Adsorption effectively removes contaminants from aqueous media and recovers valuable metals from leachates, and the field has expanded substantially over the past two decades. Adsorption research has generated numerous high-capacity, waste-derived materials, but many studies still evaluate them individually, using adsorption capacity as the principal metric, and treat both the spent adsorbent and the captured species as waste. This review proposes a different unit of analysis: a circular-adsorption framework in which feedstock origin, surface engineering, regenerability, and the fate of the captured species are designed and reported as a coupled system rather than as sequential afterthoughts. To develop this framework, we conducted a defined literature search focused on recent waste-derived adsorbents. The reviewed cases indicate that surface charge, functional-group density, and surface heterogeneity are transferable design variables; that statistical-physics modeling can provide comparative descriptors such as site occupancy and fitted adsorption-energy parameters; and that demonstrated regenerability spans approximately three to fifteen cycles depending on the regeneration chemistry, which in turn influences whether the process terminates in contaminant destruction or resource recovery. The review concludes with a research roadmap centered on real-matrix validation, co-designed regeneration and elution, durability of green crosslinks, direct benchmarking against established separations, and life-cycle accounting, so that water purification and resource recovery can be assessed as a single, auditable circular operation.
Three dimensional food printing (3DFP) enables the on-demand fabrication of edible constructs with customizable geometries, textures, and nutritional profiles. Biogel-based inks (BGink), including hydrogels, oleogels, and bigels, provide a highly versatile platform, as their rheological and physicochemical properties can be systematically tuned to meet specific processing and functional requirements. This review critically synthesizes recent advances in biogel-based 3DFP through a multiscale structure-property-function framework. It compares the roles of molecular crosslinking and water confinement in hydrogels, oil-structuring networks in oleogels, and phase organization and interfacial coupling in bigels, linking these structural mechanisms to ink properties and macroscopic functionality. Building upon these colloidal and interfacial architectures, the discussion then connects formulation-dependent properties with key printing parameters to explain the shape fidelity, structural stability, and sensory-related and functional properties of printed structures. These structure-function relationships are further discussed in the context of representative applications, including personalized and functional foods, clinical and therapeutic diets, artificial intelligence integration, and sustainable biomanufacturing. Current limitations and future research needs are also identified. Overall, this review clarifies the multiscale relationships among biogel microstructures, ink properties, and end-product performance, providing a scientific foundation for the rational design of next-generation BGink and advanced 3DFP systems.
Air pollution is a worldwide issue to be solved and catalytic purification technology is regarded as one of the most effective strategies for the removal of air pollutants. CeO2-based catalyst has attracted more and more attention for the control of air pollution due to its excellent redox properties and the highly tunable structures. This review begins by establishing the fundamental connections between synthesis conditions and the achievable nanocrystal morphologies of ceria. Subsequently, the surface characteristics of the predominantly exposed CeO2 facets are elaborated, followed by an in-depth discussion on the formation and nature of surface defects, which are crucial for the catalytic activity. On this structural basis, the review systematically surveys the catalytic removal of typical air pollutants, including the oxidation of CO, HCHO, hydrocarbons, and soot, as well as the selective catalytic reduction of NOₓ and N2O decomposition. Particular emphasis is placed on elucidating the morphology-dependent structure-performance relationships. Finally, future research directions and development prospects for next-generation CeO2-based catalysts are outlined. This review aims to provide fundamental insights and practical guidance for the rational design of highly efficient CeO2 catalysts with tailored morphologies for advanced air pollution control.
