Microscopic single particle characterization of zeolites synthesized in a soil polluted by copper or cadmium and treated with coal fly ash

Terzano, Roberto; Spagnuolo, Matteo; Medici, Luca; Dorrine, W.; Janssens, Koen; Ruggiero, P.

doi:10.1016/j.clay.2006.07.005

Cited by 25 publications

(14 citation statements)

References 29 publications

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“…However, the previous studies dealing with the removal of heavy metals by ZFA have been performed by using only one or two ZFAs [4][5][6][7][8][9][10][11][12][13][14]. Therefore, it is difficult to explore the relative importance of different components of ZFA in heavy metal retention by relating the heavy metal removal performance of the ZFAs to their chemical composition and properties.…”

Section: Introductionmentioning

confidence: 93%

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Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash

Sui

Zhang

et al. 2008

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 93%

“…However, a large proportion of fly ash is impounded or landfilled. In recent years, the hydrothermal synthesis of zeolite has been intensively investigated as an alternative for the productive reuse of coal fly ash [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and other inorganic materials [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash

Sui

Zhang

et al. 2008

Journal of Colloid and Interface Science

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“…Phosphate systems are of particular interest due to the importance of P cycles and the low solubilities of many metal-phosphate phases. Reduction of Fe(III)-oxides by iron-reducing bacteria releases Fe(II) to solution and can lead to the precipitation of vivianite (Fe 3 (PO 4 ) 2 Á8H 2 O), which is a major sink for Fe and for heavy metals in fresh water sedimentary systems (Taylor and Boult, 2007); anthropogenic contamination of groundwater and soil systems can lead to precipitation (or co-precipitation) of heavy metals as oxides and phosphate phases in these systems (e.g., Kirpichtchikova et al, 2006;Manceau et al, 2007;Terzano et al, 2007); and remediation strategies such as phosphate amendments rely on precipitation reactions in bacteria-bearing systems to reduce concentrations of dissolved metals in systems, such as those contaminated with dissolved U (e.g., Beazley et al, 2007;Martinez et al, 2007;Wellman et al, 2007;Ndiba et al, 2008) or by acid mine drainage (e.g., Schultze-Lam et al, 1996). The common denominator between all of these systems is the precipitation of phosphate and other mineral phases in environments that can be rich in non-metabolizing bacterial cells and/or bacterial exudates.…”

Section: Introductionmentioning

confidence: 99%

The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Dunham‐Cheatham

Xue

Bunker

et al. 2011

Geochimica et Cosmochimica Acta

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In this study, we test the potential for passive cell wall biomineralization by determining the effects of non-metabolizing bacteria on the precipitation of uranyl, lead, and calcium phosphates from a range of over-saturated conditions. Experiments were performed using Gram-positive Bacillus subtilis and Gram-negative Shewanella oneidensis MR-1. After equilibration, the aqueous phases were sampled and the remaining metal and P concentrations were analyzed using inductively coupled plasmaoptical emission spectroscopy (ICP-OES); the solid phases were collected and analyzed using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS).At the lower degrees of over-saturation studied, bacterial cells exerted no discernable effect on the mode of precipitation of the metal phosphates, with homogeneous precipitation occurring exclusively. However, at higher saturation states in the U system, we observed heterogeneous mineralization and extensive nucleation of hydrogen uranyl phosphate (HUP) mineralization throughout the fabric of the bacterial cell walls. This mineral nucleation effect was observed in both B. subtilis and S. oneidensis cells. In both cases, the biogenic mineral precipitates formed under the higher saturation state conditions were significantly smaller than those that formed in the abiotic controls.The cell wall nucleation effects that occurred in some of the U systems were not observed under any of the saturation state conditions studied in the Pb or Ca systems. The presence of B. subtilis significantly decreased the extent of precipitation in the U system, but had little effect in the Pb and Ca systems. At least part of this effect is due to higher solubility of the nanoscale HUP precipitate relative to macroscopic HUP. This study documents several effects of non-metabolizing bacterial cells on the nature and extent of metal phosphate precipitation. Each of these effects likely contributes to higher metal mobilities in geologic media, but the effects are not universal, and occur only with some elements and only under a subset of the conditions studied.

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“…The adsorption of lead ion based either on an ionic exchange between heavy metal Pb(II) and cations, such as sodium and potassium (in the structural sites of the zeolite) (Mondales et al 1995;Castaldi et al 2005) or on the precipitation of metal hydroxides over the zeolite external surfaces (Oste et al 2002;Terzano et al 2007) The ion exchange process in zeolites is influenced by several factors such as concentration and nature of cations and anions, pH value and crystal structure of the zeolite (Ahmet et al 2007). The adsorption Pb(II) in the zeolite was lower with respect to CEC.…”

Section: Discussionmentioning

confidence: 99%

Lead Removal from Aqueous Solution by Natural and Pretreated Zeolites

2011

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Hazardous metal cations enter water through the natural geochemical route or from the industrial wastes. Their separation and removal can be achieved by adsorptive accumulation of the cations on a suitable adsorbent. In the present work, toxic Pb(II) ions are removed from water by accumulating it on the surface of natural zeolite in three different forms; one untreated and two treated samples, one sample treated with 2 M HCI solution and other is treated with 3 M NaOH solution. Natural zeolite is mainly composed of clinoptilolite, and mordenite, with amount of nonzeolite phase (smectite and illite) and C and CT opal. The adsorption experiments are carried out using a batch process in environments of different pH, initial Pb(II) concentration, interaction time and amount of zeolites. Treated zeolite samples show high exchange capacity for Pb(II) compared to untreated sample, however, acid-treated sample shows an exceedingly good exchange capacity. Equilibrium data fitted well with the Langmuir isotherm model with maximum adsorption capacity of 115, 126, and 132 mg g -1 of untreated natural zeolites, alkali-treated zeolites and acid-treated zeolites respectively. The rates of adsorption were found to confirm to pseudo-first order kinetic with good correlation and the overall rate of lead ions uptake.

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Microscopic single particle characterization of zeolites synthesized in a soil polluted by copper or cadmium and treated with coal fly ash

Cited by 25 publications

References 29 publications

Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash

Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash

The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Lead Removal from Aqueous Solution by Natural and Pretreated Zeolites

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