Preparation of egg white@zeolitic imidazolate framework-8@polyacrylic acid aerogel and its adsorption properties for organic dyes

rGO/ZIF-8 Aerogel for Effective Removal of Malachite Green from Wastewater

In this study, dopamine-modified graphene aerogel (DGA) is synthesized through a one-step hydrothermal method using graphene oxide as the precursor and dopamine as the reducing agent. Subsequently, in situ immersion synthesis is conducted to obtain ZIF-8 loaded on a dopamine-modified graphene aerogel skeleton (ZDGA), featuring a regular honeycomb interconnected mesoporosity and a high specific surface area of 532.8 m2/g. The synthesized ZDGA exhibited exceptional adsorption performance for the cationic dye malachite green. At room temperature, ZDGA achieved an impressive equilibrium adsorption capacity of 6578.34 mg/g. The adsorption process followed pseudo-secondary kinetics and adhered to the Langmuir model, indicating chemically dominated adsorption on a monomolecular layer. Intraparticle diffusion was the primary rate determinant, with π-π stacking, electrostatic adsorption, hydrogen bonding, and Lewis acid-base interactions serving as the key driving forces. It has an ideal specific surface area and good cycling performance, which highlights its potential application in dye wastewater treatment.

ZIF-8 metal organic framework materials as a superb platform for the removal and photocatalytic degradation of organic pollutants: a review

Metal organic frameworks (MOFs) are attracting significant attention for applications including adsorption, chemical sensing, gas separation, photocatalysis, electrocatalysis and catalysis. In particular, zeolitic imidazolate framework 8 (ZIF-8), which is composed of zinc ions and imidazolate ligands, have been applied in different areas of catalysis due to its outstanding structural and textural properties. It possesses a highly porous structure and chemical and thermal stability under varying reaction conditions. When used alone in the reaction medium, the ZIF-8 particles tend to agglomerate, which inhibits their removal efficiency and selectivity. This results in their mediocre reusability and separation from aqueous conditions. Thus, to overcome these drawbacks, several well-designed ZIF-8 structures have emerged by forming composites and heterostructures and doping. This review focuses on the recent advances on the use of ZIF-8 structures (doping, composites, heterostructures, etc.) in the removal and photodegradation of persistent organic pollutants. We focus on the adsorption and photocatalysis of three main organic pollutants (methylene blue, rhodamine B, and malachite green). Finally, the key challenges, prospects and future directions are outlined to give insights into game-changing breakthroughs in this area.