Zeolite-SEPIOLITE inorganic nanoheterostructures have been hydrothermally synthesized by adding a dispersion of colloidal SEPIOLITE to a solution able to produce a nanocrystalline zeolite (silicalite). The obtained product could be recovered in good yield by simple filtration only when the relative SEPIOLITE concentration exceeded a threshold of 1.8 wt% in the synthesis mixture (amounting to 1: 3 SEPIOLITE: zeolite wt. ratio in the recovered product). The resulting heterostructures were characterized by XRD, FTIR, thermal (TG-DTA) and chemical analyses, N2 adsorption, TEM, SEM, 29Si NMR, and methylene blue adsorption. The intimate zeolite-SEPIOLITE interaction at the surface produced a good dispersion of zeolite particles and prevented their sintering upon calcination to remove the organic structure-directing agent.Experiments in conditions yielding microcrystalline silicalite support the idea that the SEPIOLITE surface acts as nucleation sites for the zeolite crystallization. The textural properties of the nanozeolite-SEPIOLITE heterostructure are not a linear combination of their components’.

SEPIOLITE deposits have been recently discovered in northeastern Iran. However, there is still little information about its physicochemical and mineralogical characteristics. Therefore, the collapse of the SEPIOLITE (with sizes of<63 mm) structure induced by temperature elevation in an electric furnace at 350, 550, and 850oC for 4 hours was studied using X-ray diffraction (XRD) in combination with Thermogravimetric analysis (TGA) and infrared spectroscopic analysis. Results showed that the main mineral constituent of the samples is a well crystallized SEPIOLITE. However, dolomite and quartz were also present in minor amounts. Results also revealed that with temperature different phases including ‘SEPIOLITE dihydrite’, ‘SEPIOLITE anhydrite’ and ‘enstatite’ were formed, as magnesium coordinated water and octahedrically coordinated hydroxyl groups, were eliminated and the dehydroxylated phase was recrystallized to enstatite, a stable form of magnesium silicate (MgSiO3).

Biodiesel production is energy-consuming and requires an appropriate catalyst to boost the reaction. In the present study, waste edible oil was used as the feedstock, an infrared lamp was utilized as the heat source, and a solid acid catalyst based on SEPIOLITE (Sep) clay was applied. The SEPIOLITE catalyst was modified with chlorosulfonic acid and exhibited a nanoscale particle size distribution. The effects of infrared irradiation on the reaction time and quality of the oil-methanol-catalyst system were investigated and compared with conventional electric heating. Material properties were characterized by XRD (X-ray diffraction) and FE-SEM (field-emission scanning electron microscopy), and the biodiesel yield and quality were evaluated by GC-MS (gas chromatography-mass spectrometry) analysis. The experimental results demonstrated that the SEPIOLITE nanocatalyst achieved a high biodiesel yield of 96.5% under infrared irradiation, about 4% higher than that of the conventional heating under the same conditions. Meanwhile, radiation heating reduced energy consumption per liter by 68% compared to electric heating. The biodiesel production cost on a laboratory scale was estimated at 1.26 to 1.65 $/lit for the infrared irradiation and 1.68 to 2.62 $/lit for the electric heating method. The separation and recovery of the catalyst from the transesterification reaction products were also studied and found to be easier, faster, and simpler than those of homogeneous catalysts. The catalyst was successfully reused for three successive cycles, with less than a 2% reduction in the yield per cycle, and still showed a biodiesel yield of above 90%.