Extraction of nano‐porous silica from hydrosodalite produced via modification of low‐grade kaolin for removal of methylene blue from wastewater. Issue 7 (6th April 2020)

• Record Type: Journal Article
• Authors: Alizadeh Arasi, Mahshid; Salem, Amin; Salem, Shiva
• Is Part Of: Journal of chemical technology & biotechnology. Volume 95:Issue 7(2020)
• Page Start: 1989
• Page End: 2000
• Publication Date: 2020-04-06
• Subjects: nano‐porous silica -- poor kaolin -- template free -- zeolite composite -- hydrosodalite -- acidification; Biotechnology -- Periodicals; Chemistry, Technical -- Periodicals; Chemical engineering -- Periodicals; Industries -- Environmental aspects -- Periodicals; 660
• DOI: 10.1002/jctb.6387
• Languages: English
• ISSNs: 0268-2575

Abstract

Abstract: BACKGROUND: This work employs low‐grade kaolin as raw material in the economical production of nano‐porous silica with extended surface area via the hydrothermal acidification of intermediate zeolite composite to remove methylene blue from wastewater. Hydrosodalite fabricated through the modification of meta‐kaolin (MK) with sodium aluminate (NaAlO2 ) was used as a precursor in the hydrothermal acidification step. RESULTS: The direct conversion of MK to zeolite composite generating a low crystalline phase, containing quartz which was eliminated in the acidification step, exhibited a strong affinity towards dye adsorption. It was indicated that the NaAlO2 /MK ratio could influence the hydrosodalite crystallization as well as adsorption efficiency of the nano‐porous silica obtained from acidification of zeolite composite. The nano‐porous silica formation involved the ion extraction from hydrosodalite cabbage‐like particles, depending on crystallinity of intermediate zeolite composite. CONCLUSION: The mesoporous silica represented the appropriate adsorptive behavior when produced from precursor modified with lower NaAlO2 content, NaAlO2 /MK = 0.24, attributed to superior specific surface area, 420 m 2 g −1, with average pore diameter about 3.3 nm. The equilibrium data was better correlated by Redlich–Peterson isotherm. Compared to the surface area of silica powders fabricated from high grade kaolins, Al2 O3 /SiO2, > 0.83, by the acid‐etched strategy, the mesoporous silica produced from the low‐grade kaolin by the template free method indicates higher value. © 2020 Society of Chemical Industry