A photo-regenerable sponge filter to continuously remove hydrophobic and hydrophilic pollutants for water reuse

Zero-harmful discharge has become an urgent need for wastewater treatment and reuse, necessitating the removal of both hydrophobic and hydrophilic pollutants. In this study, titanate nanotubes loaded activated carbon (TNTs@AC) as an adsorptive photocatalyst was impregnated onto low-cost polyurethane (PU) sponge for elimination of both hydrophobic oils and hydrophilic phenols in water. The TNTs@AC@PU filter exhibits exceptional sorption, capturing pump oil and motor oil at 92 and 69 times their weight, respectively. Remarkably, the phenol sorption capacity was increased from 4.21 mg g-1 for pristine PU to 46.41 mg g-1 for TNTs@AC@PU. Furthermore, binary experiments revealed an effective simultaneous removal of both phenol and oil. The TNTs@AC@PU filter exhibited great robustness as demonstrated by 10 oil sorption-regeneration cycles showing no significant drop in oil sorption capacity and 5 phenol sorption cycles maintaining 70 % efficiency. Notably, 90 % regeneration efficiency was achieved within an hour under UV/PMS treatment revealing the high potential for filter regeneration. The TNTs@AC@PU filter showcases successful combination of sorption, regeneration, and reuse, offering insights for tackling hydrophilic and hydrophobic pollutants in water.