Li Guoping, Xue Juanqin, Liu Nina, Yu Lihua
College of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China E-mail:
Water Sci Technol. 2016;73(12):2888-95. doi: 10.2166/wst.2016.136.
The transport of cyanide from wastewater through a bulk liquid membrane (BLM) containing tricaprylamine (TOA) as a carrier was studied. The effect of cyanide concentration in the feed solution, TOA concentration in the organic phase, the stirring speed, NaOH concentration in the stripping solution and temperature on cyanide transport was determined through BLM. Mass transfer of cyanide through BLM was analyzed by following the kinetic laws of two consecutive irreversible first-order reactions, and the kinetic parameters (k(1), k(2), R(m)(max), t(max), J(a)(max), J(d)(max)) were also calculated. Apparently, increase in membrane entrance (k(1)) and exit rate (k(2)) constants was accompanied by a rise in temperature. The values of activation energies were obtained as 35.6 kJ/mol and 18.2 kJ/mol for removal and recovery, respectively. These values showed that both removal and recovery steps in cyanide transport is controlled by the rate of the chemical complexation reaction. The optimal reaction conditions were determined by BLM using trioctylamine as the carrier: feed phase: pH 4, carrier TOA possession ratio in organic phase: 2% (V/V), stripping phase concentration of NaOH: 1% (W/V), reaction time: 60 min, stirring speed: 250 r/min. Under the above conditions, the removal rate was up to 92.96%. The experiments demonstrated that TOA was a good carrier for cyanide transport through BLM in this study.
研究了氰化物通过含有三辛胺（TOA）作为载体的支撑液膜（BLM）从废水中的传输情况。通过支撑液膜测定了进料溶液中氰化物浓度、有机相中TOA浓度、搅拌速度、反萃溶液中NaOH浓度和温度对氰化物传输的影响。根据两个连续不可逆一级反应的动力学规律分析了氰化物通过支撑液膜的传质过程，并计算了动力学参数（k(1)、k(2)、R(m)(max)、t(max)、J(a)(max)、J(d)(max)）。显然，膜入口（k(1)）和出口速率（k(2)）常数的增加伴随着温度的升高。去除和回收的活化能值分别为35.6 kJ/mol和18.2 kJ/mol。这些值表明，氰化物传输中的去除和回收步骤均受化学络合反应速率的控制。以三辛胺为载体，通过支撑液膜确定了最佳反应条件：进料相：pH 4，有机相中载体TOA占有率：2%（V/V），反萃相NaOH浓度：1%（W/V），反应时间：60 min，搅拌速度：250 r/min。在此条件下，去除率高达92.96%。实验表明，在本研究中TOA是氰化物通过支撑液膜传输的良好载体。
