Design and fabrication of CuI/CuII-MOF-incorporated hydrogel photocatalysts for synergy removal of Cr(VI) and congo red

• Published in: Chinese chemical letters 2024-04, p.109936, Article 109936
• Main Authors: Li, Quanquan, Zhao, Chenzhu, Jia, Shanshan, Chen, Qiang, Li, Xusheng, She, Mengyao, Liu, Hua, Liu, Ping, Wang, Yaoyu, Li, Jianli
• Format: Article
• Language: English
• Subjects: Cr(VI) and congo red removal; Heterogeneous photocatalyst; hydrogel photocatalyst; Metal-organic framework; Synergy removal effect
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2024.109936

Metal-organic frameworks (MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot- or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuII-MOF 1 and CuI-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal (SCSC) transformation method, respectively, and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs. Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(VI) elimination at a short time of 15-25 min. Additionally, the congo red (CR) decolorization can be effectively enhanced in the presence of Cr(VI), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(VI) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles (95% for CR after 14 runs, and 90% for Cr(VI) after 10 runs). Moreover, the Cr(VI)/CR degradation mechanism for Cu-MOF-alginate composite was investigated. In this work, we delineated a general structuring method to fabricate visible-light driven Cu-MOF-based hydrogel catalysts through incorporating Cu-MOFs into an alginate substrate, which can not only promote the photogenerated electron-hole pairs transfer and separation, but also turn MOF particles into macroscopic-size sphere-shaped structures, achieving a high Cr(VI) and congo red removal with good circularity and exhibiting a very promising application in waste-water remediation. [Display omitted]