氨基硫脲改性硅胶对Pd^(2+)的动态吸附性能

Dynamic adsorption behavior of Pd^(2+) on silica gel functionalized with thiosemicarbazide

采用异相合成法,以硅胶为基质、氨基硫脲为功能试剂,通过硅烷偶联剂连接制备出一种新型吸附材料。利用FT-IR、BET、TG与XRD等分析技术对材料的性质进行表征,并进一步研究其对Pd^(2+)的动态吸附性能。结果表明:与未改性的硅胶相比,经氨基硫脲改性后的硅胶对Pd^(2+)的吸附性能得到大幅度提升;Thomas模型能够准确地反映吸附过程特征,其相关性系数均大于0.930。在给定的实验条件下,其动态最大吸附容量为0.121mmol/g,最大回收率为55.91%;提高溶液初始浓度和吸附柱高度,或者降低流速,可提高材料的饱和吸附容量;材料经过5次循环使用后,吸附能力基本保持不变,可重复利用。

A novel thiosemicarbazide modified silica gel （SG-TSC） was prepared and characterized by Fourier transform infrared spectroscopy （FT-IR）, specific surface area （BET）, thermogravimetric （TG）, X-ray diffraction （XRD）, and so on. The property of SG-TSC of adsorbing Pd2＋ from aqueous solution was studied in fixed-bed column. The results show that the adsorption ability of thiosemicarbazide modified silica gel for Pd2＋ is enhanced obviously. The Thomas model is found to be suitable for describing the dynamic adsorption process with correlation coefficient more than 0.930. The dynamic highest loading capacity and recovery rate are 0.121 mmol/g and 55.91% under the specified experimental conditions. The dynamic saturation adsorption capacities increase with the increase of both influent metal concentration and bed height, but decrease with increase of flow rate. The adsorption capacity of the adsorbent is found to be apparently constant even after its repeating use for 5 cycles. The SG-TSC can be used as an adsorbent for recovery of Pd2＋ ions from aqueous solution.