Solvent-tolerant lignosulfonate-attapulgite/calcium carbonate coating on nylon filter mesh for oily water treatment

Abstract

Due to the rapid increasing drainage of oily wastewater, robust and durable filtration materials with underwater superoleophobic coatings are highly desired. The existing underwater superoleophobic filter materials for oil/water separation are always subject to mechanical and chemical damages, causing the significant loss of superoleophobicity. Herein, a robust and tolerant nylon filter mesh (NFM) with underwater superoleophobicity was fabricated through simple layer-by-layer (LBL) assembly of lignosulfonate (LS), attapulgite (APT) nanorods, calcium ion, and carbonate on NFM. Compared with LS@CaCO3 assembly, the obtained LS-APT@CaCO3 assembly on NFM exhibits good micro/nano-structure, uniform distribution, and excellent underwater superoleophobicity (oil contact angle: > 156°). Moreover, after the fabricated mesh is subjected to the immersion in corrosive environments (acid, base, and salt aqueous solutions) and hot water as well as severe mechanical scratch, the oil contact angle are still higher than 147.5°, implying superb durability. More importantly, the as-obtained NFM is able to treat a variety of oil/pure water and oil/corrosive solution mixtures with separation efficiencies of over 98.2 %. Therefore, the as-prepared mesh has a huge application potential in oil-polluted water remediation due to the simple, facile, and eco-friendly preparation process.