Limitation of Adsorptive Penetration of Cesium Into

Supplementary Information for

Limitation of Adsorptive penetration of Cesium into Prussian Blue Crystallite

Hirotaka Fujita*, Risa Miyajima**, Akiyoshi Sakoda*

*Institute of Industrial Science, University of Tokyo, Japan 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan e-mail: [email protected] Tel/Fax: +81-3-5452-6348

**School of Science and Technology, Meiji University, Japan 1-1-1 Higashimita, Tama-Ku, Kawasaki-city, Kanagawa 214-8571, Japan

Section S1 Preparation of Prussian Blue crystallite Section S2 Determination of average crystallite size by Williamson-Hall (W-H) method Section S3 TEM and SEM observation Section S1 Preparation of Prussian Blue crystallite

(1) Insoluble PB synthesized by an immediate precipitation reaction method (H3O+IPB-12) + The synthesis method is described in detail elsewhere (Fujita 2014). H3O IPB-12 was prepared 3+ 4- under the conditions in which Fe(III) was in excess of [Fe(II)(CN)6] (Louise 2013). Aqueous solution (300cc) containing 1.72g of K4[Fe(II)(CN)6]·3H2O was added dropwise into 600cc of aqueous solution containing 1.72g of Fe(III)Cl3 at ambient temperature. The precipitated IPB was separated by centrifugal separation, followed by 5 rinses with 50cc of ion-exchanged water. (2)Soluble PB synthesized by an immediate precipitation reaction method (K + SPB-14) + 4- 3+ K SPB-14 was prepared under conditions in which [Fe(II)(CN)6] was in excess of Fe(III) in + contrast to H3O IPB-12 (Louise 2013). Aqueous solution (600cc) containing 0.66g of Fe(III)Cl3 was added dropwise into 300cc of aqueous solution containing 4.5g of K4[Fe(II)(CN)6]·3H2O at ambient temperature. PB dispersing in the synthesis solution was filtered using a membrane filter with a 25-nm pore aperture, followed by 5 rinses with 50cc of ion-exchanged water. (3) Soluble PBs prepared by oxidation of Berlin White (K + SPB-18 and K + SPB-45) The synthesis procedure is described in detail elsewhere (Louise 2013). Aqueous solution (50cc) containing 4.2g of K4[Fe(II)(CN)6]·3H2O at 50°C was mixed with 50cc of aqueous solution containing 2.0g of Fe(II)Cl2 ·4H2O at 50°C under nitrogen atmosphere to generate Berlin White (BW). As for the K+SPB-45, the solution was further maintained at 100°C in the water bath for 2hr with complete sealing to prevent the contact of oxygen with BW. Aging is a key process for the increase of crystal size (Louise 2013). As for K +SPB-18, no aging process was performed.

Subsequently, 30 percent of H2O2 was added to the synthesis solution to oxidize BW into PB, until there was no more explosive boiling by the addition of H2O2, which seems to be an index of oxidation of BW. Then, PB was filtered using a membrane filter with a 25-nm pore aperture, followed by 5 rinses with 50cc of ion-exchanged water. + (4) Soluble PB prepared by hydrothermal synthesis from K4[Fe(CN)6 ] solution (K SPB-800) The synthesis procedure is described elsewhere (Wu 2006). We used this method with some modification of synthesis conditions, dissolving 0.6g of K4[Fe(II)(CN)6]·3H2O in 100cc of distilled water. Subsequently, the solution was maintained at 60°C in the water bath. Then, 0.15cc of 10% NaClO and 1cc of 35‒37% HCl was added to this solution and kept at 60°C with stirring at the rate of 130 rpm for 10 hr. The precipitate was filtered using membrane filter with 1-μm pore aperture, followed by 5 rinses with 50cc of ion-exchanged water. This synthesis 2+ 4- method is based on the release of Fe(II) from [Fe(II)(CN)6] in the presence of high + 3+ 2+ - concentration of H3O , and the Fe(III) generated by oxidation of the released Fe(II) by ClO serves as a source material of PB (Wu 2006). Hence, it should be noted that dangerous cyanides may be generated during the synthesis (Herrera 2008). Section S2 Determination of average crystallite size by Williamson-Hall (W-H) method

Peak fitting by the nonlinear least-squares method was performed using the Lorentzian function with consideration of the kα2 contribution, after background subtraction by the Sonneveld-Vier method (Sonneveld 1975). The peak profile function considering kα2 contribution, I(2θ), can be described in equations (S1)‒(S4)

where I(2θ) is the peak function including the contribution of both kα1 and kα2, A is the height of the kα1 peak, θ0 is the angular position of the Kα1 peak, Δ2θr is the gap in angular position between kα1 and kα2 peaks, βexperiment is the full width at half maximum (FWMH) of the kα1 peak and λkα1 and λkα2 are wavelengths. For the W-H method, instrumental broadening of the peak, βinst, was determined using a large crystallite of KCl (Langford1996; Scardi 1994). If the peak could be expressed by the Lorentzian function, the true peak broadening could be calculated by equation (S5). The value of β was used for the W-H method (Georgea 2011).

Fig.S1 (a) and (b) show an example of the peak fitting and the W-H plot, respectively. The crystallite size was calculated by the W-H plot for samples except K+SPB-800. The crystallite size is shown in Table S1.

Section S3 TEM and SEM observation

Scanning electron spectroscopy (SEM) observation of PB samples was performed using JSM- 7500 (JEOL). Also, transmission Electron Microscopy (TEM) observation was performed by the following procedure. The synthesized PB was dispersed in ethanol by sonication for 20 min. The dispersed solution was dropped onto the collodion membrane (COL-C-15 (Oken Shoji)), and then the dried membrane was subject to TEM observation (JEM-2000EX (JEOL)). The result is shown in Fig. S2.

Reference

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