Heavy Ion Research Articles

Fabrication of a polyoxometalate-based metal-organic compound and its derivative for enhanced photocatalytic, electrocatalytic, and electrochemical sensing properties

A novel polyoxometalate-based metal-organic compound (POMOC), namely [Ag(3-pna)2(H2PW12O40)]n (compound 1, where 3-pna = N-(pyridine-3-yl)nicotinamide), had been successfully synthesized and structurally characterized. The photocatalytic performance of compound 1 for the degradation of gentian violet (GV) and methylene blue (MB) was investigated in detail, which exhibited good cyclic stability as a photocatalyst. In addition, cyclic voltammetry technology was used to verify that compound 1 exhibited excellent electrocatalytic performance towards KBrO3 and H2O2. To improve the degradation of organic dyes and electrochemical sensing performance, a negatively charged oxygen vacancy metal oxide compound 1@C was prepared via pyrolysis using compound 1 as a precursor. Compound 1@C was investigated as an adsorbent, and was found to effectively remove MB and GV from wastewater, with adsorption rates of 824.36 mg/g and 957.02 mg/g, respectively. The performance of compound 1@C/glassy carbon electrode as an electrochemical sensor was studied using differential pulse dissolution voltammetry (DPV). This method proved effective in detecting heavy metal ions Cd2+ and Pb2+ in wastewater with the limits of detection as 4.65 and 1.69 μg/L, respectively. Compound 1@C/GCE showed good anti-interference capabilities and stability in detecting heavy metal ions in wastewater.

Supercritical carbon dioxide chelation extraction of heavy metal ions from drilling fluid waste: Experiment and simulation

This study evaluates the application of supercritical carbon dioxide chelation extraction technology for treating heavy metal ions (Zn2+ and Cr3+) in drilling fluid waste. Through a combination of experimental and molecular dynamics simulation methods, the influence of extraction parameters (temperature, pressure, duration, and chelating agents) on the extraction efficiency are investigated. Findings show that increased duration and pressure significantly improve extraction efficiency, while temperature has a complex effect, initially increasing efficiency but plateauing and slightly decreasing at higher temperatures. The optimum extraction condition with pressure of 220 bar, temperature 348.15 K and an extraction duration of 70 min using ethylene diamine tetraacetic acid (EDTA) as the chelating agent has been determined. Importantly, molecular simulation analysis revealed that citric acid outperforms EDTA in terms of Zn2+ and Cr3+ aggregation by forming larger aggregates with greater numbers of molecules while reducing overall aggregate count. Furthermore, optimization of extraction pressure in the EDTA system shows potential benefits. These results suggest that supercritical carbon dioxide chelation extraction technology has strong potential for environmentally friendly and reliable waste management in the drilling industry. This study represents a significant step forward in developing sustainable solutions for heavy metal removal from drilling fluid waste.

In situ synthesized Ag nanoparticles encapsulated inside carbonized ZIF-8 for efficient Cr(VI) reduction

Effective reduction of carcinogenic contaminant Cr(VI) to low-toxic Cr(III) is of global importance for environmental and water source protection. Herein, a stable metal-organic framework (MOF), ZIF-8, was carbonized as a template to synthesize a novel nanocomposite involving Ag nanoparticles (NPs) inside (Ag@C-ZIF-8). Surprisingly, the Ag NPs synthesized in situ in the Ag+@C-ZIF-8/AB system exhibited outstanding reduction ability toward Cr(VI) and eliminated 100 % of Cr(VI) (20 mg/L) within 10 min in an initial pH range of 3–5. The Cr(VI) removal efficiency was much higher compared with these systems of AB (25.5 %), C-ZIF-8/AB (44.6 %), Ag+/AB (66.8 %), and Ag@C-ZIF-8/AB (39.3 %). Increasing the initial pH of the solution and the amount of C-ZIF-8 template accelerated Cr(VI) reduction. In four cycles of experiments, over 92 % of Cr(VI) was reduced without any treatment, demonstrating the excellent stability and reusability of Ag@C-ZIF-8. X-ray photoelectron spectroscopy (XPS) characterization and mechanism exploration experiments indicated that Ag NPs catalyzed AB dehydrogenation and efficiently reduced Cr(VI) together with the generated hydrogen. This is the first report on carbonized MOF-based Ag NPs synthesized in situ for Cr(VI) reduction by combining catalytic AB dehydrogenation with metal nanoparticle reducibility. This work provides new avenues for the utilization of heavy metal ions in water environments and the development of novel and efficient reductants/catalysts of Cr(VI) removal.

Enhanced removal of lead ions from wastewaters by electrochemical adsorption using nitrogen-doped Ti3C2Tx MXene

As a two-dimensional material containing transition metal carbides and nitrides, MXene is often used in capacitive deionization for its excellent hydrophilic and pseudocapacitive properties. Nitrogen doping is widely used to improve the adsorption properties of certain materials. However, the effect of nitrogen doping on the electrochemical adsorption properties of MXene remains unclear. In this work, nitrogen-doped Ti3C2Tx MXene was synthesized using a simple hydrothermal method to achieve highly selective and efficient removal of Pb(II) at a constant cell voltage. The concentration of Pb(II) decreased from 4.95 to 0.02 mg L−1 in a 100 mg L−1 NaCl supporting electrolyte after electrosorption. The removal efficiency of Pb(II) reached 99.5 %, whereas it was only 15.2 % for Na+. The introduction of nitrogen functional groups increased the electrical conductivity and layer spacing of MXene, thereby improving the pseudocapacitive adsorption performance in the presence of Pb(II). The complexation function of the TiOH group on nitrogen-doped Ti3C2Tx surface increased and contributed to the selective adsorption of Pb(II). The removal efficiency of Pb(II) increased with increasing solution pH and cell voltage, reaching the maximum value at pH 5.0 and 1.5 V, respectively. The effect of supporting electrolyte type on the removal of Pb(II) was negligible. In addition, the removal efficiency for mixed heavy metal ion solutions, including Cu(II), Ni(II), and Pb(II), exceeded 79.0 %. It exhibited the highest removal efficiency for Pb(II) at 97.9 %. After five cycles of electrochemical adsorption–desorption, the nitrogen-doped Ti3C2Tx maintained a stable Pb(II) removal efficiency of 97.0 %. This work provides a promising material for the electrochemical removal of low-concentration heavy metal ions from wastewaters.

Fabrication of hyperbranched polyamidoamine functionalized with cucurbituril to improve dyes and heavy metals removal capability of the polyethersulfone nanofiltration membrane

A new hyperbranched polyamidoamine polymer functionalized with cucurbituril (HBPA@Cucurbituril) was fabricated to enhance the antifouling properties of polyethersulfone (PES) membrane to remove dye pollutants and heavy metal ions (e.g., As3+ and Hg2+). ATR-FTIR, TGA, SEM, zeta potential, AFM, water contact angle (WCA), and SEM analyses were used to investigate the morphology of modified membranes. The WCA evaluations indicated that the 0.5wt% HBPA@cucurbituril membranes showed the best hydrophilicity improvement compared to the bare membrane (decrement from 66.6° to 37.9°). In the best case, the optimally modified membrane (0.5wt%) indicated the best permeability (8.5L/m2.h.bar), fouling resistance (flux recovery ratio of 92.42%), dye rejection (Direct Red 16: 98.7%, Reactive Blue 19: 99.8%, Crystal Violet: 97.3% and Methylene Blue: 98.4%) and heavy metal removal of (As3+: 99.7% and Hg2+: 99.2%). This study offers a clear perspective on the treatment of industrial effluents.

Effects of saturation and fluctuating hotspots for flow observables in ultrarelativistic heavy-ion collisions

Effects of saturation and fluctuating hotspots for flow observables in ultrarelativistic heavy-ion collisions

Weak magnetic field effect on dilepton polarization in heavy-ion collisions

Weak magnetic field effect on dilepton polarization in heavy-ion collisions

Asymmetrical Solar Wind Deflection in the Martian Magnetosheath

AbstractAs incident solar wind encounters the martian upper atmosphere, it undergoes deflection particularly in the magnetosheath. However, the plasma flow exhibits asymmetrical distribution features within this transition region, which is investigated by employing a three‐dimensional Hall magnetohydrodynamic (MHD) model from an energy transfer perspective in this study. Simulation results reveal that solar wind protons transfer momentum to ionospheric heavy ions through motional electric field in the hemisphere where the motional electric field points outward from the planet. In the opposite hemisphere, solar wind flow tends to be effectively accelerated by ambipolar and Hall electric fields. The distinct dynamics of solar wind protons in both hemispheres result in the asymmetrical deflection. Furthermore, the extent of asymmetry grows as the cross‐flow component of the upstream interplanetary magnetic field increases, but diminishes as the density of the solar wind proton increases, contingent upon the energy effectively acquired from ambipolar and Hall electric fields.

Smartphone-assisted colorimetric sensor arrays based on nanozymes for high throughput identification of heavy metal ions in salmon

The rapid, precise, and high-throughput identification of multiple heavy metals ions holds immense importance in ensuring food safety and promoting public health. This study presents a novel smartphone-assisted colorimetric sensor array for the rapid and precise detection of multiple heavy metals ions. The sensor array is based on three signal recognition elements (AuPt@Fe-N-C, AuPt@N-C, and Fe-N-C) and the presence of different heavy metal ions affects the nanozymes-chromogenic substrate (TMB) catalytic color production, enabling the differentiation and quantification of various heavy metal ions. Combined with a smartphone-based RGB mode, the colorimetric sensor array can successfully identify five different heavy metal ions (Hg2+, Pb2+, Co2+, Cr6+, and Fe3+) as low as 0.5 μM and different ratios of binary and ternary mixed heavy metal ions in just 5 min. The sensor array successfully tested seawater and salmon samples with a total heavy metal content of 10 μM in the South China Sea (Haikou and Wenchang). Overall, this study highlights the potential of smartphone-assisted colorimetric sensor arrays for the rapid and precise detection of multiple heavy metal ions, which could significantly contribute to food safety and public health monitoring.

Investigating D0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^0$$\\end{document} meson production in p-Pb collisions at 5.02 TeV with a multi-phase transport model

We study the production of D0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^0$$\\end{document} meson in p+p and p-Pb collisions using the improved AMPT model considering both coalescence and independent fragmentation of charm quarks after the Cronin broadening is included. After a detailed discussion of the improvements implemented in the AMPT model for heavy quark production, we show that the modified AMPT model can provide a good description of D0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^0$$\\end{document} meson spectra in p-Pb collisions, the QpPb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Q_{\ extrm{pPb}}$$\\end{document} data at different centralities and RpPb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{\ extrm{pPb}}$$\\end{document} data in both mid- and forward (backward) rapidities. We also studied the effects of nuclear shadowing and parton cascade on the rapidity dependence of D0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^{0}$$\\end{document} meson production and RpPb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{\ extrm{pPb}}$$\\end{document}. Our results indicate that using the same strength of the Cronin effect (i.e δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\delta $$\\end{document} value) as that obtained from the mid-rapidity data leads to a considerable overestimation of the D0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^0$$\\end{document} meson spectra and RpPb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{\ extrm{pPb}}$$\\end{document} data at high pT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$p_{\ extrm{T}}$$\\end{document} in the backward rapidity. As a result, the δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\delta $$\\end{document} is determined via a χ2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\chi ^2$$\\end{document} fitting of the RpPb\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{\ extrm{pPb}}$$\\end{document} data across various rapidities. This work lays the foundation for a better understanding of cold-nuclear-matter (CNM) effects in relativistic heavy-ion collisions.

Pseudoscalar heavy quarkonium production in heavy ion ultraperipheral collision

The inclusive production of pseudoscalar heavy quarkonia (ηc, ηb, and Bc) via photon-photon fusion in heavy ion ultraperipheral collision (UPC) are calculated to QCD next-to-leading order in the framework of nonrelativistic QCD (NRQCD). The total cross section of ηc produced in Pb-Pb UPC is 194 nb and 1275 nb at nucleon-nucleon c.m. energies SNN=5.52 TeV and 39.4 TeV, respectively. The cross sections for ηb and Bc mesons are more than two to three orders of magnitude smaller. We make a detailed phenomenological analysis on the ηc production; the uncertainties caused by the renormalization scale and the charm quark mass, the cross sections in other ultraperipheral nucleon-nucleon colliding systems, and the transverse momentum distribution are discussed. At the coming HL-LHC and future FCC, the heavy ion UPC opens another door of the study on the production of heavy quarkonium. Published by the American Physical Society 2024

The Utilization of Carbonated Steel Slag as a Supplementary Cementitious Material in Cement

Carbon emission reduction and steel slag (SS) treatment are challenges in the steel industry. The accelerated carbonation of SS and carbonated steel slag (CSS) as a supplementary cementitious material (SCM) in cement can achieve both large-scale utilization of SS and CO2 emission reduction, which is conducive to low-carbon sustainable development. This paper presents the utilization status of CSS. The accelerated carbonation route and its effects on the properties of CSS are described. The carbonation reaction of SS leads to a decrease in the average density, an increase in the specific surface area, a refinement of the pore structure, and the precipitation of different forms of calcium carbonate on the CSS surface. Carbonation can increase the specific surface area of CSS by about 24–80%. The literature review revealed that the CO2 uptake of CSS is 2–27 g/100 g SS. The effects of using CSS as an SCM in cement on the mechanical properties, workability, volume stability, durability, environmental performance, hydration kinetics, and microstructure of the materials are also analyzed and evaluated. Under certain conditions, CSS has a positive effect on cement hydration, which can improve the mechanical properties, workability, bulk stability, and sulfate resistance of SS cement mortar. Meanwhile, SS carbonation inhibits the leaching of heavy metal ions from the solid matrix. The application of CSS mainly focuses on material strength, with less attention being given to durability and environmental performance. The challenges and prospects for the large-scale utilization of CSS in the cement and concrete industry are described.

Agricultural waste-based biochars for sustainable removal of heavy metals from stabilized landfill leachate.

In this work, biochars were used as adsorbents to remove Cu, Cd, and Zn ions in a real stabilized leachate from a controlled landfill. Oak fruit shells biochar (OFSBC) and date palm fibers biochar (DPFBC) were obtained by pyrolysis of oak fruit shells and date palm fibers at 700°C and 400°C, respectively. OFSBC and DPFBC showed well-developed structures and high specific surface areas (520.16 m2/g and 470.46 m2/g, respectively). Equilibrium adsorption of heavy metal ions on DPFBC and OFSBC occurred after 4h and 2h of stirring. The removal efficiencies of Cu, Cd, and Zn ions were 97.01%, 94.40%, and 80.59% with DPFBC and 90.10%, 88.33%, and 76.16% using OFSBC, respectively. The Avrami fractional order model was appropriate for describing kinetic adsorption. Increasing the dose of adsorbent improves heavy metal ion retention. Thermodynamic tests have proven the spontaneous and endothermic adsorption of these heavy metals. The electrostatic attraction, ion exchange, complexation, metal-π bending, and surface precipitation and pore filling were regarded as the most predominant heavy metal retention mechanisms from the landfill leachate onto the biochar surface. Separately, the DPFBC showed the best performance than OFSBC regarding the improvement of leachate quality. Chemical oxygen demand (COD), biological oxygen demand (BOD5), ammoniacal nitrogen (NH3-N), and phosphorus (P) were respectively removed at an efficiency of 53.57%, 29.17%, 36.07%, and 37.5%, respectively. Thus, the results allow highlighting that the adsorption on DPFBC and OFSBC can be an effective alternative in the practice of landfill leachate treatment.

Dihadron helicity correlation in photon-nucleus collisions

The helicity correlation of two back-to-back hadrons is a powerful tool that makes it possible to probe the longitudinal spin transfer G1L in unpolarized hadronic collisions. In this work, we investigate the helicity correlation of back-to-back dihadrons produced in photon-nucleus collisions with both spacelike and quasireal photons and explore its potential in understanding the flavor dependence of spin-dependent fragmentation functions. We present helicity amplitudes of partonic scatterings with both virtual and real photons and make numerical predictions for the dihadron helicity correlations at the future Electron Ion Collider experiment and the current Relativistic Heavy Ion Collider/LHC ultraperipheral collision experiment. Future experimental measurements can also illuminate the fragmentation function of circularly polarized gluons. Published by the American Physical Society 2024

The influence of acid treatment on the adsorption‑structural characteristics of filtering materials created based on steelmaking slag

Many industrial enterprises use electroplating processes that lead to the formation of water containing heavy metal ions such as chromium, copper, zinc, nickel, and others. Such water is a dangerous source of environmental pollution. Most heavy metal ions belong to hazard classes I–II, they have carcinogenic and mutagenic properties, and have a cumulative effect.The literature analysis showed that there is positive experience in the use of steelmaking slags in the processes of cleaning contaminated water of various origins from heavy metals.The study examines the effect of acid activation on the adsorption‑structural characteristics of filtering materials created based on steelmaking slag. It is shown that during the interaction of some acids with slag, new crystallographic phases are formedon its surface, and contact with other acids leads to the leaching of ions and their transition to the aqueous phase. It has been established that during acid activation, the specific surface area increases by 57–132 times compared to the original material.

Application of Electrospun Nanofiber-Based Electrochemical Sensors in Food Safety

Food safety significantly impacts public health and social welfare. Recently, issues such as heavy metal ions, drug residues, food additives, and microbial contamination in food have become increasingly prominent. Electrochemical sensing technology, known for its low cost, simplicity, rapid response, high sensitivity, and excellent selectivity, has been crucial in food safety detection. Electrospun nanofibers, with their high specific surface area, superior mechanical properties, and design flexibility, offer new insights and technical platforms for developing electrochemical sensors. This study introduces the fundamental principles, classifications, and detection mechanisms of electrochemical sensors, along with the principles and classifications of electrospinning technology. The applications of electrospun nanofiber-based electrochemical sensors in food safety detection over the past five years are detailed, and the limitations and future research prospects are discussed. Continuous innovation and optimization are expected to make electrospun nanofiber-based electrochemical sensors a key technology in rapid food safety detection, providing valuable references for expanding their application and advancing food safety detection methods.

Polarization effects of hot nuclear matter on the fusion of heavy ions

Within the framework of the modified density-dependent Seyler–Blanchard approach in the [Formula: see text] approximation, the polarization effects of hot nuclear matter (PEHNM) are investigated on the fusion process of 16 different colliding systems in the mass range [Formula: see text]. In order to calculate the nucleus–nucleus potential, we use the double-folding (DF) model supplemented with the thermal effects of compound nucleus and also a repulsive potential that takes into account the incompressibility of the nuclear matter. The calculations of the fusion cross-sections are performed based on the couplings to the low-lying [Formula: see text] and [Formula: see text] vibrational states in both target and projectile. The sensitivity of sub-barrier fusion cross-sections to the polarization effects is evident from this study. The obtained results reveal that the modified form of the DF potential in the presence of the PEHNM appropriately reproduces the energy-dependent behavior of the experimental fusion cross-sections for the studied reactions. The role of the polarization effects on the fusion barriers as well as the inner part of the potential is also discussed.

Adsorption characteristics and mechanisms of individual and a quinary mixture of heavy metal ions on novel CoFe2O4-BiFeO3 nanosorbents in water

Application of CoFe2O4-BiFeO3 nanocomposites (CFO-BFO NCs) in highly adsorptive removal of heavy metal ions (Pb(II), Co(II), Cu(II), Cd(II) and Zn(II)) by individual and simultanoeous adsorption were investigated for the first time in the present study. The characterization of CFO-BFO NCs were analyzed by using XRD, VSM, SEM, TEM and BET techniques. The CFO-BFO NCs powder consists of characteristic peaks of BFO and CFO without any trace of other crystalline phases; they were uniformly dispersed with a size of about 3–5 nm, much smaller than single – phase CFO (10–25 nm) and BFO (5–10 µm) with the surface area of 84.93 m2/g; remanence and coercivity were 14.33 emu/g, 1.99 emu/g and 195 Oe, respectively, significantly decreased compared to CFO but significantly increased compared to BFO. The single or simultaneous adsorption of a quinary mixture of Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) on CFO-BFO NCs followed the Freundlich isotherm model and the pseudo-second-order kinetic model. Adsorption capacity of single heavy metal ions were in the order Pb(II) > Co(II) > Cu(II) > Cd(II) > Zn(II) while the simultaneous adsorption was in the order Pb(II) > Cu(II) > Co(II) > Zn(II) > Cd(II). The maximum adsorption capacities (qmax) of each ion in the case of simultaneous adsorption were smaller than that for cases of the single adsorption but the total qmax of ions mixture was much higher than the highest qmax of single adsorption. The simultaneous adsorption of heavy metal ions is the competition, the best selectivity is Pb(II) and the strongest competition is Cd(II), the adsorption ability reduces as the charge and radius of interfering cation increase and the ionic strength increases. The regeneration and reuse ability were good, while the adsorption efficiency slightly decreased over three recycles. The adsorption increased slightly as temperature increased. The adsorption process was spontaneous and endothermic. Adsorption of heavy metal ions on CFO-BFO NCs consists of both electrostatic and chemisorption. The applicability for real sample is good. Our results demonstrate that the CFO-BFO NCs is a prospective adsorbent to remove Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) from aqueous environment.

Aqueous Afterglow Dispersion Enabling On‐Site Ratiometric Sensing of Mercury Ions

AbstractPollution caused by heavy metal ions has become a global issue owing to their severe threat to the ecological environment and human health. However, it remains a considerable challenge to detect heavy metal ions in an efficient, selective, and high signal‐to‐noise ratio way. Herein, a portable and sensitive method is presented to probe Hg2+ by using an ultralong afterglow dispersion. The in situ encapsulation of phosphorescent carbon dots (CDs) within rigid hydrogen‐bonded organic frameworks (HOFs) leads to ultralong room temperature phosphorescence (RTP) in water with a maximum lifetime of up to 974.86 ms. Moreover, the resultant CDs@HOFs material exhibits robust and long‐term RTP emission with enhanced performance under strongly acidic or alkaline conditions, which contributes to the practical detection of Hg2+ in water. As such, an efficient and sensitive afterglow probe is facilely fabricated by integrating CDs@HOFs with a Hg2+ probe Rhodamine B derivative (RhBTh), demonstrating selective sensing of Hg2+ with greatly improved signal‐to‐noise ratios based on the triplet‐singlet Förster resonance energy transfer system (TS‐FRET). This work not only provides a reliable and versatile method for realizing robust RTP emission in water, but also expands the applications of afterglow materials in the field of optical sensing of toxic analytes.

COF-derived porous nitrogen-doped carbon for removal of emerging organic contaminants and efficient uranium extraction from seawater

The development of adsorbents for efficient and highly selective seawater extraction of uranium was instrumental in fostering sustainable progress in energy and addressing the prevailing energy crisis. However, the complex background composition of the marine environment, including radionuclides, organic pollutants, and a large number of co-existing heavy metal ions, were non-negligible obstacles to the extraction of uranium from seawater. The present investigation successfully employed a self-templated approach to synthesize porous nitrogen-doped carbon (PNC) derived from COF, which exhibited tremendous potential as an adsorbent for pollutant removal in environmental treatment. LZU1@PNC not only retained the structural features of the original COF-LZU1, but also overcame the acid-base instability problem commonly found in COFs. Subsequently, the removal process of two typical water pollutants on the material was investigated using 2,4-DCP and [UO2(CO3)3]4-. The results demonstrated that LZU1@PNC exhibited superior removal performance for the target pollutants compared to COF-LZU1, owing to its larger specific surface area and abundant defect structure. After six desorption-regeneration cycles, LZU1@PNC still maintained a high removal rate of the target contaminants, demonstrating the stability of this material and its excellent recyclability. In addition, based on various characterization techniques, the removal mechanism of 2,4-DCP was presumed to be mainly electrostatic attraction, hydrogen bonding, and π-π stacking interactions. Conversely, the elimination process of [UO2(CO3)3]4- predominantly relied on surface complexation phenomena. The present investigation provided new perspectives and stimulated a broader study of other COF-derived carbon materials and their modifications as adsorbents for uranium extraction from seawater and other applications.