Use of carbon materials for constructing a closed water treatment system

Water purification by solar distillation has been deemed to be a green and promising approach for the production of potable water from undrinkable water resources. Carbonaceous materials have been well-known for the application of the sorption layer in the solar-to-steam system. Herein, both carbon spheres (CSs) and carbon dots (CDs) were synthesized by a one-pot hydrothermal method at 180 °C for 12h and they were used for constructing a closed water treatment system, in which CSs served as solar-thermal membranes in harvesting water and purifying Fe3+ ions in condensed water, while CDs played a role in the determination of Fe3+ ions in water. The evaporation rate of the CS membrane reaches 1.046 kg m−2 h−1 under 1 sun illumination and the efficiency treatment of Fe3+ is about 80%. The limit of detection obtained in the evaluation of Fe3+ ions in water by CDs was 3.61 μM. This work represents a significant step forward, as it opens the concept of constructing a closed water treatment system.