Preventing Fouling of Reverse Osmosis (RO) Membranes

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.

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.

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.

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.

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.

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.

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.

Reverse osmosis membrane with resistance to fouling and antimicrobial properties for water purification. The membrane has an outer antimicrobial layer covalently bonded to the polyamide layer of the membrane. A compound from the quaternary ammonium compounds family is used as the antimicrobial agent. This layer surrounds the polyamide layer to prevent fouling and microbial growth on the membrane surface.

Composite reverse osmosis membranes with improved properties for water desalination and purification. The membranes are made by interfacial polymerization using acacia gum as an additive. The acacia gum increases pore size, hydrophilicity, and surface charge and reduces roughness compared to pure polyamide membranes. This leads to higher membrane flux and reduced fouling while maintaining salt rejection. The composite membranes show improved performance and stability in filtration tests with seawater compared to commercial membranes.

This low-fouling, high-recovery, energy-efficient reverse osmosis system for brackish water desalination mitigates fouling and scaling issues. The system uses a multi-stage configuration with a bypass line to reduce fouling, balance flux, disrupt scaling, and enable easier cleaning compared to traditional RO configurations.

Reverse osmosis membranes for desalination that have a graphene oxide and crosslinker composite coating on a polyamide membrane. The coating makes the membrane resistant to chlorine degradation while maintaining high water flux and salt rejection. The coating is applied by mixing graphene oxide and a copolymer crosslinker and applying it to the membrane.

This scale inhibitor inhibits calcium carbonate scaling on reverse osmosis membranes. The inhibitor comprises two components: (A) a terpolymer of maleic acid, an acrylic acid alkyl ester, and vinyl acetate, and (B) a homopolymer of carboxylic acid. Adding this inhibitor to RO membrane processes effectively prevents calcium carbonate scale formation without increasing phosphorus in effluent.

Ultrapure water production method to maintain high purity while avoiding reverse osmosis membranes and biological fouling damage. The method uses a two-stage reverse osmosis system with a chlorine-resistant membrane in the first stage, followed by a non-resistant membrane. The chlorine-resistant membrane treats feed water containing 0.01-0.1 mg/L chlorine/bromine. An activated carbon unit prior to the RO adjusts chlorine/bromine levels. This prevents excessive chlorine/bromine exposure to the non-resistant membrane.