Lead Immobilization from Aqueous Solutions and Contaminated Soils Using Phosphate Rocks

Qu, Ying; Logan, Terry J.; Traina, Samuel J.

doi:10.1021/es00004a034

Cited by 473 publications

(307 citation statements)

References 15 publications

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“…The lower peaks in the control soil suggested there were some amounts of lead phosphate and lead hydroxyapatite-like minerals existing in the unamended soil; the addition of bone char enriched the formation of these compounds in the soil. Similarly, Ma et al (1995) and Laperche et al (1997) observed a peak at 2.96 Å upon P addition to a Pb-contaminated soil. Thermodynamic considerations predict that Pb phosphate minerals are the most stable among Pb compounds (Laperche et al, 1996;Seaman et al, 2003).…”

Section: X-ray Diffractionmentioning

confidence: 88%

“…Changes in organic forms may indicate Pb immobilization by the charcoal fraction of bone char. Since the major components in bone char are hydroxyapatite and CaCO 3 , hydroxyapatite is not just a source for adsorption but also enables ion-exchange to occur (Ma et al, 1995), so the chemisorption by hydroxyapatite and ion-exchange may be a dominant mechanism for the transformation of Pb from non-residual forms to residual fractions, because these adsorption processes could be essentially irreversible. The most effective amendments for transforming the non-residual forms of Pb to the residual forms were found to be in the E-4 and C-4 treatments in this study.…”

Section: Treatmentsmentioning

confidence: 99%

“…It has recently been suggested that poorly crystalline apatite, such as bone char apatite, might represent a low-cost, readily available phosphate source that could be used to remediate metal-contaminated soils without causing excessive P runoff (Ma et al, 1995;Ma and Rao, 1997). Bone char is a mixed compound adsorbent in which carbon is distributed throughout a porous structure of hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 or CaHAP).…”

Section: Introductionmentioning

confidence: 99%

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Effect of bone char application on Pb bioavailability in a Pb-contaminated soil

Chen

Zhu

et al. 2006

Environmental Pollution

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Bone char amendments show potential for remediation of Pb-contaminated soils. AbstractThe effects of bone char (BC) application on the bioavailability of Pb in a polluted soil from Hunan Province, China were examined. The Pb-contaminated soil was treated with two types of bone char, one from the UK and the other from China. The bioavailability of Pb was determined in terms of the uptake by Chinese cabbage (Brassica chinensis L.), sequential extraction and X-ray diffraction analysis. The results indicate that the Pb concentrations in both shoots and roots decreased with increasing quantities of added bone char, and the application of BC from the UK at the rate of 1.6% (w:w) had the largest effect. Lead Pb concentrations in the shoots and roots decreased by 56.0% and 75.9%, respectively, whereas the application of BC from Zhejiang Province, China at the rate of 1.6% (w:w) reduced Pb concentrations in the shoots and roots to 2.04 mg kg ÿ1 and 8.42 mg kg ÿ1 , respectively, only 45.8% and 30.2% compared to the control treatment. Sequential extraction results indicate that the addition of bone char, as a metal-immobilizing agent, substantially transforms soil Pb from non-residual fractions to the residual fraction. The transformation was further confirmed using X-ray diffraction studies.

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Section: X-ray Diffractionmentioning

confidence: 88%

Section: Treatmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of bone char application on Pb bioavailability in a Pb-contaminated soil

Chen

Zhu

et al. 2006

Environmental Pollution

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“…Significant effort has been made to evaluate the effec tiveness of phosphate on in situ remediation of contam inated waters and soils (Basta et al, 2001;Cotter-Howells and Caporn, 1996;Hettiarachchi et al, 2000;Ma et al, 1995;Yang et al, 2001). Phosphate minerals, i.e.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of lead, copper, and zinc retention by phosphate rock

Cao

2004

Environmental Pollution

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''Capsule'': Phosphate-induced formation of fluoropyromorphite is primarily responsible for Pb immobilization by phosphate rock, whereas Cu and Zn retention is mainly attributable to the surface adsorption or complexation. AbstractThe solideliquid interface reaction between phosphate rock (PR) and metals (Pb, Cu, and Zn) was studied. Phosphate rock has the highest affinity for Pb, followed by Cu and Zn, with sorption capacities of 138, 114, and 83.2 mmol/kg PR, respectively. In the PbeCueZn ternary system, competitive metal sorption occurred with sorption capacity reduction of 15.2%, 48.3%, and 75.6% for Pb, Cu, and Zn, respectively compared to the mono-metal systems. A fractional factorial design showed the interfering effect in the order of Pb O Cu O Zn. Desorption of Cu and Zn was sensitive to pH change, increasing with pH decline, whereas Pb desorption was decreased with a strongly acidic TCLP extracting solution (pH ¼ 2:93). The greatest stability of Pb retention by PR can be attributed to the formation of insoluble fluoropyromorphite [Pb 10 (PO 4 ) 6 F 2 ], which was primarily responsible for Pb immobilization (up to 78.3%), with less contribution from the surface adsorption or complexation (21.7%), compared to 74.5% for Cu and 95.7% for Zn. Solution pH reduction during metal retention and flow calorimetry analysis both supported the hypothesis of retention of Pb, Cu, and Zn by surface adsorption or complexation. Flow calorimetry indicated that Pb and Cu adsorption onto PR was exothermic, while Zn sorption was endothermic. Our research demonstrated that PR can effectively remove Pb from solutions, even in the presence of other heavy metals (e.g. Cu, Zn).

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“…Equilibria in water and soil solutions are mainly controlled by sorption/desorption and crystallization/dissolution processes. Therefore a promising way of eliminating mobile metals from soils is to convert them into stable metal phosphates by addition of soluble or insoluble phosphates (Levi Minzi & Petruzzelli 1984, Ma et al 1993, Ruby et al 1994, Xu & Schwartz 1994, Ma et al 1995, Cotter-Howells 1996, Lambert et al 1997, Zhang et al 1997, Fedoroff et al 1999, Shashkova et al 1999, Manecki et al 2000b, McGowen et al 2001, McGrellis et al 2001, Lusvardi et al 2002, Basta McGowen 2004, Lundager et al 2004, Raicevic et al 2005, Manecki et al 2006, Marchat et al 2007, Matusik et al 2008. This method, which is well known in the literature as in situ phosphate formation has convincing advantages.…”

Section: Introductionmentioning

confidence: 99%

Aqueous cadmium removal by hydroxylapatite and fluoroapatite

Matusik¹,

Bajda²,

Manecki³

2012

geol

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Reducing the bioavailability of toxic heavy metals in groundwaters and urban soils by phosphate addition is an effective technique described in the literature. It is based on the reaction between metal ions and phosphates and results in the precipitation of metal substituted phosphate phases. The formed phosphates are highly insoluble and thermodynamically stable over almost entire pH and Eh range. In the presented study the efficiency and mechanism of cadmium uptake by synthetic hydroxylapatite and natural fluoroapatite was examined within the pH range of 3 7 for different reaction times (2 1440 hours). The solids after reactions were characterized by XRD and SEM-EDS. Percentage reduction of cadmium concentration in the experiments with fluoroapatite and hydroxylapatite, regardless of pH, did not exceed 17% and 25%, respectively. Cadmium uptake from the solution mainly resulted from the formation of cadmium phosphates and/or Ca-Cd phosphate solid solutions on the apatites surface. The release rate of phosphate ions by hydroxylapatite was relatively high. This promoted crystallization of a large number of small crystals. In turn dissolution of fluoroapatite was slower and thus the formation of large crystals was observed. There was no clear evidence for cadmium-calcium ion-exchange mechanism.

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Lead Immobilization from Aqueous Solutions and Contaminated Soils Using Phosphate Rocks

Cited by 473 publications

References 15 publications

Effect of bone char application on Pb bioavailability in a Pb-contaminated soil

Effect of bone char application on Pb bioavailability in a Pb-contaminated soil

Mechanisms of lead, copper, and zinc retention by phosphate rock

Aqueous cadmium removal by hydroxylapatite and fluoroapatite

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