Salt crystallization-guided zein self-assembly into porous microspheres: a core-satellite platform for spatially...

Industrial dye pollution poses a significant ecological threat, yet conventional catalytic remediation faces challenges such as catalyst aggregation and the high cost of synthetic supports. Herein, interconnected multicompartment zein porous microspheres (ZPP) were synthesized via salt crystal-induced antisolvent self-assembly to construct a green core-satellite enzyme-photocatalytic platform (ZTFTPS). ZPP exhibits excellent mass transfer and adsorption performance, with its saturated dye adsorption capacity far exceeding that of nonporous solid zein. Glucose oxidase (GOX) was encapsulated in ZPP cavities and stabilized by Fe³⁺-tannic acid metal-polyphenol network (MPN) coating, which acts as a selective nanofiltration gate to suppress enzyme leakage while allowing substrate transport. With Fe³⁺ bridging, rutile-phase titanium dioxide nanoparticles were hierarchically assembled on ZPP as satellite units to form integrated ZTFTPS. The platform integrates adsorption enrichment, in-situ H₂O₂ generation and photocatalytic oxidation, and locally produced H₂O₂ significantly enhances catalytic activity. Under optimized conditions, ZTFTPS achieves a malachite green (MG) degradation efficiency of 92.14% within 180 min, and its apparent rate constant is 217% higher than that of the unassembled physical mixture. After five consecutive cycles, the system still maintains a degradation efficiency of approximately 71.36%. Moreover, ZTFTPS effectively reduces the aquatic toxicity of dye wastewater, demonstrating outstanding biocompatibility and environmental safety. Overall, this work provides a green, scalable strategy for designing efficient porous bioreactors for organic dye wastewater treatment.