A comparative study using direct hydrothermal and indirect fusion methods to produce zeolites from coal fly ash utilizing single-mode microwave energy

Bukhari, Syed Salman; Behin, Jamshid; Kazemian, Hossein; Rohani, Sohrab

doi:10.1007/s10853-014-8535-2

Cited by 51 publications

(27 citation statements)

References 30 publications

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“…In this method a dry fusion step is introduced prior to hydrothermal treatment. The procedure outlined in the previous works was followed with few amendments [19]. CFA was fused with sodium hydroxide (granules) at a ratio of 1:1.2 by weight.…”

Section: Methods Of Conversion Of Cfa To Zeolitementioning

confidence: 99%

Effect of ultrasound energy on the zeolitization of chemical extracts from fused coal fly ash

Bukhari

Rohani

Kazemian

2016

Ultrasonics Sonochemistry

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This paper investigates the effects of ultrasound (UTS) energy at different temperatures on the zeolitization of aluminosilicate constituents of coal fly ash. UTS energy irradiated directly into the reaction mixture utilizing a probe immersed into the reaction mixture, unlike previously reported works that have used UTS baths. Controlled synthesis was also conducted at constant stirring and at the same temperatures using conventional heating. The precursor reaction solution was obtained by first fusing the coal fly ash with sodium hydroxide at 550°C followed by dissolution in water and filtration. The synthesized samples were characterized by XRF, XRD, SEM and TGA. The crystallinity of crystals produced with UTS assisted conversion compared to conventional conversion at 85°C was twice as high. UTS energy also reduced the induction time from 60 min to 40 min and from 80 min to 60 min for reaction temperatures of 95°C and 85°C, respectively. Prolonging the UTS irradiation at 95°C resulted in the conversion of zeolite-A crystals to hydroxysodalite, which is a more stable zeolitic phase. It was found that at 85°C coupled with ultrasound energy produced the best crystalline structure with a pure single phase of zeolite-A. It has been shown that crystallization using UTS energy can produce zeolitic crystals at lower temperatures and within 1h, dramatically cutting the synthesis time of zeolite.

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Section: Methods Of Conversion Of Cfa To Zeolitementioning

confidence: 99%

Effect of ultrasound energy on the zeolitization of chemical extracts from fused coal fly ash

Bukhari

Rohani

Kazemian

2016

Ultrasonics Sonochemistry

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“…A lower CEC has been previously observed when utilizing waste stream instead of pure water Bukhari et al, 2014). The decrease in the CEC of the synthesized samples can be attributed to the higher production of hydroxysodalite.…”

Section: Cation Exchange Capacity (Cec)mentioning

confidence: 52%

“…There has been much research conducted on producing value added products such as zeolites (Bukhari et al, 2015a) from the accumulated CFA. Pioneering studies in zeolitization of CFA was reported using conventional heating (Holler and Wirsching, 1985;Shigemoto et al, 1993;Hollman et al, 1999), however, recently many researchers have focused their efforts on utilizing novel energy sources such as Microwave (MW) Bukhari et al, 2014;Querol et al, 1997) and ultrasound Belviso et al, 2011;Wang and Zhu, 2005;Musyoka et al, 2011a).…”

Section: Introductionmentioning

confidence: 99%

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Continuous Flow Synthesis of Zeolite-A from Coal Fly Ash Utilizing Microwave Irradiation with Recycled Liquid Stream

Bukhari¹,

Rohani²

2017

American Journal of Environmental Sciences

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Coal Fly Ash (CFA) was converted to zeolite using continuous microwave reactors while minimizing the wastewater produced during the zeolitization process. At bench scale, a continuous flow tubular microwave reactor was used to explore the effect of microwave irradiation on the crystallinity of the product. The waste water was reused in consecutive runs and Inductively Coupled Plasma (ICP) analysis was conducted during and after each run to observe the concentration of the cations. An increase in the production of hydroxysodalite compared to zeolite-A was noted at higher levels of microwave energy. The XRD and SEM analyses were also conducted to corroborate the results. The Cation Exchange Capacity (CEC) measurement showed the highest value of 0.405 meq/g when Deionized (DI) water was used, the CEC dropped to 0.177 meq/g for thrice recycled waste stream. It was also found that higher microwave irradiation resulted in faster crystal growth and the product crystallinity reached its maximum at 810 W of microwave irradiation in 60 min while 335 W of microwave irradiation resulted in the same crystallinity after 120 min of reaction.

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“…There are several reports on microwave-assisted hydrothermal conversion of CFA to different synthetic zeolites (e.g. Na-A) [31][32][33][34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of zeolite Na-P from coal fly ash by thermo-sonochemical treatment

Aldahri

Behin

Kazemian

et al. 2016

Fuel

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A comparative study using direct hydrothermal and indirect fusion methods to produce zeolites from coal fly ash utilizing single-mode microwave energy

Cited by 51 publications

References 30 publications

Effect of ultrasound energy on the zeolitization of chemical extracts from fused coal fly ash

Effect of ultrasound energy on the zeolitization of chemical extracts from fused coal fly ash

Continuous Flow Synthesis of Zeolite-A from Coal Fly Ash Utilizing Microwave Irradiation with Recycled Liquid Stream

Synthesis of zeolite Na-P from coal fly ash by thermo-sonochemical treatment

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