Rational synthesis, characterization, and application of environmentally friendly (polymer–carbon dot) hybrid composite film for fast and efficient UV-assisted Cd2+ removal from water

Abstract

Background Carbon dots (CDs) are of particular interest in numerous applications. However, their efficiency for heavy metal removal from wastewater was not yet reported. Herein, we rationally synthesized CDs from petroleum coke waste via hydrothermal treatment in the presence of ammonia. Results This drove the formation of outstanding photoluminescent, water-soluble, biocompatible, and high yield of monodispersed sub-5 nm CDs. The CDs are co-doped with high 10% of N and 0.2% of S. The as-prepared CDs possess unprecedented photoluminescent properties over broad pH range making these dots unique efficient pH sensor. Conclusions Chitosan (CH)–CDs hybrid hydrogel nanocomposite film was further prepared as a platform membrane for the removal Cd2+ metal from wastewater. The as-prepared CH–CDs membranes show relatively good mechanical properties, based on stress resistance and flexibility to facilitate handling. The equilibrium state was reached within 5 min. Intriguingly, the UV-light illuminations enhanced the Cd2+ removal efficiency of the photoluminescent CDs substantially by four times faster under. It was found that adsorption followed pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity at 25 °C was found to be 112.4 mg g−1 at pH 8. This work paves the way to new applications of CDs in water treatment.

Design of hybrid clay/ polypyrrole decorated with silver and zinc oxide nanoparticles for anticorrosive and antibacterial applications

“…However, its chemical sensitivity and poor mechanical properties limited its industrial uses. Nevertheless, many previous studies confirmed that the incorporation of PPy with other polymers, nanoparticles, or biobased materials such as cellulose or clay minerals [22] was found to improve the PPy stability and sensitivity [23,24]. Previous studies, in our team described the preparation of low-cost and conductive clay-PPy nanocomposites, with enhanced antibacterial, catalytic properties [24][25][26].…”

Sustainable Development of Enhanced Luminescence Polymer-Carbon Dots Composite Film for Rapid Cd2+ Removal from Wastewater

“…The O 1 s spectrum ( Figure 3c) showed two peaks at 530.7 and 531.9 eV corresponding to O-H and C=O, respectively. It is worth noting that the incorporation of active moietises including N-H and C=O can effectively enhance the QY of CDs, which provide more active sites for capturing a variety of analytes [4,13,48]. The corresponding elemental compositions (in atomic ratios) are summarized Table S1.…”

“…According to the Disease Registry and Environmental Protection Agency (EPA), Cd(II) ranks seventh on the top 20 toxic chemicals priority list [3]. Long-term exposure to Cd(II) results in a series of harmful diseases in humans ecosystem damage [4]. Due to its toxic effects on human health, the separation and elimination of Cd 2+ from aquatic media is still a hot research topic.…”

“…Thus, full exploitation of these low-value wastes to recycle them and develop new value-added carbonaceous materials is of great interest. The encapsulation of CDs into solid-state film is still challenging as they show photo-quenching properties after the immobilization processes, make them unsuitable for application in a variety of fields [4].…”

“…The as-formed CDs exhibit a yellow color, showing greenish emission under UV-lamp (365 nm), good water solubility and long shelf-life (up to 1 year) with no apparent agglomeration. These CDs were encapsulated with PVA polymer host to develop a solid-state hybrid film for heavy metal complexation in an attempt to overcome the separation issues of the liquid phase [4]. In comparison to the liquid CDs, the as-obtained film is transparent under daylight while they exhibited a bright blue emission under UV exposure.…”