Photothermal Diatomite/Carbon Nanotube Combined Aerogel for High‐Efficiency Solar Steam Generation and Wastewater Purification

Solar‐driven interface evaporation is a sustainable and green method for seawater desalination and wastewater purification which has attracted great attention due to the expectation to solve the global fresh water crisis. Currently, its commercial application is still limited by high cost, a complicated preparation process, and unsatisfying photothermal conversion efficiency, which are difficult to be achieved simultaneously. Herein, a nontoxic, high efficient, low cost, and facile strategy to fabricate a solar steam generator is demonstraterd, in which biocompatible agar powder, carbon nanotubes, and diatomite are combined to achieve an aerogel. All materials involved are commercially available. The aerogel exhibits a water evaporation rate of 1.67 kg m −2 h −1 with 91% conversion efficiency under one sun illumination, and can produce drinkable water from sea water, lake water, and even strong acid/alkaline water with nearly 100% rejection of organic dyes. Most importantly, the cost to produce such an aerogel is only 6.67 $ m −2 , and is expected to produce 5–8 kg m −2 of fresh water per day under natural sunlight, which is enough for a family of three to live normally for one day. Present high‐efficient and economic water purification system provides promise for commercial application in seawater desalination and wastewater purification.