Xi'an University of Architecture and Technology, School of Metallurgical Engineering, Xi'an, 710055, PR China; Shaanxi Key Laboratory of Gold and Resources, Xi'an, 710055, PR China.
Xi'an University of Architecture and Technology, School of Metallurgical Engineering, Xi'an, 710055, PR China; Shaanxi Key Laboratory of Gold and Resources, Xi'an, 710055, PR China.
Chemosphere. 2022 Mar;291(Pt 3):133052. doi: 10.1016/j.chemosphere.2021.133052. Epub 2021 Nov 23.
In this study, a trioctylmethylammonium chloride (N263)- tributyl phosphate (TBP)-n-octanol-sulfonated kerosene (N263-T) synergistic extraction system and an N263-n-octanol-sulfonated kerosene (N263-O) system were used to treat cyanide (CN)-bearing wastewater. The extraction saturation capacity of the two systems was measured. The influences of the initial pH and phase ratio (O/A) of the two systems on extraction were compared and analyzed. Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and slope methods were used to analyze the characteristic functional groups in the loaded organic phase, the compositions of the extracted compounds in the extraction reactions and the reaction mechanism. The results indicated that the saturated extraction capacity of the N263-T system, which was much larger than that of the N263-O system, for metal CN complex ions was 4354.31 mg/L. In addition, the N263-T system operated over a wider pH range. The extraction rates of copper (Cu), zinc (Zn), and iron (Fe) ions at pH 14 were 97.4%, 99.1%, and 87.2%, respectively. There was a strong compatibilization effect of TBP on the extraction system. The extraction efficiency of the N263-T system for metal CN complex ions was higher than that of the N263-O system when O/A = 0.4. The saturated loaded N263-T and N263-O systems were stripped by 1 mol/L NaOH +2 mol/L NaSCN solution at O/A = 3. The metal ion concentration in the stripping solution could be enriched to 11996.6 and 8913.3 mg/L for the N263-T and N263-O systems, respectively. During the extraction process, the binding ratios of N263 cations to Cu(CN), Zn(CN), and Fe(CN) were 2:1, 2:1, and 3:1, respectively. The binding ratios of TBP to Cu(CN), Zn(CN), and Fe(CN) in wastewater were 3:1, 4:1, and 6:1, respectively. The PO group in TBP was linked to the CN group of the metal CN complex ion by hydrogen bonds using the water molecule as a bridge to form a supramolecular anion group, which entered into the organic phase and combined with the N263 cation under the action of ion association.
在这项研究中，采用了三辛基甲基氯化铵（N263）-三丁基磷酸酯（TBP）-正辛醇-磺化煤油（N263-T）协同萃取体系和 N263-正辛醇-磺化煤油（N263-O）体系处理含氰废水。测量了两个体系的萃取饱和容量。比较分析了两个体系初始 pH 值和相比（O/A）对萃取的影响。采用傅里叶变换红外（FTIR）光谱、紫外-可见（UV-Vis）光谱和斜率法分析了负载有机相中的特征官能团、萃取反应中提取化合物的组成和反应机理。结果表明，N263-T 体系对金属 CN 络合离子的饱和萃取容量（4354.31 mg/L）远大于 N263-O 体系。此外，N263-T 体系的操作 pH 范围更宽。在 pH 14 时，铜（Cu）、锌（Zn）和铁（Fe）离子的萃取率分别为 97.4%、99.1%和 87.2%。TBP 对萃取体系具有很强的助溶作用。当 O/A=0.4 时，N263-T 体系对金属 CN 络合离子的萃取效率高于 N263-O 体系。用 1 mol/L NaOH+2 mol/L NaSCN 溶液在 O/A=3 下对饱和负载的 N263-T 和 N263-O 体系进行反萃。N263-T 和 N263-O 体系的萃余液中金属离子浓度可分别富集至 11996.6 和 8913.3 mg/L。在萃取过程中，N263 阳离子与 Cu(CN)、Zn(CN)和 Fe(CN)的结合比分别为 2:1、2:1 和 3:1。TBP 与废水中 Cu(CN)、Zn(CN)和 Fe(CN)的结合比分别为 3:1、4:1 和 6:1。TBP 中的 PO 基团通过氢键与金属 CN 络合离子的 CN 基团相连，以水分子为桥形成超分子阴离子基团，在离子缔合作用下进入有机相与 N263 阳离子结合。
