Inverted Fuel Cell: Room‐Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short‐Circuited PEM Fuel Cell without Applying any Electrical Voltage

A short‐circuited PEM fuel cell with a Nafion membrane has been evaluated in the room‐temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short‐circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released.     

Performance Evaluation of Nickel Separation and Extraction Process from Simulated Spent Cr/Ni Electroplating Bath Solutions by ELM Process Using LIX63 and PC88A

The study was conducted to investigate synergistic extraction of nickel from simulated spent Cr–Ni electroplating bath solutions by emulsion liquid membrane (ELM) process using 5,8-diethyl-7-hydroxydodecan-6-one oxime (LIX 63) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) as carriers. The importance of ELM composition and the properties of simulated spent electroplating bath solution have been optimized to synergistically extract nickel. The important parameters affecting the nickel extraction efficiency and ELM stability, such as acid concentration, stripping solution type and concentration, extractant concentration, surfactant concentration, and phase ratio, were experimentally studied. Along with obtained results, higher than 99% of nickel was selectively extracted within 30 minutes from simulated electroplating bath solutions that their metal concentrations was in the range of 100–500 mg/L. in the optimum conditions. The higher separation factor value of nickel over chromium (β_Ni/Cr) was obtained as 898. As a result, the nickel extraction kinetic was found to depend on PC88A, since extraction mechanism of PC88A is slower than that of LIX63. So, the combined use of LIX63 and PC88A improved the selective extraction of nickel in that process.