Adsorption and desorption characteristics of arsenic onto ceria nanoparticles.

Key Laboratory of Nuclear Analytical Techniques and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China. .
Nanoscale Research Letters (Impact Factor: 2.48). 01/2012; 7:84. DOI: 10.1186/1556-276X-7-84
Source: PubMed

ABSTRACT The rapid increase in the use of engineered nanoparticles [ENPs] has resulted in an increasing concern over the potential impacts of ENPs on the environmental and human health. ENPs tend to adsorb a large variety of toxic chemicals when they are emitted into the environment, which may enhance the toxicity of ENPs and/or adsorbed chemicals. The study was aimed to investigate the adsorption and desorption behaviors of arsenic on ceria NPs in aqueous solution using batch technique. Results show that the adsorption behavior of arsenic on ceria NPs was strongly dependent on pH and independent of ionic strength, indicating that the electrostatic effect on the adsorption of these elements was relatively not important compared to surface chemical reactions. The adsorption isotherms fitted very well to both the Langmuir and Freundlich models. The thermodynamic parameters (ΔH0, ΔS0, and ΔG0) for the adsorption of arsenic were determined at three different temperatures of 283, 303, and 323 K. The adsorption reaction was endothermic, and the process of adsorption was favored at high temperature. The desorption data showed that desorption hysteresis occurred at the initial concentration studied. High adsorption capacity of arsenic on ceria NPs suggests that the synergistic effects of ceria NPs and arsenic on the environmental systems may exist when they are released into the environment.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Here, we aim to develop an efficient material by eco-friendly green synthetic route that was characterized to be nano-structured. The thermal stability of the sample was well established from the consistent particle size at different temperature and also, from differential thermal analysis. The bimetal mixed oxide contained agglomerated crystalline nano-particles of dimension 10-20 nm, and its empirical composition as FeCe1.1O7.6. The surface area ( m2g-1), pore volume ( cm3 g-1) and maximum pore width (nm) obtained from BET analysis were found to be 104, 0.1316 and 5.68 respectively. Use of this material for estimating arsenic sorption kinetics in presence of some groundwater occurring ions revealed that the pseudo-second order kinetic model is unambiguously the best fit option to describe the nature of the reactions. Groundwater occurring ions exhibit a notable decrease of As(V)-sorption capacity (no other ion > chloride ˜ silicate > sulfate > bicarbonate > phosphate). However, As(III)-sorption capacity of the bimetal mixed oxide was nominally influenced by the presence of the above ions in the reaction system. Rate determining step of arsenic sorption reactions was confirmed to be a multistage process in the presence of the above ions at pH ˜ 7.0 and 30 °C.
    Applied Surface Science 10/2013; · 2.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The adsorption-desorption of toxic compounds onto engineered nanoparticles is an important process that governs their potential as sorbents for treatment applications, their toxicity and their environmental risks. This study was aimed to investigate the desorption of Pb (II), Cu (II) and Zn (II) from commercially prepared nano-TiO(2) (anatase) using batch techniques, with the evaluation of isothermal, kinetic and thermodynamic properties. Results showed that desorption was pH dependent and that more than 98% of all metals desorbed at pH 2. Short term kinetic studies were fit with a pseudo second order model and showed that a significant amount of desorption occurred in the first fifteen minutes. Surface complexation modeling determined a trend of adsorption affinity to be Pb > Zn > Cu and with adjustable surface complexation constant (K(int)) provided good fit to the experimental data. The thermodynamic studies found that desorption was exothermic and non-spontaneous in most cases. The XPS study showed that no change in oxidation state occurred due to desorption and suggested that Pb desorption was due to inner-sphere surface complexation. The results suggest three important points that will improve the capabilities of researchers to understand Pb (II), Cu (II) and Zn (II) adsorption-desorption to nano-TiO(2): (1) the desorption of metals was enhanced at lower pH values suggesting its potential to be regenerated for treatment applications; (2) the possible mechanism for adsorption-desorption varies for different metals; and (3) nano-TiO(2) could interact with metals in the environment if released due to their high sorption capacity and reversible adsorption at lower pH values which could affect the fate and behavior of metals in the environment and enhance nanoparticle toxicity.
    Science of The Total Environment 06/2012; 431:209-20. · 3.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Here, we aim to develop an efficient material by eco-friendly green synthetic route that was further characterized to be crystalline ranging in nano-dimension for filtering high arsenic content groundwater. The thermal stability of iron(III)–cerium(IV) mixed oxide nanoparticle agglomerates (NICMO) was well established from the consistent particle size at different temperature and also from differential thermal analysis. The bimetal mixed oxide contained agglomerated crystalline nano-particles of dimension 10–20 nm held together by crystal packing forces, and its corresponding empirical composition was FeCe1.1O7.6. Appearance of a weak band at 534 cm−1 in the spectrum of nano-structured iron(III)–cerium(IV) mixed oxide (NICMO) is presumed for the presence of hetero-metal bonding via oxygen linkage (i.e., Fe–O–Ce). Equilibrium sorption data described Langmuir and D-R isotherm equations fairly well particularly for As(III) with relatively high monolayer sorption capacity [55.513 mg g−1 for As(V), 86.293 mg g−1 for As(III)] in the absence of any foreign ions. Chemo-sorption is the actual nature of the reaction taking place in As(III) with the sorption process getting more favorable with the increase of temperature in contrast to As(V) in which the degree of interaction suggested physiosorption type reactions. Splitting of band in FTIR spectrum of As(V) suggested the dominance of mono protonated monodentate complex [S-OAsO2(OH)] on the oxide surface. As(III) sorption mechanism taking place over NICMO surface under sufficient time lag confirmed oxidation of surface adsorbed As(III) to As(V) in a thermodynamically controlled sorption reaction.
    Chemical Engineering Journal 07/2013; 228:665–678. · 4.06 Impact Factor

Full-text (2 Sources)

Available from
May 19, 2014