Evaporator

About: Evaporator is a research topic. Over the lifetime, 39069 publications have been published within this topic receiving 232760 citations.

A hydrogel-based antifouling solar evaporator for highly efficient water desalination

Abstract: Solar desalination is a promising method for large-scale water purification by utilizing sustainable energy. However, current high-rate solar evaporation often relies on optical concentration due to the diffusion of natural sunlight, which leads to inadequate energy supply. Here we demonstrate a hydrogel-based solar evaporator that is capable of generating vapor at a high rate of ∼2.5 kg m−2 h−1 under one sun irradiation (1 kW m−2), among the best values reported in the literature. Such highly efficient solar evaporation is achieved by a hybrid hydrogel composed of a hydrophilic polymer framework (polyvinyl alcohol, PVA) and solar absorber (reduced graphene oxide, rGO), which has internal capillary channels. The PVA can greatly facilitate the water evaporation owing to the reduced water evaporation enthalpy in the hydrogel network. The rGO penetrating into the polymeric network enables efficient energy utilization. The capillary channels sustain an adequate water supply for continuous solar vapor generation at a high rate. This hydrogel-based solar evaporator also exhibits promising antifouling properties, enabling long-term water desalination without recycling. The high-efficiency hydrogel-based solar vapor generators open significant opportunities to enhance solar water evaporation performance and reduce the cost of solar desalination systems.

A High-Performance Self-Regenerating Solar Evaporator for Continuous Water Desalination

Abstract: Emerging solar desalination by interfacial evaporation shows great potential in response to global water scarcity because of its high solar-to-vapor efficiency, low environmental impact, and off-grid capability. However, solute accumulation at the heating interface has severely impacted the performance and long-term stability of current solar evaporation systems. Here, a self-regenerating solar evaporator featuring excellent antifouling properties using a rationally designed artificial channel-array in a natural wood substrate is reported. Upon solar evaporation, salt concentration gradients are formed between the millimeter-sized drilled channels (with a low salt concentration) and the microsized natural wood channels (with a high salt concentration) due to their different hydraulic conductivities. The concentration gradients allow spontaneous interchannel salt exchange through the 1-2 µm pits, leading to the dilution of salt in the microsized wood channels. The drilled channels with high hydraulic conductivities thus function as salt-rejection pathways, which can rapidly exchange the salt with the bulk solution, enabling the real-time self-regeneration of the evaporator. Compared to other salt-rejection designs, the solar evaporator exhibits the highest efficiency (≈75%) in a highly concentrated salt solution (20 wt% NaCl) under 1 sun irradiation, as well as long-term stability (over 100 h of continuous operation).