Xiong Ying, Adhikari Chaitanya Raj, Kawakita Hidetaka, Ohto Keisuke, Inoue Katsutoshi, Harada Hiroyuki
Department of Applied Chemistry, Saga University, 1-Honjo, Saga 840-8502, Japan.
Bioresour Technol. 2009 Sep;100(18):4083-9. doi: 10.1016/j.biortech.2009.03.014. Epub 2009 Apr 21.
Persimmon waste was chemically modified with dimethylamine (DMA) to obtain a tertiary-amine-type gel, named DMA persimmon waste gel (DMA-PW). It was found to be effective for the adsorption of Au(III), Pd(II), and Pt(IV) in hydrochloric acid medium. In contrast, base metals such as Cu(II), Zn(II), Fe(III), and Ni(II) were not practically adsorbed. The formation of ion pairs of the metal chloro complex anions with the protonated adsorption gels was proposed as the main adsorption process. The gel exhibited selectivity only for precious metals with a remarkably high capacity for Au(III), i.e., 5.63 mol/kg dry gel and comparable capacities, i.e., 0.42 and 0.28 mol/kg for Pd(II) and Pt(IV), respectively. According to the kinetic and electrochemical studies, the adsorption rate of Au(III) was greatly enhanced by the chemical modification. Also, its excellent adsorption characteristics for the precious metals were confirmed by adsorption and elution tests using a column packed with the DMA-PW gel.
用二甲胺（DMA）对柿子废弃物进行化学改性，得到一种叔胺型凝胶，命名为DMA柿子废弃物凝胶（DMA-PW）。研究发现，它在盐酸介质中对Au(III)、Pd(II)和Pt(IV)具有良好的吸附效果。相比之下，Cu(II)、Zn(II)、Fe(III)和Ni(II)等贱金属几乎不被吸附。金属氯配合物阴离子与质子化吸附凝胶形成离子对被认为是主要的吸附过程。该凝胶仅对贵金属具有选择性，对Au(III)的吸附容量非常高，即5.63 mol/kg干凝胶，对Pd(II)和Pt(IV)的吸附容量分别为0.42和0.28 mol/kg。动力学和电化学研究表明，化学改性极大地提高了Au(III)的吸附速率。此外，通过使用填充有DMA-PW凝胶的柱进行吸附和洗脱试验，证实了其对贵金属具有优异的吸附特性。
