Development of a nano alumina-zirconia composite catalyst as an active thin film in biodiesel production

A Nano-alumina-zirconia composite catalyst was synthesized by a simple aqueous sol-gel method using AlCl3.6H2O and ZrCl4 as precursors. Thermal decomposition of the precursor and subsequent formation of γ-Al2O3 and t-ZrO2 were investigated by thermal analysis. XRD analysis showed that γ-Al2O3 and t-ZrO2 phases were formed at 700 °C. FT-IR analysis also indicated the phase transition to γ-Al2O3 occurred in corroboration with X-ray studies. TEM analysis of the calcined powder revealed that spherical particles were in the range of 8-12 nm. The nano alumina-zirconia composite particles were mesoporous and uniformly distributed in their crystalline phase. In order to measure the catalytic activity, esterification reaction was carried out. Biodiesel, as a renewable fuel, was formed in a continuous packed column reactor. Free fatty acid (FFA) was esterified with ethanol in a heterogeneous catalytic reactor. It was found that the synthesized γ-Al2O3/ZrO2 composite had the potential to be used as a heterogeneous base catalyst for biodiesel production processes

Lake overspill and onset of fluvial incision in the Iranian Plateau: Insights from the Mianeh Basin

Orogenic plateaus represent a prime example of the interplay between surface processes, climate, and tectonics. This kind of an interplay is thought to be responsible for the formation, preservation, and, ultimately, the destruction of a typical elevated, low-internal relief plateau landscape. Here, we document the timing of intermontane basin filling associated with the formation of a low-relief plateau morphology, followed by basin opening and plateau-flank incision in the northwestern Iranian Plateau of the Arabia–Eurasia collision zone. Our new U–Pb zircon ages from intercalated volcanic ashes in exposed plateau basin-fill sediments from the most external plateau basin (Mianeh Basin) document that the basin was internally drained at least between ∼7 and 4 Ma, and that from ∼5 to 4 Ma it was characterized by an ∼2-km-high and ∼0.5-km-deep lake (Mianeh paleolake), most likely as a result of wetter climatic conditions. At the same time, the eastern margin of the Mianeh Basin (and, therefore, of the Iranian Plateau) experienced limited tectonic activity, as documented by onlapping sediments and smoothed topography. The combination of high lake level and subdued topography at the plateau margin led to lake overspill, which resulted in the cutting of an ∼1-km-deep bedrock gorge (Amardos) by the Qezel-Owzan River (QOR) beginning at ∼4 Ma. This was associated with the incision of the plateau landscape and the establishment of fluvial connectivity with the Caspian Sea. Overall, our study emphasizes the interplay between surface and tectonic processes in forming, maintaining, and destroying orogenic plateau morphology, the transitional nature of orogenic plateau landscapes on timescales of 10^6 yr, and, finally, the role played by overspilling in integrating endorheic basins

Tectono-sedimentary evolution of the northern Iranian Plateau: insights frommiddle–late Miocene foreland-basin deposits

International audienceSedimentary basins in the interior of orogenic plateaus can provide unique insights into the early history of plateau evolution and related geodynamic processes. The northern sectors of the Iranian Plateau of the Arabia–Eurasia collision zone offer the unique possibility to study middle–late Miocene terrestrial clastic and volcaniclastic sediments that allow assessing the nascent stages of collisional plateau formation. In particular, these sedimentary archives allow investigating several debated and poorly understood issues associated with the long-term evolution of the Iranian Plateau, including the regional spatio-temporal characteristics of sedimentation and deformation and the mechanisms of plateau growth. We document that middle–late Miocene crustal shortening and thickening processes led to the growth of a basement-cored range (Takab Range Complex) in the interior of the plateau. This triggered the development of a foreland-basin (Great Pari Basin) to the east between 16.5 and 10.7 Ma. By 10.7 Ma, a fast progradation of conglomerates over the foreland strata occurred, most likely during a decrease in flexural subsidence triggered by rock uplift along an intraforeland basement-cored range (Mahneshan Range Complex). This was in turn followed by the final incorporation of the foreland deposits into the orogenic system and ensuing compartmentalization of the formerly contiguous foreland into several intermontane basins. Overall, our data suggest that shortening and thickening processes led to the outward and vertical growth of the northern sectors of the Iranian Plateau starting from the middle Miocene. This implies that mantle-flow processes may have had a limited contribution toward building the Iranian Plateau in NW Iran

Middle-late Miocene normal faulting in the intermontane Tarom basin during the collisional deformation of the Arabia-Eurasia collision zone, NW Iran: A regional process or a local feature?

The upper plate of the Arabia-Eurasia collision zone experienced orogen-perpendicular to orogen-parallel extension from 25–22 to 10–9 Ma. Although such an extension occurred during widespread collisional deformation, it is not clear if it is a local feature or if represents a major phase of upper plate extension. In this study we combine anisotropy of magnetic susceptibility (AMS) with fault kinematic analysis and sedimentologic data from 16.2- to 7.6-My-old deposits of the Upper Red Formation of the intermontane Tarom Basin (NW Iran). These strata present syndepositional, normal faults and offer the possibility to gain new insights into the spatial extent of such a Miocene extension. AMS data from the central and northern sectors of the basin document a tectonic fabric with a magnetic lineation parallel to the strike of the orogen, suggesting a compressional tectonic overprint. Conversely, the southern margin of the basin presents a purely sedimentary magnetic fabric despite a ~NE–SW orogen-perpendicular extension. This suggests that basin formation was not driven by extensional tectonics. Rather, the normal faults are gravity instabilities induced as also documented by coeval landslide deposits. This allows concluding that the orogen-perpendicular extension observed in few sectors of the collision zone is not regionally pervasive and hence it is not controlled by large-scale processes. Combined, our results indicate that if orogen-parallel extension associated with tectonic denudation and metamorphic core complex development occurred in certain sectors of the collision zone (Takab complex), it must have ended before 19–16 Ma, when widespread upper plate contractional deformation started. © 2021 Elsevier Lt