Carbon Felt Monoliths Coated with a Highly Hydrophobic Mesoporous Carbon Phase for the Continuous Oil Sorption/Filtration from Water

The recovery of oils and organic compounds is a key challenge in wastewater purification processes. Herein the authors describe a straightforward and easy-to-scale-up strategy for the fabrication of lightweight and highly hydrophobic composites with superior mechanical strength, through the coating of commercial carbon felt (CF) with a thin mesoporous carbon phase (MC). Composites are prepared by a dip-coating method starting from CF foams to be soaked in a water/ethanol solution of food-grade components before undergoing two successive thermal treatments. They exhibit an extremely high efficiency and complete reusability in the recovery of oils and organic compounds from wastewaters both as classical absorbents under batch conditions or filters under continuum separation mode. Notably, the electrical conductivity/resistivity of composites has allowed their application to the recovery of water floating waxy organic residues. Indeed, absorbents can be heated up by the passage of an electrical current (DC) thus allowing semi-solid organic pollutants to be melted and absorbed by the hydrophobic composite without sorbent fouling or deactivation. The outlined strategy towards cheap and scalable lightweight hydrophobic materials for wastewater cleaning and environmental remediation from oil spilling, is a highly attractive technology that offers concrete hints to the exploitation of these composites at industrial level.