Simultaneous Adsorption of Th(IV) and U(VI) Ions from Aqueous Solutions by a Tannic-Acid-Modified Nanomagnetite Adsorbent

Abstract

Nuclear wastewater remediation provides an intriguing opportunity to successfully remove and recover radioactive elements, especially Th(IV) and U(VI) ions, since they play a crucial role as nuclear fuel and pose a significant threat to the sustainability of the environment. In the present investigation, magnetic nanoparticles were modified by a polyphenolic compound, tannic acid (TA), to develop a tannic acid@magnetite (TA@Fe3O4) nanocomposite for effective adsorption of Th(IV) and U(VI) ions from wastewater. To more accurately predict the effective adsorption of the ions, adsorbents varying in the mass ratio of TA and Fe3O4 were synthesized, and also the practical utility of the adsorbent was evaluated by employing batch adsorption studies under the conditions of pH, adsorbent dosage, contact time, and initial concentration. The maximum removal efficiency, i.e., 99.42% and 92.63% for Th(IV) and U(VI) ions, respectively, was obtained with a 1:2 ratio of TA@Fe3O4 at pH 6 with 6 mg of absorbent dosage of 10 mL of 50 ppm thorium and uranium solution in 20 min. Further, the experimental data were attributed to the isotherms and kinetic models, corresponding the adsorption system with the Langmuir model of the isotherm and pseudo-second-order kinetics, thus revealing the monolayer chemisorption process of adsorption for both ions. The TA@Fe3O4 nanocomposite exhibited high recyclability with seven adsorption–desorption cycles via magnetic separation, indicating its potential application in wastewater treatment. Hence, on the basis of facile, low-cost precursors for large-scale manufacturing and excellent recyclability, this work presents a potential and promising strategy of the TA@Fe3O4 nanocomposite for enhanced removal of radionuclides for wastewater reclamation.

Evaluation of Adsorptive Capture and Release Efficiency of MNPs-SA@Cu MOF Composite Beads Toward U(VI) and Th(IV) Ions from an Aqueous Media

“…In this aspect, 30 mg of uranium and thorium ion loaded adsorbent was immersed in 50 mL of 0.1 M HCl solution and agitated on a shaker for 3 h. After desorption of uranium and thorium ions, beads were washed with distilled water and collected through the external magnet, dried in a hot air oven at 40 °C for 8 h, and then reused for further adsorption studies. In the acidic medium, hydrogen bonds got weakened between the uranium and thorium ions and MNPs-SA@Cu MOF composite beads and desorption takes place. , It can be seen from Figure a, beads showed the ten adsorption–desorption cycles with a slight decrease in the removal efficiencies of U­(VI) (99.99 to 92%) and Th­(IV) (97.78 to 89.25%) without the demolition of the beads. Recovery of uranium and thorium ions have also been checked after desorption.…”

“…In the acidic medium, hydrogen bonds got weakened between the uranium and thorium ions and MNPs-SA@Cu MOF composite beads and desorption takes place. 57,58 It can be seen from Figure 12a ), chloride (Cl − ), calcium (Ca 2+ ), magnesium (Mg 2+ ), and fluoride (F − ) (50 ppm) were used, and adsorption study was done under optimized conditions (pH = 6, 10 mL of 50 mg/L of U(VI) and Th(IV) solution, 6 mg dose). As shown in Figure 12b, no significant impact was seen on the adsorption of U(VI) and Th(IV) ions in the presence of various ionic salts.…”

Effective Adsorption–Desorption Kinetic Study and Statistical Modeling of Bentazon Herbicide Mediated by a Biodegradable β-Cyclodextrin Cross-Linked Poly(vinyl alcohol)–Chitosan Hydrogel

“…For this, three kinetic linear model equationspseudo-first-order (PFO), pseudo-second-order (PFO), and intraparticle diffusion­(IPD)were used for the adsorption studies (Text S2). − Figure S10a,b shows the linear fitting of kinetics models as a function of time, and Table shows all the kinetic parameters. From the table, it is evident that the adsorption kinetics of the removal of BZ were better described by the PSO model, which had the higher regression coefficient value (0.9912) compared to PFO model.…”

Batch Experimental Studies and Statistical Modeling for the Effective Removal of Tetracycline from Wastewater Using Bimetallic Zn–Cu-Metal–Organic Framework@Hydrogel Composite Beads

“…The physical properties, including surface area, pore diameter, and pore volume, of Zn–Cu-BDC and Zn–Cu-BDC@CA CBs were systematically investigated using BET analysis, as illustrated in Figures S2 and d. Nitrogen adsorption–desorption isotherms revealed that both Zn–Cu-BDC and Zn–Cu-BDC@CA composites exhibit type-III isotherms characterized by the presence of a H3-type hysteresis loop. , Detailed results obtained from the BET analysis for Zn–Cu-BDC and Zn–Cu-BDC@CA CBs are tabulated in Table S1. The Zn–Cu-BDC@CA CBs have lower value of BET parameters, which may be possible due to the filling of pores with sodium alginate.…”