Separation of oily wastewater using titanium modified multi-walled carbon nanotubes as demulsifier

Abstract

Oily wastewater causes a lot of environment problems and draws wide attention. In this paper, titanium modified multi-walled carbon nanotubes (CNTs/TiO2) for the treatment of oily wastewater were synthesized using in situ sol-gel methods. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were employed to characterize the structure and composition of CNTs/TiO2. Also, scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that TiO2 was evenly distributed in carbon nanotubes (CNTs) to induce a good synergistic effect. After the oily wastewater was treated with 400 mg/L of CNTs/TiO2 at room temperature for 30 min, the light transmittance of the aqueous phase was 89.7%. Furthermore, the composites with good interfacial activity could be reused at least five times. The combination of dynamic interfacial tension measurements, interfacial activity, interfacial film assemble and optical microscope was employed to investigate the demulsification mechanism.