Interaction of gypsum with lead in aqueous solutions

Astilleros, José Manuel; Γοδελίτσας, Α.; Rodríguez-Blanco, Juan Diego; Fernández-Dı́az, Lurdes; Prieto, M.; Lagoyannis, A.; Harissopulos, S.

doi:10.1016/j.apgeochem.2010.04.007

Cited by 30 publications

(27 citation statements)

References 23 publications

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“…Among sedimentary rock-forming minerals, calcium sulfates, and more specifically gypsum (CaSO 4 Á2H 2 O) and anhydrite (CaSO 4 ), emerge as potentially useful minerals to take up, via dissolutionprecipitation mechanisms, dissolved metals. Indeed, Astilleros et al (2010), investigating the uptake of Pb by gypsum (K sp =10 À4.48 ), concluded that this mineral has a remarkable capac-ity to remove Pb (aq) from highly contaminated aqueous solutions via the formation of the solid phase anglesite (PbSO 4 ). A close inspec-tion of the gypsum surfaces evidenced that anglesite crystals are located in a random orientation with respect to the gypsum sub-strate.…”

Section: Introductionmentioning

confidence: 99%

Uptake of dissolved lead by anhydrite surfaces

Morales¹,

Astilleros²,

Jiménez³

et al. 2014

Applied Geochemistry

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The fate of harmful metals in the Earth crust is importantly affected by sorption processes on mineral surfaces. Here, a study of the ability of anhydrite surfaces to uptake dissolved Pb is presented. Experiments were conducted at room temperature using initial Pb concentration ([Pb aq ] 0) ranging between 10 and 1000 mg/L and a batch type setup. Inductively coupled plasma optical emission spectrometry analyses showed that [Pb aq ] progressively decreased as the time of interaction increased, to reach a final steady state value of $3.0 mg/L, irrespectively of [Pb aq ] 0. However, the time elapsed before the steady state value was reached strongly depended on [Pb aq ] 0 , with the drop to this final value occurring in less than 1 day interaction when [Pb aq ] 0 ≥ 50 mg/L and after 20 days when [Pb aq ] 0 < 50 mg/L. Scanning Electron Microscopy and X-ray diffraction analyses confirmed the epitactic growth of anglesite (PbSO 4) crystals on anhydrite surfaces when [Pb aq ] 0 ≥ 50 mg/L. X-ray Absorption Near Edge Structure spectroscopy points to a different sorption mechanisms when [Pb aq ] 0 < 50 mg/L. The results show that the epitactic growth of anglesite on anhydrite has no significant impact on the ability of anhydrite surfaces to remove Pb aq , which show equal effectiveness as that of gypsum surfaces. The high reactivity of anhydrite surfaces renders this phase potentially important in the control of the fate of dissolved metals in nature.

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Section: Introductionmentioning

confidence: 99%

Uptake of dissolved lead by anhydrite surfaces

Morales¹,

Astilleros²,

Jiménez³

et al. 2014

Applied Geochemistry

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“…The presence of background electrolytes has also been shown to affect the growth features of gypsum {010} surfaces . Coupled dissolution-crystallization reactions starting with gypsum as the parent solid were observed by Astilleros et al (2007), who investigated the interaction between gypsum and Pb-bearing aqueous solutions. Combining macroscopic experiments and in situ AFM observations, these authors showed that the dissolution of gypsum is accompanied by the precipitation of anglesite * E-mail: eruiz_01@uni-muenster.de (PbSO 4 ), and that gypsum may represent an efficient tool for the sequestration of Pb.…”

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confidence: 99%

AFM study of the epitaxial growth of brushite (CaHPO4{middle dot}2H2O) on gypsum cleavage surfaces

Pinto

Ruíz-Agudo

Putnis

et al. 2010

American Mineralogist

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The epitaxial overgrowth of brushite (CaHPO 4 ·2H 2 O) by the interaction of phosphate-bearing, slightly acidic, aqueous solutions with gypsum (CaSO 4 ·2H 2 O) was investigated in situ using atomic force microscopy (AFM). Brushite growth nuclei were not observed to form on the {010} gypsum cleavage surface, but instead formed in areas of high dissolution, laterally attached to gypsum [101] step edges. During the brushite overgrowth the structural relationships between brushite (Aa) and gypsum (A2/a) result in several phenomena, including the development of induced twofold twining, habit polarity, and topographic effects due to coalescence of like-oriented crystals. The observed brushite growth is markedly anisotropic, with the growth rate along the main periodic bond chains (PBCs) in the brushite structure increasing in the order [101] > [101] > [010], leading to tabular forms elongated on [101]. Such a growth habit may result from the stabilization of the polar [101] direction of brushite due to changes in hydration of calcium ions induced by the presence of sulfate in solution, which is consistent with the stabilization of the gypsum [101] steps during dissolution in the presence of HPO 2-4ions. The coupling between growth and dissolution was found to result in growth rate fluctuations controlled by the changes in the solution composition.

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“…The initial pH value of 4.5 for solution containing 6000ppm of Pb 2+ increased slightly during the first interaction time, and reached a constant value of 5.6. This may be due to the formation of anglesite (PbSO4), and the release of Ca 2+ which is more basic than Pb 2+ , as previously found by Astilleros et al (2010) [12].…”

Section: Adsorption Isothermsmentioning

confidence: 68%

Lead and Cadmium Removal from Aqueous Solution Using an Industrial Gypsum By-product

Raii¹,

Minh²,

Sanz³

et al. 2014

Procedia Engineering

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The valorization of gypsum (by-product of phosphoric acid production) into useful product seems to be of important interest. In this study, the adsorption of lead (II) and cadmium (II) in an aqueous solution using both commercial gypsum (CG) and industrial gypsum byproduct (IG) as adsorbents, has been investigated. The use of highly-purity CG allows the understanding of the adsorption phenomenon. The use of an IG as received from an industrial site allows the evaluation of its reactivity compared to pure CG. The adsorption experiments were carried out at ambient conditions for 24 h and the pH was recorded along the reaction. FTIR analyses were performed in order to examine the modification in the sulfate bound arrangement in the case of use of lead and/or cadmium. The obtained results have shown that the retention capacity of lead (II) and cadmium (II) by IG was similar that those obtained in the case of CG. However, gypsum by-product may be used as an alternative material to remove heavy metals in wastewaters.

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Interaction of gypsum with lead in aqueous solutions

Cited by 30 publications

References 23 publications

Uptake of dissolved lead by anhydrite surfaces

Uptake of dissolved lead by anhydrite surfaces

AFM study of the epitaxial growth of brushite (CaHPO4{middle dot}2H2O) on gypsum cleavage surfaces

Lead and Cadmium Removal from Aqueous Solution Using an Industrial Gypsum By-product

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