Molybdenum is an essential trace element for humans but can be harmful with excess assimilations or chronic exposures. In this study a polymer-functionalized nanocomposite (HFO-PsAX) was fabricated for selective adsorption of molybdate from aqueous solution. HFO-PsAX was prepared by grafting hydrous ferric oxide nanoparticles (HFOs) into the porous structure of a polystyrene anion exchanger (PsAX) by in situ synthesis method. The resultant HFO-PsAX exhibited greatly enhanced selectivity toward molybdate as compared with the matrix, PsAX, which is also a fair adsorbent for scavenging molybdate. The competitive abilities of the ubiquitous anions, i.e., chloride, carbonate, sulfate, and phosphate, on the adsorption of molybdate by HFO-PsAX followed the order: chloride < phosphate < carbonate < sulfate. The unexpectedly weak competitive ability of trivalent phosphate may be due to incompletely dissociated state and formation of molybdate-phosphate complexes. The optimal pH for the adsorption of molybdate was determined as pH ≈ 4, which is associated with the dissociation constants of molybdic acid; certain adsorption capacities were also observed even under extremely alkaline condition (pH = 14) for single-component molybdate solution. Temperature (10, 25, and 40 °C) has negligible effect on the adsorption capacities by HFO-PsAX, and Freundlich model and Dubinin-Radushkevich (D-R), Temkin model can describe the adsorption isotherms well. The adsorption potential of Temkin model is calculated as ≈100 J/mol, which is between those of physisorption and chemisorption process. Fixed-bed column adsorption experiments validated the potential of HFO-PsAX in treating Mo(VI) contaminated water for practical application, and the exhausted HFO-PsAX can be regenerated by a binary NaOH-NaCl solution (both 5% in mass) without loss in adsorption capacities.

钼是人类必需的微量元素，但过量吸收或长期暴露会对人体有害。在这项研究中，制备了一种聚合物官能化的纳米复合材料（HFO-PsAX），用于从水溶液中选择性吸附钼酸盐。通过将水合三氧化二铁纳米粒子（HFOs）通过原位合成方法接枝到聚苯乙烯阴离子交换剂（PsAX）的多孔结构中来制备HFO-PsAX。与基质PsAX相比，所得的HFO-PsAX对钼酸盐的选择性大大提高，而PsAX也是清除钼酸盐的良好吸附剂。普遍存在的阴离子（即氯离子，碳酸根，硫酸根和磷酸根）对HFO-PsAX吸附钼酸盐的竞争能力的顺序为：氯<磷酸根<碳酸根<硫酸根<硫酸根。三价磷酸盐出乎意料的较弱竞争能力可能是由于不完全解离的状态和钼酸-磷酸盐复合物的形成。确定吸附钼酸盐的最佳pH为pH≈4，这与钼酸的解离常数有关。即使在极端碱性条件下（pH = 14），单组分钼酸盐溶液也具有一定的吸附能力。温度（10、25和40°C）对HFO-PsAX的吸附容量的影响可忽略不计，而Freundlich模型和Dubinin-Radushkevich（DR），Temkin模型可以很好地描述吸附等温线。Temkin模型的吸附势计算为≈100J / mol，介于物理吸附和化学吸附过程之间。