Preparation and Application of Electrodes in Capacitive Deionization (CDI): a State-of-Art Review

As a promising desalination technology, capacitive deionization (CDI) have shown practicality and cost-effectiveness in brackish water treatment. Developing more efficient electrode materials is the key to improving salt removal performance. This work reviewed current progress on electrode fabrication in application of CDI. Fundamental principal (e.g. EDL theory and adsorption isotherms) and process factors (e.g. pore distribution, potential, salt type and concentration) of CDI performance were presented first. It was then followed by in-depth discussion and comparison on properties and fabrication technique of different electrodes, including carbon aerogel, activated carbon, carbon nanotubes, graphene and ordered mesoporous carbon. Finally, polyaniline as conductive polymer and its potential application as CDI electrode-enhancing materials were also discussed

Experimental simulations of explosive degassing of magma.

The violent release of volatiles in explosive volcanic eruptions is known to cause fragmentation of magma and acceleration of the resulting mixture of gas and pyroclasts to velocities exceeding 100 m s-1 (ref. 1). But the mechanisms underlying bubble nuclea-tion, flow acceleration and fragmentation are complex and poorly understood. To gain insight into these phenomena, we have simu-lated explosive eruptions using two model systems that generate expansion rates and flow velocities comparable to those observed in erupting volcanos. The key feature of both experiments is the generation of large supersaturations of carbon dioxide in a liquid phase, achieved either by decompressing CO2-saturated water or by rapid mixing of concentrated K2CO3 and HC1 solutions. We show that liberation of CO2 from the aqueous phase is enhanced by violent acceleration of the mixture, which induces strong exten-sional strain in the developing foam. Fragmentation then occurs when the bubble density and expansion rate are such that the bubble walls rupture. In contrast to conventional models of fragmentation1,2, we find that expansion and acceleration precede—and indeed cause—fragmentation