Durably dual superlyophobic cationic guar gum‑calcium complex decorated cellulose fabrics for on-demand oil/water separation

The removal to oils from water has become a global issue because of the growing of wastewater discharge and unceasing appearance of oil leaks. Herein, a kind of durably dual superlyophobic (superhydrophobic under oil and superoleophobic under water) cotton fabric (CF) was fabricated via simple assembly route that introduced guar hydroxypropyltrimonium chloride‑calcium (GHTC-Ca) chelate compound on the fabric surface. The coated CF exhibits good resistance to mechanical abrasion, corrosive aqueous solution, high temperature, and organic solvent immersion. Furthermore, due to prewetting-caused superoleophobicity underwater and superhydrophobicity underoil, the as-prepared CF can selectively separate both heavy oils and light oils in water under extremely harsh conditions with separation efficiencies as high as 98.7 % and 98.4 %, respectively. More importantly, the as-prepared fabrics are able to remove dispersed oil droplets from oil-in-water emulsions and water droplets from water-in-oil emulsions with separation efficiency of over 89 % and 91.4 %, respectively. Hence, this prominent separation performance suggests a good application prospect of GHTC-Ca functionalized CF in oily water purification.