Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Wang, Cheng; Cao, Liyun; Huang, Jianfeng

doi:10.1002/sia.6321

Cited by 30 publications

(15 citation statements)

References 17 publications

(27 reference statements)

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“…However, a decrease can be observed in the relative intensity of the reflexions of HCLI with the increase in sulfuric acid concentration from 0.1 to 1 M. These results suggest that the treatment of natural zeolite with H 2 SO 4 caused some structural changes and loss of crystallinity in the clinoptilolite phase. This can be attributed to dealumination of the clinoptilolite as verified by the EDS analyses [29,35]. Wang et al [36] present the reaction mechanism which take place when the clinoptilolite-rich tuffs are in contact with a strong acid media (HNO 3 ).…”

Section: Influence Of Adsorbent Dosage and Effect Of Phmentioning

confidence: 93%

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Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

et al. 2019

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The removal of Pb(II) from aqueous solutions by acid-modified clinoptilolite-rich tuff was investigated in this work. Clinoptilolite-rich tuff samples were treated using H2SO4 at different concentrations. Prior to and following acid treatment, the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). The pH of the point of zero charge (pHPZC) was also determined as part of this characterization. Batch studies were studied to investigate Pb(II) removal as a function of contact time, initial Pb(II) concentration, adsorbent dosage, and solution pH. The results of the XRD and SEM techniques showed that clinoptilolite is the main mineral of the non- and acid-treated natural zeolite samples. However, EDS analysis indicated that the Si/Al ratio increases as the exchangeable ions decrease with increasing acid concentrations. The optimum conditions for Pb(II) removal for samples with 4.37 ≤ Si/Al ≤ 7.9 were found to be as follows: Contact time of 60–360 min, pH: 6–8, and adsorbent dose of 6 mg g−1; whereas for acid-modified clinoptilolite-rich tuffs with 9.01 ≤ Si/Al ≤ 9.52, these conditions were as follows: Contact time of 1440 min, pH: 8–10, and adsorbent dose of 10 mg g−1. The experimental data were analyzed by kinetic and isotherms models. The results showed that the sorption of Pb(II) on samples with Si/Al ratios of 4.37, 5.31, and 7.91 were in agreement with the pseudo-second order and Langmuir isotherm with qm = 48.54, 37.04, and 14.99 mg g−1, respectively, while the kinetic data and isotherm for samples with 9.01 ≤ Si/Al ≤ 9.52 were found to fit the pseudo-first order and Freundlich model.

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Section: Influence Of Adsorbent Dosage and Effect Of Phmentioning

confidence: 93%

“…In previous studies [16,18,19,22,23,[25][26][27][28][29][30], the researches focused mainly on the effect of the SiO 2 /Al 2 O 3 ratio on the structural properties of zeolites. Moreover, these studies used synthesized zeolites [19,22,[26][27][28]30], whereas the only raw zeolites used being mordenite and clinoptilolite.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

et al. 2019

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“…It is known that natural materials [25], metal oxides [26,27] and nanoparticles of metals and alloys [28] . Moreover, water adsorbability changes differentially as a result of the thermal treatment of various materials.…”

Section: Water Vapor Sorptionmentioning

confidence: 99%

Effect of Both the Phase Composition and Modification Methods on Structural-Adsorption Parameters of Dispersed Silicas

Rakitskaya

Kiose

Golubchik

et al. 2018

Colloids and Interfaces

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Tripoli from two Ukrainian deposits was studied in its natural and modified forms. The investigation of natural and modified tripoli involves the identification of their phase compositions through X-ray diffraction and the analysis of their water vapor adsorption-desorption isotherms. The obtained results are evidence of changes in the structural-adsorption parameters of tripoli as a result of modification. Their treatment in boiling water or acid causes apparent alterations of contents of the main phases and sizes of their crystallites, whereas their calcination causes not only the dehydroxylation of surfaces and the agglomeration of phases, but even phase transformation in the case of carbonate tripoli. After analyzing water vapor adsorption-desorption isotherms of natural and modified tripolis, some correlations between their adsorption parameters, phase compositions, main phase contents and crystallite sizes have been found.

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“…It has a one-dimensional ellipsoidal 12-ring channels (6.5Å x 7.0Å) with side pockets involving 8-ring channels (2.6Å x 5.7Å) [4,5]. The characteristics of natural zeolites can be changed by acid activation (HCl, HNO3 and H2SO4) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Partial dealumination of the zeolites lead to improve in the thermal stability and increase in the hydrophobicity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Thermal and Structural Properties of Nitric, Hydrochloric and Sulphuric Acid-Treated Zeolite

Akbelen¹,

Ezber²

2019

Eskişehir Technical University Journal of Science and Technology a - Applied Sciences and Engineering

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In this study, in order to consider the effect of the hydrochloric acid (HCl), nitric acid (HNO3) and sulphuric acid (H2SO4) treatments on thermal and structural properties, zeolite was modified with 1 M acid solutions at 70 o C during 4 h using batch method. The structural and thermal properties of zeolites were studied by X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG) and differential thermal analysis (DTA). Quantitative XRD analysis show that the natural zeolite mainly consists of mordenite and clinoptilolite with varying amounts of quartz, feldspar and clay mineral. TG-DTG and DTA curves of all zeolite samples were obtained in the temperature range between 30 and 1000 o C. Based on the TG results, the total mass losses for all acid-treated samples (8.51-8.44 %) are less than that of the natural (Z) sample (10.14 %). SiO2/ Al2O3 ratio of the natural zeolite sample (Z) increased from 5.6 to 9.8, 9.7 and 8.8 in the Z-N, Z-H and Z-S samples, respectively, indicating the removal of the significant amount of aluminum from the zeolite structure.

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Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Cited by 30 publications

References 17 publications

Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

Effect of Both the Phase Composition and Modification Methods on Structural-Adsorption Parameters of Dispersed Silicas

Investigation of Thermal and Structural Properties of Nitric, Hydrochloric and Sulphuric Acid-Treated Zeolite

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