复合溶剂萃取回收硫氰酸红霉素废水中的硫氰酸盐

Extraction of thiocyanate from erythromycin thiocyanate wastewater with composite solvent

以三辛胺(TOA)与正辛醇、磺化煤油组成萃取剂,萃取回收硫氰酸红霉素废水中的硫氰酸盐。结果表明:TOA与硫氰酸(HSCN)的萃合物在正辛醇、异辛醇、正己醇等极性溶剂中的溶解度比在煤油、环己烷及其本身中的溶解度大;在p H值为3.50和4.00时,TOA-正辛醇-煤油体系中,正辛醇起助溶和协萃双重作用,而在p H值为3.00时,正辛醇的助溶作用较为突出;以TOA-正辛醇-煤油为萃取剂萃取废水中HSCN,研究得到最佳萃取条件为:萃取剂组成V(TOA)∶V(正辛醇)∶V(煤油)=2∶1∶17,在室温下进行萃取,初始p H值约为3.50,油水相比VO/VA为1/10,萃取级数2级,在最佳萃取条件下,SCN-的萃取率可达到94.52%;且该萃取过程为放热、熵减过程,萃取焓变-39.25 k J/mol,熵变-103.78(J·mol)/K。

Thioeyanate was extracted from erythromycin thiocyanate wastewater with a solvent consists of trioetylamine （TOA） , n-oetyl alcohol and sulfonated kerosene. The results show that the extraction complex of TOA and thiocyanie acid （HSCN） has a better solubility in n-octyl alcohol, isooetyl alcohol, hexyl alcohol than that in kerosene, cyclohexane and TOA. The n-octyl alcohol in the extractant helps to the dissolution of extraction complex and synergistic extraction of thioeyanate when pH is 3.50 and 4.00, while the role of dissolution is more prominent under pH of 3.00. The optimum conditions are as follows： V（TOA）： V（n-oetyl alcohol）： V（ kerosene ） = 2： 1： 17; room temperature; initial pH value is 3.50; the phase ratio of solvent to wastewater is 1： 10; the extraction stage is 2. The extraction rate of SCN- can reach 94.52% under these conditions. This extraction is an exothermie process and has a reduction in entropy, the enthalpy change is -39.25 kJ/mol, entropy change is - 103.78 （J·mol）/K.