Positively charged polyamide nanofiltration composite membrane with uniformly distributed surface charges as well as preparation method and application of positively charged polyamide nanofiltration composite membrane

• Main Authors: CAO YIMING, LI YUNHAO, KANG GUODONG
• Format: Patent
• Language: Chinese; English
• Published: 21.11.2023
• Subjects: CHEMISTRY; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

The invention relates to a positively charged polyamide nanofiltration composite membrane with uniformly distributed surface charges as well as a preparation method and application of the positively charged polyamide nanofiltration composite membrane, and aims to improve permeability and separation selectivity, especially separation of multivalent/monovalent cation systems. The membrane includes an ultrathin polyamide layer having separation selectivity, and a porous support layer. According to the method, reverse interfacial polymerization is adopted, acetone is used for replacing water to serve as a solvent, the sequence of organic amine and a multi-element acyl chloride monomer on a porous supporting membrane is reversed, and the organic amine is located above multi-element acyl chloride. The polyacyl chloride diffuses from an organic solvent to acetone with organic amine as a main body, a compact nascent state polyamide layer is formed at a junction reaction, the polyacyl chloride is limited to penetrate