Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona
| Autor: | Michael E. Mullins, Garven M. Huntley, Rudy L. Luck, Nick K. Newberry |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
analytical_chemistry
purification Potassium Sodium chemistry.chemical_element Bioengineering Hydrochloric acid 02 engineering and technology TP1-1185 010501 environmental sciences 01 natural sciences law.invention clinoptilolites chemistry.chemical_compound law Chemical Engineering (miscellaneous) Calcination Zeolite heavy metals QD1-999 0105 earth and related environmental sciences acid modification Clinoptilolite Magnesium Process Chemistry and Technology toxic substances Chemical technology 021001 nanoscience & nanotechnology Chemistry chemistry lead removal 0210 nano-technology Nuclear chemistry BET theory |
| Zdroj: | Processes, Vol 9, Iss 1238, p 1238 (2021) Processes Volume 9 Issue 7 |
| ISSN: | 2227-9717 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|