Evaporation efficiency monitoring device based on biomass photothermal material for salt-resistant solar-driven interfacial evaporation

Abstract Solar-driven interface evaporation has received much attention due to its high-efficiency photothermal conversion efficiency. However, in practical application, it is difficult to monitor whether the evaporation efficiency of photothermal conversion materials can maintain high efficiency and stability for a long time. In this paper, taking surface modified coconut fiber (SCF) as photothermal material, we designed a set of evaporation efficiency monitoring device (EEMD) and demonstrated the strategy of building a solar evaporation efficiency monitoring system. The SCF shows superhydrophilic wettability, and its vertical multi-stage open-framework structure is benefit to the rapid transport of water. Under 1 kW m−2 illumination, evaporation rate of SCF is 1.5 kg m−2 h−1, evaporation efficiency is 90.2%. In 20% NaCl, evaporation rate of SCF is 1.37 kg m−2 h−1, and energy conversion efficiency is 85.3%. In order to monitor the stability of evaporator efficiency, we designed a simple EEMD which applied platinum wire electrode to monitor the change of electric potential in the evaporator. The results show that the electric potential is positively correlated with the evaporation efficiency. EEMD provides a new monitoring method for the efficient and stable operation of solar evaporator.