Reclamation of diesel oil from sea water using magnetic Au/Fe₂O₃ nanocomposites prepared by chemical precipitation

The present work investigates an environmental benign method for the separation of diesel from sea water in oil reservoirs using Au/Fe₂O₃ nanocomposites. The Fe₂O₃ nanoparticles were decorated with Au by chemical precipitation method to form Au/Fe₂O₃ nanocomposites. The microstructural characterizations of the Au/Fe₂O₃ nanocomposite were performed by x-ray diffraction technique, scanning electron microscopy, and transmission electron microscopy. The magnetic measurements were done using a magnetometer. The effect of Au/Fe₂O₃ dose and Au: Fe₂O₃ loading were estimated from the removal efficiency and adsorption capacity at different contact times and nanocomposite concentrations. The microstructural results showed that Fe₂O₃ nanoparticles were 20–30 nm in size and were uniformly distributed over the Au layer. It was observed that nanocomposite shows higher efficiency (98%) at an Au: Fe₂O₃ ratio of 1:8 with 0.4 g l⁻¹ of water–oil concentration compared to the pure Au adsorbent. The adsorption kinetic studies suggested first and second order pseudo-kinetic models. This separation method using magnetic Au/Fe₂O₃ can be potential and alternative way of extraction of diesel from sea water. (paper)