Adsorption of antimony(V) on kaolinite as a function of pH, ionic strength and humic acid

School of Chemistry and Chemical Engineering, Shanxi Datong University, 037009 Datong, China
Environmental earth sciences (Impact Factor: 1.57). 04/2009; 60(4):715-722. DOI: 10.1007/s12665-009-0209-z

ABSTRACT The present work investigated the adsorption and mobility (desorption) of Sb(V) on kaolinite using batch experiments. The
adsorption of Sb(V) on kaolinite was studied as a function of contact time, pH, ionic strength, humic acid (HA), initial Sb(V)
concentration and temperature. Kinetic studies suggest that the equilibrium is achieved within 24h. The adsorption of Sb(V)
was strongly affected by changes in I at low ionic strength and unaffected at high ionic strength. The adsorption is weakly
dependent on the presence of humic acid, but is strongly dependent on pH. Within the range tested, the optimal pH for Sb(V)
adsorption is 3.6, and close to 75% removal can be achieved. Desorption is dependent on the original suspension pH. The addition
sequence of Sb(V)/HA do not influence the adsorption of Sb(V) on kaolinite. The adsorption data fit both the Freundlich and
Langmuir isotherm. The thermodynamic parameters (ΔH
0, ΔS
0 and ΔG
0) were calculated from the temperature dependence, and the results suggest the endothermic and spontaneous nature of the process.


  • [Show abstract] [Hide abstract]
    ABSTRACT: Hematite coated magnetic nanoparticle (MNP@hematite) was fabricated through heterogeneous nucleation technique and used to remove trace Sb(III) from water. Powder X-ray diffraction, transmission electron microscopy (TEM), and alternating gradient magnetometry were utilized to characterize the prepared adsorbent. TEM image showed that MNP@hematite particles were spherical with size of 10-30nm. With saturation magnetization of 27.0emu/g, MNP@hematite particles could be easily separated from water with a simple magnetic process in short time (5min). At initial concentration of 110μg/L, Sb(III) was rapidly decreased to below 5μg/L by MNP@hematite in 10min. Sb(III) adsorption capacity of MNP@hematite was 36.7mg/g, which was almost twice that of commercial Fe3O4 nanoparticles. The removal of trace Sb(III) was not obviously affected by solution pH (over a wide range from 3 to 11), ionic strength (up to 100mM), coexisting anions (chloride, nitrate, sulfate, carbonate, silicate, and phosphate, up to 10mM) and natural organic matters (humic acid and alginate, up to 8mg/L as TOC). Moreover, MNP@hematite particles were able to remove Sb(III) and As(III) simultaneously. Trace Sb(III) could also be effectively removed from real tap water by MNP@hematite. The magnetic adsorbent could be recycled and used repeatedly.
    Journal of hazardous materials 01/2014; 268C:229-236. · 4.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Antimony is detected in soil and water with elevated concentration due to a variety of industrial applications and mining activities. Though antimony is classified as a pollutant of priority interest by the United States Environmental Protection Agency (USEPA) and Europe Union (EU), very little is known about its environmental behavior and adsorption mechanism. In this study, the adsorption behaviors and surface structure of antimony (III/V) on iron oxides were investigated using batch adsorption techniques, surface complexation modeling (SCM), X-ray photon spectroscopy (XPS) and extended X-ray absorption fine structure spectroscopy (EXAFS). The adsorption isotherms and edges indicated that the affinity of Sb(V) and Sb(III) toward the iron oxides depended on the Sb species, solution pH, and the characteristics of iron oxides. Sb(V) adsorption was favored at acidic pH and decreased dramatically with increasing pH, while Sb(III) adsorption was constant over a broad pH range. When pH is higher than 7, Sb(III) adsorption by goethite and hydrous ferric oxide (HFO) was greater than Sb(V). EXAFS analysis indicated that the majority of Sb(III), either adsorbed onto HFO or co-precipitated by FeCl3, was oxidized into Sb(V) probably due to the involvement of O2 in the long duration of sample preservation. Only one Sb-Fe subshell was filtered in the EXAFS spectra of antimony adsorption onto HFO, with the coordination number of 1.0-1.9 attributed to bidentate mononuclear edge-sharing ((2)E) between Sb and HFO.
    Journal of Hazardous Materials 05/2014; 276C:339-345. · 4.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A Sb(III)-imprinted iodole-functionalized organic–inorganic hybrid sorbent was synthesized by combination of surface imprinting technique with sol–gel process for the selective removal of Sb(III) from aqueous media. The material was characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis and nitrogen adsorption–desorption isotherms. Compared to the non-imprinted sorbent, the imprinted hybrid sorbent had higher selectivity and adsorption capacity for Sb(III) ion. The static adsorption capacity of the imprinted and non-imprinted sorbents for Sb(III) was 32.4 and 11.1 mg g−1, respectively. The relative selectivity coefficients of the imprinted hybrid sorbent for Sb(III)/Cr(III) Sb(III)/Fe(III) and Sb(III)/As(III) were 13.2, 10.4 and 11.8, respectively. The imprinted hybrid sorbent possessed fast kinetics for the removal of Sb(III) from aqueous solution with a saturation time of 30 min, had a stable binding capacity in the range of pH 4–6, and could be used repeatedly. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. It could be concluded from the thermodynamic parameters that the adsorption of Sb(III) on the imprinted hybrid sorbents was an exothermic and spontaneous process.
    Chemical Engineering Journal 12/2014; 258:146–156. · 4.06 Impact Factor