نتایج جستجو برای: Hydrothermal process
تعداد نتایج: 1326923 فیلتر نتایج به سال:
in this research, a single-stage low-temperature hydrothermal synthesis route was successfully developed for preparation of iron disulfide. the prepared powder was characterized by x-ray diffraction (xrd) and scanning electron microscopy (sem). these analyses showed that nanoparticles were well crystallized, pyrite was the main product and the shape of crystals was nanorod. also, the influences...
BACKGROUND Panax ginseng Meyer is cultivated because of its medicinal effects on the immune system, blood pressure, and cancer. Major ginsenosides in fresh ginseng are converted to minor ginsenosides by structural changes such as hydrolysis and dehydration. The transformed ginsenosides are generally more bioavailable and bioactive than the primary ginsenosides. Therefore, in this study, hydroth...
background: the purpose of the present study was to assess the efficiency of ultrasound/hydrogen peroxide processes and ultrasound/hydrogen peroxide/zno nanoparticles in the removal of blue cat 41 dye from aqueous solutions. methods: zno nanoparticles were prepared using the hydrothermal method. variables including ph, concentration of zno nanoparticles, initial dye concentration, concentration...
Needle-like ZnO nanostructures were synthesized by an organic-free hydrothermal process. Thehydrothermal synthesis was performed at very low pressure (~20 kPa) with duration of process only 10min. The products were characterized by X-ray powder diffraction (XRD)and transmission electronmicroscopy (TEM).The XRD pattern indicated that the needle –like ZnO nanostructures were hexag...
Tubular ZnO microstructural arrays were fabricated by a hydrothermal decomposition method. The dependence of the morphologies on the growth time and temperature was investigated in detail. An experiment was carried out to determine the mechanism of tubular ZnO formation. Our results showed that ZnO microtubes originated from an ageing process from ZnO microrods at a lower temperature (compared ...
Sub-critical or supercritical water was utilized for the degradation of glycerol in an environmentally benign reaction. The reaction was carried out in a batch reactor in the temperature range of 473-673 K, pressure of 30 MPa, and reaction time of 20-60 min. The effects of temperature and reaction time were observed. The degradation of glycerol produced acetaldehyde, acrolein, allyl alcohol and...
Prokaryotic symbionts are common in invertebrates and play an essential metabolic role in deep-sea hydrothermal vent communities. Complete genome sequences of bacterial endosymbionts of two deep-sea clams are providing new insights into evolutionary genome reduction.
The production of lactic acid from glycerol by means of the alkaline hydrothermal process was evaluated using high concentrations of glycerol. The operating conditions that influence the hydrothermal process were studied. Temperature (250 280 °C), catalyst to glycerol molar ratio (0.05 to 0.15), and water to glycerol volumetric ratio (0.8 to 1.5) were evaluated, as well as the use of NaOH and K...
Biosorption using agricultural wastes has been proven as a low cost and efficient way for wastewater treatment. Herein, grape peel treated by microwave- and conventional-hydrothermal processes was used as low cost biosorbent to remove methylene blue (MB) from aqueous solutions. The adsorption parameters including the initial pH value, dosage of biosorbents, contact time, and initial MB concentr...
A Silver (Ag) thin film is introduced as a template and doping source for vertically aligned p–type ZnO nanorods. ZnO nanorods were grown using an ammonium hydroxide based hydrothermal process. During the hydrothermal process, the Ag thin film was dissolved to generate Ag ions in the solution. The Ag ions can contribute to doping in the wurzite structure of ZnO and the (111) grain of Ag thin fi...
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