Removal Of Iodine Research Articles

Synthesis of palygorskite based microspheres for efficient and recyclable simultaneous removal of radioactive iodine and iodide

The valence state of radioactive iodine is abundant and convertible. Therefore, it is crucial to synthesize a cost-effective, recyclable adsorbent that can effectively and simultaneously remove polyvalent radioactive iodine. Polymerized microsphere adsorbents (PMs) with pore size of 10 ∼ 20 μm and surface of palygorskite (PAL) were prepared by the Pickering emulsion template method using dimethylaminoethyl methacrylate (DMAEMA) as functional monomer and affordable PAL as matrix material. Under the synergistic effect of chemical adsorption of tertiary amine group in PDEAEMA and physical adsorption, the optimized PM-2 exhibits excellent adsorption activities for gaseous iodine (2.98 g/g), iodine in n-hexane (1.39 g/g), and iodide (1.48 mmol/g). After heating and soaking in NaOH solution, the high adsorption capacity and almost unchanged morphology and crystal structure of PM-2 after 5 cycles indicate that PMs have outstanding physical and chemical stability and reusability. Importantly, PMs also show astonishing adsorption activity for the simultaneous removal of iodine and iodide. Moreover, the ultra-fast adsorption rate and ultra-high adsorption efficiency of PMs provide promising results for the removal of polyvalent radioactive iodine in environmental remediation.

Enhanced Removal of Chlorpyrifos, Cu(II), Pb(II), and Iodine from Aqueous Solutions Using Ficus Nitida and Date Palm Biochars

This study explores the adsorption efficiency of biochar derived from palm trees and Ficus nitida for the removal of various contaminants, including Cu(II), Pb(II), iodine, and chlorpyrifos from aqueous solutions. Biochar was prepared using a two-step pyrolysis process for date palm biochar and single-step pyrolysis for Ficus nitida biochar. Characterization techniques such as SEM, EDX, and FTIR revealed a significant surface area and a variety of functional groups in both types of biochar, essential for effective adsorption. The date palm biochar exhibited superior adsorption capacities for Cu(II) and Pb(II) ions, achieving efficiencies up to 99.9% and 100%, respectively, due to its high content of oxygen-containing functional groups that facilitated strong complexation and ion exchange mechanisms. Conversely, Ficus nitida biochar demonstrated a higher adsorption capacity for iodine, reaching 68% adsorption compared to 39.7% for date palm biochar, owing to its greater surface area and microporosity. In the case of chlorpyrifos, Ficus nitida biochar again outperformed date palm biochar, achieving a maximum adsorption efficiency of 87% after 24 h of incubation, compared to 50.8% for date palm biochar. The study also examines the effect of incubation time on adsorption efficiency, showing that the adsorption of chlorpyrifos by date palm biochar increased significantly with time, reaching a maximum of 62.9% after 48 h, with no further improvement beyond 12 h. These results highlight the importance of biochar characteristics, such as surface area, pore structure, and functional groups, in determining adsorption efficiency. The findings suggest that optimizing pyrolysis conditions and surface modifications could further enhance the performance of biochar as a cost-effective and sustainable solution for water purification and environmental remediation.

Capture of Iodine in Vapor and Solution Phases by a Th-Based Metal-Organic Framework.

The efficient capture of radioactive iodine is of paramount importance due to its harmfulness. In this work, a new Th-based metal-organic framework (ECUT-Th-11) for iodine capture was reported. ECUT-Th-11 exhibited a relatively high capacity of capturing vapor iodine (2.03 g/g). Besides, the maximal adsorption capacity of iodine in a cyclohexane solution reaches 258.03 mg/g. All of the results demonstrated that ECUT-Th-11 could be a candidate material for the effective removal of waste iodine.

Triazine-Tryptophan Based Mesoporous Polymer: Ultrafast Synthesis in a Minute and Efficient Removal of Iodine

Triazine-Tryptophan Based Mesoporous Polymer: Ultrafast Synthesis in a Minute and Efficient Removal of Iodine

Synthesis of bulk foam-like palygorskite based adsorbent for efficient and convenient recyclable removal of radioactive iodine and iodide

Radioactive iodine is the inevitable product of nuclear fission, and the types and valence states of iodine are relatively rich and easy to convert to each other. Therefore, the synthesis of a material that can be easily recovered and efficiently remove polyvalent radioactive iodine has great strategic significance for the safe use of nuclear power. Bulk foam-like palygorskite based adsorbents (PDMA-PAL) with the macroscopic pore size of 40 to 150 μm were synthesized by the emulsion template method using dimethylaminoethyl methacrylate (DMAEMA) as the functional monomer and cheap palygorskite (PAL) as the matrix material. The excessive addition of DMAEMA and PAL will lead to the collapse of the porous structure. Optimized PDMA2-PAL shows excellent adsorption capacity (2.14 g/g) for iodine in cyclohexane solution with the equilibrium time of 5 h. PDMA2-PAL also exhibits an excellent adsorption capacity for gaseous iodine (308 wt%), and the I2 adsorption mechanism is the strong affinity and charge transfer of electron-rich N heteroatoms for electron-deficient iodine. PDMA2-PAL also achieves an outstanding iodide adsorption capacity (2.1mmol/g) within 5 min, and the I− adsorption mechanism is the electrostatic interaction between I− and the derivatization of tertiary amine under acidic conditions. Moreover, the deprotonation in alkaline solution can desorb iodide efficiently, which makes PDMA-PAL exhibit excellent recyclability. Importantly, PDMA-PAL also shows excellent simultaneous adsorption ability of iodide and iodine, and also exhibits stable adsorption activity in actual water. This study provides promising results for the removal of polyvalent radioactive iodine by bulk foam-like palygorskite based adsorbent in environmental remediation.

Electron-rich COFs with a bis-triphenylamine structure as the main chain: Ultrafast and ultrahigh iodine capture

The construction of ideal adsorbents for the capture of radioiodine usually requires high adsorption capacity and high adsorption rate. However, this is still a challenging problem. The advantages of COFs based on their good crystallinity, pore order, and structural diversity make COFs ideal adsorbents. Here, we developed three novel electron-rich COFs based on the triphenylamine, which have good chemical, thermal, and radiation-resistant stability and are suitable for the harsh environment of radioactive iodine therapy. Upon the introduction of heteroatom N/S, TAPD-PDB and TAPD-TDB exhibited amazing adsorption capacities (75 °C: 7.88 g g−1 and 6.98 g g−1, 25 °C: 4.46 g g−1 and 3.62 g g−1), while the adsorption rates, K80%, are significantly increased to 5.34 g g−1h−1 and 4.22 g g−1h−1, which is higher than most of the reported iodine adsorbents. It was surprising that COFs also have excellent adsorption properties for iodine in cyclohexane solution up to 1260 mg L−1. FT-IR, XPS, Raman and electrostatic potential calculations indicate that the ultrafast and ultrahigh iodine uptake of COFs can be attributed to the interplay of their rich electronic structure, efficient adsorption sites, helical conformation and charge transfer. This study shows the efficient and ultrafast removal of iodine from nuclear wastewater and nuclear exhaust gas by electron-rich COFs.

Porous Organic Polymers with Embedded Fe2O3 Nanoparticles for Pathogenic Microorganism Inactivation and Iodine Removal from Nuclear Water

Porous Organic Polymers with Embedded Fe₂O₃ Nanoparticles for Pathogenic Microorganism Inactivation and Iodine Removal from Nuclear Water

A novel strategy for iodine removal from nuclear reactor accidental gases: efficient adsorption of CH3I on the moderately hydrophobic modified silver-loaded zeolite under high temperature and humidity conditions

ABSTRACT Ensuring nuclear energy safety through effective gas emission filtration from nuclear reactor containment in accident scenarios is paramount. The efficacy of hydrophobic modified Ag-loaded zeolites for methyl iodide (CH3I) removal under challenging conditions of high temperature, humidity, and irradiation is studied in this work. Through hydrophobic modification of AgX zeolite with three different silane coupling agents, a series of modified zeolites with varied hydrophobicity levels is produced. The adsorption capabilities of these modified materials are assessed using a self-designed gas adsorption setup, focusing on CH3I removal from a gas mixture emblematic of nuclear accident environments. Results indicate that all hydrophobically modified zeolites exhibited superior CH3I removal rates compared to their unmodified counterparts, with the variant modified with 10% phenyltriethoxysilane achieving the highest removal rate of 99%. Additionally, zeolites modified with octyltrimethoxysilane demonstrate commendable irradiation resistance at a radiation dose of 4.2 × 105 Gy. The results suggest that optimally hydrophobically modified AgX zeolites hold significant promise for filtering gases containing radioactive iodine, offering novel insights for the advancement of adsorbent materials in nuclear reactor containment discharge systems.

Metal-organic cages for efficient capture and convenient detection of iodine from vapor and aqueous solutions

In the pursuit of advancing radioactive waste management and mitigating the risks associated with nuclear accidents, the development of effective adsorbents for the removal of radioactive iodine from the environment is paramount. This study presents the synthesis and characterization of two metal–organic cages (MOCs) tailored for the efficient adsorption of volatile iodine vapor and iodine from aqueous solutions. The prepared MOCs exhibited efficient adsorption capacities for iodine vapor and iodine in water. Experimental and theoretical analyses underscored the significance of hydrophobic and electrostatic interactions in augmenting the iodine adsorption efficacy from aqueous solutions, providing valuable insights into the design of high-capacity iodine adsorption materials for aqueous environments. Furthermore, MOC-coated test strips were developed, enabling rapid, convenient, and sensitive detection of iodine vapor and iodine in aqueous solutions through the integration of fluorescent elements. To the best of our knowledge, this study presents a pioneering example of MOCs proficient in both adsorbing and detecting iodine vapor and iodine in aqueous solutions.

Synthesis and Characterization of Silver-Modified Nanoporous Silica Materials for Enhanced Iodine Removal.

In aquatic environments, the presence of iodine species, including radioactive isotopes like 129I and I2, poses significant environmental and health concerns. Iodine can enter water resources from various sources, including nuclear accidents, medical procedures, and natural occurrences. To address this issue, the use of natural occurring nanoporous minerals, such as zeolitic materials, for iodine removal will be explored. This study focuses on the adsorption of iodine by silver-modified zeolites (13X-Ag, 5A-Ag, Chabazite-Ag, and Clinoptilolite-Ag) and evaluates their performance under different conditions. All materials were characterized using scanning electron microscopey (SEM), energy-dispersive X-ray spectroscopy (EDS), powdered X-ray diffraction (P-XRD), Fourier-transform infrared spectrometry (FTIR), and nitrogen adsorption studies. The results indicate that Chabazite-Ag exhibited the highest iodine adsorption capacity, with an impressive 769 mg/g, making it a viable option for iodine removal applications. 13X-Ag and 5A-Ag also demonstrated substantial adsorption capacities of 714 mg/g and 556 mg/g, respectively, though their behavior varied according to different models. In contrast, Clinoptilolite-Ag exhibited strong pH-dependent behavior, rendering it less suitable for neutral to slightly acidic conditions. Furthermore, this study explored the impact of ionic strength on iodine adsorption, revealing that Chabazite-Ag is efficient in low-salinity environments with an iodine adsorption capacity of 51.80 mg/g but less effective in saline conditions. 5A-Ag proved to be a versatile option for various water treatments, maintaining its iodine adsorption capacity across different salinity levels. In contrast, Clinoptilolite-Ag exhibited high sensitivity to ionic competition, virtually losing its iodine adsorption ability at a NaCl concentration of 0.1 M. Kinetic studies indicated that the pseudo-second-order model best describes the adsorption process, suggesting chemisorption mechanisms dominate iodine removal. Chabazite-Ag exhibited the highest initial adsorption rate with a k2 value of 0.002 mg g-1 h-1, emphasizing its superior adsorption capabilities. Chabazite and Clinoptilolite, naturally occurring minerals, provide eco-friendly solutions for iodine adsorption. Chabazite superior iodine removal highlights its value in critical applications and its potential for addressing pressing environmental challenges.

Utilizing Date Palm Leaf Biochar for Simultaneous Adsorption of Pb(II) and Iodine from Aqueous Solutions

This study addresses the environmental and health hazards posed by Pb(II) and iodine, two significant contaminants. The objective was to explore the adsorption of these substances from aqueous solutions using biochar derived from the leaf midribs of the date palm through a slow pyrolysis process. The pyrolysis was conducted in two stages within a vacuum furnace: initially at 300 °C for 1 h followed by overnight cooling, and then at 600 °C with a similar cooling process. The resulting biochar was characterized for its microstructural features and functional groups using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. It exhibited a porous structure with large numbers of pores (20 to 50 μm in size) and functional groups including O-H, C-H, and C=C, which are integral to its adsorption capabilities. For the adsorption studies, a 100 ppm Pb(II) ion solution was treated with varying amounts of biochar (20, 40, 60, and 80 mg) for 24 h. In parallel, iodine adsorption was tested, with biochar quantities ranging from 0.1 to 0.4 g/50 mL. Both treatments were followed by filtration and analysis using atomic absorption spectroscopy to determine the remaining concentrations of Pb(II) and iodine. The study also explored the effect of varying incubation periods (up to 30 h) on iodine adsorption. The results were significant; 100% adsorption of Pb(II) was achieved with the addition of 60 mg of biochar per 10 mL of solution. In contrast, for iodine, a maximum adsorption of 39.7% was observed with 30 mg or 40 mg of biochar per 50 mL. These findings demonstrate the potential of date palm-derived biochar as an effective and sustainable material for the removal of Pb(II) and iodine from contaminated water, offering valuable insights for environmental remediation strategies.

Removal of radioactive iodine by Cu2O prepared with PVP as an active agent: Role of crystal facets and oxygen vacancy in adsorption mechanisms

Radioactive iodine removal continues to pose significant challenges. In this study, the advantages of crystal facet and defect engineering were utilized to synthesize six types of Cu2O nanocrystals with varying crystal facet exposed, crystal edge exposed, and abundant oxygen vacancies (OVs). Compared to pure {100} and {111} exposed Cu2O, {100}+{111} co-exposed Cu2O exhibited superior adsorption capacity and adsorption rate for iodide ions (I−), achieving a removal efficiency of 96 % for trace I− (0.1 mg/L). Moreover, OVs significantly contribute to iodide ion (I−) adsorption. Experimental and density functional theory (DFT) analyses confirmed that the active sites on {100}/{111} crystal edges possess the highest affinity for I−. The OVs disrupts the charge balance of the Cu2O surface and increases unsaturated coordination sites of Cu, therefore, it significantly enhanced the affinity for I−. This research offers insights into the design of effective I− adsorption materials using crystal facet and defect engineering strategies.

The simultaneous removal of technetium and iodine from Hanford tank waste

The simultaneous removal of radionuclides technetium-99 and iodine-129 from an actual decontaminated Hanford tank waste sample (a mixture of decontaminated waste from tanks 241-AP-105 and 241-AP-107) was demonstrated for the first time in this work. A series of commercially available ion exchange resins were evaluated in batch contact tests in the tank waste, and all showed removal of both Tc and I. The highest Tc removal from the tank waste was observed for Purolite A530e while the highest iodine removal was observed for ResinTech SIR-110-MP. Isotherm tests in simulated tank waste with these two resins showed that the SIR-110-HP-MP had consistently higher Kd for both pertechnetate and iodide; with much higher Kd than previous works on Tc removal from Hanford waste. As such, the SIR-110-MP was evaluated in a dual-column (lead/lag) test processing 5.2L of the tank waste mixture showing 50 % breakthrough of Tc on the lead column and no significant breakthrough on the lag after 641 bed volumes (BV, 6 mL size) while significant iodine breakthrough (>50 %) occurred after 28 BV. The limited iodine uptake was attributed to the column conditions generating mass transfer limitations. A fraction of the Tc and I was not captured by the resin (<10 %) in either the batch tests or column tests. The iodine fraction is not iodate and is likely organo-iodide. The fraction of the Tc was identified as a non-pertechnetate species which is the first time non-pertechnetate has been identified in AP-105 and AP-107 tanks. This non-pertechnetate fraction contained Tc(I) and for the first time a stable Tc(VI) species in Hanford waste was identified..

Removal of iodide from aqueous solutions using a silver-modified ZnAl layered double hydroxide

The removal of radioactive iodine from aqueous solutions is of great concern due to its high environmental mobility and toxicity. To improve the removal ability of layer double hydroxide (LDH) for iodide (I−), Ag-modified Zn3Al1-LDH (Ag@Zn3Al1-LDH) was prepared, characterized, and applied as an adsorbent for I−. Results indicated that the silver was included in Zn3Al1-LDH hybrid materials in the form of Ag2CO3, Ag2O, and Ag (0) nanoparticles and that the Ag contents in the Ag@Zn3Al1-LDH could be easily controlled by the amounts of Ag source added in the synthesis process. The Ag@Zn3Al1-LDH exhibited high adsorption capacity to iodide, and the adsorption capacity of the sample containing 12.2 wt% Ag was as high as 256.0 mg/g, which is 35.6 times higher than that of Zn3Al1-LDH. Furthermore, the Ag@Zn3Al1-LDH exhibited high selectivity for iodide and could function in a wide range of pH. Iodide was removed through cooperative effects mechanisms including the chemical adsorption of Ag2O and Ag2CO3, ion exchange of Zn3Al1-LDH, and the surface complexation of Zn3Al1-LDH for iodide. This work indicated that Ag@Zn3Al1-LDH could be a potentially efficient material for the removal of iodide from wastewater.

A novel ionic-liquid-mediated covalent organic framework as a strong electrophile for high-performance iodine removal

The research on the adsorption and conversion of non-polar gases (carbon dioxide, hydrogen, iodine, etc.) has attracted global attention. Extensive work has revealed the intuitive impact of the heteroatom effect on the adsorption performance of covalent organic framework (COF) adsorbents for non-polar gases. However, more influencing factors must be studied to more precisely design and construct target-specific COF adsorbents. In this work, an underlying influencing factor, local polarity, is discovered, which is defined as the polarity of the functional moiety. Due to the substitution of strong electrophile, the electron cloud distribution of the COF framework is regulated, and the local polarity that better matches the adsorption of target electrophilic gas (iodine) has been observed. The local polarity of COF has been controlled through several strong electrophilic ionic liquids, dramatically improving adsorption performance. The saturated adsorption capacity increases from 1.5 to 5.2 g·g−1, and the adsorption kinetics index k80% value increases from 0.51 to 2.69 g·g−1·h−1. The insight would support precise chemical regulation of target-specific COF in energy and environment science.

One-step synthesis of Ag@polyaniline core–shell particles for efficient removal of radioactive iodine

One-step synthesis of Ag@polyaniline core–shell particles for efficient removal of radioactive iodine

Efficient Removal of Iodine from Water by a Calix[4]pyrrole-Based Nanofilm.

The efficient removal of radioactive iodine from an aqueous solution is largely dependent on the adsorbent materials employed. In this work, we report a calix[4]pyrrole-based nanofilm and its application for the rapid removal of iodine from water. The nanofilm was synthesized through a confined dynamic condensation of tetra hydrazide calix[4]pyrrole with 1,3,5-tri-(4-formylphenyl) aldehyde at the air/dimethyl sulfoxide (DMSO) interface. The thickness of the obtained nanofilm is ∼35 nm, enabling fast mass transfer and a high ratio of accessible binding sites for iodine. The pseudo-second-order rate constant of the nanofilm for iodine is ∼0.061 g g-1 min-1, 3 orders of magnitude higher than most reported adsorbent materials. Flow-through nanofiltration tests demonstrated that the nanofilm has an adsorption capacity of 1.48 g g-1, a high removal efficiency, and good reusability. The mechanism study revealed that the moieties of Schiff base, pyrrole, and aromatic rings play a key role for binding iodine. We believe this work provides not only a new strategy for the efficient removal of radioactive iodine from water but also new ideas for designing efficient iodine adsorbents.

Covalent organic polymers for efficient removal of iodine from gas- and liquid-phase environments

Nuclear energy is a sustainable, low-carbon footprint, and cost-effective future energy source that might play an important role in the foreseeable energy demand. However, due to the volatility and long half-life of the released waste radioiodine from nuclear power stations, appropriate handling of radioactive waste is still a great challenge. Using covalent organic polymers (COPs) adsorbents to capture radioactive iodine compounds has gained much attention due to the simplicity of operation, low maintenance costs, and resistance to highly corrosive solutions. Herein, three as-synthesized amine-linked COP materials with heteroatoms (N, P, and O) are employed for iodine capture and obtain excellent iodine capture capacity due to the strong interactions of abundant heteroatoms with iodine compounds. The gas-phase iodine adsorption capacity of as-prepared COPs reached > 2.1 g gads−1 in 1 h, with an optimal gas-phase iodine adsorption capacity of 3.96 g gads−1 and a liquid-phase iodine adsorption capacity of 905.69 mg gads−1. This study showed the promising iodine removal capabilities of heteroatoms-containing COPs from nuclear wastewater and nuclear exhaust gases.

Efficient capture of iodine in steam and water media by hydrogen bond-driven charge transfer complexes

Untreated radioactive iodine (129I and 131I) released from nuclear power plants poses a significant threat to humans and the environment, so the development of materials to capture iodine from water media and steam is critical. Here, we report a charge transfer complex (TCNQ-MA CTC) with abundant nitrogen atoms and π-conjugated system for adsorption of I2 vapor and I3- from aqueous solutions. Due to the synergistic binding mechanism of benzene/triazine rings and N-containing groups with iodine, special I-π and charge transfer interaction can be formed between the guest and the host, and thus efficient removal of I2 and I3- can be realized by TCNQ-MA CTC with the adsorption capacity up to 2.42 g/g and 800 mg/g, respectively. TCNQ-MA CTC can capture 92% of I3- within 2.5 min, showing extremely fast kinetics, excellent selectivity and high affinity (Kd = 5.68 × 106 mL/g). Finally, the TCNQ-MA CTC was successfully applied in the removal of iodine from seawater with the efficiency of 93.71%. This work provides new insights in the construction of charge transfer complexes and lays the foundation for its environmental applications.

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.