Characterizations and ion-exchange properties of zeolite NaA synthesized in a continuous process (original) (raw)
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Synthesizing of Zeolite Particle Using Alkaline Plant Extract
Emerging Advances in Integrated Technology
The study explored the hydrothermal synthesis of zeolite using kaolin clay precursor in the presence of three different solvents namely, garlic extract, watermelon extract and 2M NaOH solution, with the view of testing their efficacy and potency for green synthesis. Before the zeolitization, the kaolin precursor was activated at a temperature of 850°C to produce metakaolin. The crystallization was achieved in an oven at a temperature of 90°C for 12 hours. The final product is grounded to a fine powder and subsequently undergo testing and characterization via X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopes (FESEM) methods. The purity and grade of the synthesized products vary accordingly with the suitability of the reaction solvent. The synthesized product using a solvent of watermelon plant extract was able to produce zeolite LTA of a good grade. However, the presence of secondary phases informed the effect of the accompanied impurities that might originate ...
Synthesis of Zeolite NaA from Low Grade (High Impurities) Indonesian Natural Zeolite
Indonesian Journal of Chemistry, 2014
The zeolite NaA has been successfully synthesized from the low grade natural zeolite with high impurities. The synthesis method was started by mixing natural zeolite powder with NH 4 Cl aqueous solution in the reactor as pretreatment. The use of pretreatment was to reduce the impurities contents in the zeolite. The process was followed by alkaline fusion hydrothermal treatment to modify the framework structure of natural zeolite and reduce the SiO 2 /Al 2 O 3 ratio. Finally, the synthesized zeolite was calcined at 600°C for 2 h. The final zeolite product was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the morphology of the zeolite NaA was cubic shape as observed by SEM analysis and the synthesized zeolite NaA with pretreatment gave less impurity than without pretreatment.
2016
Zeolites are aluminosilicate solids bearing a negatively charged honeycomb framework of micro pores into which molecules may be adsorbed for separation purposes as well as catalysis of chemical reactions. In this study, Na-Zeolite was synthesized via a hydrothermal reaction on the basis of dual cation/anion exchange capacities with regeneration capabilities. The sodium silicate solution used in the laboratory experiments was in the concentration range of 62-65%. Both anionic and cationic functional groups together are derived from the concentrated sodium silicate solution where during depolymerization of siloxane bonds takes place not only into silanol anions but also silanol cations. The silanol cations and anions polymerize into cyclic anionic and cationic functional groups respectively showing dual cation and anion exchange property. X-ray diffraction pattern indicates a crystalline structure with the material present in one phase. Cation exchange capacity (CEC) and anion exchang...
Synthesis of Na-A zeolite from water treatment residue using hydrothermal and microwave techniques
IOP Conference Series: Materials Science and Engineering, 2019
Na-A zeolite was synthesized from water treatment residue (WTR) using hydrothermal and microwave techniques. WTR was brought from Metropolitan Waterworks Authority (Thailand) and was activated by firing at 700 °C for 3 h in an electric furnace. The activated WTR was reacted with 3 M NaOH solution in a reactor under a controlled temperature of 80, 90 and 100 °C for 8, 10, 12, and 14 h. SEM (Scanning electron microscopy) images reveal the cubic crystal of zeolite. The highest cation exchange capacity (CEC) was obtained from sample synthesized at 90 °C for 14 h and gave the CEC value of 3.14 meq/g Ca2+. For the microwave technique, the raw materials were reacted at 80 90 and 100°C for 30, 60, and 120 min. Results showed that the sample obtained at 80 °C for 30 min represented the highest CEC value of 0.29 meq/g Ca2+.
Influence of Alcalinity on Synthesis of Zeolite a
2011
Two different systems were examined: (1) homogeneous (optically clear solution saturated with Na + , aluminate, silicate and alumosilicate species) and (2) heterogeneous (hydrogel – saturated solution with precipitated gel). Hydrothermal transformation of samples in both systems was made by heating of HDPE reactors (flasks) with samples at 80°C. All systems were prepared adding of the basic sodium silicate solution into the basic sodium aluminate solution. Both solutions were prepared by dissolving of appropriate amounts of sodium silicate (Fluka, > 97% Na2O SiO2 × 5H2O) or sodium aluminate (Riedel de Haën, 54% Al2O3; 41% Na2O) with NaOH (Kemika, 98% NaOH) in deionized water. In order to remove impurities from the sodium aluminate solutions, they were centrifuged and only clear supernatant was used for preparation of starting system. After preparation and ageing for 24 h, starting solution of systems 1 (1a, 1b, 1c) and hydrogel of systems 2 (2a, 2b, 2c) were divided among needed ...
2003
1 µm crystal-size Na A zeolite (LTA) is successfully synthesized via the sol-gel process and microwave heating technique using alumatrane and silatrane as precursors. The optimal conditions to obtain LTA were 1:1:3:410 SiO 2 :Al 2 O 3 :Na 2 O:H 2 O ratio, microwave heating temperature and a time of 110°C and 160 min, respectively. Under the same conditions, increasing the Na 2 O concentration exponentially reduces the microwave heating time from 160 min at a Na 2 O:SiO 2 ratio of 3:1 to 5 min at a Na 2 O:SiO 2 ratio of 9:1. Increasing the Na 2 O concentration strongly affects the particle size and particle size distribution, but does not affect the product composition. Increasing the amount of water increased the average particle size and also the number of irregular cubic shape crystals. Increasing the aging temperature from 90° to 150°C, everything else being the same (one hour heating time and the loading ratio of SiO 2 :Al 2 O 3 :5Na 2 O:410H 2 O), only amorphous product was produced at 90°C and between 110°-150°C only LTA was produced.
Kinetic and Thermodynamic Studies for Zeolites Synthesis
ZANCO JOURNAL OF PURE AND APPLIED SCIENCES, 2019
Zeolites are compounds which have many applications in chemistry and industry; therefore, studies of synthesis of zeolites are of great importance. In this work, kinetic and thermodynamic study of hydrothermal crystallization for zeolite synthesis process performed at different time intervals (17, 20, 23 and 26 h) and various temperatures (70, 90, 110 and 125 0 C). By time intervals we got out the rate of the zeolite synthesis reaction in this research was first order. The synthesized zeolites were similar in their crystallinity according to the Zeolites synthesis at different of the time intervals. The thermodynamic parameters indicated that the change in Gibbs free energy was negative value. The degrees of crystallinity of the synthesized zeolites decreased with increasing the hydrothermal crystallization temperature. Moreover, the change of hydrothermal crystallization time and temperature caused synthesis of different types of zeolites. The synthesized zeolite samples characterized by Infra-Red (IR), X-ray diffraction (XRD), X-ray Fluorescence (XRF) and scanning electron microscopy (SEM). The variation of chemical compositions led to differences in morphologies and crystallinity of the synthesized zeolites.
Powder Technology, 2011
Hydrothermal synthesis of zeolite T in aqueous alkaline solutions without using templates was investigated. Zeolite T crystals were prepared via hydrothermal synthesis using milk-like aluminosilicate gel with a composition of aSiO 2 :bAl 2 O 3 :cNa 2 O:dK 2 O:xH 2 O. The effects of molar compositions including silicon module (n RM = a/b) and relative alkalinity (α = OH/SiO 2), and crystallization conditions including crystallization temperature (T) and time (t) on the yield of T-type crystals were investigated. This research work examines changes in the yield of crystalline zeolite phases by varying the gel composition parameters (n RM =20-25, and α = 0.71-0.82) and crystallization process temperature and time (T = 100°−140°C, t = 120-216 h), while keeping constant the parameters [OH] = 2.77 m, U RM (Na/Na + K) = 0.75, stirring time = 24 h , stirring temperature = 30°C, and drying temperature = 100°C. The crystal species of zeolite T were characterized by XRD (X-ray diffraction) and SEM (Scanning Electron Microscope).
Journal of Colloid and Interface Science, 2012
Slow crystallization and growth rate at room temperature in the presence of surfactant micelles is a new strategy used to synthesize hierarchical Na-A zeolites. The observed structure of the hierarchical materials was consistent with a two stage growth mechanism. During the early stage of the gel evolution, miniature zeolite gel particles were formed and assembled around surfactant (cetyltrimethylammonium bromide -CTAB) micelles. In a second stage, the slow mass transformation into crystalline phase and the low growth rate of the formed crystallites retained the CTAB micelles within the crystallization domain. After the removal of CTAB templates, the products showed large mesopores which were attributed to the interstitial voids between the aggregated zeolite nanocrystallites. The size of the mesopores can be further expanded by using linear hydrocarbons as swelling agents. The influences of the added amount of the hydrocarbons and the length of the hydrocarbon chains on the mesopore size were examined. The effects of the aging period and CTAB concentration in the synthesis mixture on the pore size distribution were also investigated. The colloidal suspension of the synthesized zeolite showed negative zeta potential throughout the entire range of pH. The mesoporous Na-A zeolite synthesized in this work showed higher ethylene adsorption capacity as compared to the conventional microporous Na-A zeolite. XRD, DLS, SEM, N 2 adsorption-desorption at 77 K, TEM, 29 Si NMR and FTIR techniques were used to characterize the hierarchical Na-A zeolite.
Improvement of Cation Exchange Capacity of Natural Zeolite with Alkali Treatments
2004
The natural zeolite was treated with alkali (NaOH) solution and heating at 100 oC for 12 and 24 hours. The natural zeolite was collected from Gunungkidul, Jogjakarta, Indonesia. The series of NaOH solutions was 0.5, 1.0, 1.5, 2.5, 3.5 and 4.5 M. The final product of the reaction (precipitate) was designated as ‘activated natural zeolite (ANZ)’. The cation exchange capacity (CEC) of the ANZ increased with increasing NaOH concentration up to 1.5-3.5 M. Treatment with NaOH 3.5 M and 12 hours in period of hydrothermal reaction resulted in a maximum CEC (395.6 cmol kg-1). The maximum CEC also observed for treatment with NaOH 1,5 M, but consumed a longer time (24 hours). The increase in the CEC of the ANZ about 300 % higher than the original one. The XRD (X-ray Diffraction) peaks of the ANZ appear at 2.7, 3.2, 4.1, 5.1, 7.2 A, this indicated a new crystalline matters (possibility phillipsite) present. Electron micrograp showed that the ANZ has a large cubic/prismatic structure with a perf...