Kinetics and equilibrium parameters of Hg(II) adsorption on silica–dithizone

Cestari, Antonio R.; Vieira, Eunice F.S.; Lopes, Elaine C.N.; Silva, Roberto G da

doi:10.1016/j.jcis.2003.09.019

Cited by 60 publications

(18 citation statements)

References 34 publications

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“…2 poorly fitted to the actual experimental q t values. This divergence has been also observed in other Hg(II) adsorption studies (Cestari et al 2004;Tang et al 2012) and suggests that the sorption of Hg(II) onto RM does not follow a first-order kinetics. Furthermore, when the sorption does not follow pseudo-first-order kinetics, generally, two relevant differences are observed: (i) k 1 (q e -q t ) does not represent the number of available sites and (ii) ln q e is not equal to the intercept of the ln (q e -q t ) vs t plots, as it was the case.…”

Section: Sorption Kineticssupporting

confidence: 76%

“…As can be seen in Table 2, amongst these models, only the pseudo-second order, and to a lesser extent the Lagergren's model, adequately fits to the sorption kinetic data. Several researches have observed a good fit of the Hg(II) sorption kinetic data to the linear Lagergren equation and a decrease in the pseudo-first rate constant k 1 with increases in the initial Hg(II) concentration (Cestari et al 2004;Sahetya et al 2015;Yardim et al 2003;Zhang et al 2005). In the case of the Hg(II)-RM system, k 1 decreased as the initial Hg(II) concentration increased (Table 2), which could be indicative of the progressive saturation of available sorption sites.…”

Section: Sorption Kineticsmentioning

confidence: 92%

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Use of red mud (bauxite residue) for the retention of aqueous inorganic mercury(II)

Rubinos

Barral

2015

Environ Sci Pollut Res

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The effectiveness of the oxide-rich residue from bauxite refining (red mud) to remove inorganic Hg(II) from aqueous solutions was assessed. The aspects studied comprised the kinetics of the process (t = 1 min-24 h), the effect of pH (3.5-11.5), the interacting effect between salt concentration (0.01-1 M NaNO3) and pH and the Hg(II) sorption isotherm. Hg leaching from spent red mud was evaluated using the toxicity characteristics leaching procedure (TCLP) method. The sorption of Hg(II) onto red mud was very fast, with most of Hg(II) (97.0-99.7%) being removed from 0.5-50 μM Hg solutions in few minutes. The kinetic process was best described by Ho's pseudo-second order equation, pointing to chemisorption as the rate controlling step. Hg(II) sorption efficiency was very high (% removal between 93.9 and 99.8%) within all the studied pH range (3.5-11.5) and added Hg concentrations (5 and 50 μM), being optimal at pH 5-8 and decreasing slightly at both lowest and highest pH. The effect of background electrolyte concentration suggests specific sorption as the main interaction mechanism between Hg(II) and red mud, but the increasing non-sorbed Hg concentrations at low and high pH for higher electrolyte concentrations also revealed the contribution of an electrostatic component to the process. The sorption isotherm showed the characteristic shape of high affinity sorbents, and it was better described by the Redlich-Peterson and Freundlich equations, which are models that assume sorbent heterogeneity and involvement of more than one mechanism. The estimated Hg(II) sorption capacity from the Langmuir equation (q m ~9 mmol/kg) was comparable to those of some inorganic commercial sorbents but lower than most bio- or specifically designed sorbents. The leachability of retained Hg(II) from spent red mud (0.02, 0.25 and 2.42 mmol Hg/kg sorbed concentration) was low (0.28, 1.15 and 2.23 μmol/kg, respectively) and accounted for 1.2, 0.5 and 0.1% of previously sorbed Hg, indicating that Hg(II) is tightly bound by red mud once sorbed.

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Section: Sorption Kineticssupporting

confidence: 76%

Section: Sorption Kineticsmentioning

confidence: 92%

Use of red mud (bauxite residue) for the retention of aqueous inorganic mercury(II)

Rubinos

Barral

2015

Environ Sci Pollut Res

View full text Add to dashboard Cite

show abstract

“…The maximum adsorption capacity (q m ) for the adsorption of Hg 2+ on thiol-SNHS calculated from the Sips isotherm model is listed in Table 3 with literature values of q m of other adsorbents for Hg 2+ adsorption [27][28][29][30][31]. All of the adsorbents were used for Hg 2+ have considerably lower q m values than thiol-SNHS used in this study.…”

Section: Adsorption Isothermsmentioning

confidence: 99%

Synthesis and characterization of thiol-functionalized silica nano hollow sphere as a novel adsorbent for removal of poisonous heavy metal ions from water: Kinetics, isotherms and error analysis

Rostamian

Najafi

Rafati

2011

Chemical Engineering Journal

194

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“…In this way, an alternative fractionary kinetic equation proposed by Avrami [31,32] was described previously [31,32]. The adsorption should be visualized now using Avrami's exponential function, which is an adaptation of kinetic thermal decomposition modeling [31,32].…”

Section: Kinetic Studiesmentioning

confidence: 99%

Pecan nutshell as biosorbent to remove Cu(II), Mn(II) and Pb(II) from aqueous solutions

Vaghetti

Lima

Royer

et al. 2009

Journal of Hazardous Materials

230

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Kinetics and equilibrium parameters of Hg(II) adsorption on silica–dithizone

Cited by 60 publications

References 34 publications

Use of red mud (bauxite residue) for the retention of aqueous inorganic mercury(II)

Use of red mud (bauxite residue) for the retention of aqueous inorganic mercury(II)

Synthesis and characterization of thiol-functionalized silica nano hollow sphere as a novel adsorbent for removal of poisonous heavy metal ions from water: Kinetics, isotherms and error analysis

Pecan nutshell as biosorbent to remove Cu(II), Mn(II) and Pb(II) from aqueous solutions

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