In-situ growth strategy to fabricate superhydrophobic wood by Na3(Cu2(CO3)3OH)∙4H2O for oil/water separation

Abstract

Superhydrophobic surfaces have a number of potential applications including separating oil from water for pollution abatement. Wood is an excellent matrix for creating these surfaces because its interactive chemistry and intricate cellular matrix provides a large, reactive surface area for fabrication. The challenge to using wood is identifying simple pathways for in-situ synthesis. Na3(Cu2(CO3)3OH)∙4H2O was synthesized in-situ on delignified balsa wood reacting copper chloride and sodium hydroxide in the presence of phenol formaldehyde (PF) resin, and then using stearic acid (STA) to modify this surface to be superhydrophobic. The modified wood surface was covered with Na3(Cu2(CO3)3OH)∙4H2O tetrahedral particles, and had a surface free energy of 8.0 J/m2, which was about 90 % lower than that natural balsa wood. The modified wood had excellent absorption and filtration capabilities for various oils and was able to absorb 2.1–4.8 times its weight in oil, with oil absorption reaching a maximum of 5.2 g/g for chloroform. The modified wood could be regenerated and reused up to 14 times, and the still retained a separation efficiency of 90 % for a dichloromethane:water mixture within 11 cycles. The results suggest that wood-based superhydrophobic surfaces could represent a more environmentally benign material for remediating spills.