A multifunctional chitin fiber-melamine sponge filter for one-step purification of wastewater with multiple contaminants

The development of multifunctional materials for simultaneous removal of multiple contaminants (such as oily, metal and organic pollutants) from wastewater is urgently desired, but it is still a challenging task. Herein, a composite filter composed of chitin fibers (CF) and melamine sponge (MS) has been fabricated by assembling the dissolved chitin into crosslinked nanofibers in the macropores of MS and then deacetylating to transform partial acylamino groups of chitin into amino groups (CF-MS). The as-prepared CF-MS filter exhibits a range of outstanding properties in superhydrophilicity, underwater superoleophobicity, high elasticity and permeability, and can be conveniently integrated into continuous flow devices for water treatment. The CF-MS filtration system achieved an oil–water separation efficiency exceeding 98.5 %, with a gravity-driven water permeation flux of 3.8 × 104 L·m−2·h−1. Meanwhile, the CF-MS filter can effectively remove the water-soluble metals and dyes with desirable adsorption capacities (e.g., 27.2 mg·g−1 for Cu2+ and 653.1 mg·g−1 for congo red). The effectiveness of the CF-MS filter is further verified by treating an artificial multicomponent wastewater and a real crude oil-contaminated wastewater, confirming its great potential for practical applications.