Singapore Membrane Consortium

This technology relates to a series of block co-polymers that have the superior anti-fouling capability made through green synthesis by using water as a solvent. One of the co-polymers has been grafted onto the selective layer of thin film composite (TFC) membranes as a demonstration of its anti-fouling function. The resultant membranes show pure water permeability of up to 10 LMH/bar, NaCl rejection of ~98%, and high resistance to alginate and protein fouling. Moreover, no significant fouling is observed when realistic feed from the local RO plant is tested for 10 days.    

Isopropanol (IPA) is an important solvent and cleaning agent with wide applications in semiconductor, microelectronic and pharmaceutical industries. IPA is primarily produced by combining water and propene in a hydration reaction. The IPA produced is usually in a mixture with water and distillation is used to obtain IPA with 87.9% purity. Higher purity IPA can only be achieved through azeotropic distillation with cyclohexane or diisopropyl ether. In both cases, a large amount of energy is used for the purification process.To lower purification cost, pervaporation, a membrane‐based technology, is a promising method because of its easy operation, low energy consumption and small footprint. Pervaporation is a membrane process whereby the permeate side is under vacuum and water is vapourised as it passes through the membrane from the feed side to the permeate side. Pervaporation is able to provide a high level of separation efficiency for azeotropic mixtures of alcohols and water to obtain the purity required for the alcohols.This technology relates to a thin film composite (TFC) membranes on ceramic substrates (referred to as ceramic TFC membranes thereafter) for pervaporation dehydration of organics. The ceramic TFC membrane can be obtained by using interfacial polymerization on a microfiltration ceramic membrane. Compared to commercially available ceramic and polymeric membranes for pervaporation, it has extremely high water flux compared to other ceramic/polymeric membranes for pervaporation making it suitable for high volume processing.

This invention relates to a polyacrylonitrile (PAN)-based membrane suitable for dehumidification and oxygen enrichment, with a proprietary PDMS selective layer. The substrate material is PAN, which is a low cost and commonly available polymer for membrane fabrication. The membrane is made by coating the substrate with the selective layer. The membrane may also be suitable for gas separation, air separation, paraffin-olefin separation, oxygen enrichment, CO2 capture, hydrocarbon recovery, and volatile organic compounds separation.

Heavy metals are highly toxic contaminants found in industrial wastewater that may find their way into drinking water sources through unregulated discharge from industrial plants. Even at low concentrations, heavy metals can disrupt a human body's normal physiological activities and can accumulate in certain organs causing a range of chronic diseases. As such, heavy metal pollution has drawn attention from regulatory agencies throughout the world that has set increasingly stringent standards to curb heavy metal discharge into water bodies and membrane technology will be able to treat these wastewaters.This technology relates to nanofiltration (NF) membrane molecularly designed to remove heavy metals such as Zinc, Nickel and Lead at higher rejection rates compared to conventional NF membranes. This is done through functionalizing specialized polymers on a P84 polyimide substrate which provides an extra means to remove heavy metals through adsorption. 

Graphene-derived permeable membrane with ion selectivity permits outgoing and incoming of selective ions (e.g. positively or negatively charged in a system). They consist of ion channels that facilitate the efficient separation and transport of different ions. As such, these membranes are employed to produce required ions via electrolysis of salt solution during a process.The technology relates to the use of functionalized graphene oxide (GO) based membranes so as to separate ions from the feed stream for the purpose of kidney dialysis, nanofiltration or ion exchange. The membrane is a graphene-based membrane with an electrical charge, in which layers of graphene-based material are stacked together, with one or more nano-channels between neighboring layers.

This technology relates to a reinvention of the structure of spiral wound membrane module to increase productivity and to simplify the membrane fabrication process. Despite undergoing a long history of development, the structure of the spiral wound membrane modules remained the same. Each module is made up of several leaf sets, with each leaf set consisting of feed spacers, flat sheet membranes and a permeate carrier wrapped around the permeate collecting tube. The technology here involves combining the 3 layers in a leaf set into 2 layers on an industrial-scale casting line such that more membrane can fit into a standard specific volume. By combining the permeate carrier and the membrane into a single sheet, we were able to eliminate the need for the typical non-woven backing for the membrane. As such, the leaf set thickness can be significantly reduced by approximately 10-20%, and hence the theoretical surface area and productivity of the membrane modules can be increased by 30-50%. The material cost can potentially be reduced by 10-20% and the internal ion concentration polarization (ICP) is expected to be reduced due to less bulky structure. This design also lessen the work required to roll an element due to less sheets per leaf-set. The technology provider is currently seeking joint-venture partners for technology evaluation licensing with research collaboration agreement (RCA) to scale-up and commercialize the technology.

This innovative technology is a Vibratory-Stirring (VS) membrane module for submerged anaerobic membrane bioreactors (AnMBRs), which can control membrane fouling and also mix the biosolids within the reactor for both domestic and industrial wastewater treatment. The technology takes advantage of membrane filtration and anaerobic processes to treat high strength wastewater. In addition, the anaerobic digestion results in low sludge volume and produces biogas for energy generation. The membrane module incorporates transversely vibrating hollow fibre membranes, and special structural features for additional stirring and turbulence generation. The fouling control is achieved by the combination of vibratory shear stresses and turbulence, together with turbulent mixing of biosolids inside the reactor. The technology will allow for high permeate flux and long membrane filtration operation time in anaerobic membrane bioreactors.  The concept has been proven in an anaerobic reactor with high strength wastewater for a continuous 10-month operation, without any backwash or chemical wash of the membranes.

Separation of oil/water mixture using wetting materials has been extensively investigated. However, the wastes released in industrial processes such as multi-phase liquids extraction, food industries or chemical reaction contain more complicated liquids components. The technology presents a novel strategy to prepare a broad range of superlyophobic materials based on polydopamine (PDA) mediated coating. The results demonstrate that the deposition of PDA nanoparticles enhances the growth of silicone microsheets (SMS), which increases trapped air fraction and results in superlyophobicity towards high surface tension liquids and superlyophilicity to liquids with surface tension smaller than 30 mN/m. Superlyophobic sorbents generated from melamine foam and polyurethane foam can absorb various oils with capacity from 53 g/g to 120 g/g (melamine foam) and from 26.5 g/g to 52.5 g/g (polyurethane foam), depending on the oil type and density. High absorption capacity of porous foams towards oils makes them possible to remove low surface tension liquids from a batch of high surface tension immiscible organic liquids such as formamide or diethylene glycol. On the other hand, superlyophobic membranes fabricated from stainless steel mesh, cotton fabric and filter papers can filter chloroform and carbon tetrachloride from water and formamide with efficiency higher than 96%. All as-prepared superlyphobic materials show excellent regeneration. The preparation of superlyophobic materials introduced in this work opens a general strategy for separation of immicible liquids by both static and continuous methods. The technology provider is seeking partner for research collaboration, scale-up testing/test-bedding, product co-development, technology licencing or manufacturing.    

Pressure Retarded Osmosis (PRO) utilizes osmosis through a semi-permeable membrane to generate osmotic energy. In PRO, water spontaneous flows from a low-salinity feed solution to a high-salinity draw solution against an applied pressure, driven by the osmotic pressure difference between the feed and draw solutions. The permeation water flow is immediately pressurized to the applied pressure on the draw solution side, which can be further utilized for power generation via a turbine or an energy recovery device. The research groups utilises two waste streams (i.e. seawater RO brine and NEWater RO reject) for the harnessing of osmotic energy. This extracts additional value (i.e. energy recovery) from the two waste streams before they are discharged into the ocean. The power density of the PRO membrane is 6-fold higher than the commercial requirement of 5 W/m2 in the lab condition, and 2-fold higher when tested with the waste streams. The PRO membrane has demonstrated stable power generation under extensive pilot tests. More importantly, PRO dilutes the seawater RO brine with the NEWater RO reject and therefore mitigate the problems associated with discharge of concentrated seawater RO brine.