Hydrogen mixture separation with PEEK-WC asymmetric membranes

Adsorption Behaviors of a Twin-Tower Hydrogen Purification System Mounted onto Staggered Stainless Steel Sheets Coated with Composite Membrane

Many studies have been conducted on hydrogen production, storage, purification, and transportation. The use of fixed-bed adsorption towers for hydrogen purification is common. The operating variables involved that could affect the adsorption behavior, such as the amount of adsorbents used, the flow rate, and the concentration of the adsorbate, should be discussed further. In addition, the pressure drop caused by the operation of the adsorption tower still needs to be considered. Therefore, the staggered stainless steel sheet coatings with SiO₂/MCM41/activated carbon composite membrane were mounted in a twin-tower adsorption system to purify the hydrogen. Similar to the pressure swing adsorption (PSA) system, the amounts of SiO₂, activated carbon, and molecular sieves used in the adsorption tower were changed into the amounts of tetraethoxysilane (TEOS), activated carbon powder, and MCM41 powder added to the casting solution. The experimental results showed that the performance of this twin-tower hydrogen purification system would not be increased when one of the target adsorbents was excessive. In addition, the outflow of non-hydrogen components was found to be early when a certain adsorbent was not sufficient. Finally, the recommended switching time for this system was set at an adsorption capacity reaching about 75% saturated capacity.

Tailoring PES nanofiltration membranes through systematic investigations of prominent design, fabrication and operational parameters

Design and fabrication of nanofiltration (NF) membranes with the desired characteristics and separation performance is of paramount importance.

As(III) oxidation by MnO2 coated PEEK-WC nanostructured capsules

PEEK-WC nanostructured capsules were prepared by the phase inversion technique and used as support for the coating of a manganese dioxide layer. The coating was done by a chemical treatment of the capsules followed by a thermal one. The presence of the MnO(2) layer was confirmed by scanning electron microscopy (SEM), back scattering electron (BSE), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The produced capsules were, then, tested for As(III) oxidation in batch. The experiments consisted in treating 165 ml of As(III) solution with 1g of coated capsules at fixed temperature (15°C) and pH (5.7-5.8). In particular, the efficiency of the system was investigated for different As(III) concentrations (0.1, 0.3, 0.7 and 1 ppm). For feeds at lower As(III) content (0.1-0.3 ppm), tests lasted for 8h, while prolonged runs (up to 48 h) were carried out on more concentrated solutions (0.7 and 1 ppm). The produced capsules were able to oxidize As(III) into As(V) leading to complete conversion after 3 and 4h for feed concentrations of 0.1 and 0.3 ppm, respectively.