Trace Iodine Research Articles

Optimizing Aqueous Zinc-Sulfur Battery Performance via Regulating Acetonitrile Co-Solvents and Carbon Nanotube Carriers.

Rechargeable aqueous zinc-sulfur batteries (AZSBs) are gaining attention due to their high energy density, ultra-stable discharge platform, and safety. However, poor liquid/solid reaction processes at the anode and cathode reduce reaction kinetics, and the severe dissolution of polysulfides causes shuttle effects during discharge/charge cycles, hindering practical applications. Improving performance requires optimizing both the cathode and electrolyte. Herein, we design an organic-inorganic hybrid electrolyte (zinc trifluoromethanesulfonate and trace iodine monomer dissolved in an acetonitrile/water co-solvent (AN-X)) and a partially exfoliated multi-walled carbon nanotube (PECNT) hosted sulfur (S@PECNTs) cathode for AZSBs. The sulfur is highly dispersed along the PECNTs with appropriate wettability at the electrode/electrolyte interface using AN-3 as the electrolyte. Meanwhile, this electrolyte inhibits hydrogen evolution at negative potentials and promotes uniform Zn ion stripping/plating. Expressively, the AN-3-based AZSB exhibits a high discharge capacity of 1370 mAh g-1 with excellent Coulombic efficiency (79.9 %), outstanding rate capability, and cycling performance. These improvements are attributed to the synergistic effect between the S@PECNTs and the AN-3 electrolyte, which reduces Rct to enhance reaction kinetics and blocks the dissolution and shuttle effect of polysulfides, ensuring a reversible reaction between zinc and sulfur.

Nonporous amorphous superadsorbents for highly effective and selective adsorption of iodine in water

Adsorbents widely utilized for environmental remediation, water purification, and gas storage have been usually reported to be either porous or crystalline materials. In this contribution, we report the synthesis of two covalent organic superphane cages, that are utilized as the nonporous amorphous superadsorbents for aqueous iodine adsorption with the record–breaking iodine adsorption capability and selectivity. In the static adsorption system, the cages exhibit iodine uptake capacity of up to 8.41 g g−1 in I2 aqueous solution and 9.01 g g−1 in I3− (KI/I2) aqueous solution, respectively, even in the presence of a large excess of competing anions. In the dynamic flow-through experiment, the aqueous iodine adsorption capability for I2 and I3− can reach up to 3.59 and 5.79 g g−1, respectively. Moreover, these two superphane cages are able to remove trace iodine in aqueous media from ppm level (5.0 ppm) down to ppb level concentration (as low as 11 ppb). Based on a binding–induced adsorption mechanism, such nonporous amorphous molecular materials prove superior to all existing porous adsorbents. This study can open up a new avenue for development of state–of–the–art adsorption materials for practical uses with conceptionally new nonporous amorphous superadsorbents (NAS).

Boosting Zn Anode Utilization by Trace Iodine Ions in Organic-Water Hybrid Electrolytes through Formation of Anion-rich Adsorbing Layers.

Aqueous Zn batteries are attracting extensive attentions, but their application is still hindered by H2 O-induced Zn-corrosion and hydrogen evolution reactions. Addition of organic solvents into aqueous electrolytes to limit the H2 O activity is a promising solution, but at the cost of greatly reduced Zn anode kinetics. Here we propose a simple strategy for this challenge by adding 50 mM iodine ions into an organic-water (1,2-dimethoxyethane (DME)+water) hybrid electrolyte, which enables the electrolyte simultaneously owns the advantages of low H2 O activity and accelerated Zn kinetics. We demonstrate that the DME breaks the H2 O hydrogen-bond network and exclude H2 O from Zn2+ solvation shell. And the I- is firmly adsorbed on the Zn anode, reducing the Zn2+ de-solvation barrier from 74.33 kJ mol-1 to 32.26 kJ mol-1 and inducing homogeneous nucleation behavior. With such electrolyte, the Zn//Zn symmetric cell exhibits a record high cycling lifetime (14.5 months) and achieves high Zn anode utilization (75.5 %). In particular, the Zn//VS2 @SS full cell with the optimized electrolyte stably cycles for 170 cycles at a low N : P ratio (3.64). Even with the cathode mass-loading of 16.7 mg cm-2 , the full cell maintains the areal capacity of 0.96 mAh cm-2 after 1600 cycles.

Boosting Zn Anode Utilization by Trace Iodine Ions in Organic‐Water Hybrid Electrolytes through Formation of Anion‐rich Adsorbing Layers

AbstractAqueous Zn batteries are attracting extensive attentions, but their application is still hindered by H2O‐induced Zn‐corrosion and hydrogen evolution reactions. Addition of organic solvents into aqueous electrolytes to limit the H2O activity is a promising solution, but at the cost of greatly reduced Zn anode kinetics. Here we propose a simple strategy for this challenge by adding 50 mM iodine ions into an organic‐water (1,2‐dimethoxyethane (DME)+water) hybrid electrolyte, which enables the electrolyte simultaneously owns the advantages of low H2O activity and accelerated Zn kinetics. We demonstrate that the DME breaks the H2O hydrogen‐bond network and exclude H2O from Zn2+ solvation shell. And the I− is firmly adsorbed on the Zn anode, reducing the Zn2+ de‐solvation barrier from 74.33 kJ mol−1 to 32.26 kJ mol−1 and inducing homogeneous nucleation behavior. With such electrolyte, the Zn//Zn symmetric cell exhibits a record high cycling lifetime (14.5 months) and achieves high Zn anode utilization (75.5 %). In particular, the Zn//VS2@SS full cell with the optimized electrolyte stably cycles for 170 cycles at a low N : P ratio (3.64). Even with the cathode mass‐loading of 16.7 mg cm−2, the full cell maintains the areal capacity of 0.96 mAh cm−2 after 1600 cycles.

Visualized electrochemiluminescence iodine sensor based on polymer dots with Co-reactive group for real-time monitoring system

Trace iodine (I2) radioisotopes are commonly regarded as an indicator in nuclear security early warnings. Herein, we develop a visualized I2 real-time monitoring system using electrochemiluminescence (ECL) imaging technology for the first time. In detail, the polymers based on poly [(9,9-dioctylfluorene-alkenyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1’,3}-thiadiazole)] are synthesized for iodine detection. An ultra-low limit of detection (0.01 ppt) to iodine can be achieved by adding the modification ratio of tertiary amine onto PFBT as a co-reactive group, which is the lowest detection limit in known iodine vapor sensors. This result can be attributed to the co-reactive group poisoning response mechanism. Considering to the strong ECL behavior of this polymer dots, P-3 Pdots with ultra-low detection limit for iodine is combined with ECL imaging technology to realize the visualized rapid I2 vapor response with high selectivity. ECL imaging component based on ITO electrode can make iodine monitoring system more convenient and suitable for real-time detection in early warning of nuclear emergency. The detection result cannot be affected by vapor of organic compounds, humidity and temperature, indicating a good selectivity to iodine. This work provides a strategy for nuclear emergency early warning, showing its significance in environmental and nuclear security fields.

Water-stable porous Al24 Archimedean solids for removal of trace iodine

In this paper, we report a unique type of core-shell crystalline material that combines an inorganic zeolitic cage structure with a macrocyclic host arrangement and that can remove trace levels of iodine from water effectively. These unique assemblies are made up of an inorganic Archimedean truncatedhexahedron (tcu) polyhedron in the kernel which possesses six calixarene-like shell cavities. The cages have good adaptability to guests and can be assembled into a series of supramolecular structures in the crystalline state with different lattice pore shapes. Due to the unique core-shell porous structures, the compounds are not only stable in organic solvents but also in water. The characteristics of the cages enable rapid iodine capture from low concentration aqueous I2/KI solutions (down to 4 ppm concentration). We have studied the detailed process and mechanism of iodine capture and aggregation at the molecular level. The facile synthesis, considerable adsorption capacity, recyclability, and β- and γ-radiation resistance of the cages should make these materials suitable for the extraction of iodine from aqueous effluent streams (most obviously, radioactive iodide produced by atomic power generation).

Hierarchically Porous Poly(ionic liquid) - Organic Cage Composite Membrane for Efficient Iodine Capture.

The effective capture of iodine with high volatility and poisonousness is significant for reprocessing the spent nuclear fuel. In this article, we report a hierarchically porous poly(ionic liquid)-organic cage composite membrane (PIL@CC3) possessing a gradient content distribution of CC3 cage crystals throughout the membrane to capture iodine vapor. The introduction of microporous CC3 can significantly enhance the uptake capacity of iodine up to 980 mg g-1 , which is superior to that of a pristine PIL membrane carrying large meso- and macropores (99 mg g-1 ), and CC3 crystalline powder (662 mg g-1 ). Such enhanced performance benefits from the micro-meso-macroporous structure of the PIL@CC3 membrane in which the large meso- and macropores facilitate the mass transfer of iodine molecules from the external environment into the surface of the CC3 crystal, followed by diffusion of iodine molecules from the CC3 surface into the interior and exterior pores of the CC3 crystal. In addition, the asymmetric distribution of CC3 crystals across the PIL@CC3 membrane also displays its advantage in intercepting trace iodine, revealing its great potential for practical application. This study provides an idea for constructing hierarchically porous membrane composites for the removal of toxic vapors.

Interfacial and Ionic Modulation of Poly (Ethylene Oxide) Electrolyte Via Localized Iodization to Enable Dendrite‐Free Lithium Metal Batteries

AbstractSolid polymer electrolytes (SPEs) make contact with highly reductive lithium (Li) metal anodes, forming the interphase that largely determines the battery performance. In this work, trace iodine doping in a poly(ethylene oxide) (PEO) electrolyte to achieve a stable interphase on Li metal surface for long battery cycling, is proposed. The triiodide ion (I3−) stemming from iodine additives can coordinate with the COC bond of PEO to enable the increased ionic conductivity of the SPE. The I‐doped interphase contains I3− and IO3−, which spontaneously react with the dead Li and Li2O at the initial interphase to smooth the Li metal surface, eventually leading to significant improvements in interfacial resistance and dendrite suppression. When matching with the LiFePO4 cathode, the full cell exhibits higher capacity (150 mAh g−1) and excellent cycling stability after 300 cycles (capacity retention of 96.5%) at 0.5 C and 50 °C. This work opens up a promising avenue for using halogen to design solid‐state Li metal batteries.

A new gold nanoflower sol SERS method for trace iodine ion based on catalytic amplification

As one of the essential trace elements in metabolism, iodine is crucial to maintain the normal physiological functions. Therefore, based on health and environmental protection, it is very important to realize sensitive detection of iodide ion. Herein, we developed a simple, rapid and sensitive method for the determination of iodide ion. Trypsin was used as an ideal template for the synthesis of gold nanoflower sol (AuNFs) with anisotropic surface structure and good stability. It exhibits highly active surface enhanced Raman scattering (SERS) effect and can be used as facile SERS sol substrate. The TMBox generated by the catalytic oxidation reaction of TMB-chloramine T-iodide ion is used as the SERS probe. The enhanced SERS signal intensity is linearly related to the iodide ion with high sensitivity. In addition, TMB has fluorescence effect, and the colored TMBox can produce RRS signal due to polymerization. Based on this, a quad-mode detection method of SERS, RRS, fluorescence and colorimetry for quantitative detection of trace iodide ions was established, and this method can be applied to the detection of iodide ions in natural water and drinking water.

Electrochemical Reduction of CO2 to Ethane through Stabilization of an Ethoxy Intermediate

AbstractElectrochemical conversion of CO2 into ethane is seldom observed because of the generally higher selectivity towards methane, ethylene, and ethanol. Consequently, little experimental evidence for its reaction mechanism exists and thus remains largely unknown. Now, by combining electrochemistry with in situ X‐ray absorption fine‐structure and in situ Raman techniques, iodide‐derived copper (ID‐Cu) and oxide‐derived copper (OD‐Cu) systems were studied to obtain a deeper understanding of the CO2 to ethane mechanism. With trace iodine species on the surface and positively charged Cu species, production of ethane is significantly more favored on ID‐Cu compared to OD‐Cu, with higher selectivity and faster kinetics. For the first time, it is experimentally found that the formation of ethane follows the same pathway to ethylene and ethanol, and better stabilization of the late stage ethoxy intermediate can steer the reaction to ethane over ethanol.

Electrochemical Reduction of CO2 to Ethane through Stabilization of an Ethoxy Intermediate.

Electrochemical conversion of CO2 into ethane is seldom observed because of the generally higher selectivity towards methane, ethylene, and ethanol. Consequently, little experimental evidence for its reaction mechanism exists and thus remains largely unknown. Now, by combining electrochemistry with in situ X-ray absorption fine-structure and in situ Raman techniques, iodide-derived copper (ID-Cu) and oxide-derived copper (OD-Cu) systems were studied to obtain a deeper understanding of the CO2 to ethane mechanism. With trace iodine species on the surface and positively charged Cu species, production of ethane is significantly more favored on ID-Cu compared to OD-Cu, with higher selectivity and faster kinetics. For the first time, it is experimentally found that the formation of ethane follows the same pathway to ethylene and ethanol, and better stabilization of the late stage ethoxy intermediate can steer the reaction to ethane over ethanol.

Direct Determination of Trace Iodine in Geological Samples by Solid Sampling Electrothermal Vaporization-Inductively Coupled Plasma Mass Spectrometry

Direct Determination of Trace Iodine in Geological Samples by Solid Sampling Electrothermal Vaporization-Inductively Coupled Plasma Mass Spectrometry

A simple method for quantifying iodate and iodide fractions in solution using Ag+-impregnated activated carbon

The speciation of iodine in environment must be known in order to properly assess its geological fate and to study potential remediation materials for the decontamination of water containing radioactive iodine. In this study, the utilization of silver-impregnated granular activated carbon for separation between two iodine species, iodate and iodide, from each other was studied in different solution matrices with batch and column experiments. A high separation of the iodine species was achieved in the high concentrations of interfering ions, e.g. chloride, and in both μM and trace iodine concentrations. The method is suitable for both radioactive and non-radioactive iodine.

A method for the removal of trace iodine from wet-process phosphoric acid

AbstractAn effective method for extracting trace iodine from wet-process phosphoric acid (WPA) was designed. The iodine content in WPA was determined using an iodide-selective electrode. In addition, in this method, the sample solution, which contained approximately 2 ppm iodide, was phosphoric acid (PA) from WPA. The optimal extraction conditions were as follows: the PA/H2O2 volume ratio was 1:24, the PA/simethicone volume ratio was 1:3, the reaction time was 1 h, the reaction temperature was 45 °C, and no stirring was needed. The extraction yield of iodine reached 95%. A kinetic model was established based on bubbles with different rising velocities, and the characteristic viscosities of the gases as well as the heat flow rates of the bubbles were determined to simulate bubble movement. Then, the extraction principle was discussed, and the effect of bubble movement on extractability was analysed. The extractant (simethicone) can be recycled. Therefore, the proposed method can be considered a rapid, simple, and environmentally friendly method of extracting trace iodine from WPA.

Polyphenylene Sulfide Ultrafine Fibrous Membrane Modified by Nanoscale ZIF-8 for Highly Effective Adsorption, Interception, and Recycling of Iodine Vapor.

In this study, two novel composite membranes containing nanoscale ZIF-8 and polyphenylene sulfide (PPS) nonwoven fabric were prepared via hydrothermal (PPS-ZIF-8) and biomimetic mineralization (PPS-ZIF-8-BSA; BSA, bovine serum albumin) approaches. The biomimetic mineralization approach in particular was extremely rapid and mild, and crystalline ZIF-8 was coated on the PPS substrate in only a few seconds at room temperature. The maximum iodine adsorption capacities of the PPS-ZIF-8 and PPS-ZIF-8-BSA membranes were 2.51 and 2.07 g/g, respectively. The composite fibrous membranes were able to capture trace iodine vapor under differential pressures ranging from 0 to 1000 Pa without almost any iodine vapor leakage. The composite membranes can be applied in harsh environments because of the excellent stability of ZIF-8 and the PPS high-performance fibers. This study provides a promising strategy to fabricate novel adsorption materials for the collection of radioactive iodine during nuclear waste disposal.

Determination of Trace Iodine in Seawater — Use of Ion Chromatography and Capillary Zone Electrophoresis —

Determination of Trace Iodine in Seawater — Use of Ion Chromatography and Capillary Zone Electrophoresis —

Iodate in calcite, aragonite and vaterite CaCO3: Insights from first-principles calculations and implications for the I/Ca geochemical proxy

The incorporation of iodine into each of the three polymorphs of CaCO3 – calcite, aragonite and vaterite, is compared using first-principles computational simulation. In each case iodine is most easily accommodated as iodate (IO3−) onto the carbonate site. Local strain fields around the iodate solute atom are revealed in the pair distribution functions for the relaxed structures, which indicate that aragonite displays the greatest degree of local structural distortion while vaterite is relatively unaffected. The energy penalty for iodate incorporation is least significant in vaterite, and greatest in aragonite, with the implication that iodine will display significant partitioning between calcium carbonate polymorphs in the order vaterite > calcite > aragonite. Furthermore, we find that trace iodine incorporation into vaterite confers improved mechanical strength to vaterite crystals. Our results support the supposition that iodine is incorporated as iodate within biogenic carbonates, important in the application of I/Ca data in palaeoproxy studies of ocean oxygenation. Our observation that iodate is most easily accommodated into vaterite implies that the presence of vaterite in any biocalcification process, be it as an end-product or a precursor, should be taken into account when applying the I/Ca geochemical proxy.

A Green Extraction of Trace Iodine in Table Salts, Vegetables, and Food Products Prior to Analysis by Inductively Coupled Plasma Optical Emission Spectrometry

In this study, we report a new method for iodine extraction from table salts, vegetables, and other food products using ultrasound-assisted extraction, prior to the iodine determination by inductively coupled plasma optical emission spectrometry. For the ultrasound-assisted extraction, deionized water as the extraction solvent and an extraction time of 5 min were found to be the most optimum condition. A linear calibration curve was plotted for 0.1 to 200.0 mg L−1 iodine convention. The limits of detection and quantification were 0.049 and 0.164 mg L−1, respectively. The precision for intraand inter-day analyses was 2.75 and 4.54%, respectively. The accuracy of the method was confirmed with certified reference materials. Recoveries in 47 real samples were ranged between 80.48 and 118.1%. Therefore, the proposed method could be considered as a rapid, simple, and environmental-friendly method (the green extraction) to determine the trace amounts of iodine in different kinds of food products.

VALUES OF TRACE ELEMENTS SELENIUM, COPPER, ZINC, AND IODINE AND OF VITAMIN E IN CAPTIVE LESSER KUDUS (TRAGELAPHUS IMBERBIS).

Lesser kudus (Tragelaphus imberbis) have been kept in Zoo Basel since 1956. Juvenile mortality used to be high, and a recent study to reveal pathologic findings identified white muscle disease as a major contributor to this problem. Therefore, a retrospective study was initiated using 16 stored serum samples from lesser kudus from 2000 to 2013 to determine the concentration of selected trace elements, including selenium, copper, zinc, and iodine. Additionally, three serum samples were used to measure serum vitamin E values. Serum analysis revealed that copper, zinc, and iodine values were within reference ranges for domestic ruminants, and the supplementation status of these trace elements was assumed to be adequate. In contrast, vitamin E levels were low and selenium levels were scarce in several animals, indicating a deficiency of these essential micronutrients. The results of the analyses are compared with literature references.

Simple and rapid determination of trace iodide by cathodic stripping voltammetry

This work establishes a highly sensitive and simple stripping voltammetric method for the direct determination of trace iodide. In the presence of abounding bromide and appropriate amount of cetylpyridine bromide (CPB), the iodine was accumulated on the glassy carbon electrode surface as ion association complex (CPBI2Br). After accumulation for a period of time, a linear sweep potential with negative scanning was applied and the I2 in CPBI2Br was reduced again into the solution. Under the optimization conditions, the stripping signals (peak current) were linear relationship with iodide concentration in range of 3.81×10−3µg/mL to 0.114 μg/mL and 0.127μg/mL to 2.54μg/mL, with a detection limit of 1.02ng/mL (S/N=3) for a accumulation time of 180s. Determination of trace iodine in pharmaceutical sample, kelp and table salt were performed with high accuracy and satisfactory recovery results.