Research on the application of modified cotton fabric as an anti-oil-fouling material in oil-water separation and heavy metal removal

Cotton fabric (CF) modified with silica (SiO 2 ), chitosan (CS), and sodium alginate (SA), referred to as PDA/CF/SiO 2 -CS-SA or PCF/Si-CSA, exhibits both superhydrophilic and underwater superoleophobic properties. This dual-function material demonstrates an underwater-oil contact angle (UOCA) exceeding 159.8°. The fabric's surface has minimal oil adhesion, allowing crude oil to be easily removed by water rinsing. When used to treat simulated wastewater containing Cu(II) and oil (10 mg/L Cu(II)), PCF/Si-CSA achieved an oil/water separation efficiency of 99.0%, water flux of 32900 L·m −2 ·h −1 , and Cu(II) removal rate of 91.3 %. The surface of the PCF/Si-CSA of adsorbed Cu(II) leached with a dilute HCl solution, and the Cu(II) desorption rate reached 93 % within 150 s. PCF/Si-CSA shows superoleophobicity under water (UOCA>150°) after 1 mol/L H 2 SO 4 , 0.5 mol/L NaOH, saturated NaCl immersion for 20 days, and abrasion by 500# sandpaper 300 times. Obviously, the dual-function PCF/Si-CSA exhibited good performance for simultaneous oil/water separation and heavy-metal removal. • A dual-function superhydrophilic and underwater superoleophobic cotton fabric (CF) modified by silica (SiO 2 ), chitosan (CS), and sodiumalginate (SA), named PDA/CF/SiO 2 -CS-SA or PCF/Si-CSA. • PCF/Si-CSA treats artificial oil slick (toluene) wastewater containing 10 mg/L Cu(II) and oil/water separation efficiency, water flux, and Cu(II) removal rate of more than 99 %, 32900 L·m −2 ·h −1 , and 91.3 %, respectively. • In the process of simultaneous oil/water separation and Cu(II) removal, the decline rate of adsorption capacity of PCF/Si-CSA is approximately equal to its desorption−regeneration rate. • After being immersed into strong acid (1 mol/L H 2 SO 4 solution), strong alkali (0.5 mol/L NaOH solution), high salt (36 % NaCl solution) for 20 days and rubbed with 500# sandpaper for 300 times, the UOCA are still more than 150° and have good adsorption capacity. The results show that PCF/Si-CSA have good mechanical stability and chemical stability.