

CdS/ZnS quantum dots based on an amphipathic polymer platform for fluorescent probe of dopamine with high sensitivity and selectivity

Due to the widespread presence of dopamine in living organisms and its physiological and pharmacological effects, developing rapid and sensitive methods for detecting dopamine has been of great significance. Fluorescent probes are a commonly used and highly sensitive detection method. In this work, based on a self-developed amphipathic polymer template, CdS/ZnS fluorescent quantum dots (QDs) with a maximum absorption wavelength of 500–550 nm were synthesized and characterized. They exhibited stable fluorescence in the pH range from weak acid to alkaline, and fluorescence quenching occurred at pH = 4.5. The QDs could be applied as fluorescent probes for detecting dopamine, with a limit of detection 0.027 mM and high selectivity, unaffected by common metal ions, amino acids, glucose, etc. Compared to the high activity of dopamine being oxidized easily, this fluorescent QDs and its template polymer PEI played a stabilizing role during the testing process. Therefore, this work provides a promising dopamine fluorescent probe with application prospects.

Cobalt-Modified Black Phosphorus Nanosheets-Enabled Ferrate (VI) Activation for Efficient Chemiluminescence Detection of Thiabendazole.

The development of chemiluminescence-based innovation sensing systems and the construction of a sensing mechanism to improve the analytical performance of compounds remain a great challenge. Herein, we fabricated an advanced oxidation processes pretreated chemiluminescence (AOP-CL) sensing system via the introduction of cobalt-modified black phosphorus nanosheets (Co@BPNs) to achieve higher efficient thiabendazole (TBZ) detection. Co@BPNs, enriched with lattice oxygen, exhibited a superior catalytic performance for accelerating the decomposition of ferrate (VI). This Co@BPNs-based ferrate (VI) AOP system demonstrated a unique ability to selectively decompose TBZ, resulting in a strong CL emission. On this basis, a highly selective and sensitive CL sensing platform for TBZ was established, which exhibited strong resistance to common ions and pesticides interference. This was successfully applied to detecting TBZ in environmental samples such as tea and kiwi fruits. Besides, the TBZ detection mechanism was explored, Co@BPNs-based ferrate (VI) AOP system produced a high yield of ROS (mainly 1O2), which oxidized the thiazole-based structure of TBZ, generating chemical energy that was transferred to Co@BPNs via a chemical electron exchange luminescence (CIEEL) mechanism, leading to intense CL emission. Notably, this study not only proposed an innovative approach to enhance the chemical activity and CL properties of nanomaterials but also offered a new pathway for designing efficient CL probes for pollutant monitoring in complex samples.

Indium(III) complexes: application as organic catalyst, precursor for chalcogenides nanoparticles and starting materials in the industry

AbstractTrivalent indium ions are not toxic like the common ions, and this implies that there are limited secondary pollution associated with their photoconversion processes. They are therefore a preferred choice for several applications. However, they are not used in their ionic form. Their salts are reacted with various organic ligands to form different trivalent complexes of indium for these applications. Herein, the use of different trivalent complexes as catalysts in organic synthesis are discussed. Their usage as a precursor of indium oxide, indium sulfide, indium tellurides and indium selenides are examined. In addition, their application as organic light-emitting diodes (OLEDs), sensor, photovoltaic and luminous materials are discussed. Finally, gaps and/or areas for future research are highlighted.

Acridinedione-based fluorescence ‘turn-off’ sensor for real-time detection of carcinogenic Cr (VI) ions

This research introduces AR-1, a newly developed chemosensor tailored for Cr (VI) ion detection in semi-aqueous solutions. AR-1 demonstrates notable alterations in coloration and reduced fluorescence output upon interaction with Cr (VI) ions, showing remarkable selectivity even amidst other interfering metal ions. Fluorescence spectral titrations were employed to ascertain the binding constant and detection thresholds of the AR-1-Cr (VI) complex, with LOD and LOQ established at 0.639 µM and 0.021 μM, respectively. Further characterization via 1H NMR titrations, DFT calculations, Job’s plot, and HRMS analysis provided insights into the detection mechanism. The probe proved dependable within a pH range of 3.0 to 11.0, displaying resilience against interference from common metal ions. Overall, AR-1 presents a direct and efficient means for Cr (VI) ion detection in environmental samples, offering a promising alternative to traditional detection methods.

A compact and high-performance setup of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D).

Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has the advantages of high throughput (simultaneous detection of multiple ions), high separation efficiency (higher than 105 theoretical plates) and rapid analysis capability (less than 5 min for common inorganic ions). A compact CE-C4D system is ideal for water quality control and on-site analysis. It is suitable not only for common cations (e.g. Na+, K+, Li+, NH4+, Ca2+, etc.) and anions (e.g. Cl-, SO42-, BrO3-, etc.) but also for some ions (e.g. lanthanide ions, Pb2+, Cd2+, etc.) that require complex derivatization procedures to be detected by ion chromatography (IC). However, an obvious limitation of the CE-C4D method is that its sensitivity (e.g. 0.3-1 μM for common inorganic ions) is often insufficient for trace analysis (e.g. 1 ppb or 20 nM level for common inorganic ions) without preconcentration. For this technology to become a powerful and routine analytical technique, the system should be made compact while maintaining trace analysis sensitivity. In this study, we developed an all-in-one version of the CE-C4D instrument with custom-made modular components to make it a convenient, compact and high-performance system. The system was designed using direct digital synthesis (DDS) technology to generate programmable sinusoidal waveforms with any frequency for excitation, a kilovolt high-voltage power supply for capillary electrophoresis separation, and an "effective" differential C4D cell with a low-noise circuitry for high-sensitivity detection. We characterized the system with different concentrations of Cs+, and even a low concentration of 20 nM was detectable without preconcentration. Moreover, the optimized CE-C4D setup was applied to analyse mixed ions at a trace concentration of 200 nM with excellent signal-to-noise ratios. In typical applications, the limits of detection based on the 3σ criterion (without baseline filtering) were 9, 10, 24, 5, and 12 nM for K+, Cs+, Li+, Ca2+, and Mg2+, respectively, and about 7, 6, 6 and 6 nM for Br-, ClO4-, BrO3- and SO42-, respectively. Finally, the setup was also applied for the analysis of all 14 lanthanide ions and rare-earth minerals, and it showed an improvement in sensitivity by more than 25 times.

Ultrafast photosensitized degradation of xanthates by using methylene blue as photosensitizer under simulated and natural solar light irradiation: Operational parameters, mechanism and toxicity evolution

Xanthates have attracted considerable attention due to their broad applications in mineral flotation process and unique natures including environmental persistence and toxicity. This study proposed an innovative approach for the efficient xanthates treatment from mineral processing wastewater. Methylene blue (MB) with good water solubility and strong light absorption in visible range was used as the photosensitizer to degrade potassium ethyl xanthate (PEX) under homogeneous conditions. MB, even at a very low concentration (0.5 mg/L), was found to rapidly remove PEX in only 10 min whether under simulated or natural solar light irradiation. Besides, the influences of various operational parameters, including photosensitizer dosage, PEX concentration, pH, light intensity, common ions, and water source on the photosensitized oxidation process was evaluated and analyzed. The possible degradation path of PEX was investigated depending on the intermediates detected by Liquid chromatography-mass spectrometry (LC-MS), and the photosensitized degradation mechanism was further speculated and validated by the radicals quenching experiments and electron paramagnetic resonance (EPR) spectroscopy. Furthermore, the toxicity of PEX was assessed against Bullfrog tadpole and Lemna minor, and it was found to be greatly reduced after treating with MB photosensitization. Overall, it is the first time that MB is proved to be an outstanding candidate for actual flotation wastewater treatment, providing a more efficient, economical and greener alternative to conventional methods.

Insights on the in-vitro binding characteristics of human α-1-acid glycoprotein (HAG) with JAK inhibitor ocalcitinib: Multi-spectroscopic analysis combined with theoretical calculations

A powerful Janus kinase (JAK) inhibitor, ocalcitinib has been authorized for controlling pruritus and atopic dermatitis from canine allergic dermatitis and many kinds of cytokines. To further understand the drug action, the interaction between ocalcitinib and HAG was explored using multi-spectroscopic approaches combined with theoretical calculations. The results demonstrated that ocalcitinib effectively quenched the intrinsic fluorescence of HAG protein through a mixed quenching and formed a stable ocalcitinib–HAG complex that had the association constant of 104–105M−1, outlining that ocalcitinib binding to HAG protein had a moderate affinity. In the ocalcitinib–HAG complex, ocalcitinib implanted into the bucket-shaped hydrophobic chamber of HAG, leading to the slight variety in the hydrophobicity of the microenvironment encircled Trp-and Tyr-resides as well as the secondary structure of HAG. And, the driving forces that forms the ocalcitinib-HAG complex were mainly the hydrogen bonding interaction, Van der Waals forces, and hydrophobic interaction. It is also confirmed that the common metal ions like Ca2+, Mg2+, Fe3+, Zn2+, Cu2+, Co2+, Ni2+ ions) except K+ ion had a greater negative influence on the complexation between ocalcitinib and HAG. This study should conducive to estimating the pharmacological natures of ocalcitinib, comprehending the distribution and operation of the drug in the body, and developing novel medication devise.

Colorimetric probe for the determination of osmium through a novel optical sensor in environmental samples

A novel optical probe has been successfully developed for the selective detection of Os(VIII) ions. This osmium-sensing platform was intricately designed by incorporating 4-(thiazol-2-yldiazenyl)benzene-1,3-diol (TDBD) as the ionophore within a plasticized PVC membrane, and tributylphosphate (TBP) serving as the plasticizer. Upon exposure to Os(VIII) ions in a 0.5 M HClO4 acid milieu, the sensing membrane undergoes a distinctive chromatic transition, shifting from a yellow to a pink hue. The preparation of the sensor and the methodology for Os(VIII) determination were meticulously refined to achieve optimal performance. Under these carefully optimized experimental conditions, the proposed optode demonstrated an impressive linear detection range spanning from 2.5 × 10−9 to 2.5 × 10−5 M for Os(VIII), alongside remarkable detection and quantification limits of 7.24 × 10−10 and 2.4 × 10−9 M, respectively. The sensor consistently delivered highly reproducible results, as evidenced by relative standard deviation (RSD) values of 1.45% and 1.30% for Os(VIII) concentrations at 7.5 × 10−7 and 2.5 × 10−6 M, respectively, underscoring its precision and reliability. Furthermore, the sensor exhibited a swift response time of 3.0 min, further emphasizing its efficiency. The incorporation of PIMs into the sensor architecture led to a remarkable eight-fold enhancement in its response compared to counterparts lacking PIMs, signifying a significant performance improvement. In assessing potential interference, an investigation into the influence of other ions on Os(III) determination revealed that the prepared sensor displayed exceptional selectivity for Os(VIII) ions, with negligible responses observed in the presence of common ions. Collectively, these experimental findings underscore the sensor's efficacy as an invaluable tool for the precise analysis of osmium content in water samples, aligning it with the rigorous standards of international scientific research.

Highly Selective and Portable Fluorescence Turn-On Detection of Sc3+ in Ore and Water Based on Strong Lewis Acid-Base Coordination.

Detecting scandium (Sc) with high selectivity and sensitivity is a challenging task due to its chemical similarity to other rare earth ions. Our findings show that the fluorescence of the complex fluorescent indicator calcein (CL) is quenched under acidic conditions (pH = 2), and Sc3+ strongly inhibits this process. The results demonstrate that CL forms multimers and precipitates out of the solution under acidic conditions, while Sc3+ causes a significant decrease in the scattering intensity of the solution. Additional experiments revealed that the strong Lewis acid nature of Sc3+ complexes with the carboxyl groups of CL leads to increased dispersion of CL even under acidic conditions, thus enhancing its absorption and fluorescence. The complexation ratio of Sc3+ and CL was investigated through spectral titrations and theoretical calculations. The interaction between Sc3+ and CL is the strongest among rare earth and common metal ions due to the smallest ionic radius, resulting in high selectivity. The fluorescence turn-on strategy had a linear range of 0.04 to 2.25 μM under optimal conditions, with a detection limit of 20 nM for Sc3+. The combination of 3D printing and a smartphone program allows for portable on-site analysis of Sc3+. Mineral and water samples were used to demonstrate the potential of this strategy for the rapid, selective, and sensitive analysis of low levels of Sc3+.

Adsorption removal of cationic dyes from wastewater using the corn straw modified with diethylenetriaminepentacetic acid ligand

Taking the thiazide cationic dye methylene blue (MB), triphenylmethane cationic dye crystal violet (CV), monoazo cationic dye cationic red 46 (R-46), and polycarboxycyanine cationic dye cationic rosé FG (P-FG) as the research objects, the adsorption behaviors of a self-made corn straw modified adsorbent HQ-DTPA-I for the dyes were investigated in depth. Under optimized conditions, HQ-DTPA-I can quickly adsorb most dyes within 3 min and reach equilibrium adsorption in 15–20 min. The removal rates of HQ-DTPA-I to MB, CV, R-46 and AP-FG can reach 95.28 %, 99.78 %, 99.28 % and 98.53 %, respectively. It also has good anti-interference ability for common ions present in most actual dye wastewater. For six consecutive adsorption-desorption cycles, the adsorption performance of HQ-DTPA-I can still reach 80.17 %, 81.61 %, 90.77 % and 83.48 % of the initial adsorption capacity, indicating good recovery performance. Based on Gaussian density functional theory to calculate its surface potential energy, it is found that the adsorption mechanism of HQ-DTPA-I for the cationic dyes is mainly due to the electrostatic interaction between the carboxyl groups in ligand DTPA and amino groups in dye molecules.

A near-infrared fluorescent ratiometric probe with large Stokes shift for multi-mode sensing of Pb2+ and bioimaging

Pb2+ is a heavy metal ion pollutant that poses a serious threat to human health and ecosystems. The conventional methods for detecting Pb2+ have several limitations. In this study, we introduce a novel fluorescent probe that enables the detection of Pb2+ in the near-infrared region, free from interference from other common ions. A unique characteristic of this probe is its ability to rapidly and accurately identify Pb2+ through ratiometric measurements accompanied by a large Stokes shift of 201 nm. The limit of detection achieved by probe was remarkably low, surpassing the standards set by the World Health Organization, and outperforming previously reported probes. To the best of our knowledge, this is the first organic small-molecule fluorescent probe with both near-infrared emission and ratiometric properties for the detection of Pb2+. We present a triple-mode sensing platform constructed using a probe that allows for the sensitive and selective recognition of Pb2+ in common food items. Furthermore, we successfully conducted high-quality fluorescence imaging of Pb2+ in various samples from common edible plants, HeLa cells, Caenorhabditis elegans, and mice. Importantly, the probe-Pb2+ complex exhibited tumour-targeting capabilities. Overall, this study presents a novel approach for the development of fluorescent probes for Pb2+ detection.

From salt water to bioceramics: Mimic nature through pressure-controlled hydration and crystallization.

Modern synthetic technology generally invokes high temperatures to control the hydration level of ceramics, but even the state-of-the-art technology can still only control the overall hydration content. Magically, natural organisms can produce bioceramics with tailorable hydration profiles and crystallization traits solely from amorphous precursors under physiological conditions. To mimic the biomineralization tactic, here, we report pressure-controlled hydration and crystallization in fabricated ceramics, solely from the amorphous precursors of purely inorganic gels (PIGs) synthesized from biocompatible aqueous solutions with most common ions in organisms (Ca2+, Mg2+, CO32-, and PO43-). Transparent ceramic tablets are directly produced by compressing the PIGs under mild pressure, while the pressure regulates the hydration characteristics and the subsequent crystallization behaviors of the synthesized ceramics. Among the various hydration species, the moderately bound and ordered water appears to be a key in regulating the crystallization rate. This nature-inspired study offers deeper insights into the magic behind biomineralization.

A Machine Learning-Driven Comparison of Ion Images Obtained by MALDI and MALDI-2 Mass Spectrometry Imaging.

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) enables label-free imaging of biomolecules in biological tissues. However, many species remain undetected due to their poor ionization efficiencies. MALDI-2 (laser-induced post-ionization) is the most widely used post-ionization method for improving analyte ionization efficiencies. Mass spectra acquired using MALDI-2 constitute a combination of ions generated by both MALDI and MALDI-2 processes. Until now, no studies have focused on a detailed comparison between the ion images (as opposed to the generated m/z values) produced by MALDI and MALDI-2 for mass spectrometry imaging (MSI) experiments. Herein, we investigated the ion images produced by both MALDI and MALDI-2 on the same tissue section using correlation analysis (to explore similarities in ion images for ions common to both MALDI and MALDI-2) and a deep learning approach. For the latter, we used an analytical workflow based on the Xception convolutional neural network, which was originally trained for human-like natural image classification but which we adapted to elucidate similarities and differences in ion images obtained using the two MSI techniques. Correlation analysis demonstrated that common ions yielded similar spatial distributions with low-correlation species explained by either poor signal intensity in MALDI or the generation of additional unresolved signals using MALDI-2. Using the Xception-based method, we identified many regions in the t-SNE space of spatially similar ion images containing MALDI and MALDI-2-related signals. More notably, the method revealed distinct regions containing only MALDI-2 ion images with unique spatial distributions that were not observed using MALDI. These data explicitly demonstrate the ability of MALDI-2 to reveal molecular features and patterns as well as histological regions of interest that are not visible when using conventional MALDI.

Feasibility of phenolic contaminant removal from high-saline wastewater by chloride-mediated activation of peroxymonosulfate (PMS) and peracetic acid (PAA)

Phenolic pollutants are highly toxic and can affect the growth and reproduction of aquatic organisms, as well as contaminate drinking water resources, posing a significant threat to both ecological and human health. However, conventional biological treatment processes are constrained in treating high salinity organic wastewaters due to the potentially lethal effects of high concentrations of dissolved salts on microorganisms. While advanced oxidation processes have shown promise in removing phenolic contaminants from high-saline wastewater, their widespread application is always limited by the high costs associated with energy and chemical usage. In this study, we explored the potential application of directly introducing peroxymonosulfate (PMS) and peracetic acid (PAA) to high-salinity water for the removal of nine phenolic contaminants. By establishing a correlation between the degradation rate constants in the PMS/Cl– (kPMS) and PAA/Cl– (kPAA) systems and various molecule descriptors, two multiple linear regression models were developed to predict the degradation rate constants under investigation. Additionally, we selected bisphenol A (BPA) as the target contaminant and investigated the impact of common ions found in natural water, such as HCO3–, NO3–, and humic acid, on the removal of BPA using two systems. Finally, we conducted experiments using tap water and sewage water to demonstrate the practical application and performance of the two systems. These experiments aimed to provide valuable insights into the influence of background chloride on PMS and PAA activation, as well as the potential of direct PMS/PAA introduction for eliminating phenolic micropollutants from high-saline wastewaters.

Iodine Adsorption-Desorption-Induced Structural Transformation and Improved Ag+ Turn-On Luminescent Sensing Performance of a Nonporous Eu(III) Metal-Organic Framework.

Posttreatment of pristine metal-organic frameworks (MOFs) with suitable vapor may be an effective way to regulate their structures and properties but has been less explored. Herein, we report an interesting example in which a crystalline nonporous Eu(III)-MOF was transferred to a porous amorphous MOF (aMOF) via iodine vapor adsorption-desorption posttreatment, and the resulting aMOF showed improved turn-on sensing properties with respect to Ag+ ions. The crystalline Eu-MOF, namely, Eu-IPDA, was assembled from Eu(III) and 4,4'-{4-[4-(1H-imidazol-1-yl)phenyl]pyridine-2,6-diyl}dibenzoic acid (H2IPDA) and exhibited a two-dimensional (2D) coordination network based on one-dimensional secondary building blocks. The close packing of the 2D networks gives rise to a three-dimensional supramolecular framework without any significant pores. Interestingly, the nonporous Eu-IPDA could absorb iodine molecules when Eu-IPDA crystals were placed in iodine vapor at 85 °C, and the adsorption capacity was 1.90 g/g, which is comparable to those of many MOFs with large BET surfaces. The adsorption of iodine is attributed to the strong interactions among the iodine molecule, the carboxy group, and the N-containing group and leads to the amorphization of the framework. After immersion of the iodine-loaded Eu-IPDA in EtOH, approximately 89.7% of the iodine was removed, resulting in a porous amorphous MOF, denoted as a-Eu-IPDA. In addition, the remaining iodine in the a-Eu-IPDA framework causes strong luminescent quenching in the fluorescence emission region of the Eu(III) center when compared with that in Eu-IPDA. The luminescence intensity of a-Eu-IPDA in water suspensions was significantly enhanced when Ag+ ions were added, with a detection limit of 4.76 × 10-6 M, which is 1000 times that of pristine Eu-IPDA. It also showed strong anti-interference ability over many common competitive metal ions and has the potential to sense Ag+ in natural water bodies and traditional Chinese medicine preparations. A mechanistic study showed that the interactions between Ag+ and the absorbed iodine, the carboxylate group, and the N atoms all contribute to the sensing performance of a-Eu-IPDA.

MetabCombiner 2.0: Disparate Multi-Dataset Feature Alignment for LC-MS Metabolomics.

Liquid chromatography-high-resolution mass spectrometry (LC-HRMS), as applied to untargeted metabolomics, enables the simultaneous detection of thousands of small molecules, generating complex datasets. Alignment is a crucial step in data processing pipelines, whereby LC-MS features derived from common ions are assembled into a unified matrix amenable to further analysis. Variability in the analytical factors that influence liquid chromatography separations complicates data alignment. This is prominent when aligning data acquired in different laboratories, generated using non-identical instruments, or between batches from large-scale studies. Previously, we developed metabCombiner for aligning disparately acquired LC-MS metabolomics datasets. Here, we report significant upgrades to metabCombiner that enable the stepwise alignment of multiple untargeted LC-MS metabolomics datasets, facilitating inter-laboratory reproducibility studies. To accomplish this, a "primary" feature list is used as a template for matching compounds in "target" feature lists. We demonstrate this workflow by aligning four lipidomics datasets from core laboratories generated using each institution's in-house LC-MS instrumentation and methods. We also introduce batchCombine, an application of the metabCombiner framework for aligning experiments composed of multiple batches. metabCombiner is available as an R package on Github and Bioconductor, along with a new online version implemented as an R Shiny App.

Molten salt mediated single-step synthesis of reusable nanostructured CaTiO3 for the removal and recovery of Sr2+: A potential adsorbent for the contaminated water bodies

The facile synthesis approach for the adsorbent preparation and recyclability during decontamination of radioactive pollutants is a significant concern in water treatment. The objective of this study is to, synthesis via solid-state reaction of the nanostructured CaTiO3 for the removal and recovery of strontium (Sr2+) from the various water sources. The influence of the adsorption-dependent parameters including, initial concentration, adsorbent dose, pH, contact time and co-existing ions interference were investigated. The prepared adsorbent was characterized by different analytical techniques like FT-IR, SEM with EDAX, TEM, TGA-DTG, Powder XRD and BET surface analysis. The kinetic models were also used, and according to the kinetic models, a pseudo-second-order kinetic model (R2 = 0.999) was better fitted to the adsorption of Sr2+ ions onto CaTiO3 rather than pseudo-first-order kinetics, which could properly represent the observed adsorption of Sr2+. For the isotherm study, the results are best fitted to the Langmuir isotherm model (R2 = 0.98) with a maximum adsorption capacity of 102.04 mg/g. The common ions (Na+, Mg2+, Ca2+, and K+) and Sr2+ having a concentration of 1:2, 1:3, and 1:4, where 82.8, 79.5, and 68.2 % removal was achieved of Sr2+ in each respective matrix. In addition, the adsorption and corresponding recovery and removal for the different Sr2+spiked matrices in deionized water, tap water, well water, lake water, and seawater were investigated with 97, 65.6, 76.5, 73.9 and 17.8 % removal respectively. Also, the CaTiO3 showed excellent recyclability with minimal loss even after 5 consecutive recyclability cycles and >90% removal of strontium achieved. Hence, prepared nanostructured CaTiO3 could be considered a promising adsorbent for the removal and recovery of Sr2+ions from contaminated water bodies.

In-situ pH monitoring of pre-notched X80 pipeline steel using an all-solid-state Pt/RuOx ultra-micro pH sensor

In the notch microenvironment caused by the stress corrosion of pipeline steel, the local pH value changes mediated by anodic-cathodic corrosion reactions played an important role in comprehending the local corrosion behavior. To address this issue, a radius 5 µm all-solid-state Pt/RuOx ultra-micro pH sensor was developed using cyclic voltammetry deposition method, which was combined with scanning electrochemical microscopy (SECM) to achieve in-situ monitoring the local pH distribution and evolution of the pre-notched X80 pipeline steel. The micro-sensor demonstrates a near Nernstian slope of −60.0 ± 3 mV/pH within the pH value range of 2.00–12.00, accompanied by an exceptionally rapid response time of 200 ms. Moreover, it exhibits high accuracy, strong long-term monitoring ability and remarkable resistance to the interference of common ions in seawater and ferrous ions generated by the corrosion of pipeline steel. Through monitoring the local pH distribution in simulated seawater solution at the notch of X80 pipeline steel, it was found that obvious pH alkalization occurs first on both the surface and inside of the notch, followed by gradual acidification, and this phenomenon is more obvious at the front of the notch. Combined with other characterization methods, a possible corrosion reaction mechanism at the notch of stress corrosion was proposed.

Cytotoxicity of vanadium dioxide nanoparticles to human embryonic kidney cell line: Compared with vanadium(IV/V) ions

Vanadium dioxide (VO2) is a class of thermochromic material with potential applications in various fields. Massive production and wide application of VO2 raise the concern of its potential toxicity to human, which has not been fully understood. Herein, a commercial VO2 nanomaterial (S-VO2) was studied for its potential toxicity to human embryonic kidney cell line HEK293, and two most common vanadium ions, V(IV) and V(V), were used for comparison to reveal the related mechanism. Our results indicate that S-VO2 induces dose-dependent cellular viability loss mainly through the dissolved V ions of S-VO2 outside the cell rather than S-VO2 particles inside the cell. The dissolved V ions of S-VO2 overproduce reactive oxygen species to trigger apoptosis and proliferation inhibition via several signaling pathways of cell physiology, such as MAPK and PI3K-Akt, among others. All bioassays indicate that the differences in toxicity between S-VO2, V(IV), and V(V) in HEK293 cells are very small, supporting that the toxicity is mainly due to the dissolved V ions, in the form of V(V) and/or V(IV), but the V(V)’s behavior is more similar to S-VO2 according to the gene expression analysis. This study reveals the toxicity mechanism of nanosized VO2 at the molecular level and the role of dissolution of VO2, providing valuable information for safe applications of vanadium oxides.