X-ray photoelectron spectroscopic investigation into the surface effects of sulphuric acid treated natural zeolite

Wang, Xiaoyu; Plackowski, Chris; Nguyen, Anh V.

doi:10.1016/j.powtec.2016.03.025

Cited by 35 publications

(9 citation statements)

References 33 publications

(39 reference statements)

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“…This result suggests that nitric acid treatment can remove Al from the structure of zeolite and thus increase the covalent nature of the Si―O bond and Al―O bond within the structure. Our XPS results are consistent with the results reported by Wang et al…”

Section: Resultssupporting

confidence: 93%

“…Based on the above specific structure, zeolites exhibit high cation exchange property, polarity, and hydrophilicity and thus make them particularly suitable for removing NH 4 + , kinds of heave metal ions such as Hg, Pb, Ag, Cu, Cd, Cr, Zn, Ni, Co, Mn, etc., and polar organic contaminations such as phenol and tetrahydrofuran . The modifications of zeolites, such as ion exchange, surfactant/organosilane modification, acid treatment, and heat treatment, are applied to change the property of zeolites, which greatly influence the practical applications.…”

Section: Introductionmentioning

confidence: 99%

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

Wang

Cao

Huang

2017

Surface & Interface Analysis

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Natural zeolite was first acid treated and then heat treated. The influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite were investigated. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TG), and Brunauer-Emmett-Teller (BET) surface areas were employed to investigate the structure changes of the zeolite samples. Water vapor adsorption property of the samples was investigated in order to determine wettability of the samples. The results showed that nitric acid treatment could remove Al from the structure, decrease relative crystallinity, and significantly increase specific surface area of the zeolite samples. Heat treatment could change or even destroy the structure, effectively remove water molecules from the surface/structure, and decrease the specific surface area of the zeolite samples. Water vapor adsorptions on the acid-treated zeolite samples were significantly lower than that for the zeolite sample, and the adsorptions further reduced for the heat-treated zeolite samples. The increase of Si/Al ratio, decreases of silanol groups, and specific surface area of the samples were major reasons related to the reductions of water vapor adsorptions on the zeolite samples.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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

Wang

Cao

Huang

2017

Surface & Interface Analysis

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“…The amount of Ca 2+ in the zeolitic material also drastically diminished, limiting the ion exchenge: Pb 2+ (s) + Ca 2+ (z) → Pb 2+ (z) + Ca 2+ (s) , where s represents the solution and z the zeolitic material. The sites where the K + are located into the zeolite network [47] do not favor the ion exchange with Pb 2+ . Another explanation of this behavior is by the change of the nature of the zeolitic material from hydrophilic to hydrophobic character [36].…”

Section: Influence Of Adsorbent Dosagementioning

confidence: 89%

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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“…XPS analysis of the zeolite structural composition of zeolite samples shows the presence of the O 1s , C 1s , Na 1s , Ca 2p , Si 2p , Al 2p , and K 2p photoelectron lines [29]. The variations of the atomic concentrations are significant as shown in Figure 7.…”

Section: X-ray Photoelectron Spectroscopy (Xps) Investigation Of Sulfmentioning

confidence: 92%

Potential Desalination of Coal Seam Gas Coproduced Water Using Zeolite

Wang¹,

Nguyen²

2018

Zeolites and Their Applications

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Natural clinoptilolite type zeolite was examined for its potential to treat coal seam gas (CSG) water and remove sodium ions to lower sodium adsorption ratio and reduce pH. The effectiveness of unmodified and modified natural zeolite is due to their regular composition and open porous structure, high exchange capacity, mechanical strength and stability, and consistency in particle size. The effects of acid modification in bringing about changes to the physicochemical properties of clinoptilolite underpin the effectiveness of this material for treatment of CSG saline water. The sodium adsorption capacity of acid-modified zeolite increases up to three times greater than that of the unmodified zeolite. The atomic percentage and binding energies of the chemical elements comprising zeolite are changed significantly following the acid modification. The Si/Al atomic ratio increases with increasing sulfuric acid concentration. Dealumination is the main reason for the increase in the surface charge and cation exchange capacity of clinoptilolite after acid modification. It is due to the increased defects in the crystal structure/lattice, which result in increasing numbers of charge vacancies. Sodium-rich synthetic zeolites 4A and Na─Y after acid modification are also examined by following the dissolution of the first-order fast kinetics and recrystallization processes which can be homogeneous or heterogeneous.

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X-ray photoelectron spectroscopic investigation into the surface effects of sulphuric acid treated natural zeolite

Abstract: X-ray photoelectron spectroscopic investigation into the surface effects of sulphuric acid treated natural zeolite

Cited by 35 publications

References 33 publications

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

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

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

Potential Desalination of Coal Seam Gas Coproduced Water Using Zeolite

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