An abnormal level of dopamine (DA), a kind of neurotransmitter, correlates with a series of diseases, including Parkinson’s disease, Willis-Ekbom disease, attention deficit hyperactivity disorder, and schizophrenia. Hence, it is imperative to achieve a precise, rapid detection method in clinical medicine. In this study, we synthesized nanocomposite carbon aerogels (CAs) doped with iron and iron carbide, based on algae residue-derived biomass materials, using Fe(NO₃)₃ as the iron source. The modified glassy carbon electrode (GCE) for DA detection, denoted as CAs-Fe/GCE, was prepared through surface modification with this composite material. X-ray photoelectron spectroscopy and X-ray diffraction characterization confirmed the successful doping of iron into the as-prepared CAs. Additionally, the electrochemical behavior of DA on the modified electrode surface was investigated and the results demonstrate that the addition of the CAs-Fe promoted the electron transfer rate, thereby enhancing their sensing performance. The fabricated electrochemical DA biosensor exhibits an accurate detection of DA in the concentration within the range of 0.01~200 µM, with a detection limit of 0.0033 µM. Furthermore, the proposed biosensor is validated in real samples, showing its high applicability for the detection of DA in beverages.

With the continuous expansion of urban areas, the treatment of urban sewage is facing significant challenges. Tens of thousands of tons of municipal sludge (MS) are produced annually, which not only occupies substantial land resources but also poses potential environmental threats, thereby complicating wastewater treatment processes. Proper management of MS has thus become a critical issue requiring urgent attention. Meanwhile, water pollution continues to worsen, endangering both ecological systems and human health. MS contains a variety of organic compounds with active functional groups capable of forming strong coordination interactions with various waterborne pollutants. Building on this foundation, we successfully develop a multifunctional adsorbent using MS as the raw material through biomineralization. The synthesized adsorbent shows outstanding performance, exhibiting high adsorption capacity for fluoride (F⁻) and hexavalent uranium (U(VI)) in high-fluorine uranium-containing wastewater, effectively reducing the concentrations of these harmful substances. Additionally, the adsorbent shows strong affinity for the cationic dye methylene blue, making it highly suitable for the treatment of wastewater from the printing and dyeing industries. Notably, the adsorbent also possesses antibacterial properties, demonstrating significant bactericidal activity against Gram-negative E. coli in wastewater. The multifunctional adsorbent not only offers a novel solution to enhancing water quality and safety, but also represents a promising strategy for sustainable wastewater treatment.