A hydrogen utilizing exoelectrogenic bacterium (Geobacter sulfurreducens) was compared to both a nonhydrogen oxidizer (Geobacter metallireducens) and a mixed consortium in order to compare the hydrogen production rates and hydrogen recoveries of pure and mixed cultures in microbial electrolysis cells (MECs). At an applied voltage of 0.7 V, both G. sulfurreducens and the mixed culture generated ...

Hydrogen production via bacterial fermentation is currently limited to a maximum of 4 moles of hydrogen per mole of glucose, and under these conditions results in a fermentation end product (acetate; 2 mol/mol glucose) that bacteria are unable to further convert to hydrogen. It is shown here that this biochemical barrier can be circumvented by generating hydrogen gas from acetate using a comple...

 A model is developed for separation of multicomponent gas mixtures in a countercurrent hollow fiber membrane module. While the model’s solution in countercurrent module usually involves in a time consuming iterative procedure, a proper initial guess is proposed for beginning the calculation and a simple procedure is introduced for correcting the guesses, hereby the CPU time is decreased ess...

The PAQUES Bio Systems’ core technology, marketed under the name THIOPAQ, consists of various high-rate biological processes for metal-sulfur-water systems, complemented with common solid/liquid and gas separation steps. Sulfur species are converted to sulfide, which is a valuable component as it can be used for metals reduction and precipitation. Selective recovery of valuable metals can be em...

This paper reports on the recovery of zinc, cobalt and manganese by two-step leaching of zinc-plants purification residue with sulfuric acid. The residue, hot filter press cake (HFC), contains 14 % ZnO, 4.8 % Co3O4 and 22.9 % MnO. Effects of different parameters are determined and used to optimize the process. With acid to hot filter press cake (HFC) stoichiometry of 0.85, acid concentration of...

In this research the simulation of an air independent Proton Exchange Membrane Fuel Cell (PEMFC) propulsion system was taken into consideration. The system consists of several parts including PEM fuel cell stack, metal hydride and liquid oxygen (LOX) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. The heat recovery...

however, the conventional gold recovery process is cyanidation, due to the recent environmental laws; researchers are looking for alternative methods for the recovery of gold. furthermore, the copper anode slime is one of the most important secondary sources of gold (about 1200 ppm). so, the main objective of the current work is gold separation from copper anode slime as a rich secondary source...

In this paper, we present our studies on thermally assisted recovery of low energy electron beam induced optical degradation of gallium nitride. A clear reduction in MOVPE grown GaN band-to-band photoluminescence intensity induced by low energy electron beam irradiation has been found before. Partial recovery of the band-toband emission was observed after annealing in both H2 and N2 ambient, at...