Reversible Iodine Capture Research Articles

Benzonquanmine-based hypercrosslinked polymers for high-efficiency and reversible iodine capture

Benzonquanmine-based hypercrosslinked polymers for high-efficiency and reversible iodine capture

Recyclable β-CD-crosslinked porous polymer networks for iodine capture

Developing a green and safe reversible iodine capture material is key for nuclear waste treatment. Herein, we report a readily obtainable β-CD-based polymer network (CDPN) that can reversibly capture iodine. This white CDPN material is able to capture both gaseous iodine and liquid iodine, with a good iodine uptake capacity of 2.73 g/g. The I2 can be easily released from I2@CDPN by soaking it in methanol, achieving nearly complete release within 1 min. The CDPN powder exhibits good recyclability in its iodine capture performance. The efficient iodine capture ability of CDPN is ascribed to the cyclodextrin cavity and the crosslinked polymer network, which enhance the interactions between the host (CDPN) and guest (iodine) molecules, both intermolecularly and intramolecularly.

Nitrogen-rich nonporous covalent organic polymers for highly efficient and reversible iodine capture

Radioactive iodine is a high proportion of the fission product of nuclear power, and it is crucial to fabricate materials for capturing iodine from both vapor and solution media. The large-scale synthesis of materials in low-temperature deoxidation and high-temperature with long-time environments presented significant challenges. The Chichibabin pyridine coupling reaction was employed to design and synthesize a nonporous piperazine-linked COP (PIPCOP) under atmospheric pressure within a short reaction time of only 2 h. The PIPCOP material had a comparatively low BET surface area measurement of 4.28 m2 g−1 with an exceptionally low pore volume of 0.0083 cm3 g−1. However, it had a high ability to accept iodine vapor and iodine in hexane, with a capacity of 5.18 g g−1 and 1.95 g g−1, respectively. A novel proposal is presented in this study for the synthesis of functional nonporous polymers with enhanced iodine absorption capacity, aiming to address environmental concerns.

The flexible DADM-based covalent organic frameworks constructed by flexible knots and 4,4′-diaminodiphenylmethane as a linker for fluorescence sensing nitrophenol and adsorping iodine

Enrichment of nitro-aromatic compounds (NACs) and radioactive iodine seriously threatens the health of humans, therefore, trace detection of NACs and the efficient capture and storage of radioactive iodine have attracted a great deal of attention in recent years. Herein, we present two highly efficient flexible DADM-based covalent organic frameworks (DADM-based COFs) for the fluorescence sensing of o-nitrophenol (o-NP) and p-nitrophenol (p-NP) and reversible iodine capture, namely TDADM and HDADM. The resulting TDADM and HDADM have excellent thermal and chemical stability, some crystallinity and high BET surface areas of 1035 and 958 m2 g−1, respectively. For fluorescence sensing, TDADM and HDADM show high sensitivity to o-NP and p-NP with quenching constants (Ksv) of 6.77 × 103 and 3.39 × 104 L mol−1, respectively. The fluorescence quenching of TDADM is caused by the action of photo-induced electron transfer (PET) processes. The fluorescence quenching of HDADM is caused by the co-action of PET and resonance energy transfer (RET) processes. For iodine capture, TDADM and HDADM exhibit high iodine capture capacities, which are severally up to 4.08 and 5.32 g g−1. Such high iodine adsorption amounts are caused by the electron transfer of the electron-rich flexible DADM-based COFs to the electron-deficient I2 into the polyiodide anion complexes.

Porous pillar[6]arene-based polymers for reversible iodine capture

Iodine in nuclear waste can cause serious environment pollution and health risks, and has thus driven more development of materials for iodine capture.

Dual functional porous organic polymer: Reversible iodine capture and selective sensing of picric acid

The development of porous organic materials for removing radiotoxic iodine from nuclear plant waste is significantly relevant to environmental remediation as well as the detection of trace amounts of nitroexplosive picric acid for environmental safety is challenging. To achieve reversible iodine adsorption by the porous material, we have synthesized a highly stable porous organic polymer POF-1 by Schiff base condensation of tris(4-aminophenyl)methane and 2,2′-bithiophene-5,5′-dicarbaxaldehyde under microwave irradiation. POF-1 showed high affinity towards iodine adsorption due to electron-rich sulfur and nitrogen atoms in the porous structure which interact with iodine and form polyiodide ions by electrostatic interactions. POF-1 showed a remarkable iodine uptake capacity of 4.25 g g−1 in the vapor phase and could efficiently remove iodine from an iodine-cyclohexane solution with an adsorption efficiency of 141.0 mg/L. The iodine adsorption follows Langmuir's isothermal model i.e. monolayer adsorption and Pseudo second-order kinetics. POF-1 exhibited good recyclability towards reversible iodine capture even after five cycles. Furthermore, the luminescence characteristic of POF-1 has been employed for the selective detection of picric acid with high sensitivity with a detection limit of 8 μM among a range of nitroaromatic. The Fluorescence quenching mechanism is mainly attributed to photo-induced electron transfer and the inner filter effect.

Turning waste into wealth: Efficient and reversible iodine capture by decoration of coordinative allylic moiety to a flexible covalent organic framework and its application for catalysis

Two types of flexible N-acylhydrazone-linked 2D COFs based on the triazine-containing monomer and the allyl or propyl group modified terephthalic dihydrazide monomer were synthesized. The effect of the synthesis temperature on the surface morphology and crystallinity was studied and the results demonstrated that the synthesis temperature could lead to significant changes in the surface morphology of COFs. What’s more, the coordinative allylic moiety decorated COF (TFDH-Allyl-IV) achieved an excellent iodine adsorption capacity of 6.32 g/g and 1228.04 mg/g in vapor and in n-hexane solvent, respectively. The controlled experiments including XPS, Raman spectra, solid-state 13C NMR studies and the DFT calculations demonstrated that the high adsorption capacity was endowed by the incorporation of the distal C = C bonds with iodine, generating a relatively stable I2:olefin complex. What’s more, the iodine-loaded adsorbent (I2@TFDH-Allyl-IV) could be employed as efficient reusable molecular iodine supported catalyst for organic reactions, such as the Friedel-Crafts-type reactions and oxidative cyclization reactions, which extended the potential application scope of these COFs.

Ferrocene-based porous polymer as advanced environmental remediation material for self-enhanced synergetic photothermal-enzymatic antibacterial and reversible iodine capture

Water pollution, associated with both the modern productions and pathogen contamination, has become a worldwide safety concern, seriously threatening the health of living beings. Herein, a multifunctional porous polymer, denoted as Fc-PP-POP, composed by porphyrin (PP) and Ferrocene (Fc) unites, capable of self-enhanced synergetic antibacterial effect, as well as reversible capture of iodine pollutants, was facilely prepared through the simple but efficient Alder-Longo method via direct polymerization of pyrrole with Ferrocene dialdehyde. Fc-PP-POP integrated the features of Porphyrin (photoactivity) and Ferrocene (enzymatic activity), simultaneously, can serve as a broad-spectrum antibacterial agent, which could not only realize the rapidly and efficiently converting of light energy into local thermal energy for photothermal therapy (PTT), but also the transformation of low concentration of H2O2 into toxic hydroxyl radical (•OH) for the enzyme therapy. The as-generated local heat could further improve the enzymatic activity, displaying a remarkably enhanced synergistic therapeutic effect, realizing the efficient sterilization at low concentrations (300 μg/mL). In vivo assay revealed Fc-PP-POP can significantly promote the healing of infected wounds. Meanwhile, Fc-PP-POP can function as an efficient adsorbent, capturing the iodine contaminants from the environment. This work opens up a new mean for the application of low-cost POPs in the field of environmental remediation and public health.

A Porous π-Stacked Self-Assembly of Cup-Shaped Palladium Complex for Iodine Capture.

Acquiring adsorbents capable of effective radioiodine capture is important for nuclear waste treatment; however, it remains a challenge to develop porous materials with high and reversible iodine capture. Herein, we report a porous self-assembly constructed by a cup-shaped PdII complex through intermolecular π···π interactions. This self-assembly features a cubic structure with channels along all three Cartesian coordinates, which enables it to efficiently capture iodine with an adsorption capacity of 0.60 g g-1 for dissolved iodine and 1.81 g g-1 for iodine vapor. Furthermore, the iodine adsorbed within the channels can be readily released upon immersing the bound solid in CH2Cl2, which allows the recycling of the adsorbent. This work develops a new porous molecular material promising for practical iodine adsorption.

Preparation of an electron-rich polyimide-based hypercrosslinked polymer for high-efficiency and reversible iodine capture

Effective and reversible iodine adsorption is among the most important means to solve nuclear pollution. Herein, a novel electron-rich hypercrosslinked polymer (HCP) was obtained via a simple photocycloaddition of the cinnamoyl-containing polyimide precursor. The resulting polymer showed a high specific surface area of 531 m2 g−1 and high thermal stability. Taking advantage of the high porosity, high electron-rich heteroatoms contents and π-electron conjugated backbone, the material exhibits excellent iodine capture performance, including ultrahigh iodine vapor capture (528 wt%) and iodine removal efficiency from aqueous solution. The capture behavior is consistent with the pseudo-second-order model and the spectral results indicate that the captured iodine existed in the form of polyiodide anions. Furthermore, the HCP maintained 90.76% of the uptake capacity after four cycles. This study provides a new proposal for the preparation of functional HCP as an efficient iodine absorbent to solve environmental issues.

Developing novel amine-linked covalent organic frameworks towards reversible iodine capture

Radio iodine is one of the essential gaseous pollutions needed to be removed by the growth in nuclear energy consumption. The current paper deals with preparing an amine-linked covalent organic framework (COF) with certain advantages compared to the mainstream rigid imine-linked COFs. The flexibility and abundance of the NH groups in the structure provide an excellent medium for adopting iodine from liquid and gas phases. A hydrazone-linked COF (Hz-COF) was synthesized in a room temperature solvent-mediated method, and its linkages were reduced using NaBH4 (NH-COF). The synthesized Hz-COF and NH-COF were utilized in the iodine adsorption experiment from solution and gas phases. The NH-COF exhibited an excellent iodine uptake from gas phase at 80 °C as high as 2.60 g g−1 that is higher than Hz-COF at the same conditions (2.05 g g−1). More interestingly, NH-COF represents a qe of 173 mg g−1 for iodine uptake from iodine solution (300 mg L−1). The iodine adsorption isotherm is best fitted to the Langmuir model, and the adsorption kinetic obeys the pseudo-second-order model. The flexibility of NH-COF and the presence of –NH– groups in the NH-COF structure endows it with accommodative adaptability to guest molecules, increasing the adsorption capacities compared to Hz-COF. Full reusability, high thermal and chemical stabilities, and a high level of polar functional groups made NH-COF an excellent adsorbent for I2 capture performance.

Highly efficient and reversible iodine capture utilizing amorphous conjugated covalent triazine-based porous polymers: Experimental and computational studies

A robust conjugated covalent triazine framework, CTF-DPA, has been synthesized through a facile Friedel-Crafts alkylation reaction using cyanuric chloride as the cross-linking agent and diphenylacetylene (DPA) as the backbone building block. Benefiting from its unique textural and structural features such as high specific surface area (943 m2 g−1), accessible pores, and abundant π-electrons, CTF-DPA exhibits outstanding iodine-capturing performance. It features an ultrahigh iodine vapor capture capacity of 5.12 g g−1 at 75 °C and 1 bar and a remarkable iodine adsorption capacity of 667 mg g−1 in n-hexane solution. To the best of our knowledge, these are among the highest iodine adsorption capacities reported for porous organic polymers. In contrast, an analog CTF synthesized with trans-stilbene (TS) replacing DPA instead features a slight decrease in specific surface area (919 m2 g−1) but a noticeable reduction in iodine adsorption capacities. The iodine uptake mechanism was investigated by Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy as well as computationally. Density-functional theory (DFT) calculations reveal that charge transfer from conjugated C≡C, phenyl, and triazine moieties to iodine molecules facilitates the generation of charged (poly)iodide species (e.g.,I3−), enhancing the adsorption affinity/capacity. Moreover, CTF-DPA could be recycled five times while preserving above 87.6% of its initial iodine uptake capacity.

Lignin-based electrospinning nanofibers for reversible iodine capture and potential applications

The capture of radioactive iodine has recently attracted much attention due to the release of radioactive iodine during nuclear waste disposal and disasters. Exploring highly efficient, sustainable, and eco-friendly materials for capturing radioactive iodine has great significance in developing safe nuclear energy. We reported highly efficient, natural, lignin-based, electrospun nanofibers (LNFs) for reversible radioiodine capture. Abundant iodine adsorption sites, such as functional groups and the interaction between the intermolecular forces exist in LNFs. The capacity of the LNFs for the saturated adsorption of iodine was found to be 220 mg·g−1, which is higher than that of the majority of bio-based adsorbents studied. Moreover, the LNFs exhibited an excellent recycling behavior, and their absorption capacity remained at 84.72% after 10 recycles. Therefore, the results imply that the lignin-based nanofibers can act as a natural, sustainable and eco-friendly packed material for the purification columns in industrial applications. The results demonstrate that the novel, nanostructured, natural biomass, as an ideal candidate has the potential for practical nuclear wastewater purification.

Triptycene-based and imine linked porous uniform microspheres for efficient and reversible scavenging of iodine from various media: a systematic study

Economical synthesis of a triptycene-based and imine linked porous organic polymer for fast and reversible iodine capture from various media.

Reversible Iodine Capture by Nonporous Adaptive Crystals of a Bipyridine Cage.

The ability to capture radioactive iodine species is crucial for nuclear accident preparedness and nuclear waste treatment; however, it remains a challenge. Here we report a new readily obtainable nitrogen-rich nonporous cage (BPy-Cage) based on bipyridine building blocks that supports iodine capture. This cage is able to capture not only volatile iodine in vapor form but also iodine dissolved in various organic solvents or aqueous media with an iodine uptake capacity of up to 3.23 g g-1. The iodine within the cage (I2@BPy-Cage) can be released quickly upon immersing the bound solid form in DMF, allowing for control over acylation reactions. The cage solids reported here could be reused several times without substantial loss in their iodine capture performance. The effectiveness of the present system is ascribed to its ability to support strong iodine-bipyridine nitrogen lone pair interactions.

Preparation and application of microporous carbons as excellent adsorbents for reversible iodine capture and efficient removal of dye

Because of the application of treating hazardous wastes such as organic dyes and radioactive iodine, the porous carbon with high adsorption capacity has been a research hotspot. In this work, by the pyrolysis method with KOH activation, the hypercrosslinked polynaphthalenes were used as carbonaceous precursors to prepare porous carbons, which showed high specific surface areas between 943.8 and 2754.5 m2 g−1 with high micropore ratios. Notably, the microporous carbonaceous materials showed an excellent iodine capture capacity of 739 wt% and a high adsorption capacity of malachite green with 1194.8 mg g−1. These porous carbons provided potential applications in environmental remediation as promising adsorbent materials for adsorption of radioactive iodine, and removal of organic pollutants from aqueous solutions.

Preparation of covalent triazine frameworks with multiactive sites for efficient and reversible iodine capture

Covalent triazine skeletons (CTFs) are long-chain polymers with rigid hydrophobic aromatic skeletons and polar functional groups. Here, we selected three monomers to explore a series of stable CTFs (FCTFs, NCTFs, ClCTFs) with multiple active sites at 350 and 400 °C respectively, which can act as a porous platform for effective and reversible iodine capture. The iodine adsorption capacities of [email protected], [email protected], [email protected], [email protected], [email protected] and [email protected] are 285, 232, 231, 382, 372 and 340 wt%, respectively. Among them, the iodine capture capacities of FCTFs and NCTFs are higher than those of ClCTFs, which suggested that the introduction of electron-rich F and pyridine N groups can indeed improve the iodine adsorption capacity of the polymers. In addition, at 50 bar and 323 K, the CO2 capture capacity of [email protected], [email protected], [email protected], [email protected], [email protected] and [email protected] are 631.6, 539.2, 496.6, 876.6, 783.3, and 695.4 mg g−1, respectively. This shows that polymers have good applications in CO2 capture.

Synthesis of nitrogen-containing covalent organic framework with reversible iodine capture capability

The use of covalent organic frameworks (COFs) to cope with environmental issues was promising but making them commercial and practical remains a challenge. In this work, we explored the crystallization of a stable nitrogen-containing covalent organic framework (TAPA-PDA COF) and used it as a porous platform for efficient and reversible volatile iodine capture. The TAPA-PDA COF, prepared by simple, rapid, low temperature reactions, possesses a high BET surface area of over 685 m 2 /g, good crystallinity, high thermal stability and ultrahigh capture of iodine vapor up to 5.09 g/g, which was significantly higher than most reported iodine adsorbents. Although the Raman spectroscopy confirmed the formation of polyiodide compounds through charge transfer between sorbents and iodine molecules, the TAPA-PDA COF still has the ability to be recycled five times while maintaining a high uptake capacity. This study provides promising strategy to solve the difficult problems of commercializing COFs and utilizing them for practical application. • The TAPA-PDA COF was constructed as a porous platform for efficient and reversible volatile iodine capture. • The TAPA-PDA COF demonstrated ultrahigh capture of iodine vapor up to 5.09 g/g. • The TAPA-PDA COF's capture of iodine was a hybrid of physisorption and chemisorption. • The simple, fast and low temperature preparation method provides promising strategy to solve the difficult problems of commercializing COFs.

Fluorescent aminal linked porous organic polymer for reversible iodine capture and sensing

A novel triazene-anthracene-based fluorescent aminal linked porous organic polymer (TALPOP) was prepared via metal free-Schiff base polycondensation reaction of 9,10-bis-(4,6-diamino-S-triazin-2-yl)anthracene and 2-furaldehyde. The polymer has exceptional chemical and thermal stabilities and exhibit good porosity with Brunauer–Emmett–Teller surface area of 401 m2g−1. The combination of such porosity along with the highly conjugated heteroatom-rich framework enabled the polymer to exhibit exceptional iodine vapor uptake of up to 314 wt % and reversible iodine adsorption in solution. Because of the inclusion of the anthracene moieties, the TALPOP exhibited excellent detection sensitivity towards iodine via florescence quenching with Ksv value of 2.9 × 103 L mol−1. The cost effective TALPOP along with its high uptake and sensing of iodine, make it an ideal material for environmental remediation.

Synthesis of N-containing porous aromatic frameworks via Scholl reaction for reversible iodine capture

Abstract The effective capture of radioactive volatile iodine (131I and 129I) from nuclear waste stream is of vital significance. In this work three kinds of porous organic frameworks (POFs) knitting with N-containing building units were constructed via cost-effective and maneuverable Scholl reaction. The obtained PAFs exhibited moderate porosity and satisfying thermal stability. With coexistence of open porous structure, the electron-rich amino group featured with π-π interactions was found to improve the affinity to iodine, and the iodine uptake capacities were 408 wt%, 335 wt% and 268 wt% when the prepared POFs of P-DPDA, P-TPB and P-PC were employed for the adsorption experiments. The results were superior to most of the porous adsorbents including zeolite, metal-organic frameworks (MOFs) and porous organic polymers (POPs). Iodine adsorption capacities of 289.50 mg g−1 (for P-DPDA), 194.63 mg g−1 (for P-TPB) and 259.69 mg g−1 (for P-PC) in organic solution were achieved, and the adsorbed iodine molecules could be released to ethanol. Such promising and cost-effective materials can be envisaged for application in the field of nuclear waste management.