Trace Fe3 Research Articles

Synchronization of Ti3C2 MXene/Fe3+ with sodium persulfate for the degradation of reactive dyes

Rapid activation of sodium persulfate (SPS) for the degradation of C.I. Reactive Red 218 (RR218) was achieved using Ti3C2 MXene reduction of trace Fe3+. The degradation rate of RR218 reached 97.7% using a mixture containing 3 g L−1 of SPS, 3.35 mg L−1 of Fe3+ and 60 mg L−1 of MXene stirred at 25 °C for 30 min. The intense reduction of Ti3C2 MXene triggers the Fe3+/Fe2+ cycle thereby accelerating the activation of SPS. When reactive dyes were degraded by Fe3+/SPS/MXene process, ·OH played a major role. The dye degradation capacity of the Fe3+/SPS/MXene process decreased after 5 cycles of recycling. In addition, the wastewater treated under these conditions resulted in high dyeing efficiencies in reuse experiments. This study not only improves the understanding of the catalytic reaction of MXene but also provides a wastewater treatment and reuse process with low metal consumption and high efficiency.

Salicylic acid doped silica nanoparticles as a fluorescent nanosensor for the detection of Fe3+ in aqueous solution.

A novel organic-inorganic hybrid nanosensor (SASP) was prepared by a one-step sol-gel method and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, N2 adsorption-desorption, fluorescence spectroscopy, etc. The nanosensor showed almost 3-fold fluorescence emission quenching upon excitation with a 293 nm wavelength in the presence of 20 μM Fe3+ ions. The presence of 18 other metal ions had no observable effect on the sensitivity and selectivity of the nanosensor. A fluorescence analysis method based on the SASP for the selective detection of Fe3+ was established under optimal conditions. The results showed that there was a linear relationship between the log luminescence value and the concentration of Fe3+ over the range of 2.0 × 10-7-9.0 × 10-5 mol L-1 with a detection limit (3σ) of 2.5 × 10-8 mol L-1. Furthermore, the proposed method was successfully applied for the determination of trace Fe3+ in fetal bovine serum without the interference of other molecules and ions. Good recovery (96.5-104.5%) and a relative standard deviation of less than 8.6% were obtained from serum samples spiked with four levels of Fe3+. Additionally, the nanosensor showed a good reversibility; the fluorescence could be switched "off" and "on" in two ways, by adjusting the pH of the solution and adding metal chelating agent EDTA.

Trace Elements in Chromite as Indicators of the Origin of the Giant Podiform Chromite Deposit at Kempirsai, Kazakhstan

Abstract This study presents a complete trace element data set of chromite from the world’s largest podiform chromite deposit at Kempirsai, Kazakhstan, together with platinum group element (PGE) and Re-Os isotope compositions, to explore the potential of trace elements in the study of podiform chromite deposits. Chromite orebodies in the Karaagash area of the Kempirsai Main ore field are hosted by dunites in the mantle sequence of the ophiolite. Dunites slightly distal to the orebodies are composed of olivine (forsterite content = 91.5–93.4) and minor euhedral chromite with variable Cr# (0.73–0.83). These dunites have primitive mantle-normalized Pt-Pd–poor PGE patterns and subchondritic 187Os/188Os ratios (0.12174–0.12220). Negative correlations between Cr# and incompatible trace elements (Sc and Ti) of the chromite are consistent with melt-rock reaction, whereas positive correlations between Cr# and compatible trace elements (V and Ga) reflect the role of fractional crystallization. It is therefore proposed that chromite in the distal dunites was crystallized from magmas after reaction with mantle peridotites. In comparison, chromite grains in the ores and adjacent dunites exhibit relatively uniform Cr# numbers (0.81–0.86) and higher 187Os/188Os values (0.12319–0.12414). Both compatible and incompatible trace elements of chromite exhibit negative correlations with Cr#, which are best explained by mixing between the modified magma after melt-rock reaction and a later injected magma from a more depleted source. After the ore formation, subsolidus reequilibration between olivine and chromite reduced Mg# and modified divalent trace elements of chromite in the order of Zn > Co = Mn > Ni but did not affect distribution of nondivalent trace elements, except V and Fe3+. The decoupling of redox-sensitive and redox-insensitive trace elements suggests that the redox states have been modified during subsolidus reequilibration. The existing iron equilibrium between olivine and chromite records high fO2 values (quartz-fayalite-magnetite buffer [∆QFM] 0.8–2.4), whereas correction of subsolidus reequilibration results in a decrease of the fO2 values toward the QFM buffer (∆QFM 0.1–0.6), indicating that increase in fO2 was not a critical factor in the ore formation. Principal component analysis and factor analysis were further carried out to identify differences in trace elements between high-Cr and high-Al podiform chromite deposits worldwide. High-Cr chromite deposits have variable divalent trace element compositions and show complex distributions of nondivalent trace elements. The former reflects longer and slower cooling histories of the high-Cr chromite deposits with respect to the high-Al chromite deposits, whereas the latter indicates more variable magma compositions and complex processes during the formation of the high-Cr chromite deposits.

Fast preparation of Eu(BTB) MOFs in dielectric barrier discharge liquid plasma for luminescent sensing of trace iron.

Lanthanide metal-organic frameworks Eu(BTB) MOFs was synthesized in low-temperature plasma produced by dielectric barrier discharge (DBD). This DBD synthesis possesses the characteristics of rapid reaction (within 20 min), mild condition (low temperature and atmospheric pressure) and simple operation compared with many traditional synthesis methods. The prepared Eu(BTB) MOF material exhibits typical red light emitting of europium (Eu3+ ) at 617 nm, which can selectively and sensitively be quenched in the presence of trace iron(III) ion (Fe3+ ). A simple, fast and sensitive fluorescence sensing strategy of Fe3+ was thus constructed, with a limit of detection (LOD) of 0.5μM. Compared with reported fluorescence probes, Eu(BTB) MOFs have also demonstrated the advantages of low cost, easy and fast preparation, great stability, and excellent optical properties, thus making them a promising fluorescence candidate for trace Fe3+ sensing for the potential application in biological systems in the future.

Dynamic equilibrium of external Fe3+ to effectively construct catalytic surface of perovskite LaNi1−xFexO3 for water oxidation

The introduction of Fe into rare earth nickelate perovskite oxides such as LaNiO3 can effectively improve its intrinsic activity for oxygen evolution reaction (OER). Whereas, it is still difficult to achieve exact incorporation of Fe ion and maintain the efficient and stable catalytic surface. Bimetallic NiFe-based active sites have been constructed on the surface of LaNiO3 using a straightforward electrochemical technique that involves introducing external and trace Fe3+ ions into the electrolyte. The optimized LaNiO3 with more Ni-O bonds facilitates the adsorption of Fe3+ ions, which promotes the formation of LaNi1−xFexO3 through electrochemical activation. The synthesized LaNi1−xFexO3 exhibited a synergistic impact and electron rearrangement, resulting in a boost in intrinsic activity. The OER measurements show that the overpotential of LaNi1−xFexO3 reduces to 340 mV (η10) and the Cdl value increases by 21 times (0.10 mF cm−2 to 2.18 mF cm−2) in the existence of external Fe3+. Notably, the dynamic equilibrium between the external Fe3+ and Fe3+ in LaNi1−xFexO3 may stabilize the bimetallic NiFe-based active sites and keep the activity during the long-term OER process. The strategy of utilizing dynamic equilibrium of external ion to obtain the robust catalytic surface offers a novel approach to achieving excellent performance for OER.

Photocatalytic performance of TiO2/Bi2WO6 photocatalysts with trace Fe3+ dopant for gaseous toluene decomposition

As one of the typical volatile organic compounds, toluene is harmful to human health and challenging to decompose effectively with traditional photocatalysts, such as TiO2 or ZnO. Here, a trace Fe3+ doped TiO2/Bi2WO6 composite photocatalyst with abundant oxygen vacancies was successfully synthesized via a hydrothermal method and subsequently impregnation treatment. The Fe3+ doped TiO2/Bi2WO6 were optimized by adjusting the molar ration of TiO2 and Bi2WO6, and the optimal molar ratio was found to be TiO2:Bi2WO6 = 1:2. The obtained Fe(0.1)-TB2 with only 0.1 wt% Fe3+ dopant exhibited superior photocatalytic activity with over 90% toluene removal efficiency after 180 min under visible light irradiation. A series of characterizations reveal that the improved photocatalytic activity of Fe3+ doped TiO2/Bi2WO6 can be attributed to synergistic effects between the extension of photogenerated carrier lifetime and the increase of visible light absorption range by narrowing the energy bandgap (shortened about 0.32 eV) and the formation of oxygen vacancies. Furthermore, hydroxyl radicals and holes as the key reactive oxygen species (ROS) in the photodegradation reaction were confirmed by electron spin resonance (ESR) experiments. Therefore, introducing Fe-ions into TiO2/Bi2WO6 photocatalysts is an effective way to enhance the photocatalytic activities, and the modified catalysts can be considered as a promising material for decomposing toluene and other VOCs.

Diffusive equilibration of H2O and oxygen fugacity in natural olivine-hosted melt inclusions

Arc basalts are oxidized relative to mid-ocean ridge basalts; however, the mechanism through which arc basalts gain this elevated oxidative state is debated. This observation has been extended to include Fe3+/∑Fe measurements from olivine-hosted melt inclusions enclosed in relatively Fo-rich olivines (i.e., which have presumably trapped relatively unevolved liquid compositions as melt inclusions). Experimental data suggest, however, that Fe3+/∑Fe recorded by melt inclusions can diffusively equilibrate with the host magma on short timescales, perhaps as rapidly as timescales relevant for H+ diffusive equilibration. Here, we present major, minor, and trace element concentrations, H2O concentrations, and Fe3+/∑Fe of naturally glassy olivine-hosted melt inclusions from the Basalt of Round Valley Butte, a cinder cone in the Lassen Region of northern California. These melt inclusions record H2O loss through diffusion of H+ and can be used to constrain the extent of Fe3+/∑Fe equilibration in a suite of natural melt inclusions. The H2O concentrations of Basalt of Round Valley Butte melt inclusions decrease with decreasing melt inclusion radius, consistent with diffusive H+ loss. The Fe3+/∑Fe do not correlate with H2O or inclusion diameter, suggesting that Fe3+/∑Fe equilibration does not occur on the same timescale as H+ diffusion. Calculated oxygen fugacities (ƒO2) from the partitioning of vanadium between olivine and melt are ∼1 log unit higher than those calculated from Fe3+/∑Fe. One explanation for these combined observations is that Fe3+/∑Fe of the Basalt of Round Valley Butte melt inclusions diffusively equilibrated with a host magma at low pressure on shorter timescales than H+ diffusion. This scenario requires that the host magma decreased in ƒO2 after the time of melt inclusion entrapment to explain the offset between ƒO2 constraints from Fe3+/∑Fe of the melt inclusions and the partitioning of vanadium between olivine and melt. One volcanological process known to result in a decrease in ƒO2 of magmas stored at shallow pressure is the degassing of S, CO2, and H2O. We show that reasonable estimates for the extent of degassing of Basalt of Round Valley Butte magma, coupled with diffusive equilibration of both H+ and Fe3+/∑Fe, can reconcile Fe- and V-proxies for ƒO2. Additionally, we have compared estimates of ƒO2 from vanadium abundances of melt inclusions and their olivine hosts with recently reported measurements of Fe3+/∑Fe of the melt inclusions for several Mariana arc volcanoes and conclude that this process – small decreases in host magma ƒO2 driven by degassing and rapid equilibration of the Fe3+/∑Fe of olivine-hosted melt inclusions with this host magma - may be a widespread phenomenon.

Facile Preparation of Tunicate-Inspired Chitosan Hydrogel Adhesive with Self-Healing and Antibacterial Properties.

In order to replace traditional wound treatments such as sutures, tissue adhesives with strong wet tissue adhesion and biocompatibility have attracted more attention to the applications of non-invasive wound closure. Herein, inspired by tunicate adhesive protein, a series of 2,3,4-trihydroxybenzaldehyde (TBA)-modified chitosan hydrogels (CS-TBA-Fe) were prepared by easily mixing the solutions of chitosan-FeCl3 and TBA via the Schiff-base reaction and the coordination between Fe3+ and pyrogallol groups. The gelation time was greatly shortened to only several seconds after induced even trace Fe3+. The hydrogel (CS-TBA-Fe) exhibited ~12-fold enhanced wet tissue adhesion strength (60.3 kPa) over the commercial fibrin glue. Meanwhile, the hydrogel also showed robust adhesion to various substrates such as wood, PMMA, and aluminum. The swelling ratio and rheological property can be simply controlled by changing the concentrations of chitosan, TBA, and Fe3+. Moreover, the hydrogel displayed a rapid and highly efficient self-healing ability and an excellent antibacterial activity against E. coli. The overall results show that the CS-TBA-Fe hydrogel with enhanced wet adhesiveness will be a promising tissue adhesive material.

Multiple catalytic sites of Fe-Nx and Fe-N-C single atoms embedded N-doped carbon heterostructures for high-efficiency removal of malachite green

A series of Fe-N-C single atom catalysts embedded within the carbon nitride network (Fe-N-C/CNx) were developed to effectively degrade a commonly used organic dye, Malachite green (MG). Fe-N-C/CNx catalysts were achieved by pyrolyzing the hybrid of polypyrrole (PPy) and Melamine–cyanuric acid complex (MCA) containing trace Fe3+ (Fe/PPy@MCA) at different temperatures. Given the structural change of polymeric networks and nitridation of Fe3+, the mesoporous Fe-N-C/CNx hybrids comprise multiple components, including Fe-N-C, Fe4N, and CNx species, which show enhanced photocatalytic performance toward MG by integrating the high catalytic ability of Fe components and efficient visible-light harvest of CNx network. Notably, the Fe-N-C/CNx-700 hybrid obtained at 700 °C exhibits the high removal efficiency of 92.1% toward MG under visible light, with good reproducibility and stability. The biotoxicity of degraded products was further investigated by antibacterial experiment and plant growth effect. This work provides new insights into the development of efficient photocatalysts of nanohybrids for treating organic dyes.

Ultrafast activation of peroxymonosulfate by reduction of trace Fe3+ with Ti3C2 MXene under neutral and alkaline conditions: Reducibility and confinement effect

Ultrafast activation of peroxymonosulfate (PMS) by reduction of trace Fe3+ at the μg L-1 level with the ecofriendly Ti3C2 MXene under neutral and alkaline conditions was achieved for the first time. Complete removal of model pollutant sulfamethoxazole (SMX) was accomplished within about 5 min and 10 min at pH 7.0 and 9.0, respectively. The degradation rate of SMX in Fe3+/PMS/MXene process was increased by 72 times compared with that in the absence of Ti3C2 MXene (pH = 7). Methanol/tert-butanol quenching experiment and electron spin resonance (ESR) measurement demonstrated that hydroxyl radical (•OH) and sulfate radical (SO4•–) were the primary reactive species. The strong reducibility of Ti3C2 MXene played the key role in triggering the Fe(III)/Fe(II) cycle and accelerating PMS activation. The reducibility of Ti3C2 MXene towards Fe3+ was measured to be 3.35:1–5.03:1 (mol:mol), far higher than that of hydroxylamine (1:1). Because the confinement effect of MXene inhibited the hydrolysis of iron ions, Fe3+/PMS/MXene process exhibited excellent performance even under neutral and alkaline conditions. This study improved the understanding of MXene in Fenton-like reaction and provided an ideal Fenton-like process with ultra-low metal consumption, high efficiency and broad pH range.

Magma water content of Pico Volcano (Azores Islands, Portugal): a clinopyroxene perspective

Clinopyroxenes from the Pico Volcano (Pico Island, Azores Archipelago) have been used as a proxy to define the water content of primitive magmas and the volcanological history of the erupted rocks. This very young volcano (53 ± 5 ka) is at a primordial stage of its evolution in comparison with the other volcanoes of the Azores. Clinopyroxenes from Pico Volcano underwent important dehydration processes and after annealing experiments under H2 gas flux, a pre-eruptive H2O content between 93 and 182 ppm was recovered. A moderately high cooling rate for the cpx-host lavas expressed by the clinopyroxene closure temperature (Tc = 755–928 °C ± 20 °C) correlates with the dehydration, suggesting that this process may have occurred during magma ponding at the Moho Transition Zone (17.3–17.7 km) and/or after the eruption. By applying an IVAl-dependent partition coefficient to the measured H amount in clinopyroxene, the pre-eruptive water content of the parental magma was calculated to vary between 0.71 and 1.20 (average of 1.0) wt%. Clinopyroxene geobarometry performed by combining X-ray diffraction with mineral chemistry points to a general crystallisation from the mantle lithosphere (~ 8–9 kbar) to the oceanic mantle/crust boundary (~ 4–5 kbar). The similar major and trace chemistry, water content and Fe3+/Fetot ratio of clinopyroxene, suggest similar conditions of oxygen fugacity, water content and fractional crystallisation of the magma from which clinopyroxene cores crystallised during the Pico Volcano central eruptions from 40 ka to historical times.

Thermosensitive Fluorescent Microgels for Selective and Sensitive Detection of Fe3+ and Mn2+ in Aqueous Solutions

Thermosensitive fluorescent microgels (HMQC-MGs) were developed as selective and sensitive sensing systems for the detection of trace Fe3+ and Mn2+ ions in aqueous solutions. HMQC-MGs, which were s...

A monophosphonic group-functionalized ion-imprinted polymer for a removal of Fe3+ from highly concentrated basic chromium sulfate solution

An ion-imprinted polymer (IIP) with monophosphonic groups was prepared by thermal copolymerization. Bis(2-methacryloxyethyl) phosphate (BMAOP) was used as functional monomer to react with Fe3+ in dimethyl sulfoxide (DMSO). Ethylene glycol dimethacrylate (EGDMA) was used as cross-linker during polymerization process. A suitable molar ratio of BMAOP to Fe3+ was investigated by UV/Vis/NIR Spectrometer and ICP-OES. The obtained results showed that the monophosphonic groups could be selectively combined with Fe3+ in solutions containing other coexisting ions, and the selectivity could be further enhanced by ion-imprinted process. The prepared IIP was used for removing trace Fe3+ from high concentration basic chromium sulfate solutions. After adsorption process, the concentration of Fe3+ could be reduced from 4.486mg L−1 to 0.171mg L−1, which was much lower than the concentration in the solution treated by non-imprinted polymer (NIP). Moreover, the IIP exhibited excellent recyclability after six adsorption-desorption cycles.

Development of aminoethylpyridine based N,N,N,O-donor fluorescent probes for the detection of Fe3+ and Hg2+ in aqueous media

A couple of 2-aminoethylpyridine based fluorescent compounds (E)-1-((2-(5-nitropyridin-2-ylamino)ethylimino)methyl)naphthalen-2-ol (1) and (E)-4-nitro-2-((2-(5-nitropyridin-2-ylamino)ethylimino)methyl)phenol (2) have been designed and synthesized by setting up reactions of N-(2-aminoethyl)-5-nitropyridin-2-amine with 2-hydroxy-1-naphthaldehyde and 2-hydroxy-5-nitrobenzaldehyde, respectively. Both the probes have been characterized by elemental analyses, FTIR, 1H & 13C NMR, UV/vis and fluorescence spectral techniques. Furthermore the sensing behavior of 1 and 2 towards various metal ions were examined via UV/vis and fluorescence studies. The fluorescence of 1 and 2 enhanced upon interaction with Fe3+ ion whereas Hg2+ induced small fluorescence quenching of 1 and enhancement of fluorescence in 2. The selectivity and sensitivity assay ensured by 2 remains unaltered in presence of interfering metal ions. Hence, among these two chemosensors only 2 may be useful for practical application of detection and estimation of trace Fe3+ and Hg2+ in real water samples and/or in biological systems.

Ultra-Uniform and Very Thin Ag Nanowires Synthesized via the Synergy of Cl-, Br- and Fe3+ for Transparent Conductive Films.

The properties and applications of Ag nanowires (AgNWs) are closely related to their morphology and composition. Therefore, controlling the growth process of AgNWs is of great significance for technological applications and fundamental research. Here, silver nanowires (AgNWs) were synthesized via a typical polyol method with the synergistic effect of Cl−, Br−, and Fe3+ mediated agents. The synergistic impact of these mediated agents was investigated intensively, revealing that trace Fe3+ ions provided selective etching and hindered the strong etching effect from Cl− and Br− ions. Controlling this synergy allowed the obtainment of highly uniform AgNWs with sub-30 nm diameter and an aspect ratio of over 3000. Transparent conductive films (TCFs) based on these AgNWs without any post-treatment showed a very low sheet resistance of 4.7 Ω sq−1, a low haze of 1.08% at a high optical transmittance of 95.2% (at 550 nm), and a high figure of merit (FOM) of 1210. TCFs exhibited a robust electrical performance with almost unchanged resistance after 2500 bending cycles. These excellent high-performance characteristics demonstrate the enormous potential of our AgNWs in the field of flexible and transparent materials.

Imaging of living organisms and determination of real water samples using a rhodamine-based Fe(III)-induced fluorescent probe

In this study, we designed and synthesized a novel rhodamine-based and Fe3+-induced fluorescent probe (RBNC) and characterized by 1H NMR, 13C NMR and ESI-MS. RBNC exhibits highly specific detection of Fe3+ with little interference to other coexisting cations and anions in the MeOH/H2O (1:1, v/v, HEPES, 0.5 mM, pH = 7.35) solution. After adding Fe3+, the color change is obvious and the fluorescence intensity is rapidly enhanced. The reversibility of RBNC to Fe3+ was achieved by adding Na4P2O7. In addition, RBNC has a higher binding constant (1.17 × 104 m−1) and a lower detection limit (0.157 μM). RBNC can also be used to monitor trace Fe3+ in actual water samples. Bioimaging experiments demonstrated that RBNC is feasible for imaging in living organisms when it is used for biological detection. MTT assays indicated that RBNC is non-toxic in cells at low concentrations.

FTIR, optical, and thermal studies of cadmium borate glass doped with Bi2O3 and effects of gamma irradiation

Bi2O3-doped glasses from CdO-B2O3 glasses were prepared by the melt-annealing method. Optical and FTIR spectroscopic properties of the prepared glasses were measured before and after gamma irradiation (dose 6 M rad). The undoped glass reveals distinct UV absorption within the spectrum of the undoped glass and extended to visible peaks upon the increase of the dopant Bi3+ ions. The extended identified UV to visible absorption is related to absorption of both trace Fe3+ ions and Bi3+ ions. Fourier transform IR spectra of the prepared glasses reveal distinct and composite vibrational bands within the wavenumber range 400–1650 cm−1 indicating the presence of both triangular and tetrahedral borate groups within their specific different wavenumbers and supporting the assumption of the role of CdO to convert some of the BO3 groups to BO4 groups. The introduction of Bi2O3 shows interfered vibrational bands due to additional structural BiO6 and BiO3 groups within their characteristic sites at about 450–480 cm−1 and 860–920 cm−1 and is assumed to be mixed or interfered with the two coordinated borate species. The effect of gamma irradiation on the optical spectra differs between the undoped and Bi2O3-doped glasses showing some shielding behavior in the latter Bi2O3-containing samples.

A silver nanosol SERS quantitative method for trace F− detection using the oxidized tetramethylbenzidine as molecular probes

Fluoride constitutes an essential component for the formation of hard bones and teeth. However long-term excessive intake of fluoride causes chronic poisoning changes in the body. Therefore, the determination of its content is of great significance. Herein, a sensitive SERS quantitative analysis method was proposed to detect F−. Trace Fe3+ exhibited strong catalysis of H2O2 oxidizing 3, 3′, 5, 5′-tetramethylbenzidine (TMB) under the ultrasonic irradiation, and the reaction product called TMB diimine (TMBOX) not only had strong fluorescence, but also had SERS activity in the silver nanosol substrate. Upon addition of fluoride ion (F−), the stable complex of [FeF6]3− formed, and could inhibit the catalytic action of Fe3+, resulting in the SERS and fluorescence signal decreasing due to the TMBOX concentration decreasing. In the range of 2–1000 nmol/L F−, the SERS intensity ΔI decreased line with the concentration increased, with a detection limit of 0.7 nmol/L. Based on the catalytic amplifying strategy and the TMBOX molecular probes, ultratrace Fe3+ could be also detected by SERS and fluorescence methods.

Optical Detection of Fe3+ Ions in Aqueous Solution with High Selectivity and Sensitivity by Using Sulfasalazine Functionalized Microgels.

A highly selective and sensitive optical sensor was developed to colorimetric detect trace Fe3+ ions in aqueous solution. The sensor was the sulfasalazine (SSZ) functionalized microgels (SSZ-MGs), which were fabricated via in-situ quaternization reaction. The obtained SSZ-MGs had hydrodynamic radius of about 259 ± 24 nm with uniform size distribution at 25 °C. The SSZ-MG aqueous suspensions can selectively and sensitively response to Fe3+ ions in aqueous solution at 25 °C and pH of 5.6, which can be quantified by UV-visible spectroscopy and also easily distinguished by the naked eye. Job’s plot indicated that the molar binding ratio of SSZ moiety in SSZ-MGs to Fe3+ was close to 1:1 with an apparent association constant of 1.72 × 104 M−1. A linear range of 0–12 μM with the detection limit of 0.110 μM (0.006 mg/L) was found. The obtained detection limit was much lower than the maximum allowance level of Fe3+ ions in drinking water (0.3 mg/L) regulated by the Environmental Protection Agency (EPA) of the United States. The existence of 19 other species of metal ions, namely, Ag+, Li+, Na+, K+, Ca2+, Ba2+, Cu2+, Ni2+, Mn2+, Pb2+, Zn2+, Cd2+, Co2+, Cr3+, Yb3+, La3+, Gd3+, Ce3+, and Bi3+, did not interfere with the detection of Fe3+ ions.

A threefold interpenetrating two-dimensional zinc(II) coordination polymer: synthesis, crystal structure and selective luminescence sensing properties.

The Fe3+ ion is the most important element in environmental systems and plays a fundamental role in biological processes. Iron deficiency can result in diseases and highly selective and sensitive detection of trace Fe3+ has become a hot topic. A novel two-dimensional ZnII coordination framework, poly[[μ-4,4'-bis(2-methylimidazol-1-yl)diphenyl ether-κ2N3:N3'](μ-4,4'-sulfonyldibenzoato-κ2O:O')zinc(II)], [Zn(C14H8O6S)(C20H18N4O)]n or [Zn(SDBA)(BMIOPE)]n, (I), where H2SDBA is 4,4'-sulfonyldibenzoic acid and BMIOPE is 4,4'-bis(2-methylimidazol-1-yl)diphenyl ether, has been prepared and characterized by IR, elemental analysis, thermal analysis and X-ray diffraction analysis, the latter showing that the coordination polymer exhibits a threefold interpenetrating two-dimensional 44-sql network. In addition, it displays a highly selective and sensitive sensing for Fe3+ ions in aqueous solution.