Effective degradation of oil pollutants in water by hydrodynamic cavitation combined with electrocatalytic membrane

Jun Ma,Hongbin Liu,Guiling Lu,Mengfu Zhu,Cheng Deng,Kui Li

doi:10.1063/1.5028152

Abstract

Hydrodynamic cavitation (HC) and electrocatalytic membrane (ECM) can be used in the oxidative degradation of oil pollutants, and a combined method with both techniques can improve the overall degradation efficiency. The results of this study show that HC could promote the dispersion and dissolution of oil in water at 35°C with an inlet pressure of 0.30 MPa and cavitation time of 2 h. Under these conditions, the oil concentration increased from initial 90 mg/L to 215 mg/L, at which point the effect of the degradation by HC could be clearly detected. Then, when the cavitation time was 5 h, the oil concentration decreased from maximal 215 mg/L to 139 mg/L. Subsequently, at a current density of 2 mA/cm2, pH 6, residence time of 3.8 min, electrode spacing of 40 mm and solution temperature of 30°C, the removal rate of oil pollutants reached up to 98.81%. Gas chromatography mass spectrometry (GC-MS) analysis shows that ECM could degrade oil pollutants more effectively. Therefore the combination of HC and ECM was demonstrated to be an efficient method for the removal of oil pollutants in water.

Highlights

Oil is a very important energy in modern society, but its large utilization in recent years has inevitably caused oil spill and waste
The electrocatalytic membrane was provided by the Dalian University of Technology, which was fabricated by high temperature pyrolysis and carbonization of carbonaceous material
In the initial stage of Hydrodynamic cavitation (HC), the oil concentration at different inlet pressures increases with the increasing cavitation time

Summary

Introduction

Oil is a very important energy in modern society, but its large utilization in recent years has inevitably caused oil spill and waste. Rivers and terrestrial environments, which will harm human health.[1,2] Oily sewage contains a variety of oxygen-consuming pollutants which consume and decrease dissolved oxygen in water. This pollution leads to deterioration of water quality and impacts the survival of aquatic organisms. The traditional methods are widely used to degrade organic pollutants in water, these methods suffer from low efficiency and high cost.[11]

Methods

Results

Conclusion