Supporting Information

Synthesis of Polyamidoxime-Functionalized Nanoparticles forUranium(VI)Removal from Neutral Aqueous Solutions

Li Huang 1,Lixia Zhang 2,Daoben Hua 1,2*

1College of Chemistry, Chemical Engineering and Materials Science & School for Radiological and Interdisciplinary Sciences (RAD–X), Soochow University, Suzhou 215123, China

2Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, China

Table of Contents

Synthesis of DDACT...... S

FigureS1...... S

Synthesis of polyacrylonitrile-block-polystyrene (PAN-b-PSt)...... S

Figure S2...... S

Synthesis of polyamidoxime-block-polystyrene (PAO-b-PSt)...... S

Figure S3...... S

Figure S4...... S

ThermodynamicStudy...... S

Table S1...... S6

Figure S5...... S6

Figure S6...... S

Figure S7...... S7

Table S2...... S

Figure S8...... S8

Figure S9...... S

Table S3...... S

References...... S

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1.Synthesis of DDACT

DDATC was synthesized according to the related reference1. Typically, 1-dodecanethiol (20.19 g, 0.1 mol), acetone (48.1 g, 0.8275 mol), and tricaprylylmethylammonium chloride (1.625 g, 0.004mol) were mixed in a round-bottomed flask to 10 °C under a nitrogen atmosphere. Then sodium hydroxide solution (50%, 8.385 g, 0.105 mol) was added over 20 min. The reaction was stirred for an additional 15 min before carbon disulfide (7.605 g, 0.10 mol) in acetone (10.09 g,0.173 mol) was added over 20 min.Ten minutes later, chloroform(17.81 g, 0.15 mol) was added in one portion, followed by dropwise addition of 50% sodium hydroxide solution (40 g, 0.5 mol) over 30 min. The mixturewas stirred overnight. 150 mL of water was added, followed by 25mL of concentrated HCl to acidify the aqueous solution. Nitrogen was purged through the reactor with vigrous stirring to help evaporate off acetone. The solid was collected and then stirred in 2-propanol. The 2-propanol solution was concentrated to dryness, and the resulting solid was re-crystallized from hexanes.

Figure S11H NMR spectrum (400M, CDCl3) of DDATC.

2.Synthesis ofpolyacrylonitrile-block-polystyrene (PAN-b-PSt)

PAN-b-PStwas synthesized referred to the modified literaturemethod2. PAN was first synthesized by RAFT polymerization, and the typical recipe was as follows:0.015 g azobisisobutyronitrile (9.15×10-5 mol) and 0.083 g DDACT (2.29×10-4 mol)were added in a 10ml ampoule and degassed. 1.5 ml of acrylonitrile (2.29×10-2 mol) and 3 ml ethylene carbonate were mixed together, degassed, and then added into the above flask via syringe. The resulting mixture was then placed in an oil bath at 60 ºC for 12 h. At the end of this time, the reaction mixture was dissolved in DMF and the polymer was precipitated by addition of the solution to methanol. The solid product was dried in vacuum at 40 °C until a constant weight was obtained gravimetrically.PAN with different molecular weightwas obtained as macro-RAFT agent, and the same procedure was used for the extension reaction of St. Finally, the block copolymers PAN-b-PStwas obtained.

Figure S21H NMR spectrum (DMSO, 400MHz) of (A) PAN50 and (B) PAN50-b-PSt10; and GPC curves of: (C, trace a) PAN50 (Mn= 12000 g/mol, PDI = 1.11), and (C, trace b) PAN50-b-PSt12 (Mn = 13900 g/mol, PDI = 1.12); (D, trace a) PAN76 (Mn = 14000 g/mol, PDI = 1.17), and (D, trace b) PAN76-b-PS12 (Mn = 15400 g/mol, PDI = 1.29); (E, trace a) PAN99 (Mn = 15800 g/mol, PDI = 1.09), and (E, trace b) PAN99-b-PS10 (Mn = 16800g/mol, PDI = 1.13).

3.Synthesis of polyamidoxime-block-polystyrene (PAO-b-PSt)

PAO-b-PSt was synthesized by the reaction of PAN-b-PSt with amidoximating reagent solution3.Typically, hydroxylamine hydrochloride (0.85 g) was dissolved in 50 % methanol in water (v/v) solvent system, pH adjusted to 7 with NaOH, and the volume was made upto 28.5 ml. The mixture of PAN-b-PSt powder (0.4 g) and the 28.5 mL amidoximating reagent was heated at 65 ℃with constant stirring for 12 h. A water-cooled condenser was used toprevent evaporation of the solvent. During the procedure, the color of the PAN-b-PSt changed from light yellow to dark yellow. The synthesized PAO-b-PSt was separated by centrifuging, washed with water three times, and then dried under vacuum. The FT-IR spectra of PAN99-b-PSt10before and after amidoximation were illustrated in Figure S3. Amidoximation of the PAN99-b-PSt10 shows that the band associated with the nitrile group at 2241 cm-1 disappears and is replaced by the bands ofamidoxime in the region of 3477 cm-1 and 3359 cm-1 (for broad O–H and N–H stretching vibration, respectively); and aband at 1652 cm-1and 921 cm-1 (for C=N and N–Ostretch vibration, respectively). The result revealed that PAN99-b-PSt10 was successfully amidoximed.

Figure S3FT-IR spectra of PAN99-b-PSt10before (a) and after amidoximation(b).

Figure S4FE-SEM images and particle size distributions of PAO-functionalized polystyrene particles from emulsion polymerization using (A,B) PAO50-b-PS10, (C, D) PAO76-b-PS12, (E, F) PAO99-b-PS10 as surfactants with the same concentration of 4.0×10-4 mol/L.

4.Thermodynamic Study

The enthalpy change (ΔH) entropy change (ΔS) and Gibbs free energy change (ΔG) were estimated according to the equilibrium constant Kc:

(1)

(2)

(3)

Where R is the universal gas constant (8.314 J/mol·K) and T is the absolute temperature. ΔH and ΔS can be calculated from the slope and intercept of the plot of ln Kc versus 1/T, and the results are shown in Table S1.

Table S1 Thermodynamic data for Uranium (VI) sorption on the nanoparticles from emulsion polymerization using PAO99-b-PS10 as surfactants with the concentration of 4.0×10-4 mol/L.

ΔH (kJ/mol) / ΔS (J/mol/K) / ΔG (kJ/mol)
298 K / 308 K / 318 K / 328 K
8.13 / 104.17 / -22.89 / -24.05 / -25.08 / -26.01

Figure S5The sorption ofUranium (VI) as a function of the time for the PAO-functionalized polystyrene particles obtained from emulsion polymerization: (a) PAO99-b-PS10, (b) PAO76-b-PS12, (c) PAO50-b-PS10 as emulsifier with the same concentration of 4.0×10-4 mol/L (Experimental conditions: 200 mL solution, 75 mg/L adsorbent, 298 K, pH 6.5, concentration of Uranium (VI): 4.76mg/L.).

Figure S6The FE-SEM images and particle size distributions of PSt nanoparticle-Uranium (VI)complex. The PSt nanoparticles were obtained from emulsion polymerization using (A, B) PAO50-b-PS10, (C, D) PAO76-b-PS12, and (E, F) PAO99-b-PS10 as surfactants with the same concentration of 4.0×10-4 mol/L.(Experimental conditions: 200 mL solution, 4.76mg/LUranium (VI)75 mg/L adsorbent, 298 K, pH 6.5, contact time = 9 h).

Figure S7(A) Pseudo-first order kinetics and (B) Pseudo-second order kinetics curves ofUranium (VI) onto the nanoparticleswith different PAO chain length: (a) PAO99-b-PS10, (b) PAO76-b-PS12, and (c) PAO50-b-PS10 as emulsifier with the same concentration of 4.0×10-4 mol/L.(Experimental conditions: 200 mL solution, 4.76mg/LUranium (VI),75 mg/L adsorbent, 298K, pH 6.5, contact time = 9 h).

Table S2Kinetic parameters for the sorption of Uranium (VI) onto the nanoparticles from emulsion polymerization using PAO99-b-PS10, PAO76-b-PS12 and PAO50-b-PS10as emulsifier with the same concentration of 4.0×10-4 mol/L.(Experimental conditions: 200 mL solution, 4.76mg/LUranium (VI),75 mg/L adsorbent, 298 K, pH 6.5, contact time = 9 h).

Nanoparticles / Pseudo-first order / Pseudo-second order
qe,exp(mg/g) / k1 (h-1) / qe,cal (mg/g) / R2 / k2 (g/mg/h) / qe,cal (mg/g) / R2
a / 54.48 / 0.518 / 57.46 / 0.9439 / 0.0101 / 68.91 / 0.9918
b / 53.88 / 0.510 / 59.14 / 0.880 / 0.0079 / 66.76 / 0.9836
c / 37.64 / 0.536 / 42.23 / 0.9654 / 0.0099 / 47.92 / 0.9866

Figure S8Sorption isotherm plots for the sorption of Uranium (VI) onto the nanoparticles with (A) different chain density:usingPAO99-b-PS10 as emulsifier with the concentration of (a) 4.0×10-4 mol/L, (b) 2.0×10-4 mol/L, (c) 1.0×10-4 mol/L);and (B) different chain length:using(a) PAO99-b-PS10, (b) PAO76-b-PS12, (c) PAO50-b-PS10 as emulsifier with the same concentration of 4.0×10-4 mol/L. (Experimental conditions: 200 mL solution, 75mg/L adsorbent, 298 K, pH 6.5, contact time =9h).

Figure S9(A) Langmuir sorption isotherm plots and (B) Freundlich sorption isotherm plots for the sorption ofUranium (VI) onto the nanoparticleswith different chain length by using (a) PAO99-b-PS10, (b) PAO76-b-PS12, and (c) PAO50-b-PS10 as emulsifier with the same concentration of 4.0×10-4 mol/L. (Experimental conditions: 200 mL solution, 75mg/L adsorbent, 298 K, pH 6.5, contact time =9h).

Table S3Langmuir and Freundlich parameters for uranyl ions sorption by the nanoparticlesfrom emulsion polymerization using PAO99-b-PS10, PAO76-b-PS12 and PAO50-b-PS10 as emulsifier with the same concentration of 4.0×10-4 mol/L. (Experimental conditions: 200 mL solution, 75 mg/L adsorbent, 298 K, pH 6.5, contact time = 9 h).

Nanoparticles / Langmuir / Freundlich
qmax (mg/g) / b (L/mg) / R2 / KF (L/g) / nF / R2
a / 246.91 / 0.102 / 0.9958 / 33.62 / 2.36 / 0.8238
b / 178.89 / 0.108 / 0.9957 / 17.48 / 1.99 / 0.7859
c / 119.33 / 0.062 / 0.9902 / 7.35 / 1.69 / 0.8082

References

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2.TangCB, Kowalewski T, Matyjaszewski K.Macromolecules2003,36:8587-8589.

3.Yue Y, Mayes RT, KimJ, Fulvio PF, SunXG, Tsouris C, ChenJ, BrownS, DaiS. Angew Chem Int Edit2013, 52:13458-13462.

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