Synthesis of MIL-88@activated carbon composite as an efficient adsorbent for the removal of Rhodamine B
Sami Ullah, Azizur Rehman, Lala Gurbanova, Tayyaba Najam, Amal M. Al‐Mohaimeed, Wedad A. Al-onazi, Karim Khan, Syed Shoaib Ahmad Shah, Muhammad Altaf Nazir
Abstract
This research focuses on synthesising MIL-88@AC composite by incorporating MIL-88 and activated carbon in order to capitalise on their properties for environmental applications. Particularly, the MIL-88@AC composite aims at the removal of Rhodamine B (RhB) dye from aqueous solutions. The as synthesised materials were preliminarily investigated by SEM, EDX, FTIR and XRD techniques. The characterisation results confirmed the successful formation of MIL-88@AC, showing that the porous and irregular particles of activated carbon are uniformly attached to the surface of MIL-88’s elongated, hexagonal rods, resulting in a heterogeneous composite with enhanced surface area and architectural diversity. Thus, in order to quantify the efficiency of adsorption, numerous parameters such as dye concentration, solution pH and contact duration were investigated systematically. Moreover, adsorption isotherms and kinetic studies were employed to analyse the adsorption behaviour of the material. The experimental results showed that the maximum adsorption by MIL-88@AC occurred in the acidic solution, and the adsorption capacity was 42.61 mg.g−1 within 120 min. The adsorption process exhibited good fits with the Freundlich isotherm model with a correlation coefficient of 0.9956. The main associations contributing to RhB adsorption were attractive forces such as, π–π stacking of the aromatic moieties in RhB and MIL-88@AC, hydrogen bonding, and electrostatic interactions involving the Fe-based sites in MIL-88. Further, the maximum adsorption capacity was calculated as (qmax) of 189.75 mg.g−1. The result of this work clearly exhibits the efficiency of MIL-88@AC for the treatment of industrial wastewater.