Synthesis of Hydroxy-Sodalite/Cancrinite Zeolites from Calcite-Bearing Kaolin for the Removal of Heavy Metal Ions in Aqueous Media

Esaifan, Muayad; Warr, Laurence N.; Grathoff, Georg; Meyer, Tammo; Schafmeister, Maria-Theresia; Kruth, Angela; Testrich, Holger

doi:10.3390/min9080484

Cited by 53 publications

(42 citation statements)

References 47 publications

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“…From raw to treated materials, samples become highly enriched in Na content, which confirms the formation of thermonatrite. SEM images of hydrothermal samples seem to be similar to the homogenous pseudohexagonal crystal of hydroxy-sodalite generated at almost the same experimental conditions by Esaifan et al (2017Esaifan et al ( , 2019 [67,68]. However, despite other zeolites having been identified in low amounts by XRD, no clear characteristic morphology of these crystals has been observed in SEM.…”

Section: Discussionmentioning

confidence: 60%

Alkali-Hydrothermal Treatment of K-Rich Igneous Rocks for Their Direct Use as Potassic Fertilizers

et al. 2021

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Due to the increasing demand for conventional sources of potassium (K) and their inaccessibility by African countries, K-rich igneous rocks are increasingly studied as potential alternative sources. In this study, six potassic igneous rocks (syenites and trachytes) from the Tamazeght, Jbel Boho, Ait Saoun, and El Glo’a regions (Morocco) were sampled and characterized. Then they were hydrothermally treated to enhance their K release for potential use as potassic fertilizers. The raw materials are mainly formed by microcline (up to 74%), orthoclase (20–68%), albite (36–57%), biotite-muscovite (15–23%), and titanite, calcite, hematite, and apatite as accessory minerals. These samples were crushed and milled to reach a particle size <150 µm and mixed with 4 N NaOH solution in an autoclave. The liquid/solid (L/S) ratio was about 44 mL/50 g. The powders were allowed to react with the solution at 170 °C for 7 h. For all tests, NaOH reacted completely with the powders and no liquid was observed after the treatment. X-ray diffraction (XRD), thermal gravimetric analysis (TGA), infrared spectroscopy (IRTF), and scanning electron microscopy (SEM-EDS) were carried out on treated samples to characterize the mineralogical and structural changes due to the alkali-hydrothermal treatment. Indeed, the treated samples revealed the presence of sodic neoformed phases such as thermonatrite, sodalite, analcime, and cancrinite. The treated material was leached for a week using deionized water and the elements released were measured using inductively coupled plasma–atomic emission spectroscopy (ICP-AES). The hydrothermal process showed a strong effect on structure breakdown as well as on the release of K and other nutrients such as P, Fe, Si, Mg, and Ca. Therefore, the alkali-hydrothermal treatment allowed the release of 50.5 wt% K. Moreover, the release of Mg, Ca, Fe, P, K, and Si were significantly increased. Mg, Ca, Fe, P, K, and Si release within raw materials was about (0.5–3.6), (3.5–31.4), (0.01–0.4), (0.01–0.3), (20–55), and (4.6–8) mg/kg, respectively, whereas treated samples showed a higher release of these elements. Quantitatively, Mg, Ca, Fe, P, K, and Si releases were about (10–11.8), (60–70), (7–20), (1.2–15), (218–1278), and (1119–2759) mg/kg, respectively. Consequently, the treated igneous rocks (syenite and trachyte) could be directly used as potassic fertilizers that would also be a source of other nutrients.

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Section: Discussionmentioning

confidence: 60%

Alkali-Hydrothermal Treatment of K-Rich Igneous Rocks for Their Direct Use as Potassic Fertilizers

et al. 2021

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“…The hydrothermal treatment caused mineral phase transformations. Quartz and the mullite phase present in the coal fly ash sample changed to a zeolite structure (concretely sodalite—23.68% and phillipsite ((Ca,K,Na) 1-2 (Si,Al) 8 O 16 ·6(H 2 O)—2.28%, see Table 5 ) [ 6 , 30 ]. The amount of mullite decreased from 18.11 to 5.38%.…”

Section: Resultsmentioning

confidence: 99%

“…However, it always depends on the type and properties of the coal fly ash. The amount of zeolite phases formed is influenced by parameters such as type and composition of the coal fly ash, concentration and type of chemicals (NaOH, KOH, LiOH, H 2 SO 4 , HCl), temperature, process time, Si/Al, and liquid/solid (L/S) ratio [ 30 ].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

et al. 2021

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Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

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“…Oleh karena itu dibutuhkan upaya untuk meningkatkan daya serap kaolin. Salah satu upaya peningkatan daya serap kaolin sebagai adsorben dapat dilakukan dengan memodifikasikanya menjadi metakaolin (fase metastabil dari kaolin) dilanjutkan dengan aktivasi dengan basa sehingga membentuk struktur menyerupai zeolit [18] [19]. Metakaolin merupakan mineral lempung kaolin dalam bentuk terdehidrasi.…”

Section: Pendahuluanunclassified

Selektivitas Adsorpsi Asam Lemak Bebas (ALB) dan Beta Karoten Minyak Sawit Mentah Menggunakan Metakaolin Teraktivasi Kalium Karbonat (K2CO3)

Mukhlishin¹,

Rahmalia

Usman

2020

JCPE

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jenis adsorben metakaolin teraktivasi K2CO3 1 M dengan nilai 2:13 dalam mol/mol. Karakteristik adsorben dari metakaolin teraktivasi K2CO3 yaitu memiliki struktur sillimanite dan kynite yang merupakan kelompok aluminosilikat, dengan komposisi Si/Al = 1, dengan tipe isoterm adsorpsi gas nitrogen adalah H4, distribusi jari-jari pori heterogen yang didominasi pada 13-15 nm (mesopori), dan memiliki luas permukaan sebesar 28,74 m 2 g-1 , serta volume pori sebesar 8,018 x 10-2 cm 3 g-1. Jenis adsorben metakaolin teraktivasi K2CO3 1 M terbukti paling baik untuk mengadsorpsi beta karoten sebesar 26,15 % dan asam lemak bebas sebesar 2,49 % pada CPO dengan kondisi waktu kontak dan massa adsorben optimum adsorpsi yang sama yaitu 60 menit dan massa adsorben 0,4 gram/10 mL CPO. Isoterm adsorpsi asam lemak bebas dan beta karoten memiliki tipe yang sama yaitu isoterm Freundlich. Kinetika adsorpsi asam lemak bebas dan beta karoten memiliki model yang sama yaitu Pseudo orde 2 untuk setiap jenis adsorben.

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Synthesis of Hydroxy-Sodalite/Cancrinite Zeolites from Calcite-Bearing Kaolin for the Removal of Heavy Metal Ions in Aqueous Media

Cited by 53 publications

References 47 publications

Alkali-Hydrothermal Treatment of K-Rich Igneous Rocks for Their Direct Use as Potassic Fertilizers

Alkali-Hydrothermal Treatment of K-Rich Igneous Rocks for Their Direct Use as Potassic Fertilizers

Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Selektivitas Adsorpsi Asam Lemak Bebas (ALB) dan Beta Karoten Minyak Sawit Mentah Menggunakan Metakaolin Teraktivasi Kalium Karbonat (K2CO3)

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