Abstract
The effect of the microwave-assisted acid treatment (MAT) on the structure and texture of dioctahedral (montmorillonite) and trioctahedral (saponite) smectites, kerolitic clays and sepiolites were studied by scanning electron microscopy, nitrogen adsorption, X-ray fluorescence, X-ray diffraction and Fourier transform infrared spectroscopy. This study shows that in the smectite group of minerals the effectiveness of MAT is notably influenced by the chemical composition of the octahedral sheet, whereas in kerolitic clays it is influenced by the proportion of the expandable phase in the mixed layer sequence. On the other hand, the reactivity of sepiolites depends on the width of the natural fibres. With these treatments, extremely high specific surface area (SSA) increments are achieved in just 16 min. The SSA increments reach values up to 231 m2/g (%ΔSBET = 80) in sepiolites, 198 m2/g (%ΔSBET = 155) in Mg-smectites, and 161 m2/g (%ΔSBET = 61) in kerolitic clays.
Highlights
Some clay materials named after special clays are composed of mostly one clay mineral that has important physical and chemical properties for the industrial and technological applications.Composed of 2:1 clay minerals, the main special clays include bentonite, sepiolite and kerolitic clay.Sepiolite (Mg8 Si12 O30 (OH)4 (OH2 )4 ·nH2 O) is a clay mineral, the structure of which is similar to other 2:1 trioctahedral phyllosilicates
This study shows the effectiveness of microwave-assisted acid treatment in several 2:1 clay minerals
Extremely high specific surface area (SSA) increases are achieved in just 16 min
Summary
Some clay materials named after special clays are composed of mostly one clay mineral that has important physical and chemical properties for the industrial and technological applications.Composed of 2:1 clay minerals, the main special clays include bentonite, sepiolite and kerolitic clay.Sepiolite (Mg8 Si12 O30 (OH) (OH2 )4 ·nH2 O) is a clay mineral, the structure of which is similar to other 2:1 trioctahedral phyllosilicates (e.g., talc). Some clay materials named after special clays are composed of mostly one clay mineral that has important physical and chemical properties for the industrial and technological applications. Composed of 2:1 clay minerals, the main special clays include bentonite, sepiolite and kerolitic clay. Sepiolite (Mg8 Si12 O30 (OH) (OH2 )4 ·nH2 O) is a clay mineral, the structure of which is similar to other 2:1 trioctahedral phyllosilicates (e.g., talc). Sepiolite has a continuous two-dimensional tetrahedral sheet, but it lacks continuous octahedral sheets. Discontinuities in the octahedral sheets and inversions of the silica sheets give rise to structural tunnels and ribbons expanded along the a-axis. Sepiolite is included in the class of modulated non-planar hydrous phyllosilicates [1,2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
