The Modifications Of PTFE And ACF And Oil Removal From Oily Wastewater

The modifications and adsorption/desorption of polytetrafluoro-ethylene (PTFE) and activated carbon fiber(ACF) were investigated. After the pore aperture of PTFE and ACF were enlarged, the two fiber filters had the higher adsorption ability. Meanwhile, this paper researched the effects and mechanism of inorganic salt on the demulsification of oily wastewater.The effects of different inorganic salt on the demulsification of oily wastewater were investigated. It was found that the higher cationic charge number and the smaller radius were, the better the results of demulsification. For the NaCl, a common used inorganic salt demulsifier, its best demulsification quantity was 0.9g when the oil concentration was 400mg/L in 50mL wastewater. The longer demulsification time and the higher temperature were helpful to the demulsifiers.PTFE was modified by sulfuric acid, and carbonized in high temperature of 280℃, and then characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Comparisons of raw and modificaton of PTFE showed that the adsorption capacity increased greatly. The adsorption capacity could be up to 37.31mg/g, when the initial petroleum concentration was 90mg/L, temperature was 50℃and pH was 3. After regeneration, PTFE could be recycled more than 30 times.Viscose-based activated carbon fiber was modified by refluxing with the nitric acid, phosphoric acid and hydrogen peroxide, respectively. The pore distribution was analyzed through the adsorption isotherms, and the surface functional groups and morphology were characterized with the help of IR and SEM.The results showed that the aperture of ACF modified by nitric acid was increased, but its surface area decreased. Moreover it had the highest concentration of acid groups on its surface. The oil concentration at outlet was 4.93 mg/L after treatment by the 8th time regenerated ACF and reached the top level of re-injection water A1.