Cellulose Fibers Constructed Convenient Recyclable 3D Graphene

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Cellulose Fibers Constructed Convenient Recyclable 3D GrapheneFormicary-like #-Bi2O3 Aerogels for the Selective Capture of Iodide Ye Xiong, Baokang Dang, Chao Wang, Hangwei Wang, Shouwei Zhang, Qingfeng Sun, and Xijin Xu ACS Appl. Mater. Interfaces, Just Accepted Manuscript • Publication Date (Web): 01 Jun 2017 Downloaded from http://pubs.acs.org on June 2, 2017

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ACS Applied Materials & Interfaces

Cellulose Fibers Constructed Convenient Recyclable 3D Graphene-Formicary-like δ-Bi2O3 Aerogels for the Selective Capture of Iodide Ye Xiong,† Baokang Dang,† Chao Wang,† Hanwei Wang,† Shouwei Zhang,§ Qingfeng Sun,†,‡* Xijin Xu,§* †

School of Engineering, Zhejiang A & F University, Hangzhou, Zhejiang Province, 311300, PR

China ‡

Key Laboratory of Wood Science and Technology, Zhejiang Province, 311300, PR China

§

School of Physics and Technology, University of Jinan, Shandong Province, 250022, P.R.

China KEYWORDS: Formicary-like δ-Bi2O3, water purification, selective iodine capture, hybrid 3D structure, green chemistry.

ABSTRACT: Radioiodine is highly radioactive and acutely toxic, which can be a serious health threat, and requires effective control. To fully utilize an adsorbent and reduce the overall production cost, successive recycling applications become necessary. Here, 3D formicary-like δBi2O3 (FL-δ-Bi2O3) aerogel adsorbents were synthesized using a one-pot hydrothermal method. In this hybrid structure, abundant flower-like δ-Bi2O3 (MR-δ-Bi2O3) microspheres were inlaid

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into the interconnected ant nest channel, forming a 3D hierarchical structure, which is applied as an efficient adsorbent with easy recovery for radioiodine removal. Notably, the FL-δ-Bi2O3 aerogel adsorbent exhibited a very high uptake capacity of 2.04 mmol/g by forming an insoluble Bi4I2O5 phase. Moreover, the FL-δ-Bi2O3 worked in a wide pH range of 4-10 and displayed fast uptake kinetics and excellent selectivity due to the 3D porous interconnected network and larger specific surface area. Importantly, the recycling process is easy, using only tweezers to directly move the 3D aerogel adsorbents from one reaction system to another. Therefore, the FL-δ-Bi2O3 aerogel may be a promising practical adsorbent for the selective capture of radioactive iodide. INTRODUCTION As indispensable substances, radioiodine isotopes are widely used in nuclear power plants, scientific research, medical applications, and other areas.1-4 Their secure handling is of particular importance, however, because these iodine isotopes are potentially toxic and can bio-accumulate through the food chain and subsequently cause dysfunction of the thyroid gland.5-7 Various inorganic adsorbents have been synthesized to capture these radionuclides, such as compounds containing Bi(III), Pb(II), Hg(II), Ag(I), and Cu(I).8-13 However, powdery inorganic adsorbents have inherent drawbacks. For example, they are easy to wash away, difficult to recover, and may cause secondary pollution. Fortunately, cellulose aerogels may be used for the widespread application of defective inorganic nano-adsorbent materials.14,

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Cellulose aerogels with

multiple-levels of super-molecule structures constructed from a large number of hydrogenbonding networks can be utilized as a platform for the formation of inorganic-organic composites.16-19 This finding highlights a new direction for in situ precipitation synthesis of inorganic adsorbents.


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Recently, the Ag2O/cellulose hybrid aerogel has been successfully fabricated and displays high adsorption performance for radioactive iodine. However, the high costs of silver restrict its practical application.20 Therefore, an inexpensive, extensive and efficient delta-bismuth oxide (δBi2O3) has been selected as a substitute for silver oxide.12 δ-Bi2O3 is typically prepared by reacting bismuth nitrate pentahydrate (easy hydrolysis) with a strong base and high temperature hydrothermal conditions. Unfortunately, cellulose is completely hydrolyzed in such a harsh environment. Based on these conditions, the preparation of Bi2O3/cellulose aerogel is rather unmanageable. Here, formicary-like δ-Bi2O3 (FL-δ-Bi2O3) aerogels were creatively built via a one-pot hydrothermal process in the presence of tert-butyl alcohol, ethanediol, cellulose fibers and bismuth nitrate pentahydrate as raw materials, and abundant flowery-like δ-Bi2O3 (MR-δBi2O3) microspheres were embedded in the formicary-like architecture. With interconnected cellular channels, FL-δ-Bi2O3 aerogels quickly react with I- anions and highly store iodine vapor. Compared with the original MR-δ-Bi2O3, the iodide adsorption capacity of the FL-δ-Bi2O3 aerogel shows significant improvement and an adsorption capacity as high as 2.04 mmol g-1. Significantly, FL-δ-Bi2O3 aerogels with a controllable shape are easily separated from water, which avoids the loss of powdered δ-Bi2O3 and the ensuing secondary pollution.21 Therefore, the FL-δ-Bi2O3 aerogel is more economical and promising for the practical application of water treatment. EXPERIMENTAL SECTION Materials. Bamboo cellulose fibers (the thickness of 0.021 mm and length of 0.5 m), bismuth nitrate pentahydrate (Bi(NO3)3·5 H2O), sodium iodide (NaI), ethylene glycol (EG), and ethanol were available from Shanghai Chemical Reagent Co. Ltd. (China). All chemicals were analytical reagent grade and used without further purification.


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One-pot synthesis of FL-δ-Bi2O3 aerogels. The FL-δ-Bi2O3 aerogel was fabricated via a facile hydrothermal method. In a typical process, the Bi(NO3)3·5 H2O (0.97 g, 2 mmol) was dissolved in a mixed solution that contained ethylene glycol (17 mL) and tert-butyl alcohol (34 mL), followed by vigorous stirring for 30 min. Then, bamboo cellulose fibers (BCF) were added into the above solution and sonicated for 1 h to obtain a uniform mixture suspension (2 mg/cm3). Subsequently, the mixture was put into a Teflon-lined stainless steel autoclave with a capacity of 50 mL. The autoclave was heated and maintained at 160 °C for 10 h and then cooled to room temperature. In the last step, the reaction mixture was freeze-dried to yield the low-density FL-δBi2O3 aerogel. Equilibrium and kinetic adsorption test. In the present study, because of the higher radiation dose of 131/129I-, we used stable 127I- anions to perform I- anion adsorption experiments. A total of 50 mg adsorbent was used as sorption beds to catch I- ions from a 50 mL required concentration (0.1~10 mmol/L) of NaI aqueous solutions. The flow rate was maintained at 4.0 mL min-1. The filtered solutions were collected to determine the concentration of I- through the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Moreover, the filtrate was equilibrated at different periods to estimate the kinetics of I- adsorption by the FL-δ-Bi2O3 aerogel. Selective adsorption and the effects of pH on I- immobilization. The selective uptake of Ianions by the FL-δ-Bi2O3 aerogel adsorbent in the presence of high concentrations of Cl-, NO3-, SO42-, and CO32- anions was investigated. Briefly, the above method was unchanged except that a corresponding high concentration of competing ions is added. The effects of pH on the uptake of I- were also assessed by adjusting the pH from 4 to 11 with dilute HCl and NaOH solutions.


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Desorption test of the precipitated I- anions. Leaching or desorption was tested in various aqueous solutions. The FL-δ-Bi2O3 aerogel with abundant I- was washed in 50 mL water or 0.01 mol/L and 1 mol/L NaCl solutions. The concentrations of I- ions in the filtered solutions were determined using ICP-MS. Capture of iodine vapor. A total of 500 mg I2 was transferred to a two-neck round-bottom flask. On the top of the flask, fritted glassware was connected in which 20 mg FL-δ-Bi2O3 aerogel was placed. Iodine vapors were produced after heating the flask at 75 °C and driven upward with the nitrogen flow connected from the side neck of the flask. After treatment for 30 min, the sample was removed and placed in ventilated kitchen at room temperature for 24 h to remove residual iodine on the specimen surface. Characterization. The micromorphologies of the samples before and after adsorbing I- anions were observed on a scanning electron microscope (SEM; Quanta FEG 250/SUPRA 55). The composition of the sample after the adsorption of I- anions was determined by energy-dispersive X-ray (EDX) spectroscopy attached to the same microscope. High-resolution transmission electron microscopy (HRTEM) images were taken on a Tecnai F30 G2 field emission electron microscope under an accelerating voltage of 200 kV. The crystallized phases were identified by powder X-ray diffraction (XRD) analysis using an X-ray diffractometer (BRUKER D8 ADVANCE) with Ni-filtered Cu Kα radiation (λ = 1.5406 Å) at 40 kV and 30 mA with a fixed slit. The Brunauer-Emmett-Teller (BET) specific surface area was measured using nitrogen adsorption on a Micromeritics TriStar surface area and porosity analyzer. The X-ray photoelectron spectroscopy (XPS) data were obtained on a PHI-5400 electron spectrometer using 300 W Al Kα radiation. Raman spectra were recorded on a microscopic confocal Raman


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spectrometer (Renishaw RM 2000) with an excitation of 514.5 nm laser light. Additionally, the iodide anion adsorption value was obtained via ICP-MS (Agient 7700).

Figure 1. Structure and morphology of the as-prepared FL-δ-Bi2O3 aerogels. (a) SEM image. (b) Enlarged SEM image. (c) Diffraction ring. (d) TEM image. (e) HRTEM image. (f) IFFT image. RESULTS AND DISCUSSION Structure and morphology of FL-δ-Bi2O3 aerogels. The morphology and structural details of the as-prepared FL-δ-Bi2O3 aerogels were assessed by SEM and HRTEM. The SEM image in Figure 1a clearly shows very attractive formicary-like structures in which a large number of fluffy, flower-like δ-Bi2O3 microspheres with an average diameter of 50-60 nm were embedded in the cavity of the honeycomb body. This unique interconnected pore distribution was induced by the outside-in ice crystal formation under a rapid freezing rate (i.e., -30 °C) and inside-out solvent slow evaporation through freeze-drying.22 The enlarged SEM image in Figure 1b demonstrates that the flower-like microspheres are assembled by a large number of nanosheets.


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The corresponding diffraction ring is displayed in Figure 1c, which is consistent with the (200), (422) and (511) phases of crystalline δ-Bi2O3 (JCPDS, Card No. 27-0052). Furthermore, the presence of the Bi element in the SEM mapping (Figure S1) could assist in the formation of δBi2O3 in the BCF aerogel. Figure 1d, the TEM image of the hybrid aerogels, further shows that the sphere δ-Bi2O3 tightly contacted the cellulose fibers. Moreover, the HRTEM image (Figure 1d) indicates that the Bi2O3 nanosheets contain many micropores. Furthermore, the inverse fast Fourier transformation (IFFT) image (Figure 1e) shows the d(111) lattice fringe of the fabricated δ-Bi2O3. Additionally, the specific surface area (SBET) of the aerogel (see Figure S2 in Supporting Information) was 206.2 m2/g, which was significantly higher than that of pure MR-δBi2O3 (SBET =24.4 m2/g).12

Figure 2. Schematic illustration of the proposed formation mechanism of formicary-like δ-Bi2O3 aerogels. Based on these results, a possible formation process is schematically illustrated in Figure 2. 1). EG adsorbs Bi3+ to form a relatively stable complex, Bi2(OCH2CH2O)3, because of its strong coordination with Bi3+. Then, the Bi complex accumulates on the surface of BCF fragments (the abundant fiber fragments were obtained by ultrasonication) by hydrogen bonding.23 2). δ-Bi2O3


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spheres are acquired via the hydrothermal reaction. In this process, Bi2(OCH2CH2O)3 first hydrolyzes to generate nanoscale Bi2O3, then these two-dimensional particles gradually transform into a three-dimensional sheet-like structure and, ultimately, into a flower-like structure through the Ostwald ripening process. 3). BCF fragments interact with each other and self-assemble into a formicary-like configuration through 48 h freeze-drying. Moreover, the flowery δ-Bi2O3 microspheres are embedded into the 3D BCF architecture. Additionally, the chemical reaction of the prepared Bi2O3 particles may be formulated as follows (Eq. (1) and (2)):

2Bi ( NO3 )3 5H2O + 3HOCH2CH2OH + 6C4 H9OH → Bi ( OCH2CH2O)3 + 6C4 H9 NO2 + 16H2O

Bi ( OCH2CH2O)3 + 3H2O → Bi2O3 + 3HOCH2CH2OH

(1)

(2)

Adsorption isotherm and dynamic adsorption curve. The I- adsorption capacities of FL-δBi2O3 aerogels and MR-δ-Bi2O3 are compared in Figure 3. As shown in Figure 3a, the white FLδ-Bi2O3 adsorbent changed to bright yellow after I- adsorption for 30 min, which may be the generation of Bi4O5I2.12 The maximum adsorption capacity (Figure 3b) of FL-δ-Bi2O3 reached 2.04 mmol/g, which was significantly higher than MR-δ-Bi2O3 (1.24 mmol/g). Moreover, it was far superior to other adsorbents, such as copper-based sorbents, activated carbon, and mercurybased adsorbents (Table S1).8, 24-28 As shown in Figure 3c, MR-δ-Bi2O3 complexed with BCF (FL-δ-Bi2O3 aerogel) showed high resistance to a high concentration of iodide ions. The Iconcentration ≤ 2.00 mmol/L was completely removed by FL-δ-Bi2O3 aerogels, and approximately 80% of the I- was removed when the I- concentration was 2.50 mmol/L. The kinetics of I- uptake are displayed in Figure 3d, and the adsorption rate of the aerogel was faster than powdery δ-Bi2O3. This may be attributed to the induction of iodide ions by polyhydric


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cellulose to accumulate into the interior of the adsorbent. Moreover, the interpenetrating cellular channel could facilitate the iodide ion to reach the adsorption site more rapidly. Additionally, the FL-δ-Bi2O3 aerogel maintained the macro-morphology (large block in Figure 3a) and micromorphology (formicary-like in Figure S3) after I- sorption, which assured its easy separation from water and ultimate safe disposal, resulting in its feasibility for practical applications.

Figure 3. Removal of iodide anions from solutions by FL-δ-Bi2O3 aerogels and MR-δ-Bi2O3. (a) The color change of FL-δ-Bi2O3 aerogel after treatment with NaI solution for 30 min. (b) The isotherms of I- uptake over 48 h (25 °C, pH = 7). The photos in the inset depict the changes of adsorbent in the I- aqueous solution after 15 min. (c) Removal of different I- concentrations. (d) I- adsorption kinetics in 0.5 mmol/L I- anions.


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Figure 4. Characterization of FL-δ-Bi2O3 aerogel captured I-. (a) TEM image. (b) Diffraction ring. (c) HRTEM image. (d) The corresponding FFT image of Figure (c). (e) Elemental mapping. Adsorption mechanism of FL-δ-Bi2O3 aerogels to iodine ions. Structural evolution of the adsorbent captured I- anions was characterized by TEM. The same result for unaltered morphology was observed in the TEM image (Figure 4a) after I- uptake, and the cellulose (I) as an anchoring sorption substrate is clearly visible. The diffraction ring of the treated adsorbent in Figure 4b demonstrates the existence of a monoclinic Bi4O5I2 phase. The result is consistent with the Raman spectrum (Figure S4a). Both the redshift of the peak at 153 cm-1 (belonging to δBi2O3 lattice vibrations) transferred to 138 cm-1 (Bi-I external symmetric stretching vibration) and the appearance of a new peak at 272 cm-1 (assigned to modes involving the motion of the adsorbed iodine atoms) illustrate the creation of Bi4O5I2.29-31 Moreover, the XRD pattern of the Iδ-Bi2O3 aerogel (Figure 4c) provides evidence that the produced Bi4O5I2 is tightly adhered to the polyhydric cellulose. The typical cellulose (I) was maintained before and after I- anion adsorption. However, the peaks previously identified as δ-Bi2O3 vanished and were converted


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into the characteristic peaks of Bi4O5I2. Figure 4d is the corresponding HRTEM and FFT images of the sample. The fringe spacing of 0.291 nm was distributed to the (312) plane of the monoclinic Bi4O5I2. The δ-Bi2O3 is transformed to the Bi4O5I2 phase after capturing an amount of I- anions. Furthermore, the iodine element was observed in the elemental mapping of the particles (Figure 4e), which is consistent with the results of the energy spectrum (Figure S4b).

Figure 5. XPS spectra of FL-δ-Bi2O3 aerogels before and after I- sorption. (a) Survey scan, (b) Bi 4f and (c) O 1s of FL-δ-Bi2O3 aerogels, (d) Bi 4f, (e) O 1s and (f) I 3d of I-FL-δ-Bi2O3 aerogels. The chemical composition and surface electronic state of FL-δ-Bi2O3 aerogels before and after I- sorption were investigated by XPS (Figure 5). The appearance of an I 3d signal in XPS full spectrum (Figure 5a) near 625 eV indicated the efficient adsorption of I-anions by FL-δ-Bi2O3 aerogels. Before the uptake of I- anions, the binding energy values located at approximately 157.7 and 163.0 eV corresponded to Bi 4f7/2 and Bi 4f5/2, respectively, (Figure 5b), indicating the


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trivalent oxidation state of bismuth.32 The high-resolution of the O 1s spectrum showed three peaks. The peak at 529.5 eV is the characteristic peak of the Bi-O bond in Bi2O3,33 whereas the other peaks at 531.2 eV (O-H) and 532.6 eV (O-C) are caused by the polyhydric cellulose (Figure 5c). After adsorption of I- anions by the as-fabricated FL-δ-Bi2O3 aerogels, the two peaks of I 3d core level at 630.2 eV (I 3d3/2) and 618.7 eV (I 3d5/2) were consistent with those reported in other bismuth oxide iodides (Figure 5d).34 The Bi 4f region of the aerogel adsorbed Ianions exhibited a 0.7 eV shift to a higher binding energy compare with the original aerogel. However, for the O 1s spectrum of I-FL-δ-Bi2O3 aerogels, the area ratio of O-H was slightly reduced, which may be the reason that -OH groups participate in the adsorption process.14

Figure 6. Schematic illustration of I- uptake by FL-δ-Bi2O3 aerogels. In summary, the schematic illustration of I- anion efficient removal by FL-δ-Bi2O3 aerogels is displayed in Figure 6. First, the formicary-like matrix assembled by polyhydroxy cellulose induces a large number of iodide ions to gather into the 3D aerogel interior. Hydroxyl groups on the cellulose surface form hydrogen bonds with free iodine, thereby adsorbing iodide ions inside the gel. Then, the flowery-like δ-Bi2O3 microspheres embedded in the gel chemically adsorb


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with those aggregated iodide ions. Significantly, the honeycomb channels on all sides not only facilitate the free movement of iodide ions but also provide excellent specific surface area and reaction sites for the aerogel. Therefore, the as-prepared FL-δ-Bi2O3 aerogels display an outstanding adsorption capacity of I- anions. Additionally, the equation for the reaction of δBi2O3 with I- to form thermally stable Bi4O5I2 is shown below (Eq. (3)):

2Bi2O3 + 2I − + H2O → Bi4O5I2 + 2OH −

(3)

Figure 7. (a) Effect of pH on the removal of I- by FL-δ-Bi2O3 aerogels (adsorption equilibrium time: 48 h; temperature: 25 °C). (b) Effect of different molar ratios of Mx- to I- on I- anion removal by FL-δ-Bi2O3 aerogels. (c) Effects of different concentrations of Cl- on I- anion desorption under different temperatures (the sample was treated with I- for 48 h). Effects of external environment on iodine adsorption. To highlight the superior performance of FL-δ-Bi2O3 aerogels in removing iodine anions, the effects of different adsorption parameters, such as the pH, competitive ions, and desorption test, were studied to evaluate the sorption capacity of the aerogels. Figure 7a shows that the uptake efficiencies of FLδ-Bi2O3 aerogel rapidly decrease with increasing pH in alkaline and strong acid environments; however, the adsorption performance was maintained at 100% in a weak acid medium. Because the OH- immediately reduces the reaction product Bi4I2O5 to Bi2O3, the sorption efficiency is


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diminished. On the one hand, the H+ would neutralize OH- as a by-product during Bi2O3 capture of I- anions, such that I- could be completely adsorbed in the pH range of 4-6. However, Bi2O3 would be disintegrated by more H+. Therefore, the capture capacity of anions I- sharply declined at pH 2-3. Figure 7b shows the selective adsorption of FL-δ-Bi2O3 aerogels to I- ion under different concentrations of NO3-, Cl-, SO42-, and CO32- anions. Apparently, the presence of NO3did not compete for I- anion adsorption, whereas Cl-, SO42-, and CO32- had a great influence on Iuptake. In addition, the competitiveness followed the order CO32- > SO42- > Cl-, which was closely related to the Guinness free energy for the reaction to I- anion.12 Additionally, the effects of different concentrations of Cl- on I- anion desorption under different temperatures was also investigated (Figure 7c). The degree of desorption was very low and not affected by temperature. Nonetheless, the amount of I- leaching gradually increased after adding foreign competitive ions (Cl- anions), and the more Cl- anions, the greater the precipitation quantity. Efficient capture of iodine vapor by FL-δ-Bi2O3 aerogel. Figure S5a shows the corresponding color change of FL-δ-Bi2O3 aerogels during treatment with iodine vapor and starch potassium iodide solution. After capturing I2, the color changed from white to deep yellow due to the formation of Bi4O5I2. During the subsequent treatment with starch potassium iodide solution, the color of FL-δ-Bi2O3 aerogels transformed to dark blue, which indicated the presence of a large amount of I2 in the hybrid aerogel. To further investigate the existence of I- anions and I2, XPS analysis was used in Figure S5b-d. From the entire spectrum in Figure S5b, the signal of the I element was found. Moreover, the Bi 4f region in Figure S5c and I 3d region in Figure S5d confirm the generation of Bi4O5I2. Additionally, the characteristic peaks of I2 were disassembled from the I 3d region, providing evidence that I2 is captured by FL-δ-Bi2O3. Therefore, iodine vapor could be not only chemically adsorbed by δ-Bi2O3 embedded in formicary-like aerogels


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but also immobilized in BCF matrix via physical adsorption (hydrogen bonding with the surface -OH of the BCF skeleton may be beneficial for I2 absorption). CONCLUSIONS In summary, the one-step hydrothermal synthesis of multi-level δ-Bi2O3 aerogels using alcohol as a solvent for highly efficient noxious I- capture is feasible. Compared with pure δBi2O3 microspheres, the selective adsorption properties of the hybrid gels for iodine were significantly enhanced at 2.04 mmol/g. The key points for rapid and efficient adsorption of iodide were as follows: (1) the BCF matrix enriched the iodine inside the gel; (2) the honeycomb structure not only provided a large specific surface area of the adsorbent but also constructed an arbitrary shuttle channel and a plurality of adsorption sites for the adsorbate; and (3) the abundant δ-Bi2O3 microspheres rapidly and chemically captured iodide to form irreversible and insoluble Bi4O5I2. Additionally, the FL-δ-Bi2O3 aerogel selectively seized I- anions even in the presence of competitive ions, such as Cl- and SO42-. Therefore, a low-cost FL-δ-Bi2O3 aerogel adsorbent has a number of advantages and can serve as a candidate for practical applications of highly efficient, rapid and selective iodine adsorption.

ASSOCIATED CONTENT Supporting Information Figure S1. SEM Mapping of the as-prepared FL-δ-Bi2O3 aerogels. Figure S2. N2 adsorption/desorption isotherm curve for FL-δ-Bi2O3 aerogels.


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Figure S3. The micro-morphology of FL-δ-Bi2O3 aerogel before and after selectively captured radioactive I- anions. Figure S4. Raman spectrum and energy spectrum of δ-Bi2O3 aerogel after I- anions adsorption. Figure S5. The characterization of δ-Bi2O3 aerogel captured iodine vapor. Table S1. Comparison of several iodide sorption materials that already reported. AUTHOR INFORMATION Corresponding Author *Corresponding author: Qingfeng Sun. E-mail: [email protected] *Corresponding author: Xijin Xu. E-mail: [email protected] Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes The authors declare no competing financial interest. ACKNOWLEDGMENT This work is partially supported by the Public Projects of Zhejiang Province (No. 2015C32014), the National Natural Science Foundation of China (51672109), Natural Science Foundation of Shandong Province for Excellent Young Scholars (ZR2016JL015), Scientific research


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Foundation of Zhejiang A&F University (Grant No. 2014FR077), and the Fund for Innovative Research Team of Forestry Engineering Discipline (101-206001000713). REFERENCES 1.

Zhang, Z.; Chen, Z.; Wang, S.; Cheng, F.; Chen, L., Iodine-Mediated Etching of Gold

Nanorods for Plasmonic ELISA Based on Colorimetric Detection of Alkaline Phosphatase. ACS Appl. Mater. Interfaces 2015, 7 (50), 27639-27645. 2.

Lee, S. B.; Lee, S.-W.; Jeong, S. Y.; Yoon, G.; Cho, S. J.; Kim, S. K.; Lee, I.-K.; Ahn,

B.-C.; Lee, J.; Jeon, Y. H., Engineering of Radioiodine-Labeled Gold Core–Shell Nanoparticles as Efficient Nuclear Medicine Imaging Agents for Trafficking of Dendritic Cells. ACS Appl. Mater. Interfaces 2017, 9 (10), 8480-8489. 3.

Hosoda, M.; Tokonami, S.; Tazoe, H.; Sorimachi, A.; Monzen, S.; Osanai, M.; Akata, N.;

Kakiuchi, H.; Omori, Y.; Ishikawa, T., Activity Concentrations of Environmental Samples Collected in Fukushima Prefecture Immediately after the Fukushima Nuclear Accident. Sci. Rep. 2013, 3 (6144), 410-414. 4.

Xu, S.; Freeman, S. P.; Hou, X.; Watanabe, A.; Yamaguchi, K.; Zhang, L., Iodine

Isotopes in Precipitation: Temporal Responses to

129

I Emissions from the Fukushima Nuclear

Accident. Environ. Sci. Technol. 2013, 47 (19), 10851-10859. 5.

Rose, P. S.; Swanson, R. L.; Cochran, J. K., Medically-Derived 131I in Municipal Sewage

Effluent. Water Res. 2012, 46 (17), 5663-5671. 6.

Rose, P. S.; Smith, J. P.; Aller, R. C.; Cochran, J. K.; Swanson, R. L.; Coffin, R. B.,

Medically-Derived

131

I as a Tool for Investigating the Fate of Wastewater Nitrogen in Aquatic

Environments. Environ. Sci. Technol. 2015, 49 (17), 10312-10319. 7.

Vathaire, F. D.; Drozdovitch, V.; Brindel, P.; Rachedi, F.; Boissin, J. L.; Sebbag, J.;

Shan, L.; Bostbezeaud, F.; Petitdidier, P.; Paoaafaite, J., Thyroid Cancer Following Nuclear Tests in French Polynesia. Br. J. Cancer 2010, 103 (7), 1115-1121.


17


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

8.

Page 18 of 21

Lefèvre, G.; Walcarius, A.; Ehrhardt, J. J.; Bessière, J., Sorption of Iodide on Cuprite

(Cu2O). Langmuir 2000, 16 (10), 4519-4527. 9.

Yang, D.; Liu, H.; Zheng, Z.; Sarina, S.; Zhu, H., Titanate-Based Adsorbents for

Radioactive Ions Entrapment from Water. Nanoscale 2013, 5 (6), 2232-2242. 10. Soldz, S., Capture of Radioactive Cesium and Iodide Ions from Water by Using Titanate Nanofibers and Nanotubes. Angew. Chem., Int. Ed. 2011, 50 (45), 10594-10598. 11. Torres, M. S. T.; Ramirez, L.; Simkin, P. H.; Braverman, L. E.; Emerson, C. H., Effect of Various Doses of Recombinant Human Thyrotropin on the Thyroid Radioactive Iodine Uptake and Serum Levels of Thyroid Hormones and Thyroglobulin in Normal Subjects. J. Clin. Endocrinol. Metab. 2001, 86 (4), 1660-1664. 12. Liu, L.; Liu, W.; Zhao, X.; Chen, D.; Cai, R.; Yang, W.; Komarneni, S.; Yang, D., Selective Capture of Iodide from Solutions by Microrosette-Like δ-Bi2O3. ACS Appl. Mater. Interfaces 2014, 6 (18), 16082-16090. 13. Bo, A.; Sarina, S.; Liu, H.; Zheng, Z.; Xiao, Q.; Gu, Y.; Ayoko, G. A.; Zhu, H., Efficient Removal of Cationic and Anionic Radioactive Pollutants from Water Using Hydrotalcite-Based Getters. ACS Appl. Mater. Interfaces 2016, 8 (25), 16503–16510. 14. Lu, Y.; Liu, H.; Gao, R.; Xiao, S.; Zhang, M.; Yin, Y.; Wang, S.; Li, J.; Yang, D., Coherent Interface Assembled Ag2O Anchored Nanofibrillated Cellulose Porous Aerogels for Radioactive Iodine Capture. ACS Appl. Mater. Interfaces 2016, 8 (42), 29179–29185. 15. Carpenter, A. W.; Lannoy, C. F. D.; Wiesner, M. R., Cellulose Nanomaterials in Water Treatment Technologies. Environ. Sci. Technol. 2015, 49 (9), 5277-5287. 16. Huang, H. D.; Liu, C. Y.; Zhou, D.; Jiang, X.; Zhong, G. J.; Yan, D. X.; Li, Z. M., Cellulose Composite Aerogel for Highly Efficient Electromagnetic Interference Shielding. J. Mater. Chem. A 2015, 3 (9), 4983-4991. 17. Nishino, T.; Matsuda, I.; Hirao, K., All-Cellulose Composite. Macromolecules 2004, 37 (20), 7683-7687.


18

Page 19 of 21

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


18. Siró, I.; Plackett, D., Siro, I. & Plackett, D. Microfibrillated Cellulose and New Nanocomposite Materials: A Review. Cellulose 2010, 17 (3), 459-494. 19. Olsson, R. T.; Samir, M. A. S. A.; Salazar-Alvarez, G.; Belova, L.; Ström, V.; Berglund, L. A.; Ikkala, O.; Nogués, J.; Gedde, U. W., Making Flexible Magnetic Aerogels and Stiff Magnetic Nanopaper Using Cellulose Nanofibrils as Templates. Nat. Nanotechnol. 2010, 5 (8), 584-588. 20. Mascarelli, A. L., Funding Cut for US Nuclear Waste Dump. Nature 2009, 458 (7242), 1086-1087. 21. Si, Y.; Yu, J.; Tang, X.; Ge, J.; Ding, B., Ultralight Nanofibre-Assembled Cellular Aerogels with Superelasticity and Multifunctionality. Nat. Commun. 2014, 5, 5802-5802. 22. Xu, X.; Zhang, Q.; Yu, Y.; Chen, W.; Hu, H.; Li, H., Naturally Dried Graphene Aerogels with Superelasticity and Tunable Poisson's Ratio. Adv. Mater. 2016, 28 (41), 9223-9230. 23. Wang, Y.; Li, S.; Xing, X.; Huang, F.; Shen, Y.; Xie, A.; Wang, X.; Zhang, J., SelfAssembled 3D Flowerlike Hierarchical Fe3O4@Bi2O3 Core–Shell Architectures and Their Enhanced Photocatalytic Activity under Visible Light. Chem. - Eur. J. 2011, 17 (17), 4802– 4808. 24. Yang, O. B.; Kim, J. C.; Lee, J. S.; Kim, Y. G., Use of Activated Carbon Fiber for Direct Removal of Iodine from Acetic Acid Solution. Ind. Eng. Chem. Res. 1993, 32 (8), 1692-1697. 25. Madrakian, T.; Afkhami, A.; Zolfigol, M. A.; Ahmadi, M.; Koukabi, N., Application of Modified Silica Coated Magnetite Nanoparticles for Removal of Iodine from Water Samples. Nano-Micro Lett. 2012, 4 (1), 57-63. 26. Kentjono, L.; Liu, J. C.; Chang, W. C.; Irawan, C., Removal of Boron and Iodine from Optoelectronic Wastewater using Mg–Al(NO3) Layered Double Hydroxide. Desalination 2010, 262 (1–3), 280-283. 27. Krumhansl, J. L.; Nenoff, T. M., Hydrotalcite-Like Layered Bismuth-Iodine-Oxides as Waste Forms. Appl. Geochem. 2011, 26 (1), 57-64.


19


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 21

28. Balsley, S. D.; Brady, P. V.; And, J. L. K.; Anderson, H. L., Iodide Retention by Metal Sulfide Surfaces: Cinnabar and Chalcocite. Environ. Sci. Technol. 1996, 30 (10), 3025-3027. 29. Hardcastle, F. D.; Wachs, I. E., The Molecular Structure of Bismuth Oxide by Raman Spectroscopy. J. Solid State Chem. 2002, 97 (2), 319-331. 30. Hrizi, C.; Samet, A.; Abid, Y.; Chaabouni, S.; Fliyou, M.; Koumina, A., Crystal Structure, Vibrational and Optical Properties of A New Self-Organized Material Containing Iodide Anions of Bismuth(III), [C6H4(NH3)]2Bi2I10·4H2O. J. Mol. Struct. 2011, 992 (1–3), 96101. 31. Kanchana, G.; Arivuoli, D., Spectroscopic Investigation of BiSeI, SbSeI Compounds and BiSbSxSe1-xI Solid Solutions. Indian J. Eng. Mater. Sci. 2001, 8 (6), 373-376. 32. Wang, J.; Yu, Y.; Zhang, L., Highly Efficient Photocatalytic Removal of Sodium Pentachlorophenate with Bi3O4Br under Visible Light. Appl. Catal., B 2013, 136–137 (21), 112– 121. 33. Liu, C.; Wang, X. J., Room Temperature Synthesis of Bi4O5I2 and Bi5O7I Ultrathin Nanosheets with A High Visible Light Photocatalytic Performance. Dalton Trans. 2016, 45 (18), 7720-7727. 34. Zhang, X.; Zhang, L.; Xie, T.; Wang, D., Low-Temperature Synthesis and High VisibleLight-Induced Photocatalytic Activity of BiOI/TiO2 Heterostructures. J. Phys. Chem. C 2009, 113 (17), 7371-7378.


20

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Cellulose Fibers Constructed Convenient Recyclable 3D Graphene

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