Advanced Materials for Membrane–Based Gas Separation

The development of advanced materials for membrane gas separation has received much attention in the recent years. There are many important aspects involved in the development of new and advanced membrane materials including the type of material, transport mechanism, the relationship between membrane structure and performance and membrane preparation techniques. There are numerous materials being widely investigated as suitable candidates using advanced materials for membrane gas separation. Therefore, this paper discusses the progress in the development of an advanced membrane material and methods to prepare membranes for gas separation. The recent development and future direction in membrane material research are also presented.

EFFECTS OF MEMBRANE FABRICATION CONDITIONS TOWARDS THE PERFORMANCE OF NANOPARTICLES-INCORPORATED MEMBRANES

The development of nanoparticles-incorporated membranes is one of the recent techniques in improving membrane qualities in terms of fouling propensity. In this study, Zinc oxide (ZnO) has been selected as the nanoparticles to be embedded in membranes due to its excellent antifouling and antimicrobial properties. Several parameters such as polymer percentage and bath temperature were studied during the membrane fabrication process via phase inversion technique. The effects of each parameter towards the membrane structure and performance were significant in producing good membranes. When the polymer percentage increased from 16wt% to 20wt%, the permeability decreased from 6.9 to 3.9 L.m-2.hr-1.bar-1 and humic acid rejection increased from 78% to 95%. On the other hand, the coagulation temperature increment will lead to increment of permeability from 2 to 4 L.m-2.hr-1.bar-1 but gave rejection from 93% to 96% at 15oC to 25oC, and 86% at temperature of 35oC.In conclusion, the optimum condition for nanoparticles-incorporated membranes fabrication was shown at 20% of PSF at 25oC.

Making of Nanopore NaA Zeolite Membranes for Saline Wastewater Treatment

Zeolite membranes have been studied extensively for more than fifteen years, mainly focusing on gas separation and liquid pervaporation processes. Recently, molecular dynamic simulation has shown that zeolite membranes are theoretically suitable for ion removal from aqueous solutions. This work proposes to use zeolite membranes for desalination of saline recycled wastewater for the possibility of avoiding the costly treatment needed for saline wastewater by Conventional approaches. NaA zeolite membrane indicates that it may be possible to simultaneously separate ions and dissolved organic compounds from water by pervaporation (PV) processes. NaA zeolite membranes composed of a continuous intergrowth of NaA zeolite crystals have been prepared hydro thermally on the surface of porous tubular supports. In this research, synthesis of zeolite NaA membrane was investigated. SEM and XRD analysis have been used to confirm zeolite NaA membrane formation. Membrane performance has been evaluated using an experimental pervaporation setup. Effects of operation condition (temperature, rate and pressure) on the membrane structure and performance have been investigated for NaA zeolite membranes grown onto seeded mullite supports.

Preparation and characterization of anti-fouling PVDF membrane modified by chitin

Poly(vinylidene fluoride) (PVDF)/chitin (CH) blend membranes were prepared via the method of immersion-precipitation phase transformation with the solvent system N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl) as solvent and water as coagulant. The effect of CH on membrane structure and performance was investigated. Owing to the strong hydrophilicity, CH chains enriched on the blend membrane surface and improved the hydrophilicity of the membrane. The addition of CH also led to the formation of finger-like pores and the increase of pore size and porosity. The flux and the flux recovery ratio (FRR) of the blend membrane were higher than that of pure PVDF membrane. The fouling resistance of the blend membrane was lower than that of PVDF original membrane. In a word, the addition of CH to PVDF membrane improved the hydrophilicity and the anti-fouling ability of PVDF membrane.

Comparative Study on Effect of PEG and PVP as Additives on Polysulfone (PSF) Membrane Structure and Performance

PSf flat sheet membrane was prepared via phase inversion technique with N-methyl-2-pyrroidone (NMP) as solvent. In this study polyethylene glycol (PEG) and polyvinylpyrollidone (PVP) were compared as additives at different composition (0.5 wt%, 1 wt%, 3 wt% and 5 wt%). The structure and morphology of the resulting membranes were observed by scanning electron microscope (SEM) and the membranes permeation were evaluated in terms of pure water flux (PWF) and solute rejection. Solution of bovine serum albumin (BSA) was used to study the performance of prepared membrane. The addition of the additives into the casting solution changed the structure of the resultant membranes, which was believed to be associated with the change the permeated of water. The results demonstrated that at the same additive content, PSf/PVP membranes had higher PWF at 0.5 wt% and and 5 wt% of additive while PSf/PEG at 1 wt% and 3 wt% of additive. The BSA rejection show no significant changes for PSf/PEG while PSf/PVP, BSA rejection decrease with increase the increasing the PVP. For PEG, additive from 0% to 5%, the PWF increased from 14.73 at to 101.85 LMH. While for PVP, the PWF increased from 21.13 to 177.61 LMH. The membrane morphology showed that all images showed the membranes were having asymmetric structure consisting of a dense top layer, a porous sublayer, and a small portion of sponge-like bottom layer. The top layer of the membrane consist of finger-like structure while at bottom layer has macrovoid structure. With increasing the additive, the finger-like structure become longer to the bottom and macrovoid become smaller. The study found that PEG gives the optimum performance based on the result of rejection and flux permeation.