Xiaoyang Liu,Na Zhang,Zhen Dong,Jifu Du,Lifang Peng,Long Zhao,Miao Yang
Technetium ( 99 Tc) is a main long-lived radionuclide of nuclear waste, which poses a great threat to the environment and human health. The reasonable disposal of 99 Tc is vital important. In this paper, a series of novel materials (SMILR m , m = 0, 1/500, 1/200, m is the molar ratio of IL to RAFT reagent) was synthesized by radiation-induced grafting combined with reversible addition-fragmentation chain transfer (RAFT) polymerization. The adsorption performance of SMILR m to 99 Tc were investigated. The graft polymerization process is controlled by the RAFT reagent, resulting in a restricted dispersion of SMILR m molecular weight. With the increase of RAFT reagent content, the grafting yield (GY) decreased. The addition of RAFT reagent increases the specific surface area of the adsorbent, accelerates the adsorption rate, increases the adsorption capacity, but reduces the adsorption selectivity. Especially, the adsorption of SMILR 0 was a single step adsorption and obeyed Langmuir adsorption model, while SMILR m (1/500, 1/200) showed a stepwise adsorption isotherm model. SMILR m exhibited excellent recyclability and could efficiently capture Re O 4 - from a simulated Beishan groundwater in dynamic experiments. Finally, XPS and FT-IR analysis confirmed that the adsorption was an ion exchange mechanism. The results showed that SMILR m are suitable for the effective removal of Re O 4 - / T c O 4 - from radioactive wastewater with complex composition.
The selective elimination of radioactive TcO4− from radioactive waste is becoming increasingly critical for environmental security. In this work, a series of novel adsorbents (Si-IL-X, X = NO3, Cl, BF4, NTf2) modified with ionic liquids containing different anions (X) were synthesized via radiation grafting of 1-vinyl-3-ethylimidazolium tetrafluoroborate onto silanized silica and subsequent anion replacement. The surface and structural properties of the prepared adsorbents were characterized by FT-IR spectroscopy, TGA, XPS, and SEM-EDS. Subsequently, their adsorption properties for ReO4− (a nonradioactive surrogate of TcO4−) were studied in detail via batch and column experiments. The batch experiments indicated that the Si-IL-X showed high ReO4− removal efficiency over a broad pH range of 3–10, and their maximum adsorption capacities were in the range of 147.93–289.02 mg g−1 against ReO4−. It was found that the adsorption ability of Si-IL-X was related to the anion structure of the ionic liquid, and the order was Si-IL-NO3 > Si-IL-Cl > Si-IL-BF4 > Si-IL-NTf2, which was mainly determined by the hydrophilicity and ionic radius of the anions. Besides, their adsorption capacities barely decreased after electron beam radiation of 800 kGy. In column experiments, the adsorbents exhibited excellent selectivity and could capture ReO4− efficiently from simulated radioactive wastewater containing a large number of coexisting ions. In addition, the XPS and FT-IR spectroscopic analyses indicated that adsorption was carried out by an ion-exchange process. The results suggested that Si-IL-X showed excellent application prospect for efficient capture of TcO4− from Hanford waste and other common acidic radioactive wastes.
Fan Zhang,Qi Zheng,Yachao Tan,Fan Wang,Khalid A.M. Salih,Ningchao Zheng,Mohammed F. Hamza,Shunyan Ning,Yuezhou Wei,Xiangbiao Yin
Currently, the primary approach for treating radioactive isotopes all over the world is a great challenge. The impact of this treatment is to transform liquid radioactive wastewater (present in huge volume) into low-volume solid radioactive waste. The current work presents synthesis and application of novel adsorbent using β-lactoglobulin fibrils (βFs) on SiO 2 particles and activated carbon particles (AC particles), which considered as facile and ecologically conscious. βFs were produced by denaturing inexpensive β-lactoglobulin. This method of filtering was used for radioactive waste, which differs from most prior adsorption techniques. Polyethyleneimine (PEI) was grafted onto protein fibrils using polydopamine (PDA). The produced material shows highly removal performance of TcO 4 - under both acidic and alkaline conditions (up to 99.76 %, with filtering time of just 5–6 min). This membrane exhibits a superior preference for TcO 4 - over certain common competing ions, including SO 4 2- , NO 3 – , and Cl - . The hybrid membrane achieves maximum adsorption performance for the substituted ion ReO 4 - of 533 mg/g, which is higher than the most commonly used fiber materials. Furthermore, βFs-PDA + PEI fibrils can efficiently treat up to 8000 kg of wastewater per kg and exhibit remarkable reusability performance. This membrane’s simple production, efficient performance, and excellent selectivity make it ideal to be implemented in both hospitals and nuclear power plants.
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