Efficient adsorption of Cu2+ using ZnCo bimetallic organic frameworks loaded cellulose-based modified aerogel: Adsorption behavior and mechanism

Cellulose has been broadly used in wastewater treatment. However, its adsorption capacity is limited by the lack of strong sites interacted with pollutants. Because of the good ability of carrying other substances, cellulose-based materials still have considerable room for improvement in adsorption capacity. Therefore, in virtue of this property, we synthesized a cellulose nanofibril (CNF) composite, Zn_0.5Co_0.5-ZIF@GEL aerogel, using mussel-bionic technique and zeolitic imidazolate frameworks (ZIFs) materials, which was applied in adsorbing copper ions. The experiments indicated the adsorption kinetics was consistent with the pseudo-second-order model. Langmuir model had a better fitting effect in isotherm analysis, revealing that the maximum adsorption capacity was 274.73 mg/g at 25 °C. Furthermore, we found that the appropriate doping of Co element to achieve an optimal synergistic effect enhance the adsorption capacity of Cu²⁺ greatly. The mechanisms of synthesis and adsorption progress were also deeply researched. Overall, the findings of Zn_0.5Co_0.5-ZIF@GEL promote the application of ZIFs in the adsorption field of polydopamine-composited CNF aerogel.