In this work, bio-oil (an organic matrix rich in oxygen functionalities) was used to efficiently dissolve and disperse Fe3+ which upon thermal treatment produced a carbon containing dispersed and encapsulated Fe oxide magnetic nanoparticles. These materials were prepared by dissolution of 8, 16 and 24 wt.% Fe3+ salt in bio-oil followed by treatment at 400, 450, 500 or 600 ºC in N2 atmosphere. X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopies (TEM), elemental analysis, thermogravimetric-mass spectrometry (TG-MS), potentiometric titration, Raman and Mössbauer spectroscopies showed that Fe3+ species in bio-oil is reduced to produce magnetic nanoparticles phases: magnetite Fe3O4 and maghemite γ-Fe2O3. At low temperatures, the iron phases were less protected, and the carbon matrix was more reactive, while in temperatures above 500 ºC, the iron phases were more stable, however, the carbon matrix was less reactive. Reaction of these magnetic carbon materials with concentrated H2SO4 produced surface sulfonic acidic sites (ca. 1 mmol g-1), especially for the materials obtained at 400 and 450 ºC. The materials were used as catalysts on esterification reaction of oleic acid with methanol at 100 ºC and conversions of 90% were reached, however, after 2 consecutive uses, the conversion decreased to 30%, being required more studies to improve the material stability.

In this work, a potassium magnesium silicate mineral based on phase K2MgSiO4 was prepared from serpentinite rock and studied as a potential K and Mg slow-release fertilizer. The material was prepared by impregnation of serpentinite/KOH and calcination at 700 °C to produce K2MgSiO4 phase, olivine and forsterite. The release patterns of K and Mg in the stirred-flow trial and leaching through the soil columns showed that K2MgSiO4-based materials released K on lower rates than KCl and MgSO4.7H2O, however, there was no evidence of Mg release. The extraction with 1 mol L-1 NH4OAc showed a considerable content of Mg and K for K2MgSiO4-based materials, due to exchange of NH4+ and Mg2+. X-ray diffraction (XRD) analysis of materials impregnated with K and calcined showed peaks relative to K2MgSiO4. After leaching, the peaks intensity diminished, supporting that part of K leached. Therefore, the samples showed great potential as slow-release K-fertilizers when compared with KCl source.

Solid state reaction of serpentinite Mg3Si2O5(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 ºC (20Na700), led to the formation of a new crystalline phase Na2Mg2Si2O7. 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 20Na700 combined with XRD suggested a strong basicity with high CO2 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 Na2Mg2Si2O7 structure.