Engineering

Materials science

Silica gel

Self-healing

Polyvinyl alcohol

Chemical engineering

Geology

Oceanography

Alternative medicine

Contact angle

Organic chemistry

Portable water purification

Underwater

Composite material

Superhydrophilicity

Medicine

Chemistry

Seawater

Triethoxysilane

Pathology

Chemical Engineering Journal

Hydrogel is attracting more and more interest in the field of oil-water separation because of its hydrophilicity and underwater oleophobicity. However, most traditional hydrogel composites have poor recycling performance, can not achieve self-repairing effect in the case of external mechanical damage, and inevitably freeze and at subzero temperatures because of a lot of water-soluble solvents in the gel network. These properties limit its application in the oil-water separation field. Therefore, it is still a challenge to prepare self-repairing and recyclable gel-based materials for oil/water separation in multiple environments. Here, superhydrophilic/underwater superoleophobic anti-freezing (3-aminopropyl) triethoxysilane-functionalized silica/polyvinyl alcohol (APTES-SiO2/PVA) organohydrogel and the related gel-coated mesh were successfully synthesized through a low-cost and simple process. The gel-coated mesh can separate oil-water mixtures in various water environments (including deionized water, HCl solution (1 M), NaOH solution (1 M), saturated NaCl solution, artificial seawater and saturated NaCl solution (−20 °C)) with a separation efficiency of above 99%. Impressively, they can achieve self-repairing and the recycling of raw materials through the excellent remoldability of organohydrogel (sol-gel transformation). The low-cost and easy fabrication, harsh-environment tolerance, self-repairing and recyclable features make the organohydrogel-based mesh promising toward oil/water separation under practical conditions.

Underwater superoleophobic APTES-SiO2/PVA organohydrogel for low-temperature tolerant, self-healing, recoverable oil/water separation mesh