Microwave-Prepared Quantum Dots and Their Potential Applications as Adsorbents and Chemosensors

Abstract

A combination of different eco-friendly materials prepared promising fluorescent quantum dots (QDs) through the one-step process using the microwave heating of urea with cellulose, chitosan, and biochar. Characterizations of the prepared QDs, including the investigation of their structure by infrared spectroscopy, Raman analysis, X-ray diffraction, thermal gravimetric analysis, morphology, and optical properties, were performed. The results showed that QDs possess a small size, high UV absorption, and excitation wavelength-dependent fluorescence. The prepared QDs were also tested for metal ions removal from aqueous solutions. The adsorption at different contact times was investigated to optimize the adsorption efficiency of the prepared QDs. All QDs were found to be an ideal sorbent for Cr(II), Cu(II), Mn(II), and Pb(II). From the data, Cr(II) was more highly adsorbed than other metal ions. The results of the kinetic investigation showed that the pseudo-second-order kinetic model fit the adsorption process effectively. In addition, the fluorescence spectra of QDs were changed after the adsorption of metal ions; hence, the prepared QDs could be utilized in environmental sectors such as wastewater pollution detection, adsorption, and chemical sensing applications.

Fluffy-like amphiphilic graphene oxide and its effects on improving the antibacterial activity and thermal outstanding of ethyl cellulose /polyvinyl alcohol hydrogel film

“…To address this issue, several researchers are working to create eco-friendly packaging solutions that take advantage of the ecological benefits of biopolymers in food packaging applications. Hydrogels have the potential to open up new avenues for the creation of efficient biopolymer packaging materials with desirable properties [ 2 , 3 ]. The shelf life of food cannot be extended by pure ethyl cellulose (EC) film, however adding an antibacterial agent can prevent germs from acting on the film’s surface [ 4 ].…”

“…The shelf life of food cannot be extended by pure ethyl cellulose (EC) film, however adding an antibacterial agent can prevent germs from acting on the film’s surface [ 4 ]. In comparison to films, hydrogels may offer new opportunities for the creation of effective biopolymer packaging materials with desirable properties [ 1 , 3 ]. Due to their ability to absorb water without disintegrating, hydrogels are polymer networks that expand when exposed to water [ 3 , 5 , 6 ].…”

“…In comparison to films, hydrogels may offer new opportunities for the creation of effective biopolymer packaging materials with desirable properties [ 1 , 3 ]. Due to their ability to absorb water without disintegrating, hydrogels are polymer networks that expand when exposed to water [ 3 , 5 , 6 ]. There are several advantages to using sustainable hydrogels in packaging sector, including their biodegradability, low density, low price, and minimal energy consumption during production [ 1 , 3 ].…”

“…Due to their ability to absorb water without disintegrating, hydrogels are polymer networks that expand when exposed to water [ 3 , 5 , 6 ]. There are several advantages to using sustainable hydrogels in packaging sector, including their biodegradability, low density, low price, and minimal energy consumption during production [ 1 , 3 ]. Additionally, the hydrogels’ porous nature enables the controlled release of the majority of antibacterial chemicals.…”

“…PVA and EC could preserve swelling ability [ 10 ]. However, the spread of bacteria frequently leads to food spoilage [ 2 , 3 , 11 ]. Graphene oxide (GO–SB) will be employed as an antibacterial agent to address this issue.…”