Recovering nitrate from surface water can help address interconnected environmental, resource, and energy challenges. In response, we have developed a bioinspired photothermal evaporation platform (BPEP) for the efficient co-recovery of low-concentration nitrate and freshwater. Through the evaporation-induced localized multi-field (flowing, concentration, temperature) enhancement effect, the BPEP achieves a high nitrate recovery capacity of 8510 g m^-2 under 1 sun illumination, approximately 6.7 times higher than under dark conditions. The flowing field is identified as the dominant contributor, accounting for nearly 80% of the total enhancement. In outdoor testing, BPEP demonstrates a high nitrate recovery of around 25.9 mg m^-2, with a daily water collection rate of about 8.46 kg m^-2. The extracted nitrate by BPEP can be further converted into nitrogen fertilizer via catalytic processes, thereby promoting plant growth. Overall, BPEP offers an integrated strategy to recover nitrate and freshwater, addressing pressing issues in global sustainable development.

Magnetic nanofluids, also referred to as ferromagnetic particle levitation systems, are materials with highly responsive magnetic properties. Due to their magnetic responsiveness, excellent controllability, favorable thermal characteristics, and versatility, magnetic nanofluids have sparked considerable interest in both industrial manufacturing and scientific research. Magnetic nanofluids have been used and developed in diverse areas such as materials science, physics, chemistry and engineering due to their remarkable characteristics such as rapid magnetic reaction, elastic flow capacities, and tunable thermal and optical properties. This paper provides a full and in-depth introduction to the diverse uses of ferrofluids including material fabrication, fluid droplet manipulation, and biomedicine for the power and machinery sectors. As a result, magnetic nanofluids have shown promising applications and have provided innovative ideas for multidisciplinary research in biology, chemistry, physics and materials science. This paper also presents an overview of the device construction and the latest developments in magnetic-nanofluid-related equipment, as well as possible challenging issues and promising future scenarios.