Understanding the effect of materials, design criteria and operational parameters on the adsorption desalination performance - A review

Adsorption desalination is considered as a promising alternative to solve the problem of water scarcity, owing to the remarkable advantages of energy-saving, low cost, limited environmental effect and high-quality produced water driven by renewable low-temperature thermal energy. However, this technology is still in the early laboratory research stage, further endeavor is required to facilitate the marketization based on a comprehensive summary of the current investigation achievements. Herein, this review summarizes the main achievements of adsorption desalination technology, involving sorption materials, system configurations and operation performances. So far, physical adsorbents, salt hydrates and composite adsorbents have been adopted, and, according to the most recent findings, composite adsorbents showed better thermodynamic desalination performance. Several advanced working cycles and strategies have been proposed and validated through experimental testing and simulations, like heat and mass recovery and multi-stage cycle, they contribute to improving the performance of the system by increasing the water production, broadening the working conditions or enhancing the output delivering power. Furthermore, the most recent innovative design approaches of the adsorber have been reported. Finally, the influence of operating conditions, like heat source temperature and cycle time, on specific daily water production, specific cooling power and coefficient of performance derived from the experiment and simulation results were discussed. Market aspects and the implementation of the different solutions in terms of cost and engineering complexity were also discussed. Possible future investigation directions include developing high-performance adsorbents with low desorption temperature (<50 °C), designing reactors with less heat and mass transfer resistance, using seawater or brine water in testing prototypes and validating the operation of real-scale prototypes under real operating conditions.