Anti-swelling 2D clay nanofiltration with interlamellar fixation for efficient dye separation

• Published in: Journal of membrane science 2024-09, Vol.709, p.123141, Article 123141
• Main Authors: Zhang, Yan, Tang, Jiadong, Li, Nan, Wang, Shiwen, Zhou, Li, Gu, Yifan, Jin, Yuhong, Zhang, Qianqian, Wang, Hao, Liu, Jingbing
• Format: Article
• Language: English
• Subjects: 2D nanofiltrations; clay; Dye separation; dyes; Interlamellar fixation; Life cycle assessments; Montmorillonite; nanofiltration; nanoparticles; wastewater treatment
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2024.123141

Clay-based 2D nanofiltrations (NFs) have shown great potentials in wastewater treatment owing to their facile scale-up and low-cost feature. However, the swelling effect seriously limits their separation efficient towards the construction of high-performance NFs. Herein, an anti-swelling clay-based 2D NF is developed based on the strategy of electrostatic interlamellar fixation. The intercalation of positively-charged Fe(OH)3 nanoparticles could effectively fix the interlayer spacing of negatively-charged montmorillonite-based 2D NF, contributing to a high dye (Congo red) retention rate up to 99.78 % and also a satisfactory flux of 60.65 L m−2 h−1 bar−1. Separation mechanism was explored for the combined effects of size, electrostatic potential and conjugation on the retention rate. When scaling up (∼700 cm2), the anti-swelling 2D NF still maintain an excellent separation effect that is superior to almost all reported state-of-the-art 2D NFs. According to the detailed life cycle assessments (LCA), the advantages of MMT in the production process were demonstrated. The utilization of 2D clay material also exhibits superior resource, environmental and techno-economic benefits compared to other mainstream 2D materials. This work proposes an effective strategy to solve the swelling effect of clay-based 2D NFs towards the large-scale utilization of high-performance and low-cost separation membrane for efficient wastewater treatment. [Display omitted] •Two-dimensional clay-based membranes reduce interlayer spacing by electrostatic binding.•Composite membranes block anionic dyes through size exclusion effect.•Explore the effect of various properties of anionic dyes on the retention rate.•Large Area Preparation and LCA Calculations demonstrate the Superiority of MMT materials.