Removal and reuse of heavy metal ions on mildly oxidized Ti3C2 @BF membrane via synergistic photocatalytic-photothermal approach

The pollution of heavy metal ions in water seriously affects the ecosystem and human health. Here, an efficient synergetic photocatalytic-photothermal system is designed by combining a mildly oxidized Ti 3 C 2 (mo-Ti 3 C 2 ) with a super hydrophilic bamboo fiber (BF) membrane. The mo-Ti 3 C 2 heterojunction promotes the transfer and separation of photoinduced charges and thus enhances the photocatalytic reduction of heavy metal ions (Co 2+ , Pb 2+ , Zn 2+ , Mn 2+ and Cu 2+ ). The photoreduced metal nanoparticles with high conductivity and LSPR effect further accelerate the transfer and separation of photoinduced charges, and improve photothermal and evaporative performance. The mo-Ti 3 C 2 -2.4 @BF membrane in Co(NO 3 ) 2 solution can achieve an excellent evaporation rate of 4.6 kg·m −2 ·h −1 and a high solar-vapor efficiency of up to 97.5% under the light intensity of 2.44 kW·m −2 , which are 27.8% and 19.6% higher than those in H 2 O, respectively, demonstrating the reuse of photoreduced Co nanoparticles. No heavy metal ions are detected in any of the condensed water, and the Co 2+ removal rate in the concentrated Co(NO 3 ) 2 solution is up to 80.4%. The synergetic photocatalytic-photothermal approach on the mo-Ti 3 C 2 @BF membrane provides a new scope for the continuous removal and reuse of heavy metal ions, as well as for obtaining clean water.