Water/transcutol/lecithin/M−812 green cationic nanoemulsion to treat oxytetracycline contaminated aqueous bulk solution

Abstract

Oxytetracycline (OXT) has been recognized as the most common veterinary medicine discharge responsible to cause water contamination and subsequent health issues in aquatic animals and human health. The study addressed the use of cationic (water/transcutol/lecithin/M−812) green nanoemulsion as an efficient, effective, and cost effective approach. Components were selected based on the drug solubility and HSP (Hansen solubility parameter) software (HSPiP software). Several batches of green cationic nanoemulsions (GNE1-GNE5) were tailored using medium chain triglyceride, transcutol, and lecithin as dictated in pseudoternary phase diagrams followed by thermodynamic stability study. These were characterized for globular size and size distribution, zeta potential, refractive index (RI), viscosity, and pH. Moreover, removal efficiency (%) and the impact of exposure time (5, 10, and 20 min) on removal efficiency were investigated. Finally, the treated water was assessed to ensure free from OXT using SEM-EDX (scanning electron microscopy- energy dispersive X-ray analysis mode) and ICP-OES (inductively coupled plasma-optical emission spectrometry). Result showed that removal efficiency was significantly dependent upon (a) globular size, (b) water content, (c) oil content, and (d) viscosity. However, the exposure time for emulsification had no considerable impact. The most optimized cationic GNE5 was characterized with low size (38 nm), optimal zeta potential (+26 mV), low viscosity (316.5 cP), and the highest removal efficiency (90.3% at 20 min) as compared to respective anionic nanoemulsion. SEM-EDX and ICP-OES results corroborated the absence of OXT in the treated water. Hence, this approach is promising to decontaminate anionic OXT present in wastewater using cationic GNE5 (to get OXT loaded ONE5 after dispersion).