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Abstract: A general design for optical chemical nanosensors is necessary for the development of efficient sensing systems with high flexibility and low capital cost for the controlled recognition of heavy and toxic metals. In the present work, we designed optical chemical nanosensors for the colorimetric recognition and simultaneous removal of Cu(II) and Pd(II) ions. The optical nanosensors were designed by direct immobilization of a synthesized N,N′-disalicylidene-4,5-diamino-6-hydroxy-2-mercaptopyrimidine (DSAHMP) chelate onto hexagonal mesoporous aluminosilica carriers. The natural surfaces and active acid sites of the aluminosilicas strongly induced H-bonding and dispersive interactions with the DSAHMP chelate, leading to the formation of stable sensors without leaching of the chelate during sensing assays of metal ions. No elution of the probe molecules was evident with the addition of Cu(II) and Pd(II) analyte ions during the sensing process. In addition, the structural features of the open-pore, hexagonal mesostructures led to high rates of accessibility and adsorption capacity of the DSAHMP chelate. Within such a tailored nanosensor design, the ability to achieve flexibility in the specific activity of the electron acceptor/donor strength of the chemically responsive DSAHMP molecular probe enabled easy generation and transduction of optical color signals as a response to DSAHMP-Cu(II) or DSAHMP-Pd(II) binding events, even at ultra-trace concentrations (10−9 mol/dm3) of heavy metals. The functional and solid design of the nanosensors offered a simple, one-step sensing procedure for both the quantitate and visual detection of such elements from their sources without the need for sophisticated instruments. Controlled sensing and removal assays significantly enhanced nanosensor functionality in terms of long-term stability, reversibility, and selectivity. The key result in our study is that the design-made nanosensors exhibited significant ion-selectivity toward the target ions in environmental and waste disposal samples. [Copyright &y& Elsevier]

The monitoring and removal of abundant heavy metals such as Cu ions are considerable global concerns because of their severe impact on the health of humans and other living organisms. To meet this global challenge, we engineered a novel mesoscopic capture protocol for the highly selective removal and visual monitoring of copper (Cu2+) ions from wide-ranging water sources. The capture hierarchy carriers featured three-dimensional, microsized MgO mesoarchitecture rectangular sheet-like mosaics that were randomly built in horizontal and vertical directions, uniformly arranged sheet faces, corners, and edges, smoothly quadrilateral surface coverage for strong Cu2+-to-ligand binding exposure, and multidiffusible pathways. The Cu2+ ion-selectively active captor surface design was engineered through the simple incorporation/encapsulation of a synthetic molecular chelation agent into hierarchical mesoporous MgO rectangular sheet platforms to produce a selective, visual mesoscopic captor (VMC). The nanoscale VMC dressing of MgO rectangular mosaic hierarchy by molecularly electron-enriched chelates with actively double core bindings of azo- and sulfonamide- groups and hydrophobic dodecyl tail showed potential to selectively trap and efficiently remove ultratrace Cu2+-ions with an extreme removal capability of ~233 mg/g from watery solutions, such as drinking water, hospital effluent, and food-processing wastewater at specific pH values. In addition to the Cu2+ ion-selective removal, the VMC design enabled the continuous visual monitoring of ultratrace Cu2+ ions (~3.35 × 10−8 M) as a consequence of strong chelate-to-Cu2+ binding events among all accumulated matrices in water sources. Our experimental recycle protocol provided evidence of reusability and recyclability of VMC (≥10 cycles). With our mesoscopic capture protocol, the VMC can be a promising candidate for the selective decontamination/removal and sensitive detection of hazardous inorganic pollutants from different water sources with indoor or outdoor applications. ga1 • Copper ions removal is of global concern due to its severe impact on human health. • Heterogeneous visual capture protocol was designed to remove Cu(II) ions from water. • The 3D microsized MgO mesoarchitecture was used as the capture design platform. • The VMC showed high efficiency and selectivity removal of Cu with q m of ~233 mg/g. • The VMC provides sensitive/selective captor to treat indoor/outdoor water sources. [ABSTRACT FROM AUTHOR]