Hyder M K Mohammad Ziaul, Ochiai Bungo
Department of Chemistry and Chemical Engineering, Faculty of Engineering, Yamagata University, Jonan 4-3-16, Yonezawa, Yamagata 992-8510, Japan.
ACS Omega. 2022 Mar 14;7(12):10355-10364. doi: 10.1021/acsomega.1c06988. eCollection 2022 Mar 29.
We report the synthesis and practical application of a novel scavenger for precious metals. The scavenger was prepared from cellulose filter paper with grafted chains of poly(glycidyl methacrylate) modified with a novel ligand group of -methyl-2-hydroxyethylcarbamothioate moieties, introduced by the reaction with -1-mercapto-3-phenoxypropan-2-yl -methyl-2-hydroxyethylcarbamothioate. Batch experiments were performed to evaluate the capability of the scavenger in ranges of pH and acid concentration as well as to determine the kinetics and isotherm models. The scavenger was found to adsorb only Ag(I), Pd(II), and Au(III) from an aqueous media in the presence of coexisting ions of different bases and precious metals at wide ranges of pH and acid concentration. The adsorption rates fit a pseudo-second-order kinetic equation, and the adsorption reached equilibrium within 60 min. The isotherm studies indicated that the obtained data were a good fit with the Langmuir model. The maximum adsorption capacities of Ag(I), Pd(II), and Au(III) were 126.95, 124.67, and 230.67 mg g, respectively. Regeneration experiments indicated that the adsorbent maintained 97% of its initial efficiency even after five adsorption/desorption cycles. The scavenger was effectively utilized to recover Ag(I), Pd(II), and Au(III) from an aqua regia solution of waste printed circuit boards.
我们报道了一种新型贵金属 scavenger 的合成及实际应用。该 scavenger 由纤维素滤纸制备而成，其接枝有聚（甲基丙烯酸缩水甘油酯）链，并用新型配体基团 -甲基-2-羟乙基氨基硫代甲酸酯部分进行了改性，该基团通过与 -1-巯基-3-苯氧基丙-2-基 -甲基-2-羟乙基氨基硫代甲酸酯反应引入。进行了批次实验，以评估 scavenger 在不同 pH 和酸浓度范围内的性能，并确定动力学和等温线模型。结果发现，在广泛的 pH 和酸浓度范围内，在不同碱金属和贵金属共存离子存在的情况下，该 scavenger 仅从水性介质中吸附 Ag(I)、Pd(II) 和 Au(III)。吸附速率符合准二级动力学方程，吸附在 60 分钟内达到平衡。等温线研究表明，获得的数据与朗缪尔模型拟合良好。Ag(I)、Pd(II) 和 Au(III) 的最大吸附容量分别为 126.95、124.67 和 230.67 mg/g。再生实验表明，即使经过五次吸附/解吸循环，吸附剂仍保持其初始效率的 97%。该 scavenger 被有效地用于从废印刷电路板的王水溶液中回收 Ag(I)、Pd(II) 和 Au(III)。
