Sustainable microalgae extraction for proactive water bloom prevention

The recurring and unpredictable occurrences of water blooms have emerged as an escalating global threat to both the environment and water resources. Superior to the unsatisfactory post-bloom treatment techniques, the proactive strategy of reducing microalgae density in an economical and safe manner holds promise for effective water bloom control and prevention; however, it remains an important challenge. Here we report an efficient microalgae extraction mediated by a sustainable microalgae grabber (SMAG), which fully integrates tailored water depth suspending, electrostatic microalgae capture and magnetic collection. More importantly, the photothermal conversion capability of SMAG allows for the denaturation of extracellular polymeric substances, enabling on-demand desorption of microalgae for desired multiple reuses. Through the cyclic operation of these recyclable SMAGs, it demonstrates a remarkable microalgae removal efficiency of 94% and photothermal-driven spontaneous desorption, with a recovery efficiency of over 90%. Furthermore, a customized self-cruising floating device has been designed for the large-scale implementation of SMAGs, showcasing solar-powered sustainable microalgae extraction and harvesting in natural water bodies. The customizable and scalable SMAG offers a refreshing perspective in reinvigorating industries related to proactive water bloom prevention and microalgae resource capitalization.