Robust and efficient oil-water separation using candle soot deposited stainless steel mesh

Abstract

In recent years, the rising concerns regarding oil pollution and the emissions of organic pollutants from industrial activities have posed significant environmental and public health challenges. The treatment of oily wastewater and organic pollutants has emerged as pressing issue, necessitating the development of efficient solutions. Oil-water separation stands out as a promising approach to address these challenges. However, the effictiveness and robustness of the separating membranes have been identified as key limitations hindering the advancement of oil–water separation technologiess. This paper introduces a novel superhydrophilic/underwater superoleophobic membrane tailored specifically for oil–water separation with enhanced water flux. This film is prepared by depositing candle soot on a stainless steel mesh and then polymerizing phytic acid (CSM-PA). The contact angle of CSM-PA membranes underwater for a wide range of oils is above 140°, reaching a maximum of 152.73°. The CSM-PA membrane demonstrates excellent separation performance for various oils, achieving separation efficiencies flux surpassing 99.990 %, achieving separation efficiencies flux surpassing 18950.360 L·m⁻²·h⁻¹. Notably, the membrane exhibits contact angles under water exceeding 142° for all oils tested. After conducting immersion, sand impact, and water impact tests, the underwater contact angle for both light and heavy oils was found to exceed 139°. The surface roughness of the CSM-PA film on the initial stainless steel mesh improved significantly, increasing from 106 nm to 452 nm. Impressively, even after 70 cycles, the CSM-PA membrane maintains an oil (n-hexane) water separation efficiency exceeding 99.997 % and a remarkable flux rate of 21055.956 L·m⁻²·h⁻¹, the maximum separation flux is even 29154.400 L·m⁻²·h⁻¹. Furthermore, the CSM-PA membrane shows significant stability and resistance to mechanical abrasion, ensuring long-term and reliable operational performance. The findings of this study hold significant implications for the advancement of oil–water separation technologies, offering a promising avenue for addressing oil pollution and organic pollutant emissions in a sustainable and effective manner.