Photothermal conversion-assisted oil Water separation by superhydrophobic Cotton yarn prepared via the silver mirror reaction

In this paper, a novel superhydrophobic cotton yarn was prepared for the first time via the surface modification method of silver mirror reaction to form silver nanoparticles on top, followed by the immobilization of n-dodecyl mercaptan (NDM) as the hydrophobic modifier. The modified cotton yarn (CF-Ag-NDM) owns both superhydrophobic and photothermal conversion properties, which synergistically favor the removal of viscous crude oil from water. The average water contact angle of CF-Ag-NDM is 155°. In addition, the photothermal conversion property caused a rapid increasing temperature of the CF-Ag-NDM surface up to 70℃ under one sun radiation in just 2 min, which significantly decreased the viscosity of the crude oil and increased the penetration of oil across CF-Ag-NDM. The oil-water separation efficiency reached as high as 98 % for crude oil and other organic solvents. In addition, CF-Ag-NDM also showed better performance for emulsified oils. Furthermore, CF-Ag-NDM showed excellent temperature resistance, wear resistance, and acid/alkali resistance. A simple lab-made oil-water rotary separation device was also constructed, which achieved excellent crude oil separation from water under one sun radiation.