Synthesis of composite zeolite membrane by low-temperature water bath for efficient dynamic hardwater softening. Issue 2 (April 2023)

• Record Type: Journal Article
• Authors: Liu, Lian; Deng, Xingfa; He, Yan; Cui, Xue-min
• Is Part Of: Journal of environmental chemical engineering. Volume 11:Issue 2(2023)
• Publication Date: 2023-04
• Subjects: Membrane separation -- Metakaolin/slag -- Composite zeolite membrane -- Hard water softening; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2023.109482
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: In recent years, zeolite membrane has developed rapidly in the application of water treatment technology. However, the traditional zeolite membrane preparation process has the shortcomings of high temperature hydrothermal and other complex processes, which hinder its potential for large-scale industrial applications. In this study, a metakaolin/slag composite NaA zeolite membrane (GNaAM-20) on stainless steel substrate was prepared by composite geopolymer (metakaolin mixed with 20% slag) in a low-temperature water bath method, and GNaAM-20 was applied to the dynamic separation of Ca 2+ from hard water. In this work, the mechanical strength (10.08 MPa) and crystallinity (92.13%) of composite zeolite membrane were enhanced by adjusting the slag content, so that a compact and higher removal efficiency zeolite membrane was prepared. The results showed that the GNaAM-20 had excellent acid resistance (pH = 1) with a removal efficiency of 92.03%, and the Ca 2+ average removal efficiency by dynamic filtration after ten times of filtration (500 mL per filtration) was 91.2% using a 500 mg·L −1 Ca 2+ solution. The maximum dynamic membrane adsorption capacity of GNaAM-20 was 102.54 mg·g −1 . Compared with powder or gel adsorbents. GNaAM-20 virtually maintained its initial removal abilities after 5 regeneration cycles (average removal rate of more than 95%), and it had more significant advantages in terms of recycling and regeneration. Therefore, this study provides new ideas for achieving hard water softening and provides scientific guidance for industrial production. Graphical Abstract: ga1 Highlights: GNaAM was successfully prepared with high crystallinity in 80ºC water bath. GNaAM had excellent acid resistance (pH=1) with a removal efficiency of 92.03%. GNaAM achieved a stable dynamic removal rate (91.2%) after 10 times (500 ppm Ca 2+ ). The maximum dynamic Ca 2+ adsorption of GNaA membrane was 102.54 mg·g −1 .