Preparation of magnetic carbon nanotube nanocomposite for enhancing the separation of dissolved hydrocarbon from petroleum wastewater

Abstract

Multi-walled carbon nanotubes decorated with magnetite (MMWCNTs) were prepared then modified with silicon oxide (MMWCNTs/SiO2) and characterized using high-resolution transmission electron microscope (HRTEM), dynamic light scattering (DLS), thermal gravimetric analysis (TGA), Fourier transform infrared photometer (FTIR), and X-Ray diffraction techniques (XRD). A bench scale experimental setup was designed for the oil in water mixture separation of the prepared materials. Subsequently, individual and interaction effects of operational parameters, e.g., MMWCNTs and MMWCNTs/SiO2 doses, initial oil concentration, pH and water salinity were investigated and optimized using response surface methodology (RSM) and ANOVA analysis at α=0.05. The results of experimental data were fitted with polynomial models developed using RSM, and the regression analysis with an R2 value of ≈0.99 showed the goodness of fit for the experimental results with predicted values. The experimental results showed higher oil/water separation for MMWCNTs/SiO2 than MMWCNTsitself with a separation rate of 92.8% and 72.4%, respectively at 1g/l of initial oil concentration. Compared with other approaches for fabricating oil-water materials, the as-prepared MMWCNTs/SiO2 is a promising candidate for efficient oil-water separation even after 5 cycles.