Experimental investigation on novel desalination system via gas hydrate

Freshwater scarcity has been troubling the high-quality development of many countries and regions, and seawater desalination is a vital source of freshwater. Recently, gas hydrate based desalination (GHBD) technology attracts much attention because of bringing no extra pollution to water. We developed a novel multifunctional desalination apparatus via gas hydrate with various operation modes and separation methods. In this study, the desalination characters under different separation modes were conducted using simulated seawater, and the hydrate-purging method with a desalination efficiency of more than 80% was selected to desalt the natural seawater sample. In addition, the purging method can greatly improve the desalination effects of both squeezed hydrate column and loose hydrates. The experimental results indicate that the removal efficiencies of different ions in the seawater were similar and their difference was related to the strength of ionic hydration. And above all, we designed and conducted a continuous desalination process including multiple injection, separation, washing and purging operations. The ultimate desalination efficiency using hydrate-purging method was over 80%, and the freshwater recovery was above 30% with 200 mL initial seawater in this study. The experimental proposal and results of this study are of great significance to the development of GHBD technology.