Tongji University

Tianjin Polytechnic University

Tianlin Wang

Zhiwei Wang

Ruobin Dai

Hongyi Han

Chenxin Tian

Liang Wang

Hongwei Zhang

Huimin Zhou

Jiansuxuan Chen

Provided is a high permeance nanofiltration membrane with nanoring-like structure and preparation method thereof. The membrane includes a base film and a polyamide layer having nanoring-like structure morphology on its surface. The method includes: (1) formulating a piperazine nanoemulsion containing a surfactant, vegetable oil, piperazine and water; and (2) infiltrating a base film with the piperazine nanoemulsion, and removing excess droplets from the surface of the base film to obtain a treated base film; covering the surface of the treated base film with a solution of trimesoyl chloride in n-hexane to perform interfacial polymerization; and drying the resulting membrane. Introduction of nano-oil droplets into aqueous phase as templates to construct nanoring-like structure morphology on the surface of the polyamide layer significantly increases the specific surface area and free volume of the polyamide layer without losing the salt rejection rate of the membrane, thereby greatly improving its water permeance.

High permeance nanofiltration membrane with nanoring-like structure and preparation method thereof

A method for recycling a scrapped polyvinylidene fluoride (PVDF) membrane through chemical cleaning-structural transformation-hydrophilicity is disclosed, which can extend the service life of scrapped PVDF membrane materials (namely, membrane at the end of service life). The method includes the following steps: cleaning a scrapped membrane with sodium hypochlorite and citric acid; treating the membrane with a structural transformation agent, where, irreversible contaminants are washed away while the PVDF membrane is subjected to pore expansion and hydrophilization; and with self-polymerization of dopamine on a membrane surface, further improving the hydrophilicity of the membrane surface, enhancing the anti-contamination performance, and repairing damaged points on the surface of the scrapped PVDF membrane produced during long-term operation.

Method for recycling scrapped polyvinylidene fluoride (PVDF) membrane produced in water treatment

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.

Polyamide (PA) nanofiltration (NF) membrane, and preparation method thereof by regeneration from scrapped microfiltration (MF) membrane

A high-performance thin-film composite polyamide membrane upcycled from a substrate fouled with a biopolymer and a preparation method thereof are provided. The method includes fouling the substrate preferably with the biopolymer to obtain a composite of the substrate and a biopolymer foulant layer; then immersing the composite into a first solution formed by dissolving a polyamine monomer in water, followed by taking the composite out of the first solution and removing excess droplets from a surface of the composite; then immersing the composite treated in the previous step into a second solution formed by dissolving an acyl chloride monomer in n-hexane for interfacial polymerization to form a rejection layer on the surface of the composite; and after completion of the reaction, taking the composite out of the second solution, followed by drying and heat treatment, to obtain the target polyamide membrane.

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Shanghai, China

Tianlin Wang