Enhanced water purificationviaredox interfaces created by an atomic layer deposition strategy

What is it about?

The crisis of water scarcity has become one of the most urgent issues to be settled. It is still a challenge to develop a highly efficient water purification technology. In this work, highly efficient capacitive removal of metal ions from wastewater was demonstrated by using Ti–C redox interfaces created by an atomic layer deposition (ALD) strategy. It has been illustrated that the TiO2 nanolayer was formed by reaction on the surface of porous carbon (PC) by using an ALD strategy, which could effectively build the Ti–C redox interfaces; and thus, the TiO2 nanolayer on PC was beneficial for facilitating ion diffusion/transmission and adsorption/insertion. Impressively, this process showed a deionization capacity of 38.54 mg g−1 in a 500 mg L−1 NaCl solution at 1.2 V. In addition, this process had excellent capacitive removal efficiency to treat complicated water containing multiple metal ions (K+, Mg2+, Ca2+, Ni2+, Co2+, Cu2+, Pb2+, Cd2+, Cr2+, Fe3+ and Al3+). This work has important practical implication for highly efficient removal of metal ions from wastewater.

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Photo by Sime Basioli on Unsplash

Photo by Sime Basioli on Unsplash

Why is it important?

With the rapid growth of pollution and the development of industry and agriculture, the widespread problems of water shortage and water contamination are seriously increasing across the world and threatening human health. Capacitive deionization (CDI) is a promising water purification technology due to its unique advantages of low energy consumption, low cost, rapid regeneration, and environmental friendliness. However, the deionization capacity of CDI is insufficient for the demand of clean water from saline water. Hence, enhanced water purification was demonstrated by using Ti–C redox interfaces as cathodes created by an atomic layer deposition (ALD) strategy via asymmetric CDI. The interfaces and the nanolayer of TiO2 on PC were conducive to forming more active adsorption sites, promoting ion insertion/adsorption and making the most of capturing ions to be removed from saline water. It was worth noting that the deionization capacity reached as high as 38.54 mg g−1 in a 500 mg L−1 NaCl solution at 1.2 V. Furthermore, the electrodes exhibited excellent ability to treat complicated water containing multiple metal ions. This work has important practical implication for highly efficient capacitive deionization of saline water and removal of metal ions from wastewater.