A desalination performance restoration agent for a cellulose acetate membrane contains: a solvent; and a modified polyvinyl alcohol mixed in the solvent. The modified polyvinyl alcohol has an acetyl group structure in at least part of polyvinyl alcohol.

A repair method for a separation membrane including a step of applying a colloidal solution to a surface of a separation membrane formed on a support. The colloidal solution has a predetermined pH. In colloidal solution, repair material particles are dispersed in an aqueous solvent. The repair material particles have an electrical charge that is opposite to an electrical charge of the support at the predetermined pH.

A polyamide (PA) nanofiltration (NF) membrane and a preparation method thereof by regeneration from a scrapped microfiltration (MF) membrane are provided. The method adopts a cleaning-repairing-interfacial polymerization upgrading strategy, where, sodium hypochlorite and oxalic acid are used for deeply cleaning a scrapped MF membrane. PDA is used as a repairing agent to construct a reaction platform on the membrane surface, and finally a reaction system of piperazine and trimesoyl chloride (TMC) are used to form a PA NF membrane with a PA active layer. The repairing can construct a coating with a given thickness and prominent hydrophilicity on the membrane surface, which provides favorable base membrane conditions for upgrading and preparing an NF membrane.

A method of forming a membrane is described. A graphenic-based membrane is formed on a growth substrate, where the graphenic-based membrane have one or more layers of graphenic-based material. The graphenic-based membrane is removed from the growth substrate. A region of the graphenic-based membrane having intrinsic or native defects is identified. The region of the graphenic-based membrane is irradiated with charged particles while introducing carbonaceous material on a surface of the one or more layers of graphenic-based material to heal the intrinsic or native defects.

Two-dimensional materials having apertures in their basal planes are described, where at least a portion of the apertures are occluded with a selectively introduced occluding moiety. Occluding moieties that pass into apertures function to occlude apertures. Composite membranes are described having a porous substrate with a two-dimensional material disposed on the membrane and covering only a portion of the pores, wherein at least a portion of uncovered substrate pores are occluded. Pore occlusion can be achieved by introduction of an occluding particle optionally followed by chemical reaction, deformation or swelling of the particle to facilitate occlusion of pores. Two-dimensional materials covering substrate pores can be size-selected and optionally functionalized providing for selective permeability through composite membranes. Methods for occluding defects and apertures in two-dimensional materials and for selectively occluding pores in composite membranes are provided. Selectively occluded materials and membranes are useful in filtration and other applications.

A method for the repair of defects in a graphene or other two-dimensional material through interfacial polymerization.

A ceramic separation membrane structure in which a zeolite separation membrane formed on a ceramic porous body is repaired, and a repair method thereof. In the ceramic separation membrane structure, a zeolite separation membrane is disposed on a ceramic porous body, and defects of the zeolite separation membrane are repaired by zeolite repaired portions containing zeolite of structure different from the structure of zeolite of the zeolite separation membrane. The zeolite separation membrane and the zeolite repaired portions are made of a hydrophobic zeolite having a ratio of SiO.sub.2/Al.sub.2O.sub.3=100 or more.

A polyamide (PA) nanofiltration (NF) membrane and a preparation method thereof by regeneration from a scrapped microfiltration (MF) membrane are provided. The method adopts a cleaning-repairing-interfacial polymerization upgrading strategy, where, sodium hypochlorite and oxalic acid are used for deeply cleaning a scrapped MF membrane. PDA is used as a repairing agent to construct a reaction platform on the membrane surface, and finally a reaction system of piperazine and trimesoyl chloride (TMC) are used to form a PA NF membrane with a PA active layer. The repairing can construct a coating with a given thickness and prominent hydrophilicity on the membrane surface, which provides favorable base membrane conditions for upgrading and preparing an NF membrane.

Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

A method for repairing a membrane filtration module in fluid communication with a plurality of additional membrane filtration modules includes fluidly connecting a fluid transfer assembly to the membrane filtration module, fluidly isolating the membrane filtration module from the plurality of additional membrane filtration modules, forcing liquid within the membrane filtration module into the fluid transfer assembly by introducing a pressurized gas into the membrane filtration module, releasing the pressurized gas from the membrane filtration module, fluidly disconnecting the fluid transfer assembly from the membrane filtration module, repairing one or more damaged membranes in the membrane filtration module, and fluidly reconnecting the membrane filtration module to the plurality of additional membrane filtration modules.