Water Purifying by Gas Hydrate: Potential Applications to Desalination and Wastewater Treatments

Freshwater scarcity has been troubling the high-quality development of many countries and regions, and water purification process is a vital source of freshwater. The traditional water purification processes such as distillation (multi-stage flash) and membrane processes (reverse osmosis) have been evaluated to be reliable and established processes. The desalination or water treatment technologies are mature enough to be a reliable source for fresh water but there is still a need to develop innovative technologies that can reduce energy costs. The water purifying by gas hydrate (hydrate-based) process is based on a liquid to solid phase change coupled with a physical process to separate the solids from the remaining liquid. In this study, we investigated the water purification by hydrate process for seawater and wastewater samples. In a single stage of hydrate process without any pre-treatment, dissociated water from the extracted hydrate pellets show that the removal efficiency of each ionic compound in seawater was 89 % (average). In the case of wastewater test from leachate sample, 77-95 % of dissolved contaminants and nutrients were excluded. Therefore, the experimental proposal and results of this study are of great significance to the development of water purification technology.