Functionalized carbon nanotubes interconnected with metal-organic frameworks for in-situ solar-driven evaporation and salt recovery from seawater

Abstract

Innovative solutions are needed to meet global water demand and to ensure the sustainable management of saline water resources. Indeed, solar-driven interfacial evaporation systems hold great environmental significance as they offer a sustainable and eco-friendly solution to several pressing issues. Herein, a 3D umbrella-shaped hybrid solar evaporator is innovatively developed by functionalized carbon nanotubes interlinked with metal-organic framework (MOF) nanocubes ZIF-67@CNT is sequentially anchored on cotton fabric with a centralized water supply. Combining these two materials results in a remarkable synergy, where the MOFs may trap and release water molecules (5.75 gg^-1), and the CNTs facilitate broadband solar absorption (95 %). The hybrid solar evaporator endows solitary heat accumulation (49.5 °C) under 1k Wm^-2 solar irradiance owing to its effective thermal management supported by centralized wicks-inspired water supply as compared to the conventional direct contact structures. More importantly, an efficient evaporation rate (2.1 kg m^-2 h^-1) was achieved, along with 99.9 % rejection efficacy and sustained reproducibility under natural conditions. Meanwhile, the system effectively concentrates and recovers salts from the brine stream, reducing waste and minimizing environmental impact. The sustainable utilization of solar energy reduces the energy cost associated with desalination, contributing to the economic viability of this technology.