Smart hydrogel and adaptive feedback control system: A novel paradigm for the brackish water treatment

Abstract

As the issue of the global water scarcity becomes increasingly severe, it is urgent to explore alternative water sources. Wherein, the effective treatment of the brackish water is considered as a promising strategy. In this study, a novel temperature-sensitive double-network (TDN) hydrogel was developed, which exhibited exceptional responsiveness to the temperature changes. Upon heating, the TDN hydrogel facilitated the water release and physical contraction, immediately increasing the internal H⁺ concentration, which allowed for the highly efficient adsorption of the metal salt ions and the simultaneous neutralization of the alkalinity under relatively low-temperature condition (35 °C). Additionally, a smart adaptive feedback control system was designed to dynamically visualize the hydrogel adsorption behavior through changes in the light emitting diode (LED) color. Experimental findings indicated that the adsorption capacity was raised from 4.53 to 7.17 g_Na+/g_TDN at the salt concentration of 15 g/L and pH increment from 7.5 to 10, demonstrating the outstanding desalination efficiency and superior selectivity for the Na⁺. This delivers an efficient, sustainable and eco-friendly solution for the water resource management, and it also pioneers innovative strategies for the automation and intelligent advancement of the water treatment processes.