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 (Co2+, Pb2+, Zn2+, Mn2+ and Cu2+). 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 Co2+ 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. [Display omitted] • Synergistic photocatalytic-photothermal system was designed for metal ions removal. • Ti 3 C 2 concentrates heavy metal ions by high efficiency water evaporation. • The heterojunction promotes the transfer and separation of photoinduced charges. • Photoreduced nanoparticles promote photothermal effect and charge separation. • The membrane achieves a solar-vapor efficiency up to 97.5% in Co2+ solution. [ABSTRACT FROM AUTHOR]