Integrated decontamination of off-odors and ammonia nitrogen in aquaculture using a core-satellite MOF-on-MOF...

Off-odors in aquatic products reduce marketability, while aquaculture ammonia emissions exacerbate eutrophication, impeding sustainable industrialization. Herein, we report a surfactant-mediated epitaxial growth strategy to construct a core-satellite CDMOF-on-CaMOF heterostructure, which features ordered anchoring and strong interfacial coupling between γ-cyclodextrin MOF (CD-MOF) nanosatellites and a hydrophobic Ca-MOF core. This unique architecture endows hierarchical porosity and multifunctional active sites (including -OH, -COOH, and chelatable Ca²⁺), facilitating hydrogen bonding and Ca^2 + coordination. Biosafety evaluations confirm excellent biocompatibility both in vitro and in vivo. Static adsorption demonstrated outstanding efficiency of CDMOF-on-CaMOF: 95.7% for dimethyl trisulfide (DMTS), 94.2% for nonanal, 90.2% for 1-octen-3-ol (OCT), 88.1% for 2-methylisoborneol (2-MIB), and 76.8% for trimethylamine (TMA). Kinetic and isotherm analyses, complemented by density-functional-theory (DFT), reveal a synergistic adsorption driven by physicochemical interactions and host-guest encapsulation: DMTS and TMA are specifically anchored via Ca²⁺ coordination at the Ca-MOF core, with the smaller molecular size of TMA (≈0.65 nm) leading to a weaker confinement effect in the layered pores (≈1.81 nm); NON and OCT are primarily captured within the large pores(≈2.12 nm) of the CD-MOF nanosatellites through hydrogen bonding and host-guest encapsulation; and 2-MIB is adsorbed through van der Waals forces on the heterostructure surface. In real-world scenarios, CDMOF-on-CaMOF effectively reduced key off-odor by 41% and 36% for freshwater and saltwater surimi, respectively, and removed ammonium nitrogen compounds from aquaculture wastewater (85%). This work establishes a scalable, high-performance nanoplatform for aquatic products processing and aquaculture wastewater purification, offering innovative strategy that enhances product quality and promote sustainability in aquaculture.