对叔丁基杯[4]芳烃乙酸萃取模拟制革废水中的Cr^(3+)

Extraction of Cr^(3+) with p-tert-Butylcalix[4]arene Acetate from Artificial Tannery Wastewater

通过对一系列杯芳烃及其衍生物载体对萃取分配比的影响的考察,选出萃取Cr3+的最佳萃取剂对叔丁基杯[4]芳烃乙酸;通过考察杯芳烃及其衍生物分子结构,研究了对叔丁基杯[4]芳烃乙酸(简称杯[4]水解)从模拟制革废水体系中萃取Cr3+的反应机理,通过考察溶液pH值对萃取平衡分配比的影响,确认了杯[4]水解萃取Cr3+符合阳离子交换机理为Cr3++HnL(O)→(CrHn-1L(O))2++H+;得到了萃取反应的表观平衡常数为1.815×103;通过考察反应温度对分配比的影响,求得萃取热焓为69.89kJ/mol;由热焓和表观平衡常数计算了自由能为-18.601kJ/mol,熵变为294.97J/(mol.K)。杯[4]水解萃取Cr3+的反应为吸热反应;分别考察了水相溶液初始Cr3+浓度、萃取剂初始浓度、搅拌速度等影响因素对萃取分配比效果的影响。结果表明,经过一级萃取,Cr3+的萃取率可达85%以上。

The extraction of Cr^3＋ by a series of calixarenes and their derivatives was studied, and it was found that the extraction selectivity for Cr^3＋ of p-tert-butylcalix[ 4 ] arene acetate（ HnL（0） ） was outstanding. Based on the molecular structure of the cup aromatic hydrocarbon and its derivative, the mechanism of extraction of Cr^3＋ from the tannery wastewater for p-tert-butylcalix [ 4 ] -arene acetate （ hydrolysis of cup [ 4 ] ） was studied. The dependence of the participation ratio D on pH was studied, and it was confirmed that the extraction of Cr^3＋ performed via the hydrolysis of cup [4] obeyed the positive ion exchange mechanism, i.e. , Cr^3＋ ＋ HnL（0）→（CrHn-1L（0））^2＋ ＋ H^＋ , and the apparent equilibrium constant of the extraction was 1. 815 × 10^3. The influence of temperature on D was also studied, and the enthalpy for the extraction was 69. 89 kJ/mol, and the free energy - 18. 601 kJ/mol and the entropy 294.97 J/（mol · K）. In addition K was calculated. The extraction was exothermic. The influences of major factors such as the initial concentration of Cr^3＋ , the initial concentration of extractant, and the agitation rate on the participation ratio of Cr^3＋ were also investigated. The experimental results show that 85% of Cr^3＋ can be removed from tannery waste water with HnL（0） as extractant.