Comparative Study Between Metronidazole Residues Disposal by Using Adsorption and Photodegradation Processes onto MgO Nanoparticles

Abstract

The photodegradation and adsorption processes of metronidazole (MNZ) was conducted utilizing the batch reactor onto magnesium oxide nanoparticles (MgO NP) as the catalyst surface affected by UV radiation, initial concentration of MNZ, pH, catalyst loading, inorganic salts addition, time, and temperature. Chemical composition and morphological properties of the prepared MgO NP can also be portrayed by several techniques such as XRD, EDX, SEM, and TEM, while GC–MS analysis was used to monitor the photodegradation pathway for MNZ molecules. The results indicated that the actual removal of 93.2% of 80 mg/L MNZ present in 25 mL of a solution containing 0.1 mg/L of MgO NP could be distributed as 35.7% for maximum adsorption and 57.5% for degradation efficiency during 180 min. The degradation process is mainly of two steps; dark adsorption experiment, and photocatalytic degradation performance. Hence, Kinetic analyses indicate that adsorption constant estimated in dark conditions is smaller than the adsorption equilibrium constant derived from the Langmuir–Hinshelwood kinetic model through photodegradation of MNZ that follows pseudo-first-order kinetic. The adsorption isotherm result specified that the adsorption nature is chemisorption and fit Langmuir model, as well as thermodynamic results indicated that it is a nonspontaneous and endothermic reaction.