Fluorescent carbon dots crosslinked cellulose Nanofibril/Chitosan interpenetrating hydrogel system for sensitive detection and efficient adsorption of Cu (II) and Cr (VI)

Simultaneous Detection and Adsorptive Removal of Cr(VI) Ions by Fluorescent Sulfur Quantum Dots Embedded in Chitosan Hydrogels

“…It is worth noting that there is a good linear relationship between the fluorescence quenching rate ( I / I 0 ) of CS-SQDs and the concentration of the Cr­(VI) ion solution in the range of 0–76 μM (Figure c), which lays a foundation for the quantitative determination of Cr­(VI) ions in aqueous solution. Under the condition of a signal-to-noise ratio of 3, it is found that the detection limit of CS-SQDs for Cr­(VI) ions can reach 176.2 nM (0.009 mg L –1 ), which is better than that of many reported solid-state fluorescent probes (Table ) and can meet well with the requirement of the determination of Cr­(VI) ions in drinking water (0.05 mg L –1 ). ,,,− In addition, the fluorescence quenching interaction of Cr­(VI) ions is fast. As can be seen in Figure d, the emission intensity of CS-SQDs decreased rapidly in the first 30 s and reached equilibrium within 60 s, which indicates the potential of CS-SQDs for the rapid detection of Cr­(VI) ions.…”

“…So far, adsorption is recognized as one of the most effective methods to eliminate Cr­(VI) ions from wastewater, which is widely applicable with simple operation at a low cost. − Hydrogel, with a unique three-dimensional network-like structure, is highly preferred by researchers in adsorbing heavy-metal ions from water. − Among various hydrogel adsorbents, chitosan (CS)-based hydrogel is a promising candidate, which could be obtained at low price with wide availability of raw materials. Moreover, there are abundant amine and hydroxyl groups on the surface to provide binding sites for adsorption. − For example, CS-based hydrogels with good adsorption properties for Cr­(VI) ions have been synthesized by using glutaraldehyde and tetraethylenepentamine as cross-linking agents, respectively. , However, hydrogels with a single adsorption function for Cr­(VI) ions can no longer meet the needs of practical applications because more and more applications require the simultaneous detection and uptake of Cr­(VI) ions. In this regard, a viable method is to combine fluorescent quantum dots with a hydrogel to prepare a composite hydrogel, so as to realize the synergy of their properties. , To date, a composite hydrogel that can simultaneously realize the sensitive fluorescence detection and efficient adsorption of Cr­(VI) ions has rarely been reported.…”

Carbon Dots in Bioimaging, Biosensing and Therapeutics: A Comprehensive Review

“…Several studies have identified specific surface functional groups of CDs that can coordinate metal ions (such as Cu 2þ and Fe 3þ ) in biological systems. [166,167] For example, CDs with abundant phenolic hydroxyl groups exhibited a good binding affinity towards Fe 3þ , with complexation leading to splitting of the d orbitals of Fe 3þ . Electrons in the photoexcited CDs were partially transferred to Fe 3þ , resulting in fluorescence quenching.…”

Light-nutrition coupling effect of degradable fluorescent carbon dots on lettuce

“…40 Peaks around 1652, 1581 and 1563 cm −1 in the N-doped CDs were assigned to the CC/CO and N-H bends of an amide group. 25,41,42 For the N1-CDs, the peak for the N-H bend in the amide group (1563 cm −1 ) disappeared under LED and LED + UV light (Fig. S5b †), Environmental Science: Nano Paper indicating that the photobleaching firstly occurred on the N-H bend in the amide group.…”