Macroporous monoliths based оn natural mineral sources, clay аnd diatomite

Maja Kokunesoski,Jelena Majstorovic,Aleksandra Saponjic,Svetlana Ilic,Marina Vukovic,Miroslav Stankovic,Djordje Saponjic

doi:10.2298/sos2003339k

Maja Kokunesoski, Jelena Majstorovic + Show 5 more

Open Access

https://doi.org/10.2298/sos2003339k

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Abstract

Macroporous silica ceramic was obtained using clay and diatomite. Boric acid as a low-cost additive in the amount of 1 wt% was used. These porous materials were obtained at low forming pressure (40-80 MPa) and lower sintering temperature (850-1300 ?C) for 4h in air. The influence of boric acid, forming pressure, and sintering temperature on the microstructure, porosity parameters, and mechanical properties of obtained porous monoliths were investigated. As-received and the modified samples were characterized by X-ray diffraction, FTIR, SEM, and mercury porosimetry measurements. As for modified clay and diatomite, they were pressed at 60 MPa and then sintered at 1150 ?C, obtaining porosities of about 10 % and 60 %, respectively. Both of the analyzed samples had the pore diameter in the range of macroporous materials. The pore diameters of clay samples are ranging from 0.1-10 ?m, whereas the pore diameter of diatomite samples was slightly lower with values ranging from 0.05-5 ?m. Modified diatomite samples have a lower Young modulus in comparison to modified clay samples.

Highlights

In the last few decades, significant progress has been made in the development of porous materials from natural minerals
Macroporous SiO2 ceramics based on the clay/diatomite were obtained by using an inexpensive method
As for the clay samples sintered at 1150 oC, the pore size distribution curves over the entire range of diameters are situated from 2.5 μm to over 10 μm which is higher in comparison to the diatomite samples (0.15-5 μm)

Summary

Introduction

In the last few decades, significant progress has been made in the development of porous materials from natural minerals. Porous ceramics provide an opportunity for combining important properties of materials, such as high porosity with high strength and high thermal, mechanical and chemical stability. This combination of properties is very important for various industrial applications in advanced environmental applications as filters, heat insulators, absorbents, catalyst supports, membranes, and chromatography columns [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. We used economical and green strategy in contrast to complicated processes which are usually applied in the synthesis of porous ceramics [15]

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