{"title":"Novel polyamide nanofiltration membrane PEI-(β-CD@g-C3N5)/TMC based on microfiltration substrate for efficient separation of lithium and magnesium","authors":"","doi":"10.1016/j.desal.2024.118136","DOIUrl":null,"url":null,"abstract":"<div><div>With the development of industry, the scarcity of lithium resources is becoming increasingly prominent. Therefore, the development of high-performance nanofiltration (NF) membranes for lithium extraction from salt lakes has become crucial. Herein, β-Cyclodextrin (β-CD) and amino-rich graphitic carbon nitride (g-C<sub>3</sub>N<sub>5</sub>) sol were uniformly mixed to form β-CD@g-C<sub>3</sub>N<sub>5</sub>, which was then mixed with polyetherimide (PEI) monomer and subjected to interfacial polymerization (IP) reaction with trimesoyl chloride (TMC) on a 0.22 μm microfiltration (MF) membrane to prepare the PEI-(β-CD@g-C<sub>3</sub>N<sub>5</sub>)/TMC composite NF membrane. Through thin plate theory and gradient operation pressure filtration tests, it was found that the composite NF membrane prepared on the MF membrane substrate was not only defect-free but also exhibited superior compression resistance. In Li<sup>+</sup>/Mg<sup>2+</sup> filtration tests, the PEI-(β-CD@g-C<sub>3</sub>N<sub>5</sub>)/TMC membrane showed superior NF performance, with a Li<sup>+</sup>/Mg<sup>2+</sup> selectivity coefficient of 38.85 and a permeability of 8.91 L·m<sup>−2</sup>·h<sup>−1</sup>·bar<sup>−1</sup>. This was attributed to the effect of β-CD@g-C<sub>3</sub>N<sub>5</sub>, which could thin the separation layer, slightly enlarge and more uniformly distribute the pores, increase hydrophilicity, and enhance positive charge; meanwhile, the cavity structure provided by β-CD helped to effectively separate Li<sup>+</sup>/Mg<sup>2+</sup>. Furthermore, under conditions of mixed salt solutions with different Mg<sup>2+</sup>/Li<sup>+</sup> mass ratios and 80 h of continuous filtration, the membrane exhibited excellent stability. This work introduces innovative membrane materials and design concepts to the field of lithium extraction via NF, potentially paving the way for the industrial application of NF technology.</div></div>","PeriodicalId":299,"journal":{"name":"Desalination","volume":null,"pages":null},"PeriodicalIF":8.3000,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Desalination","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0011916424008476","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
With the development of industry, the scarcity of lithium resources is becoming increasingly prominent. Therefore, the development of high-performance nanofiltration (NF) membranes for lithium extraction from salt lakes has become crucial. Herein, β-Cyclodextrin (β-CD) and amino-rich graphitic carbon nitride (g-C3N5) sol were uniformly mixed to form β-CD@g-C3N5, which was then mixed with polyetherimide (PEI) monomer and subjected to interfacial polymerization (IP) reaction with trimesoyl chloride (TMC) on a 0.22 μm microfiltration (MF) membrane to prepare the PEI-(β-CD@g-C3N5)/TMC composite NF membrane. Through thin plate theory and gradient operation pressure filtration tests, it was found that the composite NF membrane prepared on the MF membrane substrate was not only defect-free but also exhibited superior compression resistance. In Li+/Mg2+ filtration tests, the PEI-(β-CD@g-C3N5)/TMC membrane showed superior NF performance, with a Li+/Mg2+ selectivity coefficient of 38.85 and a permeability of 8.91 L·m−2·h−1·bar−1. This was attributed to the effect of β-CD@g-C3N5, which could thin the separation layer, slightly enlarge and more uniformly distribute the pores, increase hydrophilicity, and enhance positive charge; meanwhile, the cavity structure provided by β-CD helped to effectively separate Li+/Mg2+. Furthermore, under conditions of mixed salt solutions with different Mg2+/Li+ mass ratios and 80 h of continuous filtration, the membrane exhibited excellent stability. This work introduces innovative membrane materials and design concepts to the field of lithium extraction via NF, potentially paving the way for the industrial application of NF technology.
期刊介绍:
Desalination is a scholarly journal that focuses on the field of desalination materials, processes, and associated technologies. It encompasses a wide range of disciplines and aims to publish exceptional papers in this area.
The journal invites submissions that explicitly revolve around water desalting and its applications to various sources such as seawater, groundwater, and wastewater. It particularly encourages research on diverse desalination methods including thermal, membrane, sorption, and hybrid processes.
By providing a platform for innovative studies, Desalination aims to advance the understanding and development of desalination technologies, promoting sustainable solutions for water scarcity challenges.