Mixed Acetic Acid Research Articles

Construction and metabolic analysis of acetone-butanol-ethanol fermentation using mixed acetic acid and lactic acid in wastewater

To reuse organic acids in wastewater, efficient acetone-butanol-ethanol (ABE) fermentation was constructed using mixed acetic acid and lactic acid. The mixed acids were co-consumed with glucose, producing higher butanol concentration (6.96 g/L) and butanol yield (0.494 C-mol/C-mol) than using each single acid (6.22 g/L and 0.432 C-mol/C-mol). This result was verified by 13 C tracer experiment that addition of lactic acid improved carbon distribution to butanol instead of acetone , while acetic acid was readily consumed than lactic acid at initial fermentation stage. Subsequently, pH-stat fed batch fermentation at low pH of 5.5 further improved acid consumptions (6.34 g/L acetic acid and 9.06 g/L lactic acid) and solvent productions (12.4 g/L butanol and 6.50 g/L acetone). Finally, ABE fermentation using wastewater of lactic acid fermentation was performed without inhibition. Thus, efficient ABE fermentation can be implemented using mixed acetic acid and lactic acid, which is superior to using single acid. • This is the first study using mixed acetate and lactate for ABE fermentation. • 13 C experiment verified the metabolic flux to butanol was improved by the acids. • pH and glucose played an important role in acid consumption and solvent production. • Fermentation from lactic acid fermentation broth was performed without inhibition.

Application of ZnO/epoxy resin superhydrophobic coating for buoyancy enhancement and drag reduction

The air layer produced by superhydrophobic coating can change the contact mode between the surface and water, which grants it potential application prospects in buoyancy enhancement and drag reduction. However, the buoyancy mechanism of superhydrophobic coating still lacks systematic understanding. Herein, a superhydrophobic glass was prepared by coating a ZnO/epoxy resin (ER) solution onto the glass, which was subsequently reacted with mixed acetic acid, stearic acid, and ethanol solution. The introduction of superhydrophobic coating changes the contact mode between the surface of the glass and water, and the coated position will affect the final floating state of superhydrophobic glass. Edge-coated, top-coated and whole-coated glass can float on the surface of water due to surface tension. In addition, whole-coated glass possesses the highest loading capacity of 7.48 g. Furthermore, the whole-surface coating method was applied to a model boat to investigate the drag reduction effect of superhydrophobic coating on a model boat at terminal velocity. The drag reduction efficiency of superhydrophobic model boat increased from 5 % to 21 % with the increase of pulling force, which demonstrating a good drag reduction effect. Thus, this superhydrophobic coating may offer a relevant strategy for buoyancy enhancement and drag reduction in practical applications.

Low-Temperature Electrochemical Upgrading of Bio-oils Using Polymer Electrolyte Membranes

While bio-oil-derived fuels hold much promise as a replacement for petroleum, transformation of the highly oxygenated mixture has proven challenging. In particular, bio-oils are reactive and difficult to upgrade through catalytic pyrolysis. To reach a stabilized product capable of deep deoxygenation at elevated pressure and temperature, conversion or separation of reactive groups is required. This paper describes an electrochemical process for stabilization and upgrading of bio-oils prior to hydrotreating at high pressure and temperature. This electrolytic process uses a three-compartment cell designed to hydrogenate reactive carbonyl components while separating small acid molecules, such as acetic and formic acids, which act as catalysts for condensation reactions and consume hydrogen gas to produce low-value gases in hydrotreating. To avoid conductivity issues, electrodes are appended to anion- and cation-exchange membranes. The cell was tested using a mixed acetic acid and formic acid surrogate fed to ...

One-step hydrothermal synthesis of hierarchical Ag/Bi2WO6 composites: In situ growth monitoring and photocatalytic activity studies

Hierarchical Ag/Bi2WO6 nanomaterials were prepared by a facile one-step hydrothermal method in mixed acetic acid and ethylene glycol (EG) medium. EG is employed as mild reducing agent for the formation of metallic Ag from Ag+ precursors. In situ energy dispersive X-ray diffraction (EDXRD) monitoring showed that the hydrothermal formation kinetics of Bi2WO6 in the presence of EG was significantly slowed down due to its very high viscosity. The photocatalytic activities of Ag/Bi2WO6 composites were evaluated by the photodegradation of methylene blue (MB) under visible light irradiation. The photocatalytic activity of Bi2WO6 is strongly influenced by the Ag loading. The enhanced catalytic activity of the composites is based on the cooperative effects of plasmon absorption band and separation of photogenerated electron-hole pairs.