To prepare chemically stable asymmetric microporous membranes with a hydrophilic surface, which would be expected to have better antifouling properties, poly(vinylidene fluoride) (PVDF) blend membranes were prepared by the phase inversion process. PVDF mixture solutions in N-methylpyrrolidone (NMP) blended with several polar potential ionic polymers such as polyacrylonitrile (PAN), poly(methylmethacrylate) (PMMA) and poly(N-isopropylacrylamide) (NIPAM) were used for the formation of the PVDF blend membranes. They were then characterized with several analytical methods such as FESEM, FTIR, contact angle measurement, pore size distribution and permeability measurement. Regardless of different polar polymers blended, they all showed a finger-like structure with more hydrophilic surface than the pristine PVDF membrane. For all the PVDF blend membrane, due to the polar potential ionic polymers used, the flux of those was improved. Especially the PVDF blend membrane with NIPAM showed the highest flux among the membranes prepared. Also antifouling property of the PVDF membrane was improved by the use of the polar polymers.

We performed periodic water-back-flushing using permeate water to minimize membrane fouling to enhance permeate flux in tubular ceramic microfiltration system for water treatment of high turbid source. The filtration time (FT) = 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume $(V_T)\;=\;6.805L$. Also in the result of BT effect at fixed FT = 10 min and BT (back-flushing time) = 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_o$, and we could obtain the highest $V_T\;=\;6.660\;L$. Consequently, FT = 2 min and BT = 6 sec could be the optimal condition in water treatment of high turbid source above 10 NTU. However, FT = 10 min and BT = 20 sec was superior to reduce operating costs because of lower back-flushing frequency. Then the average quality of water treated by our tubular ceramic MF system was turbidity of 0.07 NTU, $COD_{Mn}$ of 1.86 mg/L and $NH_3-N$ of 0.007 mg/L.

The transport and removal characteristics of cobalt ions were investigated in a continuous electrodeionization with cation exchange textile (CEDI-CET). It was shown that the removal properties of cobalt ions are strongly dependent on the operating parameters such as temperature, flow velocity, and the solution pH. The transport and removal of cobalt ions was mainly related to the sorption on the surface and the convection and electro-migration through the ion exchange medium. In this study, the CEDI-CET showed good process performance for the removal of metal ions compared with the conventional CEDI with resins.

PVDF membrane formation via TIPS was performed for PVDF/DBP and PVDF/DMP systems. PVDF/DBP system showed solid-liquid phase separation behavior, while PVDF/DMP system has liquid-liquid phase separation characteristic as well as solid-liquid phase separation characteristic. PVDF contents and cooling conditions had great influence on structure, and the effects of each parameter were examined. Spherulitic structure was obtained due to the dominant PVDF crystallization. Diluent rejected to the outside of spherulite occupied the surface of the PVDF spherulites to result in the microporous spherulite formation and micro-void between spherulites. PVDF/DMP system had competitive solid-liquid and liquid-liquid phase separation depending on the cooling path.

A perovskite-type ($La_{0.6}Sr_{0.4}Ti_{0.2}Fe_{0.8}O_{3-{\delta}}$) dense ceramic membrane was prepared by polymerized complex method, using citric acid as a chelating agent and ethylene glycol as an organic stabilizer. Effect of Ti addition on lanthanum-strontium ferrite mixed conductor was investigated by evaluating the thermal expansion coefficient, the oxygen flux, the electrical conductivity, and the phase stability. The thermal expansion coefficient in air was $21.19\;{\times}\;10^{-6}/K$ at 473 to 1,223 K. At the oxygen partial pressure of 0.21 atm ($20%\;O_2$), the electrical conductivity increased with temperature and then decreased after 973 K. The decrement in electrical conductivity at high temperatures was explained by a loss of the lattice oxygen. The oxygen flux increased with temperature and was $0.17\;mL/cm^2{\cdot}min$ at 1,223 K. From the temperature-dependent oxygen flux data, the activation energy of oxygen ion conduction was calculated and was 80.5 kJ/mol at 1,073 to 1,223 K. Also, the Ti-added lanthanum-strontium ferrite mixed conductor was structurally and chemically stable after 450 hours long-term test at 1,173 K.

This paper describes the preparation and characterization of two kinds of fluorinated polybenzimidazole (PBI)s which can be potentially used for phosphoric acid-doped, high-temperature polymer electrolyte membrane fuel cells. Two kinds of perfluorocyclobutane (PFCB)-containing monomers were prepared via following synthetic steps; after fluoroalkylation of methyl 3-(hydroxy) benzoate and methyl 4-(hydroxy) benzoate with 1,2-dibromotetrafluoroethane and subsequent Zn-mediated dehalogenation, these compounds were cyclodimerized at $200^{\circ}C$ affording the ester-terminated monomers containing PFCB ether groups. The synthesized intermediates and monomers were characterized using FT-IR, $^1H-NMR,\;^{19}F-NMR$, and mass spectroscopy. The fluorinated PBIs were then successfully prepared through the solution polycondensation of the monomers and 3,3'-diaminobenzidine in polyphosphoric acid. Compared with traditional PBI, the glass transition temperatures of the fluorinated PBIs were obtained at $262^{\circ}C\;and\;269^{\circ}C$ which are lower than that of PBI and their initial degradation temperatures were still high over $400^{\circ}C$ under nitrogen. The fluorinated PBIs showed higher d-spacing values and improved solubility in several organic solvents as well as phosphoric acid, which confirmed they could be good candidates for the high temperature fuel cell membranes.

A proton exchange membrane was prepared by ${\gamma}-irradiation-induced$ grafting of styrene into poly(tetrafluoro-ethylene-co-perfluoropropyl vinyl ether) (PFA) and subsequent sulfonation reaction. The degree of grafting (DOG) increased with an increase in the absorbed dose. The prepared membranes showed high ion exchange capacity reaching 3.0 meq/g, which exceeded the performance of commercially available perfluorosulfonic acid membranes such as Nafion. The proton conductivity of PFA-g-PSSA membrane increased with the DOG and reached 0.17 S/cm for the highest sample at room temperature. The DMFC performance of the prepared membranes with 50% DOG was comparable to that of Nafion membrane.

Amphiphilic graft copolymer from poly(vinylidene fluoride) (PVDF) was synthesized using atom transfer radical polymerization (ATRP) for composite nanofiltration membranes. Direct initiation of the secondary fluorinated site of PVDF facilitates grafting of tert-butyl methacrylate (tBMA). Amphiphilic PVDF-g-PMAA graft copolymer with a 51:49 wt ratio was obtained by hydrolyzing poly(tert-butyl methacrylate) (PtBMA) to poly(methacrylic acid) (PMAA). Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) confirmed the decrease of crystallinity of PVDF upon graft copolymerization. Composite nanofiltration membranes were prepared from PVDF-g-PMAA as a top layer coated onto PVDF ultrafiltration (UF) support membrane. The morphology and hydrophilicity of membranes were characterized using scanning electron microscopy (SEM) and contact angle measurement. The rejections of composite membranes were 80.2% for $Na_2SO_4$ and 28.4% for NaCl, and the solution flux were 9.5 and $14.5\;L/m^2\;h$ at 1.0 MPa pressure.