Multi-functional self-cleaning superhydrophobic cotton fabric as photothermal-reinforced crude oil separator, oil skimmer and underwater oil absorbent

Removing oil pollution from seawater prior to its desalination helps in saving time and cost. In this study, a novel superhydrophobic cotton fabric with photothermal effect and self-cleaning property was prepared via the incorporation of Fe 3+ -polydopamine (PDA) coating and carbon nanotubes (CNTs) on the fabric surface (termed as CF@PDA/CNT), followed by the grafting of (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and octadecylamine (ODA) (termed as the CF@PDA/CNT-GPTMS-ODA). CF@PDA/CNT exhibits good desalination with photothermal conversion capability on the high-salinity water (evaporation rate > 1.11 kg/(m 2 ⋅h)), providing an effective basis for the preparation of the photothermal-assisted oil–water separator (CF@PDA/CNT-GPTMS-ODA), with which the crude oil permeation time was improved from 58 s without light to only 9 s with light, showing the pronounced contribution of the photothermal effect on the oil permeation. In addition, CF@PDA/CNT-GPTMS-ODA used in the form of oil skimmer and underwater oil absorbent demonstrates excellent oil–water separation performance (separation efficiency > 97 %). Notably, the fabric can isolate various oil phases from both pure water and simulated seawater, with separation efficiencies exceeding 97 %. This novel material offers a promising solution for addressing complex water pollution issues and introduces a potential approach for integrating photothermal conversion effect into the field of oil–water separation.