Elevating the stability and adsorption performance of metal-organic frameworks by chitosan and attapulgite for capturing methylene blue in the water

Here we firstly report a novel adsorbent based on metal-organic frameworks (MOFs) which were modified by chitosan (CS) and attapulgite (ATP), including ZIF-8@ATP-CS, Zr-MOF@ATP-CS, and Al-MOF@ATP-CS. The preservative CS constructed a network framework for uniform diffusion of MOFs powder. The ATP not only strengthened the stability, but also improved the adsorption ability. Among these materials, Zr-MOF@ATP-CS had the most optimal adsorption capacity for methylene blue (MB), which could reach the equilibrium within 30 min and obtained the maximum adsorption of 442.86 mg g(-1). Zr-MOF@ATP-CS went through five regenerations without significant reduction, which meant Zr-MOF@ATP-CS owned excellent stability. The ratio of ATP: CS in Zr-MOF@ATP-CS was also explored, and it was found that the best modification effect ratio was 0.75:1. More importantly, the potential practical application was presented in this article. Finally, a possible mechanism was proposed. The novel materials were expected to further expand MOFs materials.

Automated summary

In this study, a novel adsorbent based on metal-organic frameworks (MOFs) modified by chitosan (CS) and attapulgite (ATP), including ZIF-8@ATP-CS, Zr-MOF@ATP-CS, and Al-MOF@ATP-CS, was reported. Among them, Zr-MOF@ATP-CS demonstrated the highest adsorption capacity for methylene blue (MB) and exhibited excellent stability and regenerability.