Adsorptive removal of pharmaceutically active compounds from multicomponent system using Azadirachta indica induced zinc oxide nanoparticles: analysis of competitive and cooperative adsorption


 In this research, the ZnO nanoparticles (N-ZnO) synthesized using neem leaf (Azadirachta indica) extract was used as an adsorbent for removing two widely used pharmaceutical compounds acetaminophen (AMP) and sulfadiazine (SDZ). The synthesized N-ZnO was characterized using SEM-EDS, FTIR, TEM, BET, and XRD analysis. The synthesized N-ZnO nanoparticles were found to be in the size range of 10 nm with a surface area of 48.551 m2/g. The adsorptive performance of N-ZnO in both mono-component (MoS) and multi-component system (MuS) were investigated under various operational parameters viz. contact time, temperature, pH, concentration of pharmaceutical compound and N-ZnO dose. It was observed that the maximum adsorption capacity of N-ZnO was 7.87 mg/g and 7.77 mg/g for AMP and SDZ, respectively under the optimum conditions of 7 pH and 2 g/L adsorbent dosage. The experimental data best-fitted with the pseudo-second-order model and Langmuir model, indicating monolayer chemisorption. Further investigation on removal of AMP and SDZ from multicomponent system was modelled using Langmuir competitive model. The desorption study has shown 25.28% and 22.4% removal of AMP and SDZ from the surface of N-ZnO. In general, green synthesized ZnO nanoparticles can be utilized effectively as adsorbent for removal of pharmaceutically active compounds from wastewater.