Process for obtaining polyamide membrane with nanostructured coating, membranes and use

Patent metadata

Field	Value
Publication number	US-12447441-B2
Application number	US-202217994686-A
Country	US
Kind code	B2
Filing date	Nov 28, 2022
Priority date	Nov 27, 2021
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

The present invention refers to a surface coating of commercial polyamide (PA) membranes with graphene oxide (GO) using a technology that involves spin-coating with specific sequence of low and high rotation, interface phenomena provided by a set of materials containing ethyl alcohol in high concentration, as well as morphological characteristics and customized surface chemistry of GO, among other conditions that allow a differentiated technology to obtain an effective coating of GO on PA membrane.

First claim

The invention claimed is:

1. A process for obtaining polyamide membrane with nanostructured coating, the process comprising the following steps:
(a) prepare dispersion of graphene oxide (GO) in absolute ethyl alcohol (99.5%) between 0.1 g/L and 2 g/L;
(b) apply the dispersion obtained in step (a) on reverse osmosis membranes made of a selective polyamide (PA) layer, using spin coating technique, with low rotation stage followed by high rotation;
(c) repeat step (b) between 1 and 5 times; and
(d) immerse the membranes in water immediately after step (c).

2. The process according to claim 1 , wherein in the step (a) the GO presents a degree of oxidation greater than 35% by mass, layer distribution of up to 10 nanosheets and an average lateral dimension greater than 1 micrometer.

3. The process, according to claim 1 , wherein in the step (b) the application includes a ratio of between 10 and 30 ml of GO dispersion in ethyl alcohol per cm2 of PA membrane.

4. The process, according to claim 1 , wherein in step (b), the low rotation step in spin-coat is between 500 and 1000 rpm and the high rotation step is between 1600 and 2400 rpm.

5. The process, according to claim 1 , wherein after step (d) the membranes have properties of a permeability greater than 3.5 L/h·m2·bar, saline rejection greater than 96%, and preservation of oxygenates groups and groups related to polyamide after exposure to 1000 ppm/h of chlorine.

Assignees

• Petroleo Brasileiro S A —Petrobras
• Univ Federal De Minas Gerais—Ufmg

Inventors

• Suhett De Souza Rodrigo
• De Araujo Cid Da Silva Ricardo
• Brasil Zanon Yara Luiza
• Gomide De Castro Vinícius
• Santos Amaral Moravia Miriam Cristina
• Goulart Silva Glaura
• De Jesus Ribeiro Bruna Caroline
• Silvestre Assis Ana Luiza

Classifications

• B01D67/00931

  by introduction of specific groups after membrane formation, e.g. by grafting · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• B01D71/56

  Polyamides, e.g. polyester-amides · CPC title

• B01D67/0002

  Organic membrane manufacture · CPC title

• B01D2323/21819

  Carbon, carbon nanotubes, graphene or derivatives thereof · CPC title