Functional porous Ce-UiO-66 MOF@Keratin composites for the efficient adsorption of trypan blue dye from wastewater: A step towards practical implementations

Abstract

In recent years, adsorbents such as porous metal–organic frameworks (MOFs) and biopolymer-based materials showed a wide range ofapplications in wastewater purification. However, these adsorbents have some constraints, such as stability concerns, recovery difficulty, and high synthetic cost, while other biopolymers have fewer active sites, hazardous chemicals for extraction, high-cost extraction procedure, and limited stability. Thus, to address all such drawbacks, the current work reports the design of novel porous composites by combining the natural low-cost keratin biopolymer with the synthetic cerium MOF (Ce-UiO-66 MOF) to treat dye-contaminated wastewater. Significantly, with just 10 mg of adsorbent, it was possible to treat around 20 mL of 50 mg/L TB dye solution which displayed excellent 98 % of removal efficiency within rapid 10 mins of contact time. The isotherm values are well matched with Langmuir isotherm and the designed porous composites evidenced an outstanding maximum adsorption capacity (qm) of 469.5 mg/g. To prove the capability of composites, adsorption reactions were performed in the presence of interfering ions, which evidenced promising removal performances. Importantly, the designed porous composites were validated with real-time sample analysis which showed 92 % removal efficiency. Furthermore, the adsorbents were evaluated with recyclability just by washing with methanol and retained with 75 % removal efficiency observed until the third cycle. All these investigations will pave the direction towards the development of promising efficient cost effective next-generation composites/adsorbents for the treatment of organic dyes near the future.