Carbon Dot-Integrated Hydrogel Systems for Solar-Driven Water Evaporation and Purification: Materials Design, Mechanisms, and Recent Advances

Abstract

Water plays a pivotal role as a resource for ecological sustenance. Water conservation is considered as one's sole responsibility. There is an emerging need to come up with sustainable, cost-effective purification technologies with appreciable efficacy to avail fresh water from plentiful sources such as seas, oceans, brackish water and water from sewages that possess independency from the hydrological cycle. Numerous sustainable solutions and technologies have been already practiced for water treatment by scientists and researchers worldwide. This review paper summarizes the role and advantages of carbon dots incorporated in hydrogels facilitating solar water evaporation. Firstly, the mechanism of solar water evaporation has been discussed followed by the photothermal properties of carbon dots, thereby highlighting the developments in carbon dot-based solar water evaporators. Next the various characteristics of hydrogels including their photothermal properties were elaborated. While reviewing the advantages of hydrogel-based solar water evaporators as well as synergistic effects of Carbon Dot (CD) -based hydrogel composites, the recent advancements in CD-hydrogel composites were also overviewed. Utilization of hydrogels for water purification and solar distillation has emerged as one of the most propitious sustainable initiatives to combat water contamination and scarcity. The core concept of solar water evaporators is the vapor generator which evaporates impure water through the use of solar energy. Efficient energy confinement facilitated by solar vapor generation can progress with updated designs which can turn out to be evolutionary towards sustainable development.