Succinamic Acid Grafted Nanosilica for the Preconcentration of U(VI) from Aqueous Solution

Abstract

Succinamic acid-functionalized nanosilica (SA@SiO 2 ) was synthesized, characterized, and tested for hexavalent uranium preconcentration from contaminated aqueous solutions. The succinamic acid grafted nanosilica exhibited improved uranium preconcentration capacity in comparison with that of raw nanosilica. The effects of environmental conditions such as pH, ionic strength, solid concentration, foreign ions, and temperature on uranium(VI) preconcentration performance were investigated by batch technique in detail, and the related mechanism is discussed with the aid of X-ray photoelectron spectroscopy. Results showed that U(VI) preconcentration by SA@SiO 2 was strongly dependent on pH while less dependent on ionic strength; the preconcentration was mainly dominated by inner-sphere surface complexation. The coexisting cations had no effects, while anions influenced U(VI) preconcentration significantly. The preconcentration of U(VI) was favorable at lower temperatures; the maximum preconcentration capacity was 44.5 mg/g at pH 4.0 ± 0.1 and T = 298 K. Thermodynamic parameters indicated that the preconcentration process was exothermic and spontaneous. The SA@SiO 2 exhibited desirable selectivity for uranium and can be reused at least five times without decreasing capacity. Accordingly, the SA@SiO 2 is a potential and suitable candidate for the preconcentration of U(VI) from a considerable volume of contaminated water.

An Efficient Uranium Adsorption Magnetic Platform Based on Amidoxime-Functionalized Flower-like Fe3O4@TiO2 Core–Shell Microspheres

“…Based on the kinetic and thermodynamic adsorption results, we speculated that the chemical chelation of amidoxime groups mainly governed the adsorption mechanism of U­(VI) on Fe 3 O 4 @TiO 2 -AO. Moreover, the maximum U­(VI) adsorption capacity of various reported artificial sorbents is summarized in Figure F, ,− from which the as-prepared Fe 3 O 4 @TiO 2 -AO microspheres in the present work exhibited prominent U­(VI) adsorption performance.…”

“…(F) Comparison of competing uranyl adsorption of various materials by capacity. (Data are from refs and − . )…”

Sensitivity enhancement of microelectromechanical sensors using femtosecond laser for biological and chemical applications

“…The peak at 615–630 cm −1 represents Si–O bending 28,29 . The peak at 878 cm −1 corresponds to silanol (Si–OH) bending, 30–32 and that the peak from 1090 to 1150 cm −1 corresponds to the Si–O–Si asymmetric bonding 24,33,34 . The peak from 1386 to 1410 cm −1 is attributed to COO − symmetric stretching 34–36 .…”

“…28,29 The peak at 878 cm À1 corresponds to silanol (Si-OH) bending, [30][31][32] and that the peak from 1090 to 1150 cm À1 corresponds to the Si-O-Si asymmetric bonding. 24,33,34 The peak from 1386 to 1410 cm À1 is attributed to COO À symmetric stretching. [34][35][36] The peaks at 1510, 1561, and 1646 cm À1 represent C=O stretching vibration 34,37 whereas those at 2050-2300 cm À1 correspond to SiH.…”

The preparation of organophosphorus ligand-modified SBA-15 for effective adsorption of Congo red and Reactive red 2

“…Several intrinsic peaks of SBA-15 such as the peaks at 3446 cm À1 (-OH vibration of hydrated silane group), 1634 cm À1 (the bending vibration of surface hydroxide), 1085 cm À1 (asymmetric Si-O-Si stretching), 803 cm À1 (symmetric Si-O-Si stretching) and 464 cm À1 (Si-O-Si bending vibration) were observed . 27,30,44 The FT-IR prole of SBA-15-BOP presents characteristic peaks at 1760 cm À1 for -C]O stretching vibrations, 1480 cm À1 for -CH 2 group bending vibration (scissor vibration), and 1398 cm À1 for P]O stretching vibrations, suggesting that the organophosphorus groups have been successfully graed onto the SBA-15 matrix. 37 Moreover, aer graing, the pH pzc of SBA-15-BOP was 3.0, which was determined by the titration method (Fig.…”