Reconfigurable and regenerable liquid metal surface oxide for continuous and quantifiable adsorption of biological dye

Among water purification techniques, adsorption is one of the most effective and economical methods. However, the adsorbents are usually static materials, which are faced with issues such as regeneration and recovery difficulties. Here we report a reconfigurable and sustainable liquid metal oxide as adsorbent for effectively removal of a common azo dye, Ponceau S (PS), in water. Gallium-based alloy (GaInSn) with excellent reconfigurability and fluidity at room temperature is revealed to continuously produce surface gallium oxide for PS adsorption by simply mild shaking or stirring. The adsorption process is fast and energy saving in water. Besides, the oxide is easily removed from wastewater by taking out the whole liquid metal. Moreover, combined with electrical conductivity of liquid gallium, the impedance alteration after PS adsorption can be characterized by impedance sensing technique, which offers an electrical quantification method for PS absorption. This study put forward a unique way for the design and fabrication of adsorbents with continuous and multifunctional performance. Moreover, it will inspire more possible applications of reconfigurable materials in the fields of dye adsorption, environmental engineering and even detection methods for molecular monitoring.