Iodine Adsorption Research Articles

Synthesis of “all-in-one” hypercrosslinked organic polymers: experimental and kinetic models for CO2 chemical fixation and iodine adsorption

A series of “all-in-one” hypercrosslinked polymers have been constructed by Friedel–Crafts alkylation and quaternization reactions, which exhibit superior CO2 conversion performance and effective iodine adsorption capacity.

Optimization and kinetics of crown ether-based hydroxyl-rich organic polymers for sustainable CO2 fixation and iodine vapor adsorption

Hydroxyl-rich organic polymers with crown ethers were fabricated and utilized for sustainable CO2 fixation and iodine adsorption. The synergistic mechanism was proved in terms of experimental results and study of kinetics.

Spirobifluorene-BINOL-based microporous polymer nanoreactor for efficient 1H-tetrazole synthesis and iodine adsorption with facile charge transfer.

Porous polymeric nanoreactors capable of multitasking are attractive and require a judicious design strategy. Herein, we describe an unusual approach for the synthesis of a porous polymer SBF-BINOL-6 by in situ formation of the BINOL entity taking substituted naphthols and spirobifluorene as co-monomers with high yield (81%). The as-synthesized polymer exhibited nanotube and nanosphere-like morphology, thermal endurance up to 372 °C and a BET surface area as high as 590 m2 g-1. The polymer endowed efficient loading of silver nanoparticles to generate Ag@SBF6, as confirmed from X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. Ag@SBF6 was effectively used as a heterogeneous catalyst towards the [3 + 2] dipolar cycloaddition reaction for the synthesis of biologically important 5-substituted 1H-tetrazoles with yields in the range of 75-99% and recyclability for at least seven times without a significant decline in its catalytic efficiency. Additionally, a superior host-guest interaction by the polymer offered iodine adsorption in the vapour phase with a high uptake capacity of up to 4.0 g g-1. Interestingly, the iodine-loaded polymer, I2@SBF6, demonstrated iodine-promoted increased conductivity (1.3 × 10-3 S cm-1) through facile charge transfer interactions.

A comparison of molecular iodine evolution on the chemistry of lead and tin perovskites

The development of new strategies which target simultaneous adsorption of corrosive iodine (I2), facilitate reduction into I− and reintroduction within the crystal lattice are highly promising for addressing the longevity of perovskite-based devices.

Recent progress in iodine capture by macrocycles and cages.

The effective capture of radioiodine is vital to the development of the nuclear industry and ecological environmental protection. There is, therefore, a continuously growing research exploration in various types of solid-state materials for iodine capture. During the last decade, the potential of using macrocycle and cage-based supramolecular materials in effective uptake and separation of radioactive iodine has been demonstrated. Interest in the application of these materials in iodine capture originates from their diversified porous characteristics, abundant host-guest chemistry, high iodine affinity and adsorption capacity, high stability in various environments, facile modification and functionalization, and intrinsic structural flexibility, among other attributes. Herein, recent progress in macrocycle and cage-based solid-state materials, including pure discrete macrocycles and cages, and their polymeric forms, for iodine capture is summarized and discussed with an emphasis on iodine capture capacities, mechanisms, and design strategies.

Rapid, high-capacity adsorption of iodine from aqueous environments with amide functionalized covalent organic frameworks

Water pollution from iodine is dangerous to human health because of its long-lived radioisotopes. We show that covalent organic frameworks containing amide groups (COFamides) can quickly remove iodine from water with large adsorption capacities.

Accurate construction of monolayer, bilayer, sandwich bilayer, four-layer, multi-layer and chiral bilayer 2D pillararene-type supramolecular networks.

The accurate construction of mono-, bi- and multi-layer networks has been an important challenge, especially for bi- and multi-layer networks. Monolayer, bilayer, sandwich bilayer, four-layer, and multi-layer two-dimensional pillararene-type metal-organic coordination networks have been constructed from functionalized pillar[5]arene and pillar[6]arene by utilizing the coordination interaction of cobalt and copper ions and combining with temperature control and guest induction. These two-dimensional coordination networks exhibit the excellent plasticity of pillararenes and structural variety, which are characterized by X-ray single crystal diffraction and PXRD, confirming that pillararenes units can function as excellent tunable scaffolds for structural regulation. Two-dimensional chiral double-layer structure products are also constructed from R- and S-pillar[6]arene, which are obtained by high-performance liquid chromatography. Atomic force microscopic imaging confirms the thicknesses of these networks. Moreover, these networks also exhibit high iodine adsorption capacity in aqueous environments at ambient temperature. The monolayer, bilayer, sandwich bilayer, four-layer and multi-layer structures of the pillararene-type networks represent a new facile supramolecular self-assembly strategy and platform for designing more mono-, bi- and multi-layer two-dimensional nanomaterials and chiral two-dimensional double-layer structures provide a new method for the construction of more two-dimensional chiral polymers.

High-Capacity Iodine Adsorption and Nonporous to Porous Structural Transformation in an Originally Nonporous Coordination Polymer

A rare example of the high-capacity uptake of iodine guest molecules by nonporous CP is reported. Moreover, the release of iodine from the iodine loaded framework induces the CP change from nonporous to porous stage.

AIEgen-functionalized metal-organic gel as a bifunctional platform for efficient adsorption and portable sensing of gaseous iodine.

Herein, we proposed a novel metal-organic gel (YTU-G-1) for efficient adsorption and portable sensing of gaseous iodine. YTU-G-1 exhibits an unprecedentedly high detection sensitivity (KSV = 2.21 × 106 L mol-1) and an extremely low limit of detection (LOD) down to the pmol level (481 pmol L-1). YTU-G-1 also shows a marked iodine adsorption capacity of 1.398 g g-1. A wearable membrane was successfully fabricated via the electrospinning technique, which exhibits excellent skin-compatibility and serves as a portable tool for sensitive response to potential on-site nuclear emergencies.

Initiating a composite membrane with a localized high iodine concentration layer based on adduct chemistry to enable highly reversible zinc-iodine flow batteries.

The issue of polyiodide crossover at an iodine cathode significantly diminishes the efficiency and practicality of aqueous zinc-iodine flow batteries (ZIFBs). To address this challenge, we have introduced a localized high iodine concentration (LHIC) coating layer onto a porous polyolefin membrane, which featured strong chemical adsorption by exploiting adduct chemistry between the iodine species and a series of low-cost oxides, e.g., MgO, CeO2, ZrO2, TiO2, and Al2O3. Leveraging the LHIC based on the potent iodine adsorption capability, the as-fabricated MgO-LHIC composite membrane effectively mitigates iodine crossover via Donnan repulsion and concentration gradient effects. At a high volumetric capacity of 17.8 Ah L-1, ZIFBs utilizing a MgO-LHIC composite membrane exhibited improved coulombic efficiency (CE) and energy efficiency (EE) of 96.3% and 68.6%, respectively, along with long-term cycling stability of 170 cycles. These results significantly outperform those of ZIFBs based on a blank polyolefin membrane (78.2%/61.9% after 60 cycles) and the widely used commercial Nafion N117 (67.8%/53.0% after 23 cycles). Even under high-temperature conditions (60 °C), the LHIC-based battery still demonstrates superior CE/EE of 95.1%/67.5% compared to those of the blank polyolefin membrane (CE/EE: 61.1%/46.8%). Our pioneering research showcases enormous prospects for developing high-efficiency and low-cost composite membranes based on adduct chemistry for large-scale energy storage applications.

Covalent organic polyrotaxanes based on β-cyclodextrin for iodine capture.

Herein, covalent organic polyrotaxanes (COPRs) were integrated with supermolecule self-assembly and dynamic imine bond formation to act as absorbents that captured radioactive iodine from water. The aromatic building blocks were initially complexed with β-cyclodextrin (β-CD) to form pseudorotaxanes, which were then condensed with aromatic tri-aldehyde via mechanical grinding and solvothermal synthesis in sequence. The threading of β-CD throughout the polymer skeleton effectively reduced the usage of expensive building blocks and significantly lowered the cost, while also remarkably enhancing the skeleton polarity, which is closely related to many special applications. Impressively, the threading of CD improved the water dispersibility of COPRs, which displayed an abnormally high iodine adsorption capacity. This novel synthetic strategy allows the incorporation of mechanically interlocked CDs into porous polymeric materials, which provides access to low-cost preparations of COPRs with a brand new structure for specific applications.

Controlling the structural and adsorption features of polyoxovanadate-based metal–organic clusters by adjustable template effect

An adjustable template effect was employed to activate the evolution of polyoxovanadate-based metal–organic clusters, resulting in unprecedented structural archetypes as well as customized dye and iodine adsorption features.

Characterization and Analysis of Activated Carbon from Coconut Shells Applied to Supercapacitors

Activated carbon is used materials as an electrode for supercapacitors. The aim of this research is to characterize and analyze activated carbon for results with high specific surface area, chemical resistance, electrical conductivity, and affordability. The pyrolysis technique is used in the activation process to remove water content and achieve optimal carbonization at an activation temperature of 600°C. For chemical activation, the carbon is immersed in 10% KOH and 10% Na2CO3 activating agents. The X-RD results in crystalline phases of graphite at peaks 25° and 44°, showing diffraction peaks of carbon and graphite. SEM characterization microstructure morphology at 3000 times magnification, with a 10 µm image size, the formation of porosity that carbon activation. The iodine adsorption measurement KOH-activated carbon sample is 630.70 mg/g, and Na2CO3 activation at 567.89 mg/g. Conductivity measurement results indicate that the conductivity values of activated carbon with the addition of KOH and Na2CO3 activation, measuring 1724.10 S/m and 1660.60 S/m.

Synthesis of magnetic-responsive imidazole-based poly (ionic liquid)s as a recycle adsorbent for simultaneously removing iodine molecules and iodide ions

Nuclear waste management and nuclear energy generation require the proper disposal of 129I and 131I, which are radioactive isotopes of iodine. For recognition of different types’ iodine, a magnetic poly (ionic liquid)s (Fe3O4@SiO2-MPS-PILs) was formed by the selected imidazole ionic liquid monomer and core–shell Fe3O4@SiO2-MPS via free radical polymerization. The resulting adsorbent containing plenty of imidazole N-heterocycle units, benzene rings, and ionic bonds in the backbones was suitable for simultaneously adsorbing iodine molecules and iodide ions. The adsorption mechanisms for iodine in cyclohexane and iodide ions from aqueous solution were based on charge transfer and ion exchange mechanisms, respectively. The adsorption equilibrium for iodine in cyclohexane was attained at 12 h, and the kinetics of iodine adsorption closely followed the pseudo-second-order model. Iodine adsorption on Fe3O4@SiO2-MPS-PILs was best described by Langmuir model with a maximum iodine adsorption capacity of approximately 714.29 mg g−1. Iodide ions adsorption was best explained with Freundlich model and a maximum adsorption capacity of 335.80 mg g−1 was achieved in an iodide solution with a 500 mg L–1 concentration. Notably, Fe3O4@SiO2-MPS-PILs retained over 90 % of its original adsorption performance after the 5th cycle. This work proves that the adsorbent Fe3O4@SiO2-MPS-PILs was efficient and recyclable, and has good application prospects in the practical treatment of iodine and iodide.

Novel hydrophobic hierarchical porous carbon from sewage sludge for the efficient capture of gaseous iodine

Finding an inexpensive and efficient porous adsorbent to capture the gaseous radioiodine generated during spent fuel reprocessing has been challenging. Herein, we present a design philosophy for waste control to develop porous carbon for gaseous iodine capture from sewage sludge waste. Among them, the novel in situ etching of polytetrafluoroethylene was employed to improve pore accessibility. The hazards of the conventional preparation of sludge-derived carbon using highly corrosive NaOH and HF solutions were overcome. Polytetrafluoroethylene etched porous carbon with large specific surface area (1103 m2/g), interconnected hierarchical porous structure, and excellent hydrophobicity (water contact angle 126.52°), providing efficient adsorption of gaseous iodine in hot (30–150 °C) and humid (50–96% relative humidity [RH]) environments. The iodine adsorption of hierarchical porous carbon was tested under static and dynamic conditions, and high records have been achieved. Notably, due to the structural advantage of hydrophobicity, a considerable dynamic adsorption capacity (1746.77 mg/g) was also maintained in a mixed iodine gas stream containing water vapor in a humid (50% RH) hot (75 °C) condition. This study is the first to use an in situ etching strategy for polytetrafluoroethylene, which opens a new avenue for converting sludge waste into low-cost porous carbon and provides an attractive option for capturing iodine in hot and humid environments.

Monolithic Cu/Al2O3-palygorskite composite aerogel for high-efficiency iodine elimination in a multimedia environment

Radioactive iodine has highly radioactive and biological toxicity, and its effective recovery is of primary importance. However, few materials can show good iodine adsorption in different media. Herein, Cu/Al2O3-Pal aerogels with improved mechanical properties and hierarchical pore structures were prepared by constructing the three-dimensional support skeleton of the aerogel with palygorskite fibers. The Cu/Al2O3-Pal aerogel exhibited excellent adsorption properties for I− (aqueous phase, 264–411 mg/g) and I2 (organic phase, 503–744 mg/g), I2 vapor (459–1122 mg/g), and CH3I vapor (559–1032 mg/g). Notably, the aerogel also exhibited ultra-high removal rates for trace iodide in solution (>90 %) and was able to efficiently convert to stable CuI. Importantly, the Cu/Al2O3-Pal aerogel can be prepared directly for use as a monolithic material, allowing for an easy recovery process. Overall, our work demonstrates the great potential of Cu/Al2O3-Palx wt% aerogels for radioactive iodine elimination.

Room temperature synthesis of piperazine-based nitrogen-rich porous organic polymers for efficient iodine adsorption

The proper management of radioactive iodine waste generated from nuclear energy has become one of the challenges in the sustainable development of nuclear power. With the continuous development of POPs materials, their high-efficiency iodine adsorption performance has been demonstrated to be related to the material's structural units and porous structure. In light of this, three two-dimensional porous organic polymers were synthesized using environmentally friendly non-metallic catalyzed coupling reactions. Their excellent chemical stability and nitrogen-rich porous structure endowed them with the ability to exhibit outstanding capture performance and recyclability in various media. Its iodine adsorption performance reached 3.81 g/g, 3.55 g/g and 3.19 g/g respectively. The research results provide a potential pathway for the design and synthesis of organic porous polymers with good chemical stability and iodine adsorption performance, showcasing the significant potential of POP-PDTE, POP-PDTK, and POP-PDTB in capturing radioactive pollutants.

Construction of Ketoenamine-Based Covalent Organic Frameworks with Electron-Rich Sites for Efficient and Rapid Removal of Iodine from Solution.

Porous covalent organic frameworks (COFs) have been widely used for the efficient removal of iodine from solution due to their abundance of electron-rich sites. In this study, two kinds of ketoenamine-based COFs, TpBD-(OMe)2 and TpBD-Me2, are successfully synthesized via Schiff base reaction under solvothermal conditions using 1, 3, 5-triformylphoroglucinol as aldehyde monomer, o-tolidine and o-dianisidine as amino monomers. The ability of TpBD-(OMe)2 and TpBD-Me2 to adsorb iodine in cyclohexane or aqueous solutions has been quantitatively analyzed and interpreted in terms of adsorption sites. TpBD-Me2 possesses two adsorption sites, -NH- and -C=O, and exhibits an adsorption capacity of 681.67 mg/g in cyclohexane, with an initial adsorption rate of 0.6 g/mol/min with respect to COF unit cell. The adsorption capacity of TpBD-(OMe)2 can be as high as 728.77 mg/g, and the initial adsorption rate of TpBD-(OMe)2 can reach 1.2 g/mol/min in the presence of oxygen atoms between the methyl group and the benzene ring. Compared with TpBD-Me2, the higher adsorption capacity and adsorption rate of TpBD-(OMe)2 towards iodine are not only reflected in organic solvents, but also in aqueous solutions. It is proven through X-ray photoelectron spectroscopy and Raman spectroscopy that iodine exists in the form of I2, I3-, and I5- within TpBD-(OMe)2 and TpBD-Me2 after adsorption. This work not only expands the application of COFs in the field of iodine adsorption, but also provides research ideas and important an experimental basis for the optimization of iodine adsorption sites.

Porous organic polymer containing Tröger’s base skeleton and crown ether for cycloaddition of CO2 and efficient iodine vapor adsorption

A wide range of templating reagents containing crown ether-based Tröger's base structure and coordinating of various co-catalysts were synthesized by polymerization, and characterized using various analytic techniques. Their catalytic performance for CO2 conversion and adsorption properties for iodine vapor were examined. Delightfully, after CETB-X recognized with HBr, all exhibited excellent catalytic activity in the presence of cetyltrimethylammonium bromide. The best-performing catalyst could convert CO2 into cyclic carbonate with a yield of 93.1% under optimal reaction conditions. Furthermore, CETB-C16Br/C16N+Br- possessed excellent stability and substrate suitability with six times without any significant loss of catalytic activity. A preliminary kinetic study was investigated using CETB-C16Br/C16N+Br- and the activation energy has been calculated to be 41.51 kJ/mol. All of these polymers also exhibited iodine adsorption capacities above 3.0 g/g, with the most powerful adsorption reaching 4.68 g/g. Through kinetic simulations, the adsorption process was simulated as a pseudo-first-order kinetic model.

Constructing cationic flexible covalent organic frameworks through post-functionalization for enhancing the iodine adsorption capacity

With the incresing development of nuclear power plants, the radioactive iodine produced from nuclear waste and nuclear accidents poses increasing threat to the human health and environment. The iodine adsorption behavior of the neutral flexible covalent organic skeleton has been somewhat studied, but to our knowledge, there are no reports of iodine capture by ionized flexible COFs. Herein, we apply a post-functionalization process to construct two cationic flexible COFs (iCOFs-AB-1 and iCOFs-AB-2) for the first time. The iCOFs-AB-1 and iCOFs-AB-2 exhibit I2 uptake capacities of 3.36 and 4.26 g g−1 at 77 °C, which are improved 1.19 and 1.14 times compared to that of neutral flexible COFs. The promotion of ionic groups on iodine adsorption and the iodine valence states adsorbed at diverse sites have identified by experiments. The adsorption mechanism studies show that the segregative bromide and iodide anions in iCOFs-AB-1 and iCOFs-AB-2 can induce molecular iodine to engender polyiodide anions, and the quaternary ammonium salt cations in iCOFs-AB-1 and iCOFs-AB-2 can come into being the Coulomb interaction force with the aforementioned polyiodide anions. This study demonstrates an efficient method to synthesize cationic flexible COFs and further use them as adsorbents for capturing iodine.