scholarly journals Top-Down Synthesis of NaP Zeolite from Natural Zeolite for the Higher Removal Efficiency of Cs, Sr, and Ni

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 252
Author(s):  
Seokju Hong ◽  
Wooyong Um
Keyword(s):  
Cation Exchange ◽  
Removal Efficiency ◽  
Natural Zeolite ◽  
Cation Exchange Capacity ◽  
Solid Phase ◽  
Exchange Capacity ◽  
Order Kinetic ◽  
Top Down ◽  
Kinetic Experiment ◽  
Bet Analysis

A solid phase of natural zeolite was transformed to Na-zeolite P (NaP zeolite) by a “top-down approach” hydrothermal reaction using 3 M of NaOH solution in a 96 °C oven. Time-dependent X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), XRF, and scanning electron microscopy (SEM) analysis as well as kinetic, isotherm, and cation exchange capacity experiments were performed to understand the mechanism of mineral transition from natural zeolite to NaP zeolite. The XRD crystal peaks of the natural zeolite decreased (decrystallization phase) first, and then the NaP zeolite XRD crystal peaks increased gradually (recrystallization phase). From the XRF results, the dissolution rate of Si was slow in the recrystallization phase, while it was rapid in the decrystallization phase. The specific surface area measured by BET analysis was higher in NaP zeolite (95.95 m2/g) compared to that of natural zeolite (31.35 m2/g). Furthermore, pore structure analysis confirmed that NaP zeolites have more micropores than natural zeolite. In the kinetic experiment, the results showed that the natural zeolite and NaP zeolite were well matched with a pseudo-second-order kinetic model, and reached equilibrium within 24 h. The isotherm experiment results confirmed that both zeolites were well matched with the Langmuir isotherm, and the maximum removal capacity (Qmax) values of Sr and Ni were highly increased in NaP zeolite. In addition, the cation exchange capacity (CEC) experiment showed that NaP zeolite has an enhanced CEC of 310.89 cmol/kg compared to natural zeolite (CEC = 119.19 cmol/kg). In the actual batch sorption test, NaP zeolite (35.3 mg/g) still showed high Cs removal efficiency though it was slightly lower than the natural zeolite (39.0 mg/g). However, in case of Sr and Ni, NaP zeolite (27.9 and 27.8 mg/g, respectively) showed a much higher removal efficiency than natural zeolite (4.9 and 5.5 mg/g for Sr and Ni, respectively). This suggests that NaP zeolite, synthesized by a top-down desilication method, is more practical to remove mixed radionuclides from a waste solution.

scholarly journals Aflatoxin B1 adsorption by the natural aluminosilicates - concentrate of montmorillonite and zeolite

2016 ◽  
Vol 70 (5) ◽  
pp. 519-524 ◽  
Author(s):  
Marija Markovic ◽  
Aleksandra Dakovic ◽  
George Rottinghaus ◽  
Mirjana Stojanovic ◽  
Vera Dondur ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Aflatoxin B1 ◽  
Natural Zeolite ◽  
Cation Exchange Capacity ◽  
Active Sites ◽  
Solid Phase ◽  
Bentonite Clay ◽  
Exchange Capacity ◽  
Composition Determination

Aflatoxin B1 adsorption by the concentrate of bentonite clay - montmorillonite and the natural zeolite - clinoptilolite and was investigated at the initial toxin concentration 4 ppm, with different amonunts of solid phase in suspension (10, 5, 2 and 1 mg/10 mL) and different pH values - 3, 7 and 9. Results indicated that for both minerals, decreasing the amount of solid phase in suspension, decrease the amount of active sites relevant for adsorption of aflatoxin B1. Thus, for concentrate of montnorillonite, at the lowest level of solid phase in suspension (1 mg/10 mL), aflatoxin B1 adsorption indexes were 97% at pH 3, 88% at pH 7 and 82% at pH 9, while for the natural zeolite, adsorption of toxin was 9% at pH 3 and 7% at pH 7 and 9. Since inorganic cations in minerals are mainly responsible for aflatoxin B1 adsorption, even the natural zeolite - clinoptilite has much higher cation exchange capacity (the content of inorganic exchangeable cations) compared to the concentrate of montmorillonite, adsorption of aflatoxin B1 by this mineral is much lower. Comparing the molecular dimensions of aflatoxin B1 molecule with the dimension of channels of clinoptilolite and interlamellar space of montmorillonite it is obvious that this toxin is adsorbed only at the external surface of clinoptilolite while in the montmorillonite all active sites are equally available for its adsorption. Thus, the concentrate of montmorillonite posess by higher adsorption capacity for aflatoxin B1. Results presented in this paper confirmed the fact the differences in the structure of minerals led to their different efficiency for adsorption of aflatoxin B1. Mineralogical and chemical composition, determination of cation exchange capacity, etc., are very important parameters influencing the effectiveness of minerals as aflatoxin B1 adsorbents. [Projekat Ministarstva nauke Republike Srbije, br. 451-03-2802-IP Tip1/142, br. 172018 i br. 34013] <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/HEMIND170208003E">10.2298/HEMIND170208003E</a><u></b></font>

scholarly journals Propiedades Básicas de Zeolitas Naturales de Panamá con Potencial de Desarrollo Industrial

2018 ◽  
Vol 3 (1) ◽  
pp. 721
Author(s):  
Dr. Cecilio Hernández B. ◽  
M.Sc. Jorge Olmos ◽  
Licda. Yahaira Espinosa
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Cation Exchange ◽  
Volcanic Activity ◽  
Natural Zeolite ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Natural Zeolites ◽  
Low Levels ◽  
Initial Results

The initial results of the properties that have been determined to a sample of natural zeolite, coming from areas of volcanic activity of Panama, and that has been identified with potential for its industrial explotation, are presented. Some physicochemical properties, chemical composition and morphology were determined. A natural zeolite with an intermediate level of Si/Al (2.62), low levels of dissolved salts and a morphology with pores-shaped channels with a diameter of 5 mm are observed.Keywords: natural zeolites, chemisorption, morphology, macropores, cation exchange capacity

Treatment of Natural Mordenite with Alkali and the Ammonium Exchange Capacity of the Modified Zeolite

2012 ◽  
Vol 554-556 ◽  
pp. 2031-2036
Author(s):  
Yi Fei Wang
Keyword(s):  
Exchange Rate ◽  
Cation Exchange ◽  
Removal Efficiency ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Regeneration Ability ◽  
Reaction Conditions ◽  
Modified Zeolite ◽  
Ammonium Removal

The natural mordenite was treated hydrothermally with NaOH solutions, either with or without fusion with NaOH powder as pretreatment. Zeolite Na-P and analcime were identified as the reacted products, depending on the reaction conditions. The zeolites were identified by X-raydiffraction, and their cation exchange capacity (CEC) was determined. Zeolite Na-P has higher CEC (338 meq/100g) contrasted with the mordenite (181 meq/100g). Further more, the uptakes of NH4+ onto the zeolites have also been investigated. The Na-P has faster exchange rate, higher exchange amounts and better regeneration ability. The ammonium removal efficiency for the Na-P is above 90% at the ammonium initial concentrations less than 150 mg NH4+/g. It seemed that Na-P was fit for the further treatment of waters polluted with ammonium.

Complex conductivity tensor of anisotropic hydrocarbon-bearing shales and mudrocks

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. D403-D418 ◽  
Author(s):  
A. Revil ◽  
W. F. Woodruff ◽  
C. Torres-Verdín ◽  
M. Prasad
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Solid Phase ◽  
Exchange Capacity ◽  
Electrical Anisotropy ◽  
Dielectric Tensor ◽  
Two Samples ◽  
Complex Electrical Conductivity

A model was recently introduced to describe the complex electrical conductivity and high-frequency dielectric constant of isotropic clayey porous materials. We generalized that approach to the case of anisotropic and tight hydrocarbon-bearing shales and mudrocks by introducing tensorial versions of formation factor and tortuosity. In-phase and quadrature conductivity tensors have common eigenvectors, but the eigenvectors of the dielectric tensor may be different due to influence of the solid phase at high frequencies. In-phase and quadrature contributions to complex electrical conductivity depend on saturation, salinity, porosity, temperature, and cation exchange capacity (alternatively, specific surface area) of the porous material. Kerogen is likely to have a negligible contribution to the cation exchange capacity of the material because all exchangeable sites in the functional groups of organic matter may have been polymerized during diagenesis. An anisotropic experiment is performed to validate some of the properties described by the proposed model, especially to verify that the electrical anisotropy factor is the same for in-phase and quadrature conductivities. We used two samples from the Bakken formation. Experimental data confirm the validity of the model. Also, the range of values for cation exchange capacity determined when implementing the new model with experimental data agree with the known range of cation exchange capacity for the Bakken shale. Measurements indicate that the bulk-space tortuosity in the direction normal to bedding plane can be higher than 100.

Batch equilibrium study on sorption, desorption, and immobilisation of cadmium in some semi-arid zone soils as affected by soil properties

Soil Research ◽  
2011 ◽  
Vol 49 (5) ◽  
pp. 444 ◽  
Author(s):  
H. Khodaverdiloo ◽  
A. Samadi
Keyword(s):  
Cation Exchange ◽  
Negative Correlation ◽  
Cation Exchange Capacity ◽  
Solid Phase ◽  
Negative Relationship ◽  
Exchange Capacity ◽  
Least Square ◽  
Retention Data ◽  
Positive Correlation ◽  
Caco3 Content

Little information is available for cadmium (Cd) sorption/desorption behaviour in soils with relatively variable CaCO3 content. The objectives of this study were to: (i) parameterise the sorption and desorption of Cd and the hysteretic behaviour of Cd sorbed to soils with varying CaCO3 content; and (ii) correlate sorption, desorption, and retention parameters with physicochemical characteristics of the soils. Twenty soil samples of different physico-chemical properties were taken from agricultural regions of Western Azerbijan province, Iran. A batch equilibrium experiment was conducted to construct sorption/desorption curves of Cd. The linear, Langmuir, and Freundlich isotherm equations were fitted to the experimental data of Cd sorption and retention, using either linear regression procedure or nonlinear least square optimisation (LSO). Both the Freundlich and Langmuir approaches described the Cd sorption and retention data well. A strong and irreversible binding of Cd in the soils was recorded, using a desorption approach. In the case of Cd sorption, a significant positive correlation (r = 0.38, P ≤ 0.05) was found between the Freundlich constant (Kf) and active CaCO3 equivalent (ACCE). The Freundlich n was positively correlated with cation exchange capacity (r = 0.49, P ≤ 0.05) and clay (r = 0.61, P ≤ 0.01) and negatively with ACCE (r = –0.60, P ≤ 0.01). The soil partition coefficient (KSD) showed a positive correlation with ACCE. The sorption maxima (b) were much less than the cation exchange capacity of soils. However, the relatively high pH (7.0–8.0) of the experimental soils and presence of relatively high values of free and active carbonate in the soils, along with the large sorption capacity of the soils, suggest the possibility of solid-phase precipitation as octavite (CdCO3). Parameter b, when fitted through LSO, showed a negative correlation with clay (r = –0.51, P ≤ 0.05) and a positive correlation with ACCE (r = 0.63, P ≤ 0.01). Langmuir K (Kl) showed a positive correlation with clay (r = 0.52, P ≤ 0.05) and a negative relationship with pH (r = –0.58, P ≤ 0.05) and ACCE (r = –0.65, P ≤ 0.01). Sorption of Cd showed a positive correlation (r ≥ 0.54, P ≤ 0.05) and its desorption a high negative correlation (r ≤ –0.61, P ≤ 0.05), with ACCE. It can be concluded that the ACCE is the important soil property controlling the sorption and retention of Cd in the studied soils.

Preparation and characterization of Theobroma cacao pod-modified feldspar composite for possible metal adsorption in wastewater management

2021 ◽  
Vol 1 (1) ◽  
pp. 001-012
Author(s):  
Kabir Adebayo Sanusi ◽  
Yakubu Yahaya ◽  
Murtala Maidamma Ambrusa ◽  
Aminu Koko Rabiu ◽  
Moshood Hamzat
Keyword(s):  
Cation Exchange ◽  
Theobroma Cacao ◽  
Cation Exchange Capacity ◽  
Fourier Transforms ◽  
Exchange Capacity ◽  
Wastewater Management ◽  
The Novel ◽  
Bet Analysis ◽  
Naoh Solution ◽  
Calcination Method

In this study modified feldspar composite (MFC) was prepared from the combination of Theobroma cacao pod (TCP) and feldspar (FS) using calcination method. The Theobroma cacao pod-feldspar sample was first Na-modified by treatment using 0.1M NaOH solution before calcination in the muffle furnace at 3000C to complete the process of composite preparation. The Theobroma cacao pods (TCP), feldspar (FS) and modified feldspar composite (MFC) were characterized using XRF, X-ray diffraction (XRD), Brunauer Emmett and Teller ( BET) analysis, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The results showed that the cation exchange capacity of the modified feldspar composite (30.66 ± 0.21 meq/100 g) was 5 times higher than that of raw feldspar (6.42 ± 0.45 meq/100g). More so, the novel biohybrid material, MFC has a surface area of 53.60 ± 0.3 m2/g and particle size of 105.4 ± 0.18. The XRD patterns revealed that after the modification process, there is only slight shift in the position of some diffraction peaks of feldspar and the composite material indicating the retention of the crystalline properties of the feldspar in the novel composite (MFC). FTIR results showed that some functional groups present in the two starting materials were also available on the surface of the composite (MFC) indicating that the intercalation of TCP biomass into feldspar surface was successful. Owing to its improved cation exchange capacity and eco-friendliness, the modified feldspar composite (MFC) has a good potential application as adsorbent for heavy metals in wastewater treatment besides other industrial explorations.

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