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We used ethanol, methanol, butanol, and hydrogen as electron donors and acetate and propionate as electron acceptors to test the occurrence of microbial chain elongation in four soils with different physicochemical properties and microbial communities. Common chain elongation products were the even numbered chains butyrate, caproate, and butanol, the odd numbered carboxylates valerate and heptanoate, along with molecular hydrogen. At a near neutral pH and mesophilic temperature, we observed a stable and sustained production of longer fatty acids along with hydrogen. Microbial community analysis show phylotypes from families such as Clostridiaceae, Bacillaceae, and Ruminococcaceae in all tested conditions. Through chain elongation, the products formed are less biodegradable. They may undergo transformations and end up as organic carbon, decreasing the greenhouse gas emissions, thus, making this process important to study.
There has been a recent push to examine the materials that nature is able to synthesize and consider whether the materials that humans have invented are geomimetic in nature, and whether designing nature-inspired materials is economically and environmentally beneficial. Mesoporous silica represents a class of materials with pore sizes of 2-50 nm and has been studied in catalysis, separations, and drug delivery. It has generally been made using organosilicon precursors, but in this work, we demonstrate for the first time the successful synthesis of mesoporous silica with uniform mesoporosity of 10 nm using the mineral forsterite (Mg2SiO4) as a silica source, providing a potentially cheaper and more Earth-friendly route to making this technologically important material. Forsterite was synthesized by a solid-state chemistry route and underwent dissolution-reprecipitation in an aqueous acid solution containing the soft template surfactant, Pluronic P123. The formation of forsterite was confirmed with X-ray diffraction (XRD), the successful templating of surfactant was demonstrated with thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR), the surface area was determined through Brunauer-Emmett-Teller (BET) analysis, and pore size and distribution were demonstrated with Barrett-Joyner-Halenda (BJH) analysis. The synthesized mesoporous silica at optimal conditions has surface area of 740 m2/g and pore volume of 1.4 mL/g.