Melamine resin-coated lignocellulose fibers with robust superhydrophobicity for highly effective oil/water separation

Abstract

• Superhydrophobic strategies based on condensation and addition reactions. • Oil spill clean-up through selective absorption and active filtration processes. • The scalable manufacturing strategy is low-cost and environment-friendly. oil pollution incidents emerge in endlessly, threatening global ecological security and environmental sustainability. It is a consensus of current scientific research to develop environmentally friendly, sustainable and degradable materials for polluted water body restoration. Cellulose is one of the most attractive candidate materials due to its abundant reserves and all-green degradability. Herein, a technique used to modify lignocellulose fibers via the condensation and addition reactions is reported, and the modified lignocellulose fibers exhibit excellent superhydrophobic and degradation properties. The modification process consists of two main steps: 1) the in situ construction of micro-nano structures on the surface of lignocellulose fibers through the condensation reaction using melamine and formaldehyde; 2) using the addition reaction between the isothiocyanate compound with low surface energy and the amino groups of the melamine resin. The superhydrophobic isothiocyanate/melamine/formaldehyde (IMF) lignocellulose fibers are extremely repellent to water both in atmospheric conditions and underoil. It can separate various oil–water mixtures by absorption (with a high oil absorption capacity of > 1000 wt%) and gravity-driven filtration (with a separation efficiency of > 96%). The embedded superhydrophobicity in the IMF lignocellulose fibers remained unperturbed (with the water contact angle of > 150° and the oil–water separation efficiency of > 97%) even after repeating for 50 cycles. The presented strategy not only indicates a new direction for the comprehensive utilization of abundant lignocellulose fibers, but also proposes a promising way for the development of oil–water remediation technology.