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.

As an essential trace element in the human body, fluoride is beneficial in appropriate amounts, but excessive intake can cause serious harm. Therefore, addressing the global water pollution caused by fluoride is an urgent issue. In this study, a functional composite membrane is successfully prepared using Enteromorpha prolifera (EP) as the raw material, cinnamaldehyde (CIN) as a functional modifier, and EP-bioinduced ZrO₂ nanoparticles (NPs) as the loading material via biomimetic mineralization technology. The experimental results demonstrate that the composite membrane removes fluoride ions (F⁻) with an efficiency of over 99.9% within the concentration range of 100–400 mg/L. This excellent F⁻ removal performance is attributed to the ability of the hydroxyl groups on the surface of ZrO₂ to exchange and bind with F⁻. The formed CIN/EP-ZrO₂ composite membrane also reveals significant antibacterial activity against E. coli. In addition, the adsorption rate for methylene blue at the concentration of 5–300 mg/L reaches 99.99%, which is due to the synergistic interaction of functional groups such as hydroxyl (-OH), carboxyl (-COOH), and amino groups (-NH₂) in EP. The overall sustainability footprint (OSF) assessment exhibits that the CIN/EP-ZrO₂ composite membrane has comprehensive advantages, including a simple preparation process, low cost, high performance, and environmental friendliness. This study provides an innovative solution for the sustainable treatment of F⁻, bacteria, and dye pollution in water, showcasing significant potential for applications in environmental science.