Modification of sulfonated poly (ether ether ketone) (SPEEK) membrane was conducted by incorporating Cloisite 15A® clay and 2,4,6-triaminopyrimidine (TAP) via solution intercalation method. The effect of the Closite and TAP introduction was evaluated in terms of the membrane’s physicochemical and hydration properties. The membrane’s properties were compared among the SPEEK based membranes, including parent SPEEK, SPEEK/Cloisite and SPEEK/Cloisite 15A®/TAP. The uniform dispersion of Cloisite 15A® particles in SPEEK polymer matrices was confirmed by SEM analysis. The stability in water; in terms of dimensional change and dissolution, of the modified membrane was investigated and compared to the parent SPEEK membrane. SPEEK/Cloisite 15A®/TAP nanocomposite membrane exhibited the highest selectivity by means of the ratio of proton conductivity to methanol permeability. Owing to its higher proton conductivity and significantly lower methanol permeabilities and high stability in water environment, SPEEK/Cloisite 15A®/TAP nanocomposite membrane was found to be a potential alternative polymer electrolyte membrane for DMFC applications.
This paper reports the preparation of the dual layer ceramic hollow fiber membrane that made of alumina and a mixed
ion electron conducting (MIEC) material for simultaneous reaction and separation applications. Alumina hollow fiber
membrane was prepared using the phase inversion process followed by a sintering technique at elevated temperature. The
alumina hollow fiber membrane was used as membrane support onto which a thin and dense layer of lanthanum strontium
cobalt ferrite (LSCF) was deposited. The main objective of this study was to investigate the LSCF coating formulations
used in the deposition of LSCF layer onto alumina substrate membrane. The sintering temperature of thin LSCF layer was
varied to investigate gas-tightness properties of LSCF membrane. A series of characterizations were conducted for both
the support and the LSCF membrane. The result showed that the thin layer membranes with thicknesses ranging from 3
to 20 µm were successfully deposited on the surface of alumina hollow fiber support. The sintering process improved the
gas-tightness properties but the sintering temperature above 1150o
C caused defects on the surface of LSCF membrane.
This article describes the preparation of titanium dioxide (TiO2) hollow fiber membrane using phase inversion and sintering technique. In this study, nano-sized TiO2 powders with different particle sizes were used to prepare ceramic hollow fiber membranes. In a series of preparation steps, a dispersant was dissolved in organic solvent before the addition of ceramic powders. These steps were followed by the addition of polymer binder. The membrane precursor was obtained by extruding the ceramic suspension into a coagulation bath, which enabled the precipitation of the precursor of ceramic hollow fiber membrane. The dried precursor was later sintered at temperatures ranging from 1200 to 1300oC to obtain TiO2 hollow fiber membrane. Scanning electron microscopy (SEM) was used to study the morphology of TiO2 hollow fiber membrane. The SEM images show the membrane can be shaped into asymmetric structure and symmetric structure based on the ceramic suspension compositions. The highest mechanical strength obtained was 223 MPa when the membrane prepared using 20 wt. % ceramic loading of single nano-sized powder and sintered at 1300oC. TiO2 hollow fiber membrane prepared using similar ceramic loading showed high permeation rate of inert gas. High pure water fluxes were obtained when permeability tests was carried out using TiO2 hollow fiber membrane, prepared using mixture of nano-sized particles, even though its cross-section have a sponge-like structure.
Reduced graphene oxide nanosheet (RGO)/Pt nanocomposite have been successfully prepared through a facile chemical reduction method. The reduction of Pt precursor was carried out using sodium borohydride as the efficient chemical reductant. The morphology of RGO/Pt nanocomposite was investigated using high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). HRTEM analysis showed that platinum nanoparticles were homogenously distributed onto the surface of RGO. The electrochemical study proved that Pt nanoparticles were successfully incorporated onto RGO. Therefore, it can be concluded that the proposed method could provide well-dispersed of Pt nanoparticles onto RGO to form RGO/ Pt nanocomposite.