Adsorptive removal of antibiotic ofloxacin in aqueous phase using rGO-MoS₂ heterostructure

This paper reports the synthesis, characterization and detailed adsorption studies of rGO-MoS₂ heterostructure. The heterostructure was explored for the adsorption of ofloxacin from the aqueous phase. Detailed studies were conducted to study the effect of crucial parameters such as pH of drug solution, adsorbent dose, temperature and initial drug concentration on the adsorption capacity. Even with a low surface area of 17.17 m²/g, the adsorbent exhibited maximum removal efficiency of 95% at a dose of 0.35 g/L and an initial drug concentration of 10 mg/L in 240 min. Thermodynamic study revealed the values for ∆H⁰ and ∆G⁰ to be - 101.15 and - 7.47 kJ/mol respectively, indicating that the process is spontaneous and exothermic in nature. The heterostructure adsorbent exhibited remarkable reusability and stability up to five cycles. The heterostructure combines excellent adsorption capabilities arising from the two-dimensional structures of rGO and MoS₂ with the stronger and more specific interaction with the drug molecules which results in better performance towards the removal of the drug. The excellent performance of the heterostructure indicates that combining 2D materials can be a good strategy for producing highly efficient materials towards the adsorptive removal of pollutants.