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Developing novel adsorbents for efficient U(VI) adsorption from wastewater is of great significance in both nuclear energy development and environmental protection. Herein, a novel functional resin (AO67/MA33-resin) with large particle size (100–200 μm) was controllably synthesized and employed for U(VI) elimination. The AO67/MA33-resin overcomes the shortcoming of small particle size of traditional adsorbents and shows strong antacid and high-temperature resistance stability and reusability. Meanwhile, the AO67/MA33-resin also exhibits excellent U(VI) removal ability including wide pH adaptability, fast adsorption kinetic, and high adsorption capacity. The adsorption mechanism was determined to involve chelation between amidoxime carboxyl functional groups and uranyl ions. A further application for U(VI) removal from real uranium mine wastewater was evaluated by dynamic column experiments. The present work indicated that the AO67/MA33-resin would be a promising adsorbent material for uranium removal from wastewater. [ABSTRACT FROM AUTHOR]

Decontamination of the toxic selenium compound, selenite (Se(IV)) and selenate (Se(VI)), from wastewater is imperative for environmental protection. Efficient approaches to remove Se(IV) and Se(VI) are in urgent needs. In this work, an accessible adsorbent Fe–OOH–bent was prepared and applied for the removal of Se(IV) and Se(VI) from wastewater. The batch experimental results demonstrate that Fe–OOH–bent exhibits high adsorption capacities of 5.01 × 10−4 and 2.28 × 10−4 mol/g for Se(IV) and Se(VI) respectively, which are higher than most of the reported bentonite based materials, especially in the case of Se(VI). Moreover, the Fe–OOH–bent displayed superior selectivity towards Se(IV) and Se(VI) even in the presence of excess competitive anions (Cl−, HCO3−, NO3−, SO42− and PO43−) and HA with concentrations of 1000 times higher than Se(IV) and Se(VI). By evaluating the adsorption ratio of Se(IV) and Se(VI), the reusability of Fe–OOH–bent was great through five adsorption-desorption cycles. For practical application, the column experiments were performed with simulated wastewater samples. The breakthrough and eluting curves of Se(IV) and Se(VI) were investigated through the columns packed with Fe–OOH–bent, and the results show that Se(IV) and Se(VI) can be successfully separated and recovered using 0.1 mol/L Na2SO4 (pH = 9.0) and 0.1 mol/L Na3PO4 (pH = 9.0), respectively. Our work provides a new approach for fractional separation as well as the recovery of Se(IV) and Se(VI) from wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel extractant resin DtBuCH18C6@CG-71 was successfully prepared with simple and low-cost method. • DtBuCH18C6@CG-71 exhibited remarkable separation ability of Sr(II) even in high concentration HNO 3 (3–12 mol/L). • DtBuCH18C6@CG-71 possessed great acid, irradiation and thermal resistance stability. • DtBuCH18C6@CG-71 can adeptly sequesters and recovers Sr(II) from wastewater via an automated separation system. Effective removal of radioactive 90Sr is crucial for both management of spent nuclear fuel and recovery of radioactive strontium resources, while it's still a great challenge due to the presence of high acid levels and intense radiation. Herein, a novel porous resin (DtBuCH18C6@CG-71) were synthesized by introducing 4′,4″(5″)-di- tert -butyldicyclohexano-18-crown-6 onto CG-71 resin using vacuum impregnation. The DtBuCH18C6@CG-71 resin maintains superior adsorption abilities in extreme conditions, including high acid resistance (3–12 mol/L HNO 3), substantial γ-irradiation (200 kGy 60Co), and elevated temperatures (50–100 ℃). Impressively, even when exposed to a high concentration of matrix ions (59 elemental ions), the Sr(II) adsorption ratio onto DtBuCH18C6@CG-71 resin remains near 100 % even in highly acidic condition, which performance outpaces most of commercial resins. Dynamic column tests using an automated separation system further confirmed the superior ability of DtBuCH18C6@CG-71 in term of extracting Sr(II) from wastewater. Given its impressive features, cost-effectiveness, and scalability, DtBuCH18C6@CG-71 resin holds promising potential for 90Sr disposal in nuclear wastewater. [ABSTRACT FROM AUTHOR]

99Tc primarily exists high mobility in the natural aqueous environment due to its extremely high solubility and non-complexing features, which can easily cause radioactive pollution. We herein report a general strategy for constructing a novel resin (SiPAN-PEI) with multiple positive charges nitrogen, exhibiting ultrafast adsorption kinetics (< 3 min), superior adsorption capacities (463.96 mg g−1), and excellent selectivity in the presence of excess competitive anions, which exceed those of most commercial resins. Moreover, based on impressive structure stability in extreme conditions, SiPAN-PEI can still maintain superior adsorption abilities after suffering irradiation, calcination, and immersion in strong acid. In addition, the separation performance kept excellently after five loading-washing-eluting cycles and the total adsorption ratio can still reach 97 %. Outstandingly, SiPAN-PEI can remove most of ReO 4 - from simulated nuclear wastewater through a sequential injection automatic separation system and can reduce the concentration of ReO 4 - to the maximum concentration standard set by the World Health Organization (WHO) in a short time. Leveraging density functional theory calculations and other characteristics clearly elucidated adsorption mechanism of anion-exchange between Cl- and TcO 4 -/ReO 4 -. In terms of superior adsorption property, SiPAN-PEI is demonstrated to be a pretty candidate for 99Tc elimination from wastewater. [Display omitted] • A novel resin SiPAN-PEI was successfully synthesized for selective capture of 99Tc. • SiPAN-PEI exhibited excellent adsorption ability of 99Tc in harsh conditions. • Multiple positive charge nitrogen plays a critical role in capture of 99Tc. • SiPAN-PEI demonstrated efficiency capture of 99Tc in simulated wastewater. [ABSTRACT FROM AUTHOR]

Efficient and cost-effective removal of radioactive iodine anions from contaminated water has become a crucial task and a great challenge for waste treatment and environmental remediation. Herein, we present hexadecylpyridinium chloride monohydrate modified bentonite (HDPy-bent) for the efficient and selective removal of iodine anions (I− and IO 3 −) from contaminated water. Batch experiments showed that HDPy-bent could remove more than 95% of I− and IO 3 − within 10 min, and had maximum I− and IO 3 − adsorption capacities of 80.0 and 50.2 mg/g, respectively. Competitive experiments indicated that HDPy-bent exhibited excellent I− and IO 3 − selectivity in the excessive presence of common concomitant anions including PO 4 3−, SO 4 2−, HCO 3 −, NO 3 −, Cl− (maximum mole ratio of anions vs iodine anions was ∼50,000). An anion exchange mechanism was proposed for the selective adsorption of iodine anions. Optimal adsorption structure of HDPy+/I− (IO 3 −) at atomic level and driving forces of the I− (IO 3 −) adsorption were calculated by density functional theory (DFT) simulations. Moreover, the good durability and reusability of the HDPy-bent has been demonstrated with 5 adsorption-desorption cycles. Dynamic column experiment also demonstrated that HDPy-bent exhibited excellent removal and fractional recovery capabilities towards I− and IO 3 − from simulated groundwater and environmental water samples. In conclusion, this work presents a promising adsorbent material for the decontamination of radioactive iodine anions from wastewater on a large scale. [Display omitted] • HDPy-bent showed excellent adsorption abilities for iodide and iodate. • Anions exchange mechanism was confirmed by batch experiments and DFT simulations. • The pyridine N was the intrinsic active site of the modified bentonite. • HDPy-bent was efficient for removing radioiodine anions from wastewater. [ABSTRACT FROM AUTHOR]