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Mimetite precipitation on Pb-clinoptilolite: an effective approach for arsenate removal from water Cover

Mimetite precipitation on Pb-clinoptilolite: an effective approach for arsenate removal from water

Mineralogia
Volume 56 (2025): Issue 1 (January 2025)
By: Ewa Stępień,  Maciej Manecki and  Tomasz Bajda  
Open Access
|Jul 2025

Figures & Tables

Figure 1.

(A) Sorption of Pb(II) by clinoptilolite as a function of the initial Pb(II) concentration in solution. (B) Sorption isotherm of Pb(II) on clinoptilolite, illustrating the relationship between equilibrium Pb(II) concentration and the amount sorbed.
(A) Sorption of Pb(II) by clinoptilolite as a function of the initial Pb(II) concentration in solution. (B) Sorption isotherm of Pb(II) on clinoptilolite, illustrating the relationship between equilibrium Pb(II) concentration and the amount sorbed.

Figure 2.

XPRD patterns of: (A) Natural zeolite (clinoptilolite) enriched in admixtures of orthoclase (O), illite (I), and quartz (Q), (B) Clinoptilolite after modification through sorption of Pb(II) and (C) Precipitate resulting from reaction of Pb-modified zeolite with AsO43− aqueous solution at pH 7 (50 mg As/L). XPRD, X-ray powder diffraction.
XPRD patterns of: (A) Natural zeolite (clinoptilolite) enriched in admixtures of orthoclase (O), illite (I), and quartz (Q), (B) Clinoptilolite after modification through sorption of Pb(II) and (C) Precipitate resulting from reaction of Pb-modified zeolite with AsO43− aqueous solution at pH 7 (50 mg As/L). XPRD, X-ray powder diffraction.

Figure 3.

SEM images in BSE mode display the morphology of Pb-modified clinoptilolite and mimetite precipitates. (A) Pb-modified clinoptilolite, before reaction with an arsenate solution, exhibited a granular surface structure. (B) After reaction with an arsenate solution (50 mg As/L; pH 7) containing Cl− ions (20 mg Cl−/L), mimetite (Pb5(AsO4)3Cl) precipitated. (C) Lead chloro-arsenate formed as needle-like crystals distributed across the surface of the Pb—modified zeolite. (D) These needles developed as incrustations enveloping the grains of the primary Pb-clinoptilolite. (E) The mimetite needles reached lengths of approximately 2.5 μm, exhibiting characteristic hexagonal cross-sections. BSE, backscattered electron; SEM, scanning electron microscopy.
SEM images in BSE mode display the morphology of Pb-modified clinoptilolite and mimetite precipitates. (A) Pb-modified clinoptilolite, before reaction with an arsenate solution, exhibited a granular surface structure. (B) After reaction with an arsenate solution (50 mg As/L; pH 7) containing Cl− ions (20 mg Cl−/L), mimetite (Pb5(AsO4)3Cl) precipitated. (C) Lead chloro-arsenate formed as needle-like crystals distributed across the surface of the Pb—modified zeolite. (D) These needles developed as incrustations enveloping the grains of the primary Pb-clinoptilolite. (E) The mimetite needles reached lengths of approximately 2.5 μm, exhibiting characteristic hexagonal cross-sections. BSE, backscattered electron; SEM, scanning electron microscopy.

Final concentrations of arsenic (As) and lead (Pb), along with arsenic removal efficiency, after a 7-day reaction between Pb-zeolite and As solution in the presence of chloride ions (20 mg/L)

Arsenic Removal Experiment
Initial pHEquilibrium pHInitial [As] = 50 mg/L
Final [As] mg/LRemoval rate %Final [Pb] mg/L
2.02.812.5874.8420.00
7.06.30.0799.88<0.02

Results of Pb(II) sorption by natural clinoptilolite

Initial assumed concentration [mg Pb/L]Initial measured concentration [mg Pb/L]Equilibrium concentration [mg Pb/L]Difference between initial and equilibrium concentrationAmount of Pb [mg] sorbed by 0.8 g of zeoliteAmount of Pb [mg] per 1 kg of zeolitePb Removal [%]
100.092.01.690.43.64520.098.3
500.0473.4<0.5472.918.923,645.099.9
1000.0966.07.4958.638.347,930.099.2
2000.01948.0355.01593.063.779,650.081.8
4000.03926.02212.01714.068.685,700.043.7
DOI: https://doi.org/10.2478/mipo-2025-0006 | Journal eISSN: 1899-8526 | Journal ISSN: 1899-8291
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Language: English
Page range: 44 - 51
Submitted on: Apr 25, 2025
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Accepted on: Jun 19, 2025
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Published on: Jul 23, 2025
Published by: Mineralogical Society of Poland
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
Arsenic,
Lead apatite,
Zeolite,
Water remediation,
Sorption
Related subjects:
Geosciences,
Geophysics,
Geosciences, other

© 2025 Ewa Stępień, Maciej Manecki, Tomasz Bajda, published by Mineralogical Society of Poland
This work is licensed under the Creative Commons Attribution 4.0 License.

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