Abstract
Pumice is a porous volcanic rock containing a significant proportion of silica and alumina, and which has a low iron content. This natural, silica-rich material attracts wide attention because of its applications in adsorption processes, heterogeneous catalysis and nanotechnology. In this contribution, the white amorphous silica nanoparticles were extracted using an optimized alkaline treatment and an acid-precipitation process using grey pumice powder. The isolated amorphous silica SiO2 was characterized via X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electronic Microscopy (TEM-EDS), N2 adsorption/desorption measurements and simultaneous Thermal Gravimetry/Differential Thermal Analysis (TG/DTA). The obtained results indicated that the nanosilica powder was successfully prepared via the acid-base route with a predominantly amorphous mesoporous structure having a high surface area (422m2/g). The TEM images exhibited relatively homogeneous dispersed nanosilica particles with small sizes about 5–15 nm, in accordance with XRD data. Thermal analysis of the silica powder under air atmosphere showed total mass losses of 6.5%, with endothermic effects corresponding to the removal of water molecules and the OH of silanol groups contained in the material. The investigations performed in this work have indicated that there is great scope for pumice exploitation as a raw material in the production of amorphous silica nanopowder on large scale.
Highlights
Pumice is a cheap and abundant vesicular rock of volcanic origin, formed by the combination of SiO2 and Al2O3 at variable proportions
The production of silica from cheap raw materials has attracted much attention because it is more economical than conventional methods, which are based on the synthesis of pure silica from tetraethyl-orthosilicate (TEOS) using the sol-gel process [7, 8] or from quartz sand by alkaline-melting at high temperature [9]
This paper deals with the extraction method of amorphous silica material from local pumice rock, which is abundantly available in many parts of Morocco, by using acid-base leaching
Summary
Pumice is a cheap and abundant vesicular rock of volcanic origin, formed by the combination of SiO2 and Al2O3 at variable proportions. The first form is aggregated particles of colloidal dimensions and the second is fine-powder amorphous silica with a large surface area, obtained by coagulation of particles from an aqueous solution [10] Both materials have many potential applications, such as catalyst supports [11, 12], in pharma‐ ceuticals [13], in vegetable-oil refining [14] and in thin films or coatings for electronic and optical materials [15, 16]. This paper deals with the extraction method of amorphous silica material from local pumice rock, which is abundantly available in many parts of Morocco, by using acid-base leaching This easy and effective procedure leads to the production of nanosilica materials with special properties. Identification of the particles' texture and morphology was performed using MET-EDS microscopy, and the surface area was measured via the BET method
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
