Preventing Fouling in Reverse Osmosis Membranes

Real-time monitoring of reverse osmosis (RO) membrane fouling to enable early detection, characterization, and mitigation of fouling. The technique involves isolating the permeate of a lead or tail element in each stage of an RO system and measuring its flux and rejection directly. This provides much higher sensitivity and faster detection of fouling compared to monitoring the entire stage or system. By isolating the lead or tail element permeate and measuring its performance, fouling can be detected several times faster. This allows for more targeted and effective fouling management strategies.

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A liquid separation membrane with improved fouling resistance for applications like reverse osmosis and ultrafiltration. The membrane has a base material with a porous layer and a coating layer that covers part of the surface. The coating layer contains an oil-repellent polymer. The oil-repellent polymer can contain fluorine-containing monomers and/or antibacterial monomers. The coating layer adheres to the base material via forces like crosslinking, van der Waals, ionic, hydrogen bonding, and anchoring. The membrane prevents fouling by reducing protein adsorption and oil accumulation on the surface.

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Composite reverse osmosis membranes for water purification and desalination have improved fouling resistance and water permeability. The membranes have a modified polyamide skin layer on a porous support. The modification is done by treating the polyamide with an alkylenediamine derivative after interfacial polymerization. This modification improves the antifouling properties of the membrane compared to unmodified polyamide membranes.

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Membrane separation technology with improved separation performance and durability for applications like ultrapure water, food processing, desalination, metal extraction, etc. The membrane has a porous substrate layer and an active layer on top that is partially crosslinked and contains a superhydrophilic agent. The active layer with crosslinked superhydrophilic agent enhances water flux and separation efficiency compared to unmodified layers. The membrane can be made by coating the substrate with intermediate layers, then the active layer containing the superhydrophilic agent, and drying.

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Preparing an anti-fouling, wetting-resistant composite membrane distillation membrane to improve performance and stability of membrane distillation systems for treating high-salt wastewater. The method involves modifying the surface of hydrophobic microporous membranes to make them more hydrophilic, then coating them with a mixture of tannic acid and polyvinyl alcohol. This composite membrane has both oil pollution resistance and surfactant wetting resistance. The hydrophilic coating prevents foulants from adhering to the membrane and blocking pores, while the tannic acid provides oleophobicity to prevent oil passage. The composite membrane maintains high flux and rejection for long-term operation stability.

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Polyamide reverse osmosis membrane with excellent durability and antifouling properties for desalination applications. The membrane has a layered structure with a polymer support layer, a polyamide active layer, an antifouling layer, and a protective coating. The antifouling layer contains a crosslinked polymer made from a primary amine compound and a polyfunctional acid halide. This layer provides antifouling resistance. The protective coating prevents chlorine degradation. The layered structure improves membrane durability and fouling resistance compared to traditional membranes.

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Preventing reverse osmosis membrane fouling for water purification with enhanced performance. The membranes have a protective layer made from a composition containing a specific polymer material that improves salt and boron rejection while maintaining high flux. The composition includes a material with a specific chemical formula, molecular weight, optional hydrophilic polymers, and crosslinking agents.

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A thin-film composite polyamide reverse osmosis membrane with improved fouling resistance and an efficient preparation method using metal-organic frameworks for water purification. The membrane has antibacterial and anti-biofouling properties to prevent fouling and extend membrane life. The method involves loading a specific metal-organic framework (CuBTTri) into a polyamide thin film on an ultrafiltration membrane substrate.

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An anti-fouling reverse osmosis membrane assembly for water filtration that reduces fouling and prolongs membrane life in poor water quality applications. The assembly has a central pipe with the membrane wound around it. The membrane unit is located in the middle of the pipe with the inlet and outlet ends extending out. The membrane has an angled mesh facing the inlet that prevents particles from adhering to the membrane surface. This configuration allows water to flow into the angled mesh and prevent fouling on the main membrane.

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Anti-fouling, semi-permeable membrane for treating liquid foodstuff-derived streams like whey, coffee extracts, fruit juice, coconut milk, etc. The membrane has a porous support layer, a thin film composite (TFC) layer on the support layer, and a cross-linked polyvinyl alcohol (PVA) layer on top of the TFC layer. The cross-linked PVA layer is formed by reacting an aqueous PVA solution with a polybasic acid like citric acid. The open structure of the cross-linked PVA layer allows increased water permeation and reduces fouling compared to unmodified PVA layers.

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Reverse osmosis membrane element that resists high COD and impurity pollution. The element has a central guide pipe and a reverse osmosis membrane group. The reverse osmosis membrane group contains an assembly with an uneven membrane surface coated with a smooth hydrophilic layer. This improves fouling resistance by smoothing the surface, making it easier to clean, and promoting pollutant flowoff. The central guide pipe has passages connecting it to the membrane assembly. This allows the concentrated water to flow away from the membrane instead of stagnating. The wide open channels reduce attachment of impurities compared to diamond-shaped channels.

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Composite reverse osmosis membrane with improved flux, salt rejection, and fouling resistance for seawater desalination. The membrane structure includes a non-woven layer, a porous support layer, an amphiphilic block copolymer modified layer, and a hybrid polyamide functional layer containing cyclic ethers. The amphiphilic block copolymer modifies the support layer for better polyamide layer bonding. The cyclic ethers in the hybrid polyamide layer improve water affinity and flux. By controlling amine and acid chloride diffusion during polyamide formation, it allows thicker, crosslinked layers with improved salt rejection.

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A water inlet grid for wide flow channel roll reverse osmosis membrane elements that reduces fouling and scaling on the membrane surface and improves efficiency by preventing contaminant adhesion. The grid has a rectangular thin plate with hemispherical bumps arranged in a ring. The bumps are made of polypropylene and alternate with smooth areas on the plate. This design creates a turbulent water flow with reduced attachment points for fouling particles.

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High-flux anti-pollution reverse osmosis membrane for water treatment with reduced permeate flux loss and improved anti-fouling properties compared to conventional membranes. The membrane has a composite structure with a hydrophilic framework layer sandwiched between the base membrane and anti-pollution coating. The framework layer is made by dispersing hydrophilic materials like mesoporous silica, carbon nanotubes, or graphene oxide in water and coating it on the base membrane. This creates a hydrophilic channel network between the membranes to transport water while preventing fouling. The anti-pollution coating is applied over the framework using a hydrophilic organic solution.

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Membrane for membrane distillation that resists fouling and scaling while maintaining high vapor flux for desalination. The membrane has a hydrophobic basement membrane and a superhydrophilic coating. The coating is made of alginate, a positively charged polymer, and a divalent metal ion solution (MCl2, where M is not Mg). The coating provides antifouling against oil and organic solvents in feed solutions, and antiscaling against mineral fouling during desalination.

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A separation membrane with improved fouling resistance and water flux compared to conventional membranes. The membrane has a stacked structure of support layer, base membrane, functional layer, and protective layer. The protective layer is made of polyvinyl alcohol (PVA), a crosslinking agent, and an anti-crystallization agent. The anti-crystallization agent reduces PVA crystallization which can clog membranes. By adding the anti-crystallization agent, the PVA protective layer prevents fouling without significant flux reduction.

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This is a copolymer that can be used as an antifouling agent for water treatment membranes like RO membranes. The copolymer contains structural units with oxyalkylene side chains having hydroxy end groups. It adheres well to water treatment membranes and imparts excellent antifouling properties.

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Reverse osmosis membranes coated with a hydrogel layer that improves resistance to fouling while maintaining high water permeability and salt rejection. The hydrogel is formed from a hydrophilic, non-crosslinked polymer that is water soluble and subsequently crosslinked, adhering it to the membrane surface. The hydrogel coating prevents foulants like salts, organics, and bio-matter from adhering to the membrane without impacting its performance.

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Composite membrane for reverse osmosis filtration that has improved fouling resistance compared to traditional membranes. The composite membrane includes a porous substrate, a thin polyamide layer, and a copolymer coating. The copolymer has zwitterionic groups to repel fouling agents and is covalently bonded to the polyamide layer to maintain stability during filtration. The membrane is formed by reacting monomers to make the copolymer, attaching it to the polyamide layer, and then rinsing to remove excess copolymer.

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Method of maintaining, cleaning, and defouling reverse osmosis systems using a stabilized hypochlorous acid solution as a biocide. The solution is prepared by reacting a chlorine source with a stabilizer in a molar ratio of 1:9 to 9:1. A bromide ion source can be added to produce stabilized hypobromous acid. The biocide is effective at preventing biofouling of RO membranes without harming them.

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