Yamada Manabu, Kimura Shun, Rajiv Gandhi Muniyappan, Shibayama Atsushi
Research Center of Advanced Materials for Breakthrough Technology, Graduate School of Engineering Science, Akita University, 1-1 Tegatagakuen-machi, Akita, 010-8502, Japan.
Applied Chemistry Course, Department of Materials Science, Graduate School of Engineering Science, Akita University, 1-1 Tegatagakuen-machi, Akita, 010-8502, Japan.
Sci Rep. 2021 Jan 11;11(1):365. doi: 10.1038/s41598-020-79614-2.
Extractant-impregnated resins have potential for recovering platinum group metals selectively and efficiently. Herein, 1,3-bis(2-(octylthio)propan-2-yl)benzene (1), a pincer-type extractant, was impregnated in Amberlite XAD-7 resin (1-EIR), and the batch Pd(II) sorption conditions, including impregnated amount, shaking time, Pd(II) concentration, HCl concentration, and Pd(II) desorption reagents, were optimized. The maximum Pd(II) sorption capacity of 1-EIR was 49 mg g after 24 h in a 700 ppm Pd(II) solution. Over 20 adsorption-desorption cycles, 1-EIR showed good reusability, with a sorption percentage (S%) of > 92%. However, not all Pd(II) was desorbed from 1-EIR. Complete Pd(II) collection was achieved by combining desorption with flaking of the Pd-extractant complex from Pd(II)-loaded 1-EIR by Soxhlet extraction, as ~ 13 mg g remained after the 20th adsorption-desorption cycle by absorptiometric method. The sorption mechanism was elucidated based on the Langmuir isotherm model, thermodynamic parameters, and sorption kinetics. Pd(II) sorption by 1-EIR was spontaneous and endothermic, and the sorption kinetics followed a pseudo-second-order model. Notably, 1-EIR also exhibited high selectivity for Pd(II) from a simulated mixed metal solution and a spent automotive catalyst leachate (S% = 98% and > 99%, respectively). Thus, this extractant-impregnated system is promising for selective Pd(II) recovery from spent automotive catalysts and other secondary resources.
负载萃取剂的树脂具有选择性高效回收铂族金属的潜力。在此，将钳形萃取剂1,3-双(2-(辛硫基)丙烷-2-基)苯(1)负载于Amberlite XAD-7树脂(1-EIR)中，并对包括负载量、振荡时间、钯(II)浓度、盐酸浓度和钯(II)解吸试剂在内的批量钯(II)吸附条件进行了优化。在700 ppm钯(II)溶液中，1-EIR在24小时后的最大钯(II)吸附容量为49 mg/g。在超过20个吸附-解吸循环中，1-EIR表现出良好的可重复使用性，吸附百分比(S%)>92%。然而，并非所有钯(II)都能从1-EIR上解吸下来。通过索氏萃取将负载钯(II)的1-EIR中的钯-萃取剂络合物剥落与解吸相结合，实现了钯(II)的完全回收，因为通过吸光光度法在第20次吸附-解吸循环后仍残留约13 mg/g。基于朗缪尔等温线模型、热力学参数和吸附动力学对吸附机理进行了阐释。1-EIR对钯(II)的吸附是自发且吸热的，吸附动力学遵循准二级模型。值得注意的是，1-EIR对模拟混合金属溶液和废旧汽车催化剂浸出液中的钯(II)也表现出高选择性(吸附百分比分别为98%和>99%)。因此，这种负载萃取剂体系有望从废旧汽车催化剂和其他二次资源中选择性回收钯(II)。
