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.

Automated summary

In this study, a filter for simultaneous removal of hydrophobic and hydrophilic pollutants was developed by impregnating titanate nanotubes loaded activated carbon onto polyurethane sponge. The filter exhibited exceptional sorption capacity and could be regenerated and reused. The results showed that the filter effectively removed both hydrophobic oils and hydrophilic phenols from water.