Vermiculite layer, preparation method thereof and composite nanofiltration membrane

CN121846929APending Publication Date: 2026-04-14WANHUA CHEM GRP CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-01-04
Publication Date
2026-04-14

AI Technical Summary

Technical Problem

Existing composite nanofiltration membranes face challenges in balancing water flux and selectivity. The density of the polyamide layer and the surface roughness of the porous support layer lead to problems such as water molecule mass transfer resistance and pore size unevenness. Furthermore, existing intermediate layer materials such as graphene and MXene are costly and have poor stability, making them difficult to apply on a large scale.

Method used

A vermiculite layer is used as an intermediate layer. A carboxylated vermiculite dispersion is formed by preparing a vermiculite dispersion and adding a dicarboxylic acid. The dispersion is then uniformly deposited on the support layer using a filtration technique to form a smooth and defect-free vermiculite layer. This process controls the interfacial polymerization reaction and optimizes the performance of the polyamide layer.

Benefits of technology

It achieves a significant improvement in water flux and retention rate of composite nanofiltration membranes, solves the problem of flux-selectivity trade-off in traditional composite nanofiltration membranes, and is low in cost and easy to mass-produce.

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Abstract

The invention relates to the technical field of ion separation, and discloses a vermiculite layer, a preparation method thereof and a composite nanofiltration membrane. The preparation method of the vermiculite layer provided by the invention comprises the following steps: preparing a vermiculite dispersion liquid; adding dicarboxylic acid into the vermiculite dispersion liquid for reaction to obtain carboxylated vermiculite dispersion liquid; and carrying out suction filtration on the carboxylated vermiculite dispersion liquid, so that carboxylated vermiculite is deposited on the supporting layer to form a vermiculite layer. According to the preparation method disclosed by the invention, the vermiculite is modified by adopting dicarboxylic acid, and carboxyl is introduced into the vermiculite, so that the hydrophilicity and the surface electronegativity of the vermiculite nanosheet can be enhanced, the agglomeration of the nanosheet is effectively prevented, and the carboxylated vermiculite dispersion liquid with high quality and stability is obtained; the preparation method comprises the following steps: preparing a carboxylated vermiculite nanosheet, fully stretching the carboxylated vermiculite nanosheet through suction filtration, and uniformly depositing the carboxylated vermiculite nanosheet on a supporting layer to form a nanoscale vermiculite layer which is flat in surface, uniform in pore diameter and free of defects, so that a new reaction place is designed for interfacial polymerization reaction for forming a polyamide layer, and the water flux and the salt rejection rate of the composite nanofiltration membrane are improved.
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