Carbon-Dot-Decorated Layered Double Hydroxide Nanocomposites as a Multifunctional Environmental Material for Co-immobilization of SeO₄^2– and Sr²⁺ from Aqueous Solutions

Abstract

Co-immobilization of cationic and anionic radionuclides is highly desirable for total remediation of radioactive wastewater. Carbonaceous nanomaterials have received much attention in the field of water remediation and pollution control in recent years. However, the handling of these nanomaterials is challenging due to increased bioavailability and toxicity. In this work, MgAl-NO3 layered double hydroxide (LDH) was synthesized and modified using carbon nanodots (C-dot). The prepared materials were characterized using powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), zeta potential, and transmission electron microscopy (TEM) observation. Adsorption of SeO4 2– and Sr2+ on MgAl-NO3-LDH/C-dot composites showed that the Sr2+ immobilization capacities increased with an increase in the amount of C-dot. The mechanism of Sr2+ adsorption on these composites occurs via coordination with the −COO– group of C-dot, whereas that of SeO4 2– occurs through ion exchange with NO3 – in the interlayer galleries of LDH. The adsorption of Sr2+ and SeO4 2– was enhanced in both bicomponent (Sr2+ + SeO4 2–) and tricomponent systems (Sr2+ + SeO4 2– + M+/M2+ = coexisting cations or A n– = coexisting anions) with the presence of other anion and cations. The MgAl-NO3-LDH/C-dot composites demonstrated that the high adsorption efficiency of Sr2+ and SeO4 2– than most of other materials reported. These results demonstrate that MgAl-NO3-LDH/C-dot composites are an effective adsorbent for total remediation of anionic and cationic radioactive nuclides from wastewater.

Metal–Organic Framework-74 for Ultratrace Arsenic Removal from Water: Experimental and Density Functional Theory Studies

“…Among the large numbers of MOF structures to date, only a tiny fraction are found to be chemically stable and have been explored as adsorbents for water purification. UiO-66, HT-Zn-MOF-74, ZIF-8, AUBM-1, and MIL-53 are some examples of chemically stable MOF structures that have been studied recently for pollutant removal from water. − Therefore, exploring and developing new MOF adsorbents that are chemically stable are particularly interesting. Herein, we investigate the use of the highly stable Zn-MOF-74 [Zn 2 (DOT), where DOT = 2,5-dioxidoterephthalate; Figure ] as a new sorbent for removing As­(V) from water.…”

Inorganic and Hybrid (Organic–Inorganic) Lamellar Materials for Heavy Metals and Radionuclides Capture in Energy Wastes Management—A Review

“…Finally, a modified MgAl-NO 3 LDH using carbon nanodots for Sr 2+ adsorption was prepared [117], enabling a boost in the adsorption capability of the material as the quantity of carbon nanodots is increased (Figure 9a). This phenomenon is explained by a coordination between the –COO − groups of carbon nanodots with Sr 2+ .…”

“…MgAl-NO 3 LDH synthesized by Koilraj et al and containing: ( a ) carbon nanodots [117]; and ( b ) graphene oxide [118]. Reprinted with permission from references [117,118]. …”

Mg-Cr layered double hydroxide (LDH) intercalated with sodium dodecyl sulfate as sorbent for Alizarine Red-S in aqueous solutions

“…LDHs were used as adsorbents for the removal of heavy metals, radionuclides, oxyanions [30][31][32][33], dyes [34][35][36][37][38][39][40]. Intrercalation using organic surfactants to increase the hydrophobicity have found many applications in the removal of organic materials from industrial wastewater.…”