Heavy metal adsorption by humic umbrisols: selectivity sequences and competitive sorption kinetics

Covelo, Emma F.; Andrade, Liliana María; Vega, F.A.

doi:10.1016/j.jcis.2004.07.024

Cited by 154 publications

(68 citation statements)

References 56 publications

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“…Values of relative concentration much higher than 1 were obtained for this assay, with more expression in the first 5 h before the breakthrough point of the other metals (Figure 1). The Zn cations can be easily exchanged when competing with other metal cations (Covelo et al, 2004). Therefore, it can be assumed that a fraction of the highly concentrated native Zn (Table 1) was washed out from the column, increasing its concentration in the effluent, especially before the saturation of the exchangeable surfaces.…”

Section: Flow Experimentsmentioning

confidence: 99%

Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil: A comparative study

et al. 2011

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Interest in soil contamination has been growing in recent years due to the ongoing degradation of soil environments. Therefore, the development of remediation techniques and the study of contaminant sorption and migration are areas of intense research. In this study, the authors sought to evaluate the scenario of co-contamination of a loamy sand soil by multiple heavy metals. To that end, the sorption and transport of five metals-Cr, Pb, Cd, Cu and Zn-was evaluated using representative samples of a soil from the north of Portugal. The tests were conducted in batch and continuous systems using single-and multiple-metal acid solutions to evaluate the effect of metal competition. In accordance with the type of assay-batch or continuous-Langmuir or Convection Dispersion Two-Site Nonequilibrium models were adjusted to explain the sorption/transport data. FTIR analyses were performed on the final samples of the continuous systems. Generally, the results revealed good fitting of the tested models for the metals in competitive and noncompetitive scenarios, with the exception of Zn that was originally present in soil samples at higher concentrations. As expected, the influence of competition was observed in both batch and continuous systems, but with different tendencies. The FTIR spectra also revealed a strong influence of clay minerals and organic matter on the sorption of the metals.

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Section: Flow Experimentsmentioning

confidence: 99%

Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil: A comparative study

et al. 2011

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“…Covelo et al (2004) reported that Cr sorption by humic substances is more rapid than that of Cu, Cd, Ni, or Zn. Therefore, Cr(III) reduced from Cr(VI) is likely to bind to humic substances in a first-order reaction before precipitating as Cr(OH) 3 ·nH 2 O or adsorbing onto minerals, as Peterson et al (1997), Kappen et al (2008), and Elzinga and Cirmo (2010) have reported.…”

Section: Introductionmentioning

confidence: 99%

Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

et al. 2012

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“…In ALVv, the sorption process was biphasic, a phenomenon attributable to sorption to sites of variable reactive and/or diffusion limited sorption (Covelo et al, 2004). The shape of the curve was linear, suggesting that the sorption process increased with time.…”

Section: Sorption Kineticsmentioning

confidence: 98%

“…With the current awareness of heavy metals as very toxic contaminants there have been many studies considering adsorption by solid surfaces as the most important mechanism for controlling metal content in soil solution and natural waters (Echeverria, Morera, Mazkiaran, & Garido, 1998;Bradl, 2004;Appel, Ma, Rhue, & Reve 2008;Javaid, Bajwa, Shafique, & Anwar, 2011). The most important chemical processes affecting the behavior and bioavailability of heavy metals in soils are those concerned with sorption mechanisms of metals from liquid phase onto solid phase (Rybicka, Calmano, & Breeger, 1995;Covelo, Andrade, & Vega, 2004). Moreover, clay minerals and to a lesser extent organic matter have been identified as among the major soil constituents that interact with almost all soil contaminants especially positively charged metallic species.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Heavy Metals by Ferralic-Arenosol and Vertic-Luvisol: A Comparative Isothermal Study

Mosekiemang¹,

Dikinya²,

Toteng³

2014

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Modeling of sorption data is essential for characterizing retention of heavy metals by the soil matrices as well as to predict the fate of heavy metals in the environment. We carried out a study to evaluate adsorption characteristics of metallic ions (Cr 3+ , Pb 2+ and Cu 2+ ) as sole sorbates as well as in coexistence onto clay extracts of Vertic-Luvisol and Ferralic-Arenosol, the generally under-researched yet wide-spread semi-arid soils. Additionally, sorption kinetics of these heavy metals was evaluated in these soils. Equilibrium sorption data for both non-competitive and competitive metal systems were found to obey the Langmuir isotherm. Overall metal loading capacity was higher in Vertic-Luvisol than Ferralic-Arenosol whereas metal-wise affinity to binding sites favoured sorption of Cr 3+ over Pb 2+ and Cu 2+ in that order. Contrary to the hypothesis of this study, the preferential sorption process was found to be driven by cationic properties as opposed to soil properties. Adsorption of metallic ions onto soils was significantly reduced in competitive systems than non-competitive systems, a phenomenon attributable to the antagonistic effects of coexisting species. Cr 3+ suppressed sorption of Pb 2+ and Cu 2+ on both soils as validated by the competitive adsorption capacity ratios which were < 1 in all instances where Cr 3+ coexisted with either one of Pb 2+ or Cu 2+ . The adsorption kinetics of metal ions in both soils followed the pseudo-second-order rate law, suggesting chemical sorption as the rate-limiting step of the adsorption process.

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Heavy metal adsorption by humic umbrisols: selectivity sequences and competitive sorption kinetics

Cited by 154 publications

References 56 publications

Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil: A comparative study

Mobility of Cr, Pb, Cd, Cu and Zn in a loamy sand soil: A comparative study

Speciation study of Cr(VI/III) reacting with humic substances and determination of local structure of Cr binding humic substances using XAFS spectroscopy

Sorption of Heavy Metals by Ferralic-Arenosol and Vertic-Luvisol: A Comparative Isothermal Study

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