Iodine Species Research Articles

Metal-Free Electrocatalytic Synthesis of Fused Azabicycles from N-Allyl Enamine Carboxylates.

An electrocatalytic approach to access structurally significant azabicyclic scaffolds from N-allyl enamine carboxylates is illustrated. This metal-free method functions exclusively with a catalytic amount of iodide, strategically employed to electrochemically generate a reactive hypervalent iodine species, which facilitates the cascade bicyclization processes with enhanced precision and efficiency. Excellent functional group compatibility was observed, enabling the synthesis of a series of azabicycle derivatives. Detailed mechanistic and electrochemical studies enhance the comprehension of the reaction sequence.

Enrichment of Geogenic Organoiodine Compounds in Alluvial-Lacustrine Aquifers: Molecular Constraints by Organic Matter.

Organoiodine compounds (OICs) are the dominant iodine species in groundwater systems. However, molecular mechanisms underlying the geochemical formation of geogenic OICs-contaminated groundwater remain unclear. Based upon multitarget field monitoring in combination with ultrahigh-resolution molecular characterization of organic components for alluvial-lacustrine aquifers, we identified a total of 939 OICs in groundwater under reducing and circumneutral pH conditions. In comparison to those in water-soluble organic matter (WSOM) in sediments, the OICs in dissolved organic matter (DOM) in groundwater typically contain fewer polycyclic aromatics and polyphenol compounds but more highly unsaturated compounds. Consequently, there were two major sources of geogenic OICs in groundwater: the migration of the OICs from aquifer sediments and abiotic reduction of iodate coupled with DOM iodination under reducing conditions. DOM iodination occurs primarily through the incorporation of reactive iodine that is generated by iodate reduction into highly unsaturated compounds, preferably containing hydrophilic functional groups as binding sites. It leads to elevation of the concentration of the OICs up to 183 μg/L in groundwater. This research provides new insights into the constraints of DOM molecular composition on the mobilization and enrichment of OICs in alluvial-lacustrine aquifers and thus improves our understanding of the genesis of geogenic iodine-contaminated groundwater systems.

Cyanide Bridged Framework Nanoplates Catalytic Interlayer for High Performance Zinc‐Iodine Battery

AbstractIodine is a promising candidate among the cathode materials in zinc‐ion battery. However, iodine cathode suffers from serious shuttle effect by spontaneous generated polyiodide species. In this work, we developed a CoNi(CN)4/CNT interlayer to prevent shuttle effect by adsorption‐catalysis process. The adsorption of the iodine species on CoNi(CN)4/CNT interlayer is justified by UV‐vis spectroscopy and X‐ray photoelectron spectroscopy, where the concentration of polyiodides is significantly reduced, and the binding energy of cobalt, nickel, and nitrogen is remarkably reduced by binding with polyiodides. The zinc‐iodine dual‐plating battery shows significantly higher areal capacity and cycle stability with CoNi(CN)4/CNT. Moreover, battery with impressive areal capacity of 3.6 mAh cm−2 and negligible fading over 100 cycles is also achieved, which outperforms state‐of the art literatures on zinc‐iodine batteries.

Insight into the activation of periodate by Mn(II) for rapid degradation of sulfadiazine: Performance and mechanisms

The present study investigated the mechanism of manganese ion (Mn(II))-activated periodate (PI) for rapid removal of sulfadiazine (SDZ). The Mn(II)/PI system showed excellent SDZ degradation results with 99.8 % degradation efficiency within 2 min at pH = 5.5. Mechanism study reveals that the degradation of SDZ in the Mn(II)/PI system takes place mainly through an electron transfer process. Mn(II) can be oxidized by PI to formed the in-situ MnO2, followed by the generation of MnO2-PI complex. Electrochemical methods have confirmed that the generated MnO2-PI complex significantly contributes to the degradation of pollutants. MnO2-PI mediates the transfer of electrons from SDZ to PI surface through surface vacancies, thereby achieving efficient degradation of pollutants. p-methoxyphenyl sulfone (PMSO) is used as a probe compound, and almost 90 % of PMSO is converted into PMSO2 in the Mn(II)/PI/SDZ system, manifesting that excessive PI may oxidize active Mn(IV) to Mn(V). And the generated Mn(V) also contributes to the SDZ degradation. The SDZ degradation pathway is proposed and the transformation of iodine species is detected. The final iodine species in the system are iodate. The chloride culture experiment has confirmed that the production of organic iodine is very low, indicating no significant health risks. This study reveals mechanism of periodate-based process, providing theoretical and technical implementation guidelines of periodate in water treatment.

Sustainable bioelectric activation of periodate for highly efficient micropollutant abatement

The periodate (PI)-based advanced oxidation process is valued for environmental remediation, but current activation methods involve high costs, secondary contamination risks, and limited applicability due to external energy inputs (e.g., UV), catalyst incorporation (e.g., Fe2+), or environmental modifications (e.g., freezing). In this work, novel bioelectric activation of PI using the electrons generated by electroactive bacteria was developed and investigated for rapid removal of carbamazepine (CBZ), achieving 100 %, 100 %, and 76 % removal efficiency for 4.22 µM of CBZ in 20 min at pH 2, 120 min at pH 6.4, and HRT of 30 min at pH 8.5, respectively, with a 1 mM PI dose and without an input voltage. It was deduced that electrons derived from bacteria could directly activate PI using Ti mesh electrodes and generate •IO3 via single electron transfer under strongly acidic conditions (e.g., pH 2). Nevertheless, under weak alkaline conditions (e.g., pH 8.5), biogenic electrons indirectly activated PI by generating OH−via 4e−reduction at the Ti mesh cathode, resulting in the formation of •O2− and 1O2. In addition to the metal cathode, a carbon-based cathode finely modulates the 2e−reduction, yielding H2O2 and activating PI to mainly form •OH. Moreover, primarily non-toxic IO3− was produced during treatment, while no detectable reactive iodine species (HOI, I2, and I3−) were observed. Furthermore, the bioelectric activation of PI demonstrated its capability to remove various micropollutants present in secondary-treated municipal wastewater, showcasing its broad-spectrum degradation ability. This study introduces a novel, cost-effective, and environmentally friendly PI activation technique with promising applicability for micropollutant elimination in water treatment.

Iodide, iodate & dissolved organic iodine in the temperate coastal ocean

The surface ocean is the main source of iodine to the atmosphere, where it plays a crucial role including in the catalytic removal of tropospheric ozone. The availability of surface oceanic iodine is governed by its biogeochemical cycling, the controls of which are poorly constrained. Here we show a near two-year time series of the primary iodine species, iodide, iodate and dissolved organic iodine (DOI) in inner shelf marine surface waters of the Western English Channel (UK). The median ± standard deviation concentrations between November 2019 and September 2021 (n=76) were: iodide 88 ± 17 nM (range 61-149 nM), iodate 293 ± 28 nM (198-382 nM), DOI 16 ± 16 nM (<0.12-75 nM) and total dissolved iodine (dIT) 399 ± 30 nM (314-477 nM). Though lower than inorganic iodine ion concentrations, DOI was a persistent and non-negligible component of dIT, which is consistent with previous studies in coastal waters. Over the time series, dIT was not conserved and the missing pool of iodine accounted for ~6% of the observed concentration suggesting complex mechanisms governing dIT removal and renewal. The contribution of excess iodine (I*) sourced from the coastal margin towards dIT was generally low (3 ± 29 nM) but exceptional events influenced dIT concentrations by up to ±100 nM. The seasonal variability in iodine speciation was asynchronous with the observed phytoplankton primary productivity. Nevertheless, iodate reduction began as light levels and then biomass increased in spring and iodide attained its peak concentration in mid to late autumn during post-bloom conditions. Dissolved organic iodine was present, but variable, throughout the year. During winter, iodate concentrations increased due to the advection of North Atlantic surface waters. The timing of changes in iodine speciation and the magnitude of I* subsumed by seawater processes supports the paradigm that transformations between iodine species are biologically mediated, though not directly linked.

Janus Binder Chemistry for Synchronous Enhancement of Iodine Species Adsorption and Redox Kinetics toward Sustainable Aqueous Zn-I2 Batteries.

Currently, the desired research focus in energy storage technique innovation has been gradually shifted to next-generation aqueous batteries holding both high performance and sustainability. However, aqueous Zn-I2 batteries have been deemed to have great sustainable potential, owing to the merits of cost-effective and eco-friendly nature. However, their commercial application is hindered by the serious shuttle effect of polyiodides during reversible operations. In this work, a Janus functional binder based on chitosan (CTS) molecules was designed and prepared; the polar terminational groups impart excellent mechanical robustness to hybrid binders; meanwhile, it can also deliver isochronous enhancement on physical adsorption and redox kinetics toward I2 species. By feat of highly effective remission to shuttle effect, the CTS cell exhibits superb electrochemical storage capacities with long-term robustness, specifically, 144.1 mAh g-1, at a current density of 0.2 mA g-1 after 1500 cycles. Simultaneously, the undesired self-discharging issue could be also well-addressed; the Coulombic efficiency could remain at 98.8 % after resting for 24 h. More importantly, CTS molecules endow good biodegradability and reusable properties; after iodine species were reloaded, the recycled devices could also deliver specific capacities of 73.3 mAh g-1, over 1000 cycles. This Janus binder provides a potential synchronous solution to realize high comprehensive performance with high iodine utilization and further make it possible for sustainable Zn-I2 batteries.

Optimizing Iodine Enrichment through Induced-Fit Transformations in a Flexible Ag(I)-Organic Framework: From Accelerated Adsorption Kinetics to Record-High Storage Density.

Efficient capture and storage of radioactive I2 is a prerequisite for developing nuclear power but remains a challenge. Here, two flexible Ag-MOFs (FJI-H39 and 40) with similar active sites but different pore sizes and flexibility are prepared; both of them can capture I2 with excellent removal efficiencies and high adsorption capacities. Due to the more flexible pores, FJI-H39 not only possesses the record-high I2 storage density among all the reported MOFs but also displays a very fast adsorption kinetic (124 times faster than FJI-H40), while their desorption kinetics are comparable. Mechanistic studies show that FJI-H39 can undergo induced-fit transformations continuously (first contraction then expansion), making the adsorbed iodine species enrich near the Ag(I) nodes quickly and orderly, from discrete I- anion to the dense packing of various iodine species, achieving the very fast adsorption kinetic and the record-high storage density simultaneously. However, no significant structural transformations caused by the adsorbed iodine are observed in FJI-H40. In addition, FJI-H39 has excellent stability/recyclability/obtainability, making it a practical adsorbent for radioactive I2. This work provides a useful method for synthesizing practical radioactive I2 adsorbents.

Iodine oxoacids and their roles in sub-3 nm particle growth in polluted urban environments

Abstract. New particle formation contributes significantly to the number concentration of ultrafine particles (UFPs, d ≤ 100 nm) and has a great impact on human health and global climate. Iodine oxoacids (HIOx, including iodic acid, HIO3, and iodous acid, HIO2) have been observed in pristine regions and proved to dominate new particle formation (NPF) at some sites. However, the knowledge of HIOx in polluted urban areas is rather limited. Here, we conducted a long-term measurements of gaseous iodine oxoacids and sulfuric acid in Beijing from January 2019 to October 2021 and also in Nanjing from March 2019 to February 2020 and investigated the contribution of HIOx to UFP number concentration in both urban environments. HIO3 is highest in summer, up to 2.85 × 106 and 2.78 × 106 cm−3 in Beijing and Nanjing, respectively, and is lowest in winter by 96 % and 75 %, respectively. HIO3 exhibits more prominent variation than H2SO4 in both urban sites. HIO3 concentration shows a clear diurnal pattern at both sites with a daily maximum at around noontime, similar to the atmospheric temperature, solar radiation, and ozone (O3) levels. HIO2 concentration has the same diurnal and seasonal trend as HIO3 but is overall about an order of magnitude lower than HIO3 concentration. Back trajectory analysis suggests that the sources for inland iodine species could be a mix of marine and terrestrial origins, with both having peak iodine emission in warm seasons. While the contribution of HIO2 to particle growth is marginal in Beijing and Nanjing, our results demonstrate that HIO3 enhances the particle survival probability of sub-3 nm particles by about 40 % (median) and occasionally by more than 100 % in NPF events, suggesting HIOx are significant contributor to UFPs in polluted urban areas. As the growth contribution from HIO3 and H2SO4 is similar on a per-molecule basis, we propose that the sum of HIO3 and H2SO4 could be used to estimate sub-3 nm particle growth of inorganic acid origin in polluted atmospheres with a significant amount of HIOx.

Speciation of iodine on biogenic iron oxyhydroxides by I K-edge and LIII-edge XANES

Abstract The host phase of iodine (I) in biogenic iron oxyhydroxides (BIOS) was determined using X-ray absorption near-edge structure (XANES). I K-edge and LIII-edge XANES analyses of BIOS collected from deep-sea hydrothermal environments revealed that the primary form of I in the BIOS is an organic species. Furthermore, LIII-edge XANES fitting implied the dominance of aromatic-bound I among BIOS. Our first observation of organic–trace element association in natural BIOS can explain the enhanced adsorption of I on BIOS compared to synthetic ferrihydrite. This further suggests the importance of various chemistry on this organic–mineral composite for understanding the geochemical cycling of trace elements.

Development of Inverse-Opal-Structured Charge-Deficient Co9S8@nitrogen-Doped-Carbon to Catalytically Enable High Energy and High Power for the Two-Electron Transfer I+/I- Electrode.

The iodine (I) electrode involving two-electron transfer chemistry by converting between I+ and I-, has the potential to deliver theoretically doubled capacity and higher working voltage platforms, thus achieving higher energy density. However, owing to the slow kinetics of the cascade two-electron transfer reactions, the system suffers from large overpotentials and low power density, especially at high working currents and low temperatures. Here, an inverse-opal-structured cobalt sulfide@nitrogen-doped-carbon (Co9S8@NC) catalyst with unique charge-deficient states is developed to promote the reaction kinetics of the I-/I+ electrode. The charge-deficient Co9S8@NC catalyst not only enables strong physicochemical adsorption with the iodine species but also significantly reduces the activation energy and interfacial charge transfer resistance of the cascade I+/I0/I- conversion reaction. Consequently, the prototypical Zn‖I+/I0/I- battery equipped with the Co9S8@NC catalyst can deliver a high energy density of 554 Wh kg-1 and a stable cycle life of 5000 cycles at 30°C. Moreover, at a subzero temperature of -30 °C, the battery can exhibit enhanced kinetics and a high power density of 1514 W kg-1, high energy density of 485 Wh kg-1.

Ni Single-Atom Bual Catalytic Electrodes for Long Life and High Energy Efficiency Zinc-Iodine Batteries.

Zinc-iodine batteries (Zn-I2) are extremely attractive as the safe and cost-effective scalable energy storage system in the stationary applications. However, the inefficient redox kinetics and "shuttling effect" of iodine species result in unsatisfactory energy efficiency and short cycle life, hindering their commercialization. In this work, Ni single atoms highly dispersed on carbon fibers is designed and synthesized as iodine anchoring sites and dual catalysts for Zn-I2 batteries, and successfully inhibit the iodine species shuttling and boost dual reaction kinetics. Theoretical calculations indicate that the reinforced d-p orbital hybridization and charge interaction between Ni single-atoms and iodine species effectively enhance the confinement of iodine species. Ni single-atoms also accelerate the iodine conversion reactions with tailored bonding structure of I─I bonds and reduced energy barrier for the dual conversion of iodine species. Consequently, the high-rate performance (180mAhg-1 at 3Ag-1), cycling stability (capacity retention of 74% after 5900 cycles) and high energy efficiency (90% at 3Ag-1) are achieved. The work provides an effective strategy for the development of iodine hosts with high catalytic activity for Zn-I2 batteries.

High-performance rechargeable aqueous zinc-iodine batteries via a dual strategy of microporous carbon nanotubes for cathodic iodine immobilization and modified separator

Compared with lithium-ion battery, aqueous rechargeable zinc-iodine is of interest due to their high safety and low cost. Unfortunately, the host material's low conductivity, small specific surface area, shuttling effect, and high soluble iodine species (I2, I-, and I3-) are inhibiting its wide development. In this work, a dual strategy of fixing iodine active material with nanotubular microporous carbon (MCN) and modified cotton fiber separator (MCN@CF) is employed to solve the above-mentioned problem. The Zinc-ion batteries (ZIBs) assembled with an MCN/I2 cathode and MCN@CF separator show up to 162 mA h g-1 of reversible initial capacity with 85 % capacity retention at 100 mA g-1 after 100 cycles. Moreover, besides featuring excellent long-term cyclability, MCN@CF battery delivers a Coulombic efficiency of 99 % over 2000 cycles with a current density of 1 A g-1. This study would lead to opening of a new paradigm for the development of highly reversible aqueous rechargeable ZIBs.

How I– alters UV and UV/VUV processes' redox capacities: Evidences from iodine species evolution, hydrogen peroxide formation, and oxyhalides degradation?

Although UV and/or VUV tandem I– are often proposed as advanced reduction processes (ARPs) to eliminate micropollutants by generating eaq–, the fate of I– and its byproducts formation remain to be explored. Therefore, this study investigated the iodine species evolution during UV/I– and UV/VUV/I– processes under different influencing factors. Results show that UV/VUV oxidized most of I– to IO3– whereas UV only oxidized a portion of I– to intermediate reactive iodine species (RISs, including I2, HOI, and I3–); meanwhile, substantial H2O2 was generated only in UV/VUV/I– process but not in UV/I– process, proving that UV/VUV owns stronger oxidation ability than UV alone. Spiking I– into water exerted triple-sided effects by consuming •OH, generating eaq–, and shielding light, thus complicating the systems. Holistically, increasing pH or decreasing dissolved oxygen converted oxidizing environment into reducing condition and caused less RISs formation, especially for UV/VUV/I–. For oxyhalides, neither UV/I– nor UV/VUV/I– degraded ClO4–. While UV/I– cannot remove ClO3–, UV/VUV/I– reduced ClO3– to Cl–. Expectedly, both UV/I– and UV/VUV/I– reduced BrO3– to Br– more efficiently than UV and UV/VUV, confirming that I– can enhance the reduction capacities of UV/VUV and UV technologies.

Cobalt Single‐Atom Electrocatalysts Enhanced by Hydrogen‐Bonded Organic Frameworks for Long‐Lasting Zinc‐Iodine Batteries

AbstractHerein, a hydrogen‐bonded cobalt porphyrin framework is presented that can efficiently host iodine and serve as an electrocatalyst for aqueous zinc‐iodine (Zn‐I2) organic batteries. The Fourier Transform infrared spectroscopy (FT‐IR), X‐ray Photoelectron Spectroscopy (XPS), and Density functional theory (DFT) results demonstrate that hydrogen‐bonded organic frameworks (HOFs) possess excellent adsorption properties for iodine species. In situ Raman spectroscopy illustrates that the redox mechanism of Zn‐I2 battery depends on the redox reaction of I/I−, with I3−/I5− serving as intermediary products. The in situ Ultraviolet‐visible (UV–vis) spectroscopy further reveals that HOFs restrict polyiodide solubilization. The aqueous Zn‐I2 organic batteries with I2@PFC‐72‐Co cathodes exhibit excellent rate capability, achieving 134.9 mAh g−1 at 20 C. Additionally, these batteries demonstrate long‐term cycle stability, enduring > 5000 cycles at 20 C. The impressive electrochemical performance of I2@PFC‐72‐Co can be attributed to the cooperative Co single‐atom (CoSA) electrocatalyst in the HOF‐Co structure. Moreover, the benzene ring structure and the carboxyl functional group of HOFs possess a strong ability to adsorb iodine and iodide. Owing to these synergistic effects, the aqueous Zn‐I2 batteries with the I2@PFC‐72‐Co cathode exhibit excellent electrochemical performance.

Rates and pathways of iodine speciation transformations at the Bermuda Atlantic Time Series

The distribution of iodine in the surface ocean – of which iodide-iodine is a large destructor of tropospheric ozone (O3) – can be attributed to both in situ (i.e., biological) and ex situ (i.e., mixing) drivers. Currently, uncertainty regarding the rates and mechanisms of iodide (I-) oxidation render it difficult to distinguish the importance of in situ reactions vs ex situ mixing in driving iodine’s distribution, thus leading to uncertainty in climatological ozone atmospheric models. It has been hypothesized that reactive oxygen species (ROS), such as superoxide (O2•−) or hydrogen peroxide (H2O2), may be needed for I- oxidation to occur at the sea surface, but this has yet to be demonstrated in natural marine waters. To test the role of ROS in iodine redox transformations, shipboard isotope tracer incubations were conducted as part of the Bermuda Atlantic Time Series (BATS) in the Sargasso Sea in September of 2018. Incubation trials evaluated the effects of ROS (O2•−, H2O2) on iodine redox transformations over time and at euphotic and sub-photic depths. Rates of I- oxidation were assessed using a 129I- tracer (t1/2 ~15.7 Myr) added to all incubations, and 129I/127I ratios of individual iodine species (I-, IO3-). Our results show a lack of I- oxidation to IO3- within the resolution of our tracer approach – i.e., <2.99 nM/day, or <1091.4 nM/yr. In addition, we present new ROS data from BATS and compare our iodine speciation profiles to that from two previous studies conducted at BATS, which demonstrate long-term iodine stability. These results indicate that ex situ processes, such as vertical mixing, may play an important role in broader iodine species’ distribution in this and similar regions.

A hydroxy containing, naphthalene-based and imine linked porous organic polymer for rapid iodine uptake

Nuclear energy is turning out to be one of the best alternatives to fossil fuels in order to meet the global electricity demand. Radioactive iodine is a volatile and hazardous component that may be present in aqueous nuclear waste and off-gas streams of a spent fuel processing plant. Iodine species are also quite mobile and their accidental leakage into the environment can adversely affect the health of animals and humans to an alarming extent. Thus, design and development of materials capable of capturing/storing iodine effectively for a long time, is of utmost importance in contemporary research. Herein, facile synthesis of a unique nitrogen rich and thermally stable porous organic polymer (POP_DH) is described that has a porous structure comprising of both micro and mesopores. The POP_DH has a specific surface area (128.3 m2 g-1), and can capture 2.855 g g−1 of iodine (vapours) at 75 °C. The POP_DH can retain the trapped iodine up to seven days without any significant release which makes it a suitable material suitable for storing iodine. The presence of O and N heteroatoms (imine linkages) also enable POP_DH to remove iodine species dissolved in water. Herein, the iodine removal is quite rapid with about 99 % of iodine captured within 2 h. POP_DH samples can be recycled up to five rounds for iodine capture with only small changes in performance as an adsorbent. Overall, POP_DH is promising material for capture of radioactive iodine from various media.

Speciation and cycling of iodine in the subtropical North Pacific Ocean

Iodine intersects with the marine biogeochemical cycles of several major elements and can influence air quality through reactions with tropospheric ozone. Iodine is also an element of interest in paleoclimatology, whereby iodine-to-calcium ratios in marine carbonates are widely used as a proxy for past ocean redox state. While inorganic iodine in seawater is found predominantly in its reduced and oxidized anionic forms, iodide (I−) and iodate (IO3−), the rates, mechanisms and intermediate species by which iodine cycles between these inorganic pools are poorly understood. Here, we address these issues by characterizing the speciation, composition and cycling of iodine in the upper 1,000 m of the water column at Station ALOHA in the subtropical North Pacific Ocean. We first obtained high-precision profiles of iodine speciation using isotope dilution and anion exchange chromatography, with measurements performed using inductively coupled plasma mass spectrometry (ICP-MS). These profiles indicate an apparent iodine deficit in surface waters approaching 8% of the predicted total, which we ascribe partly to the existence of dissolved organic iodine that is not resolved during chromatography. To test this, we passed large volumes of seawater through solid phase extraction columns and analyzed the eluent using high-performance liquid chromatography ICP-MS. These analyses reveal a significant pool of dissolved organic iodine in open ocean seawater, the concentration and complexity of which diminish with increasing water depth. Finally, we analyzed the rates of IO3− formation using shipboard incubations of surface seawater amended with 129I−. These experiments suggest that intermediate iodine species oxidize to IO3− much faster than I− does, and that rates of IO3− formation are dependent on the presence of particles, but not light levels. Our study documents the dynamics of iodine cycling in the subtropical ocean, highlighting the critical role of intermediates in mediating redox transformations between the major inorganic iodine species.

Review of iodine behavior from nuclear fuel dissolution to environmental release.

During nuclear fuel reprocessing, radioiodine, can be released. The speciation of iodine drives its volatility, and partitioning processes are highly variable because they depend on facility operating conditions. Starting from iodine behavior in the fuel and progressing to its behavior in the environment, this review article describes the current understanding of iodine partitioning during aqueous fuel reprocessing. This review outlines knowledge gaps and describes the effects of state-of-the-art reprocessing techniques on iodine speciation and volatility. Whereas many review articles have described iodine behavior during specific reprocessing steps, this review provides a holistic overview of radioiodine, from the forms of iodine in different types of irradiated fuel to the forms of iodine released into the environment. The resultant behavior of radioiodine compared with stable iodine in the environment is also described.

Triflate anion chemistry for enhanced four-electron zinc-iodine aqueous batteries.

I+ hydrolysis, sluggish iodine redox kinetics and the instability of Zn anodes are the primary challenges for aqueous four-electron zinc-iodine batteries (4eZIBs). Herein, the OTf- anion chemistry in aqueous electrolyte is essential for developing advanced 4eZIBs. It is elucidated that OTf- anions establish weak hydrogen bonds (H bonds) with water to stabilize I+ species while optimizing a water-lean Zn2+ coordination structure to mitigate Zn dendrites and corrosion. Moreover, the interaction of the OTf- anions with the iodine species results in an increased equilibrium average intermolecular bond length of the iodine species, facilitating the 4e redox kinetics of iodine with improved reversibility.