Steam generation through efficient utilization of solar energy is a promising technology in addressing the challenge of global freshwater shortage and water pollution. One of the biggest hurdles for traditional photothermal membranes to function continuously in a high temperature, high salt, and corrosive environment has been attributed to their rapid decline of mechanical properties. In this work, a highly efficient solar-driven interfacial water evaporation system has been developed via a polydopamine/carbon/silicon (PCS) composite membrane supported by a floating insulation foam substrate. A 3.1 fold increase in the water vaporization rate was recorded compared with the pure water system. The 2D-carbon nanolayer on the surface was successfully prepared by carbonizing low-cost linear polyethylene with a glass fiber (GF) membrane as the substrate, and then the carbon membrane was modified with dopamine to control water transport on the carbon coating and within the glass fiber. The PCS membrane has a high efficiency for solar steam generation owing to high optical absorption and has excellent solar thermal conversion capability. The evaporation rate and solar thermal conversion efficiency of the PCS membrane under simulated sunlight irradiation with 1 sun (1 kW·m–2) are 1.39 kg·m–2·h–1 and 80.4% respectively, which are significantly higher compared to GF membrane, carbon/silicon (CS) membrane, and pure water without a photothermal membrane. The water evaporation system retained high efficiency after 20 cycles under simulated sunlight irradiation of 1 sun. This study provides critical insight on the design and fabrication of a highly efficient and durable evaporation system.

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Chinese ink nanofluids were prepared successfully by “two-step” method. The optical properties of Chinese ink nanofluids were investigated. And the effects of the base fluid types and ultrasonic time on their dispersion stability also were investigated. Results show that Chinese ink have high absorption characteristics and very low transmittance on light radiation in the wavelength range of 190-1100 nm; The dispersion stability of nanofluids increases first and then decreases with the increase of ultrasonic dispersion time. There is an optimal ultrasonic dispersion time of 90 min; the base fluid has a certain influence on the dispersion stability of Chinese ink nanofluid, among which DMF base solution has the best dispersion stability, followed by thermal conductive oil. Ethanol has no obvious improvement compared with water, both of which have lower dispersion stability than DMF and thermal conductive oil. This research provides a fundamental guidance for the preparation of Chinese ink nanofluids and their further application in Solar photo-thermal conversion.

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