In this investigation, we have reportedthe synthesis of the complex [Th(5, 5´-dmbpy)3](NO3)4](1)that 5, 5´-dmbpy =5, 5´-dimethyl-2, 2´-bipyridine. This complex has been characterized using spectral methods (FT-IR, UV-Vis, 1H-NMR and luminescence), elemental analysis and the Cyclic Voltammetry (CV) method. The FT-IR data shows that 5, 5´-dimethyl-2, 2´-bipyridine (5, 5´-dmbpy) ligand adduct to metal centers by nitrogen atoms. Electronic spectra of (1) shows ligand field transitions and charge transfer (CT) bands. Electrochemical data for the complex in the DMF solution show reduction and oxidationprocessesfor the Thorium ionandligand. The interactions of complex (1)withFS-DNAhave been investigated using UV– Vis and gel electrophoresis. The binding constant (Kb) was calculated using UV– Vis technique (Kb=3. 5×105). Also, DNA cleavage was studied using agarose gel electrophoresis. The antibacterial properties and fluorescence property of complex (1) have also been examined. The in vitro biological screening effects of the complex and ligand were tested against different types of bacterium and [Th(5, 5´-dmbpy)3](NO3)4](1)shows antibacterial properties.

Immobilized Cystoseira indica algae and Saccharomyces Cerevisiae on the silica gel were used for the biosorption of Th(IV) from aqueous solutions. Ability and capacity of bi-functionalized algae-yeast biosorbent for adsorption of thorium(IV) from aqueous solutions were investigated in a batch method. The response surface methodology (RSM) based on the central composite design (CCD) was used to investigate the effect of pH (2-6), time (10-180 min), initial thorium(IV) concentration (50-300 mg/l) and adsorbent dosage (0. 5-5 g/l) on the sorption of thorium(IV) from aqueous solutions, and to optimize the biosorption of Th(IV). Variance analysis showed that the adsorbent dosage, initial Th(IV) concentration, time and pH were respectively, the most effective factors in the biosorption of thorium(IV). Under optimal conditions (pH 5, contact time 137. 5 min, initial Th(IV) concentration 237. 5 mg/l, and adsorbent dosage 1. 63 g/l) the capacity of the biosorbent for Th(IV) was estimated to be 128. 82 mg/g. The kinetic data were fitted well the pseudo-second-order rate equation. The biosorption data could be well described by Langmuir isotherm in comparison to Freundlich and Temkin isotherms. The maximum sorption capacity of the biosorbent for Th(IV), by Langmuir isotherm was estimated to be 142. 86 mg/g. The thermodynamic parameters indicated that the biosorption of Th(IV) on the biomass was a spontaneous, and endothermic process, at the studied temperatures and would occur via physical adsorption.

Mesoporous TiO2-SiO2 nanocomposite (TS) was synthesized via sol-gel method and Amino-functionalized using 3-(aminopropyl) triethoxysilane. prepared amino-functionalized TiO2-SiO2 (NH2TS) was evaluated for eliminating radioactive Th(IV) ion in comparison with (TS). The prepared nanocomposites were characterized using FT-IR, XRD, DSC-TGA, SEM, EDS, BET, and BJH analyses. DSC and TGA analyses revealed that the total organic content of the NH2TS was at about 4%. According to the XRD patterns, synthesized nanocomposites exhibited only the crystalline anatase phase, and the sizes of the anatase crystallites in the prepared TS and NH2TS calculated to be 10. 4 and 14. 1nm, respectively. Moreover, the pore diameters of TS and NH2TS estimated to be 4. 65 and 3. 632 nm according to their BJH plot. The kinetic data of Th(IV) uptake process on both of two nanocomposites corresponded well to the pseudo-second-order equation. Adsorption thermodynamic parameters including the standard enthalpy, entropy, and Gibbs free energy revealed that the ion exchange reactions on both of NH2TS and TS nanocomposites were endothermic and spontaneous processes. The results indicated that NH2TS exhibited higher adsorption affinity toward Th(IV) compared to TS. Moreover, based on the Langmuir model, the maximum adsorption capacity of NH2TS nanocomposite towards the Th (IV) was found to be 1000 mg/g.

An immobilized hybrid biosorbent (IHB) was prepared by hybridizing two biosorbents and evaluated for its ability to remove thorium ions from an aqueous solution. The combined effect of the initial pH of the solution (2 to 6), initial Th(IV) ion solution concentration (50 to 300 mg. L− 1), IHB dose (0. 5 to 5 g. L− 1), and sorption duration (10-180 min) were investigated using central composite design (CCD). Experimental data were analyzed using Design Expert 8. 0. 6 software and fitted to a second order polynomial model with logarithm transform function. The adequacy of the model was verified using three indices, model analysis, coefficient of determination (R2), and the lack-of-fit test. The initial pH of the solution was determined as the most effectual factor on Th(IV) ions biosorption removal by using the analysis of variance (ANOVA). According to the obtained results, pH value of 4. 5, initial metal ion concentration of 210 mg. L− 1, IHB dose of 5 g. L− 1, and sorption duration of 95 minutes were proven to be the optimum conditions, for maximum biosorption removal of Th(IV) ions from aqueous solutions. Thermodynamic parameters have been evaluated, and it has been determined that the sorption process is feasible in going forward with more products than reactants, exothermic in nature and the reaction is entropy-driven. The equilibrium data were analyzed by the Langmuir, Freundlich, and Temkin sorption isotherms. The maximum monolayer sorption capacity of the IHB was found to be 142. 86 mg. g− 1. Pseudo-second-order kinetics model provided a better fit for all the biosorption processes which let suppose a physical rate-limiting step for the process.

The sorption of thorium and uranium ions by functionalized SBA–15 mesoporous silica materials with Schiff base ligating groups N–propylsalicylaldimine (SBA/SA) and ethylenediaminepropylesalicylaldimine (SBA/EnSA) from aqueous solution was investigated in fixed-bed column method. The effect of pH, sample solution volume, and the column design parameters such as sample and eluent flow rates, and column bed height were studied. These investigations allowed to obtain the experimental breakthrough curves. Regardless to the adsorbent used, application of the columns with 2.5 cm bed height and sample flow rate 0.4 mL/min, resulted in the quantitative removal of 0.5 mg of Th (IV) and U (VI) ions from 200 and 250 mL aqueous solutions, adjusted at pH 4. The quantitative desorption of the loaded ions provided a preconcentration factor of 40 and 50 for Th (IV) and U (VI), respectively. Breakthrough studies showed the higher capacity of the column packed with SBA/EnSA in comparison to that packed with SBA/SA. The breakthrough curves indicated that both of the sorbents presents higher capacity towards uranium than thorium ions. The columns could be used for at least 3 sorption-desorption cycles. The investigated columns were examined for the recovery of Th (IV) and U (VI) from tap water and seawater samples.

Batch extraction investigation was carried out to elucidate the stochiometry of the extracted Th(IV) species. The effects of nitric acid concentration, extractant concentration and temperature were studied. The results showed that the extraction of thorium follows solvation mechanism in the low (0.001 mol L-1) and high (8 mol L-1) nitric acid concentration, while the cation exchange mechanism dominates the middle acidic area (1 mol L-1). The extracted species was found to be Th(OH)2(NO3)A.HA on the basis of the slope analysis method. The results of the thermodynamic investigations indicated that the extraction process is spontaneous (G<0), exothermic (H<0), and less random in nature (S<0). The value of activation energy of the extraction reaction was calculated to be 17.46 kJ mol-1 which indicates that the extraction reaction is controlled by the diffusion process.

Extraction-separation of Eu (III) and Th (IV) ions from nitrate media into the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate by a phosphorylated salen extractant, bis (chlorophosphoryle) decahydro-2, 4-di (2-hydroxyphenyl) benzo [d] [1, 3, 6] oxadiazepine (DPO), is investigated. It is found that Eu (III) ions are extracted via a solvation mechanism, and the extraction of Th (IV) ions proceeds through an ion exchange mechanism. The analysis of the experimental data reveals that the extraction of Eu (III) and Th (IV) ions is taken place by formation of Eu (DPO) (NO3) 3 and Th (DPO) 2 (PF6) 4 complexes. A significant selectivity towards thorium ions with respect to trivalent lanthanides (lanthanum, europium, and erbium) was observed. Thorium (IV) can be efficiently extracted from nitric acid solutions into the studied ionic liquid in the presence of DPO.