Supercritical fluid extraction (SFE) provides an environmentally green technique to decontaminate chromium species from solid matrices using supercritical fluid carbon dioxide (ScCO2). Methanol and a small amount of water were found to significantly improve the extraction efficiency. The fluorinated chelating agent lithium bis(trifluoroethyl)-dithiocarbamate (LiFDDC) was effective in removing C...

Ethanol oxidation rate in high pressure steam at the pressure of 10 MPa in the temperature ranging from 430 to 490 °C was studied with the fuel equivalence ratio of 0.4. On the assumption that the reaction order is first order, the reaction rate parameters obtained in the experiments are 10 ± 0.4 s for the pre-exponential factor and 166.5 ± 6.1 kJ·mol for the activation energy. This ethanol oxi...

In this work we compared the efficiency of a laccase treatment performed on steam-exploded wheat straw pretreated under soft conditions (water impregnation) or harsh conditions (impregnation with diluted acid). The effect of several enzymatic treatment parameters (pH, time of incubation, laccase origin and loading) was analysed. The results obtained indicated that severity conditions applied du...

4,4'-Bis(dihexylaminocarbonyl)-2,2'-bipyridine (BDC-Bipy) was synthesized and studied systematically as a chelating reagent for metal ions extraction in supercritical CO(2). The compound showed high extraction efficiency for Co(2+) (100%), Cu(2+) (100%), Cd(2+) (98.2%), and Zn(2+) (100%) ions and good extraction efficiency for Sr(2+) (79.4%) and Pb(2+) (89.8%) when the extraction was performed ...

The oxidation of benzene at a lead dioxide electrode which produces predominantly benzoquinone, maleic acid, and carbon dioxide, has been investigated in aqueous NaHSO4 solutions as a function of temperature up to 250~ An increase in the benzene concentration does not increase the concentration of benzoquinone formed at high temperature, which is different from the behavior at 25~ The formation...

Study presents that supercritical methanol has the ability to convert oils/fats consisting of triglycerides and free fatty acids (FFAs) into fatty acid methyl esters through transesterification and methyl esterification, respectively, without any catalyst. This one-step method (Saka process) is simpler process realizing shorter reaction time and higher yield of methyl esters than those of the c...

As the important signal of once-through boiler's water-fuel ratio control, intermediate point temperature of supercritical boiler plays a key role in the decision of steam and water’s boundary, the match of fuel and water, the control of main steam temperature. The condition of its control directly impacts the once-through boiler’s safety and economy running. For an uncertainty model, a good co...

Sonic velocities of geologic fluids, such as volcanic magmas and geothermal fluids, can be as low as 1 m/s. Critical velocities in large rivers can be of the order of 1-10 m/s. Because velocities of fluids moving in these settings can exceed these characteristic velocities, sonic and supersonic gas flow and critical and supercritical shallow-water flow can occur. The importance of the low chara...