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Article

Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona

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Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
*
Author to whom correspondence should be addressed.
Academic Editors: Monika Wawrzkiewicz and Anna Wołowicz
Processes 2021, 9(7), 1238; https://doi.org/10.3390/pr9071238
Received: 15 June 2021 / Revised: 12 July 2021 / Accepted: 13 July 2021 / Published: 17 July 2021
(This article belongs to the Special Issue Various Adsorbents for Water Purification Processes, Volume II)
Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites. View Full-Text
Keywords: clinoptilolites; acid modification; heavy metals; toxic substances; purification; lead removal clinoptilolites; acid modification; heavy metals; toxic substances; purification; lead removal
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MDPI and ACS Style

Huntley, G.M.; Luck, R.L.; Mullins, M.E.; Newberry, N.K. Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona. Processes 2021, 9, 1238. https://doi.org/10.3390/pr9071238

AMA Style

Huntley GM, Luck RL, Mullins ME, Newberry NK. Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona. Processes. 2021; 9(7):1238. https://doi.org/10.3390/pr9071238

Chicago/Turabian Style

Huntley, Garven M., Rudy L. Luck, Michael E. Mullins, and Nick K. Newberry 2021. "Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona" Processes 9, no. 7: 1238. https://doi.org/10.3390/pr9071238

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