College of Chemistry, Sichuan University, 29# Wangjiang Lu, Chengdu, 610064, Sichuan, PR China.
J Hazard Mater. 2010 Apr 15;176(1-3):119-24. doi: 10.1016/j.jhazmat.2009.11.005. Epub 2009 Nov 10.
A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min(-1) from the first order rate equation. Thermodynamic parameters (DeltaH(0)=-46.2 kJ/mol; DeltaS(0)=-98.0 J/mol K; DeltaG(0)=-17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na(+), Co(2+), Sr(2+), Cs(+) and La(3+).
一种新型的基于苯甲酰基硫脲的固相亲水相萃取剂被开发出来，用于选择性萃取六价铀。该萃取剂通过羟化、酰胺化和与苯甲酰异硫氰酸酯反应的顺序被固定在活性炭上。傅里叶变换红外光谱和全元素分析证明苯甲酰基硫脲已经成功地接枝到活性炭的表面上，其负载量为每克活性炭 1.2mmol 的苯甲酰基硫脲。研究了影响铀（VI）吸附的参数，如接触时间、溶液 pH 值、初始铀（VI）浓度、吸附剂剂量和温度等。结果通过 Langmuir 和 Freundlich 等温线进行了分析；前者更适合描述吸附过程。在实验条件下，该合成萃取剂对铀（VI）的最大吸附容量为 82mg/g。通过一级速率方程，该合成萃取剂对铀的吸附速率常数为 0.441min(-1)。热力学参数（DeltaH(0)=-46.2kJ/mol;DeltaS(0)=-98.0J/mol K;DeltaG(0)=-17.5kJ/mol）表明吸附是一个放热过程，具有自发性。进一步的研究表明，苯甲酰基硫脲-活性炭（BT-AC）在存在竞争离子 Na(+)、Co(2+)、Sr(2+)、Cs(+)和 La(3+)的情况下，选择性地吸附铀酰离子。
