Studies on Ni(II) removal from industrial wastewater by magnetic activated carbon nanocomposite

Abstract

A novel and effective bio-adsorbent based on magnetic activated carbon nanocomposites (MCHLAC) has been created from citrus hystrix leaves (CHL) as agricultural waste and then utilised for Ni(II) removal. Different parameters such as contact duration, metal ion concentration, pH, adsorbent dosage and temperature are optimised for the removal of Ni(II) metal. The FTIR, SEM, EDX, BET and TEM analysis are used to investigate the functionality, surface morphology, and elemental structure of CHL and MCHLAC. The adsorption isotherms fit well to Langmuir model and the maximum adsorption capacities of CHL and MCHLAC was 40.17 and 420.75 mg g^-1, respectively. Kinetic studies show that the CHL and MCHLAC are well fitted with the pseudo-second-order due to surface processes involving chemical adsorption of Ni(II) ions. Furthermore, the thermodynamic analysis of the process reveals that Ni²⁺ ion adsorption by the produced magnetic activated carbon is exothermic and spontaneous. According to the adsorption-desorption results, the MCHLAC can be used up to five cycles with excellent efficiency. As a result, the findings indicate that the magnetic nanocomposite loaded activated carbon, which demonstrated high efficiency, could be an effective option for a long-term water purification.