An official website of the United States government
Abstract Iodine is widely used as an antimicrobial reagent for water disinfection in the wilderness and outer space, but residual iodine and iodide need to be removed for health reasons. Currently, it is challenging to remove low concentrations of iodine and iodide in water (≈5 ppm). Furthermore, the remediation of iodine and iodide across a broad temperature range (up to 90 °C) has not previously been investigated. In this work, we report a nitrate dimer‐directed synthesis of a single‐crystalline ionic hydrogen‐bonded crosslinked organic framework (HCOF‐7). HCOF‐7 removes iodine and iodide species in water efficiently through halogen bonding and anion exchange, reducing the total iodine concentration to 0.22 ppm at room temperature. Packed HCOF‐7 columns were employed for iodine/iodide breakthrough experiments between 23 and 90 °C, and large breakthrough volumes were recorded (≥18.3 L g−1). The high iodine/iodide removal benchmarks recorded under practical conditions make HCOF‐7 a promising adsorbent for water treatment.
more »
« less
Key aspects of the iodine metabolism in brown algae: a brief critical review
Abstract Brown algae include the strongest accumulators of iodine known among living systems. This paper reviews the current state of bioinorganic research in the field, focusing on the models Laminaria digitata, Macrocystis pyrifera and Ectocarpus siliculosus, and covering uptake and efflux, localization and biological significance of storage, as well as marine and atmospheric chemistry of iodine.
more »
« less
- Award ID(s):
- 1664657
- PAR ID:
- 10462481
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Metallomics
- Volume:
- 11
- Issue:
- 4
- ISSN:
- 1756-5901
- Page Range / eLocation ID:
- p. 756-764
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Iodine cycling in the ocean is closely linked to productivity, organic carbon export, and oxygenation. However, iodine sources and sinks at the seafloor are poorly constrained, which limits the applicability of iodine as a biogeochemical tracer. We present pore water and solid phase iodine data for sediment cores from the Peruvian continental margin, which cover a range of bottom water oxygen concentrations, organic carbon rain rates and sedimentation rates. By applying a numerical reaction‐transport model, we evaluate how these parameters determine benthic iodine fluxes and sedimentary iodine‐to‐organic carbon ratios (I:Corg) in the paleo‐record. Iodine is delivered to the sediment with organic material and released into the pore water as iodide (I−) during early diagenesis. Under anoxic conditions in the bottom water, most of the iodine delivered is recycled, which can explain the presence of excess dissolved iodine in near‐shore anoxic seawater. According to our model, the benthic I−efflux in anoxic areas is mainly determined by the organic carbon rain rate. Under oxic conditions, pore water dissolved I−is oxidized and precipitated at the sediment surface. Much of the precipitated iodine re‐dissolves during early diagenesis and only a fraction is buried. Particulate iodine burial efficiency and I:Corgburial ratios do increase with bottom water oxygen. However, multiple combinations of bottom water oxygen, organic carbon rain rate and sedimentation rate can lead to identical I:Corg, which limits the utility of I:Corgas a quantitative oxygenation proxy. Our findings may help to better constrain the ocean's iodine mass balance, both today and in the geological past.more » « less
-
Abstract Hypervalent iodine compounds have found broad application in modern organic chemistry as reagents and catalysts. Cyclic hypervalent iodine reagents based on the benziodoxole heterocyclic system have higher stability compared to their acyclic analogues, which makes possible the preparation and safe handling of the reagents with special ligands such as azido, cyano, and trifluoromethyl groups. Numerous iodine‐substituted benziodoxole derivatives have been prepared and utilized as reagents for transfer of the substituent on hypervalent iodine to organic substrate. Reactions of these reagents with organic substrates can be performed under metal‐free conditions, in the presence of transition metal catalysts, or using photocatalysts under photoirradiation conditions. In this review, we focus on the most recent synthetic applications of cyclic hypervalent iodine(III) reagents with the following ligands: N3, NHR, CN, CF3, SCF3, OR, OAc, ONO2, and C(=N2)CO2R. The review covers literature published mainly in the last 5 years.more » « less
-
Abstract Previous efforts to measure atmospheric iodine have focused on marine and coastal regions. We report the first ground‐based tropospheric iodine monoxide (IO) radical observations over the central continental United States. Throughout April 2022, IO columns above Storm Peak Laboratory, Colorado (3,220 m.a.s.l.) ranged from 0.7 ± 0.5 to 3.6 ± 0.5 × 1012(average: 1.9 × 1012 molec cm−2). IO was consistently elevated in air masses transported from over the Pacific Ocean. The observed IO columns were up to three times higher and the range was larger than predicted by a global model, which warrants further investigation into iodine sources, sinks, ozone loss, and particle formation. IO mixing ratios increased with altitude. At the observed levels, iodine may be competitive with bromine as an oxidant of elemental mercury at cold temperatures typical of the free troposphere. Iodine‐induced mercury oxidation is missing in atmospheric models, understudied, and helps explain model underestimation of oxidized mercury measurements.more » « less
-
ABSTRACT RationaleCorals are continuous, time‐resolved archives of ambient seawater geochemistry and can extend climate records beyond direct monitoring. The iodine‐to‐calcium (I/Ca) ratio may be a proxy for local oxygen depletion in corals, but the current solution‐based ICP‐MS protocol limits sampling resolution. A protocol was developed for rapid analysis of coral I/Ca using laser ablation ICP‐MS. MethodsTwo reference materials, a powdered coral (JCp‐1) and a synthetic carbonate (MACS‐3), were compared for precision in measuring Sr, Mg, I, Ba, and U. Then, the influence of laser parameters (spot size, fluence, repetition rate, and scan speed) on iodine sensitivity from the reference material was evaluated to optimize laser settings for accurate and reproducible I/Ca calibration. Then, I/Ca was measured in line scans along and across the ambulacrum in aDiploria labyrinthiformiscoral. ResultsWe find that JCp‐1 has greater precision in measuring iodine, as well as other traces, compared to MACS‐3. At a 10 Hz repetition rate, spot sizes from 150 to 85 μm obtained concentrations in agreement with certified values, but higher repetition rates overestimated iodine concentrations from JCp‐1. Certain scan speeds and fluence can introduce noise, likely due to matrix effects, but the signal‐to‐noise ratio can be improved by adjacent‐average filtering. Using this simple data filtering routine and optimized laser settings, the highest resolution for accurate I/Ca analysis is < 100 μm. While the fine‐scale (< 250 μm) I/Ca variabilities in parallel transects in a coral sample likely resulted from biomineralization processes, large ‐scale features (> 500 μm) along the ambulacrum tend to correlate. ConclusionsLA‐ICP‐MS has great potential for accurate, high‐resolution I/Ca profiling in corals using JCp‐1 as a calibration standard. Because of compositional variability near centers of calcification, it is important to pay attention to how the laser transect is aligned relative to skeletal elements, which may incorporate iodine differently.more » « less
