Sorption of uranyl ions from aqueous solutions using crosslinked maleic anhydride‐octene‐styrene terpolymer

Maleic anhydride‐octene‐styrene terpolymer has been modified with allylic alcohol and methylmethacrylate to prepare a new crosslinked functional polymer sorbent. The sorption behaviors of uranyl ions on the optimum sorption conditions were determined. The synthesized crosslinked polymer sorbent has a network structure and contains carboxylic acid, carbonyl, and ester groups, all of which are capable of interacting with metal ions. The maximum experimental sorption capacity of the sorbent for uranyl ions has been measured as 1.25 mmol g^?1. Langmuir and Freundlich isotherm constants and correlation coefficients for the present system have been calculated and compared. Uranyl ions are desorbed from the sorbent by treatment with hydrocholric and nitric acids at various concentrations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

用重结晶法纯化重铀酸铵和高钼三碳酸铀酰铵

重铀酸铵用浓碳酸铵溶液制浆，生成三碳酸铀酰铵。所制备的三碳酸铀酰铵和高钼三碳酸铀酰铵晶体，分别用热软化水溶解、过滤或澄清、渣洗涤。清液加热煮解，所得浆液浓密，浓浆体加浓碳酸铵溶液转化，重结晶，晶体洗涤，过滤，制得高纯三碳酸铀酰铵晶体。小型试验和半工业试验结果表明，该纯化流程是可行的，省去了苹取过程，大幅度降低了化工材料消耗费用，减少了环境污染，工艺易实现。     

Enhancement of uranium bioaccumulation by a Citrobacter sp. via enzymically-mediated growth of polycrystalline NH4UO2PO4

The objective of this work was to study the effect of pH and ionic matrix on product release and on the removal of uranyl ion by a Citrobacter. sp phosphatase enzyme-catalysed reaction. An improvement in the efficiency of uranyl removal was obtained by incorporating ammonium acetate (NH₄Ac) into the solution. It was confirmed using X-ray diffraction (XRD), and other analytical techniques, that the insoluble, cell-bound product was NH₄UO₂PO₄.     

Improved AIE‐Active Probe with High Sensitivity for Accurate Uranyl Ion Monitoring in the Wild Using Portable Electrochemiluminescence System for Environmental Applications

The development of highly sensitive and selective uranyl ion (UO₂²⁺) probes has attracted significant attention owing to the threat to human health caused by high toxicity, radioactivity, and long half‐life. Herein, the development of aggregation‐induced emission (AIE) active polymer dots (Pdots) is described for an accurate UO₂²⁺ monitoring using a portable electrochemiluminescence (ECL) system. An AIE‐active polymer containing tetraphenylethene and boron ketoiminate moieties is prepared into Pdots and modified with ssDNA to capture UO₂²⁺, which can amplify the ECL signal of the Pdots through a resonance energy transfer mechanism. This probe provides an ultralow detection limit of 10.6 pm /2.5 ppt, which is at least two orders of magnitude lower than the known UO₂²⁺ luminescent probes. Only UO₂²⁺ can provide an obvious ECL enhancement among the various metal ions, indicating the excellent selectivity of this probe. Furthermore, a portable ECL analyzer is designed to realize UO₂²⁺ measurements in the wild. The anodic ECL mechanism of UO₂²⁺ is discovered and ECL technology is first applied in monitoring radioactive substances. This study provides a novel strategy for the development of accurate UO₂²⁺ probes and a practical UO₂²⁺ monitoring method, indicating its potential application in the environmental and energy fields.     

Polyelectrolyte CASA hydrogels for uptake of uranyl ions from aqueous solutions

In this study, uranyl ion adsorption from aqueous solutions has been investigated by chemically crosslinked acrylamide/sodium acrylate (CASA) hydrogels. Adsorption studies were investigated by the spectroscopic method. CASA hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), sodium acrylate (SA), and water by free radical polymerization in aqueous solution, using multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA). Uranyl ion adsorption from aqueous solutions was studied by the batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of adsorbent on the uranyl ion adsorption were examined. In experiments of sorption, L‐type sorption in the Giles classification system was found. Some binding parameters, such as initial binding constant (K_i), equilibrium constant (K), monolayer coverage (n), site‐size (u), and maximum fractional occupancy (Ô) for the CASA hydrogel–uranyl ion binding system, were calculated using the Langmuir linearization method. Finally, the amount of sorbed uranyl ion per gram of dry hydrogel (q) was calculated to be 4.44 × 10^?4–14.86 × 10^?4 mol uranyl ion per gram for CASA hydrogels. Adsorption of uranyl ion (percentage) was changed within a range of 12.86–46.71%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 200–204, 2007     

ZnS/AC复合材料的制备及其对铀酰离子的吸附性能

采用化学沉淀法制备了活性炭负载纳米硫化锌的复合材料ZnS/Ac，利用SEM、EDS、XRD、FTIR、BET等手段对该复合材料进行了表征分析。研究了ZnS/Ac对水溶液中铀酰离子的吸附性能，探讨了吸附时间、初始铀酰离子浓度、pH值、吸附剂投加量、温度等因素对吸附性能的影响，并对吸附过程进行了热力学和动力学模拟，探讨了吸附机理。结果表明：ZnS/Ac的比表面积为201.1961 m2/g，比活性炭的比表面积（165.0240 m2/g）明显增大，平均孔径为4.70 nm，孔容为0.038 cm3/g。在初始质量浓度为35 mg/L，pH=6，吸附时间为120 min，投加量为10 mg，处理温度为50 ℃的条件下，吸附剂对铀酰离子的吸附量为64.4736 mg/g。吸附过程符合准二级动力学方程和Langmuir 吸附等温线模型，热力学参数<0、>0、>0，表明该吸附是一个自发的吸热过程。     

Use of amidoximated acrylonitrile/N‐vinyl 2‐pyrrolidone interpenetrating polymer networks for uranyl ion adsorption from aqueous systems

Poly(N‐vinyl 2‐pyrrolidone) (PVP)/acrylonitrile (AN) interpenetrating polymer networks (IPNs) were synthesized and amidoximated for the purpose of uranyl ion adsorption. The adsorption of amidoximated IPNs was studied from different uranyl ion solutions (850, 1000, 1200, 1400, and 1600 ppm). The result of all our adsorption studies showed that the bonding between UO‐amidoxime groups complied with the Langmuir‐type isotherm. The adsorption capacity was found as 0.75 g UO/g dry amidoximated IPN. In order to increase the UO ion adsorption capacity the amidoximated IPN was treated with alkali, but no significant increase could be observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2324–2329, 2001     

Smart Photonic Crystal Hydrogel Material for Uranyl Ion Monitoring and Removal in Water

Uranyl ion (UO₂²⁺) pollution is a serious environmental problem, and developing novel adsorption materials is essential for UO₂²⁺ monitoring and removal. Although some progress is achieved, it is still a challenging task to develop an adsorption material with indicating signal for real‐time evaluation of the adsorption degree and the UO₂²⁺ concentration. Herein, this paper describes a smart photonic crystal hydrogel (PCH) material, which not only can be used for real‐time monitoring function but also can be utilized for UO₂²⁺ removal based on the chelation of UO₂²⁺ with ligand groups in PCH material. The working principle is based on the binding of a uranyl ion to multiple ligand groups, which results in the shrinkage of PCH material and triggers a blue‐shift of diffraction wavelength. Consequently, the adsorption degree and the UO₂²⁺ concentration can be sensitively evaluated by measuring the diffraction shift or observing the color change with naked eye. With this PCH material, the lowest detectable concentration for UO₂²⁺ is 10 × 10^?9m , and the maximum adsorption capacity at 298 K is 169.67 mmol kg^?1. In addition, this material also holds good selectivity and regeneration feature, and shows desirable performance for UO₂²⁺ analysis in real water samples.     

具有UV探测灵敏性、稳定性和重复利用性的层状铀酰配位聚合物研究

灵敏的UV探测对于工业生产和个人防护非常重要, 本研究旨在开发新型UV探测材料。一般而言, 铀酰单元具有相对高的UV吸收效率和荧光强度。本课题组成功地在水热条件下制备了一例铀酰配位聚合物[(TEA)₂(UO₂)₅(PhPC)₆] (TEA = 四乙基胺离子, PhPC = (2-羧基乙基)苯膦酸, 标记为UPhPC-1)。基于单晶XRD数据的结构分析表明UPhPC-1中有三个不同的铀酰中心, 其中两个铀酰单元为五角双锥构型, 而第三个铀酰单元为四角双锥构型。全部三个铀酰中心与配体在[bc]平面配位形成无限的铀酰层。通过氢键网格和π-π相互作用, 这些铀酰层堆积成整体的层状结构。此化合物具有很好的热稳定性、水稳定性和高抗辐照能力。UV辐照实验结果表明UPhPC-1的本征荧光强度对365 nm的UV辐射高度敏感, 检测下限低且响应速率快, 而发光强度与UV辐照剂量呈负相关。电子顺磁共振谱分析证实在UV光照射下, UPhPC-1中极有可能产生自由基, 造成铀酰荧光部分淬灭。进一步, 被淬灭样品中的自由基能够在加热后被去除, 从而实现UPhPC-1发光强度的快捷恢复。目前的结果表明UPhPC-1在UV辐照的定量探测领域具有一定的发展潜力。