An innovative and efficient strategy for removing Congo red using magnetic hollow Zn/Co zeolitic imidazolate framework composite

The discharge of wastewater containing Congo red (CR) poses a significant threat to aquatic ecosystems and human health, underscoring the urgent need for effective removal methods. In this study, we have developed a novel strategy for efficient removing CR, utilizing the synthesized magnetic hollow Zn/Co zeolitic imidazolate framework composite (MH-ZIF). Comprehensive characterization of MH-ZIF and comparison with contrasting materials were conducted. The adsorption behavior of MH-ZIF towards CR followed the pseudo-second-order kinetic model and Langmuir isothermal adsorption model, demonstrating monolayer chemisorption. Remarkably, MH-ZIF exhibited an impressive adsorption capacity of 1167.9 mg g^-1 for CR at 293 K. The addition of merely 0.15 g L^-1 of MH-ZIF achieved nearly complete adsorption of CR within a concentration of 150 mg L^-1. With the assistance of an external magnetic field, CR adsorbed on MH-ZIF can be effectively and swiftly removed within just 30 s. Hence, MH-ZIF demonstrates great promise in effectively removing CR from wastewater, attributed to its high adsorption capacity, selectivity, and magnetic properties.