The present disclosure discloses a preparation method of an organosilica/ceramic composite membrane with a gradient pore structure. The preparation method comprises: (1) selecting a porous ceramic material as a membrane support layer; (2) gradually replacing a solvent with water to prepare zirconium colloidal sols with different particle sizes, and successively coating the prepared zirconium colloidal sols onto a ceramic support from large to small so as to form a membrane transition layer with a gradient pore structure; and (3) catalytically synthesizing an organosilica polymeric sol using hydrochloric acid, coating the prepared organosilica sol onto the preheated transition layer through ultrasonic thermal spraying to undergo heat treatment, so as to prepare the organosilica/ceramic composite membrane with the gradient pore structure. According to the present disclosure, the transition layer with the gradient pore structure is prepared by using the zirconium colloidal sols with different particle sizes. An ultrathin defect-free organosilica separation layer is prepared through ultrasonic thermal spraying. As a result, the obtained organosilica/ceramic composite membrane can be applied to the fields of salt-containing dye wastewater treatment and polypeptide bioactive substance separation.

There is provided a method of forming a cross-linked polymeric membrane, the method comprising: contacting a polymeric membrane with a cross-linking solution to form the cross-linked polymeric membrane, wherein the crosslinking solution comprises a cross-linker comprising at least one acyl halide functional group dissolved in a polar protic solvent. There is also provided a cross-linked polymeric membrane. In a preferred embodiment, hollow fiber polybenzimidazole (PBI) is crosslinked by trimesoyl chloride (TMC) or isophthaloyl chloride (I PC) in a solvent of ethanol or isopropyl alcohol (IPA).

The present invention is directed to nanofiltration (NF) composite membranes comprising at least one polymeric porous substrate layer (S) and at least one porous selfassembled supramolecular membrane layer (F); a method of preparing such composite membranes; method of separation/filtration/purification of heavy metal cations, inorganic anions, and organic small molecules by applying such composite membranes; as well as filter cartridges and filtration devices comprising said composite membranes.

Provided is a method including the steps of producing a melt-kneaded product and discharging the melt-kneaded product. In the step of producing a melt-kneaded product, a thermoplastic resin, a non-solvent and an inorganic compound are mixed and melt-kneaded, wherein the non-solvent does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250 C., whichever is lower.

The invention relates to a process for making a membrane M comprising the following steps: providing a dope solution D comprising a polymer P selected from polyphenylenesulfone or mixtures of polyphenylenesulfone with nonionic polyarylene ethers, a first solvent selected from aprotic polar solvents, and a cosolvent selected from C.sub.2-C.sub.8 alkanediol, C.sub.3-C.sub.8 alkanetriol, polyethylene glycol, or mixtures thereof; and preparing the membrane by bringing the dope solution D into contact with a coagulating agent. The invention further relates to a membrane M obtainable in said process.

Methods for making porous polyelectrolyte complex (PEC) films are provided. In an embodiment, such a method comprises coating the surface of a substrate with a polyelectrolyte (PE) coacervate mixture, the PE coacervate mixture comprising a cationic polymer, an anionic polymer, water, and a salt, the PE coacervate having a salt concentration; exposing the coating to an aqueous medium having another salt concentration, for a time to induce solidification of polyelectrolyte complexes (PECs) in the form of a PEC film having pores distributed throughout, wherein a difference ?C-M #191 between the salt concentration of the PE coacervate mixture and the salt concentration of the aqueous medium is selected to achieve a predetermined porosity for the porous PEC film.

Processes for the preparation of composite membranes are disclosed, as well as the composite membranes obtainable by these processes. The processes employ a step of roller coating a porous support substrate with an essentially solventless coating mixture containing a cationically UV curable compound, which can then be cured in an oxygen-containing atmosphere. The process thereby dispenses withor greatly reduces the impact ofa number of the prominent processing constraints of prior art techniques, thereby affording a more streamlined and less energetically burdensome membrane manufacturing process.

An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained. The asymmetric carbon membrane may be useful to separate gases such as olefins from their corresponding paraffins, hydrogen from syngas or cracked gas, natural gas or refinery gas, oxygen/nitrogen, or carbon dioxide and methane.

A method for producing an asymmetric porous membrane includes: forming a first casting film from a casting solution on a carrier, the casting solution containing a hydrophobic polymer, a hydrophilic polymer, a water-soluble polymer, and a solvent; placing the first casting film in an environment containing water vapor to contact the first casting layer with the water vapor, thereby obtaining a second casting film, the environment having a temperature ranging from 20 C. to 33 C. and a relative humidity of 30% to 80%; and contacting the second casting film with a coagulating agent so as to perform a wet-phase inversion. The hydrophilic polymer is polyvinylpyrrolidone, polyalkylene glycol, or a combination thereof. The water-soluble polymer is a copolymer of vinylpyrrolidone and vinyl acetate, a copolymer of vinylpyrrolidone and alkylene glycol, a vinyl alcohol-based polymer, an ethylene glycol/propylene glycol based copolymer, an ethyleneimine-based polymer, a water-soluble cellulose, or combinations thereof.

Provided are a high temperature-resistant composite nanofiltration membrane and a preparation method thereof. The high temperature-resistant composite nanofiltration membrane includes a base membrane and a polyamide membrane arranged on the base membrane; wherein the polyamide membrane is prepared from raw materials comprising: an amine, an inorganic salt, a silane additive, a polyacyl chloride, and an oil phase solvent; and the silane additive is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, divinyltriaminopropyltrimethoxysilane, N-cyclohexyl-?-aminopropyltrimethoxysilane, and trimethoxy[3-(phenylamino)propyl]silane.