Solid State Reaction of Serpentinite Mg3Si2O5(OH)4 with NaOH to Produce a New Basic Catalytic Phase Na2Mg2Si2O7 for Biodiesel Production

Abstract

Solid state reaction of serpentinite Mg 3 Si 2 O 5 (OH) 4 with NaOH was investigated to produce new NaMgSi oxide phases with basic properties for application in catalysis. X-ray powder diffraction (XRD) showed that NaOH impregnated on serpentinite, specially 20% sodium and treated at 700 °C (20Na 700 ), led to the formation of a new crystalline phase Na 2 Mg 2 Si 2 O 7 . This solid state reaction is discussed in terms of a first step involving Na + diffusion and intercalation in the interlayer space of the serpentinite structure followed by a dihydroxylation and formation of the NaMgSi oxides. Temperature programmed reaction and desorption experiments with 20Na 700 combined with XRD suggested a strong basicity with high CO 2 uptake likely due to diffusion and interaction with the basic sites in the material structure. These materials were tested as catalysts for the transesterification of soybean oil with methanol. The obtained results are discussed in terms of a basic site Si-O -Na + present in the in the Na 2 Mg 2 Si 2 O 7 structure.

Caracterização Tecnológica De Metapiroxenito Da Formação Córrego Dos Boiadeiros, Nova Lima (Mg), Brasil

“…Also, this material has shown to be viable for the composite production through the reaction of the serpentine (Mg3Si2O5(OH)4) with LiOH, which has high CO2 retention capacity (Vieira et al, 2018). Paz et al (2018) synthesized a new catalytic phase Na2Mg2Si2O7 by the solid reaction of serpentine with NaOH to be used in the production of biodiesel. In addition to the serpentinite, in this region there is occurrence of metapyroxenite, which contains high talc content, reaching in some regions up to 50%.…”