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

Abstract

Water pollution caused by hexavalent chromium [Cr-(VI)] ions has attracted increasing attention because Cr(VI) ions are highly toxic and carcinogenic, which may cause serious harm to aquatic organisms and human health. More and more research has focused on the sensing or adsorption of Cr(VI) ions. However, so far, it is still a challenge to prepare advanced materials that can simultaneously detect and adsorb Cr(VI) ions. Herein, we present a facile and effective strategy to prepare a chitosan−sulfur quantum dots (CS-SQDs) composite hydrogel with both excellent sensing and uptake capability toward Cr(VI) ions. The CS-SQDs show excellent fluorescence stability against pH variation, high ionic strength, UV−light irradiation, and long-term storage. Moreover, the CS-SQDs exhibit sensitive and selective fluorescence responsiveness to Cr(VI) ions. The detection limit can reach 176.2 nM. Additionally, the CS-SQDs also show high uptake capability and favorable reusability for the adsorptive removal of Cr(VI) ions with a maximum adsorption capacity of 186.22 mg g −1 . The adsorption behavior is spontaneous, and the adsorption process conforms to Langmuir isotherm and pseudosecond-order kinetic models. This work provides an effective strategy for the preparation of multifunctional hydrogels with the potential to simultaneously monitor and remove water contaminants.

Pyridinium‐Functionalized Ionic Porous Organic Polymer for Rapid Scavenging of Oxoanions from Water

“…Whereas, in the case of dichromate exchange, the Cr(VII) peak was further deconvoluted into two distinct peaks ≈587.68 eV and 578.68 eV corresponding to Cr 2p 3/2 and Cr 2p 1/2 , respectively (Figure 6b). [ 7,60 ] The peak separation between the two doublets was found to be ≈9 eV, confirming the presence of Cr(VII) after ion‐exchange. [ 60 ]…”

“…[ 7,60 ] The peak separation between the two doublets was found to be ≈9 eV, confirming the presence of Cr(VII) after ion‐exchange. [ 60 ]…”

Ultrasound-Assisted Hydrothermal Synthesis of Highly Fluorescent Sulfur Quantum Dots for Fe3+ Ion and Ascorbic Acid Detection in Real Samples

“…Of these peaks, two were observed at 163 and 164.2 eV, belonging to zerovalent sulfur. 38 The binding energies of 167.2, 168.3, and 169.6 eV were attributed to oxidized sulfur species in the form of SO 2 − (2p 2/3 ), SO 2 2− (2p 1/2 ) or SO 3 2− (2p 2/3 ), and SO 3 2− (2p 1/2 ), respectively. 22 These results indicate that the SQDs are primarily composed of sulfonyl/sulfonate groups on their surface, consistent with previous literature reports.…”

Shaping Sulfur Precursors to Low Dimensional (0D, 1D and 2D) Sulfur Nanomaterials: Synthesis, Characterization, Mechanism, Functionalization, and Applications

“…0D sulfur nanomaterials, especially SQDs, are commonly applied in fluorescence sensing owing to their tunable fluorescence, high solubility, low toxicity, good biocompatibility, and superior stability. [ 111 ] The presence of rich surface functional groups enables a versatile interaction with other species, leading to dramatic fluorescence changes.…”