功能化纳米氧化硅在银离子回收中的应用

发布时间：2018-01-14 21:13

本文关键词：功能化纳米氧化硅在银离子回收中的应用　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：银及含银产品在电子电镀、感光材料、化工和科研等领域的广泛应用所产生的大量含银废液不仅造成了严重的环境污染,而且使得银资源大量浪费。因此,回收含银离子废液中的银具有非常重要的研究和实用意义。本论文将不同结构和性能的有机功能分子嫁接到纳米二氧化硅表面,制备出了三种对银离子具有选择性吸附功能的材料,为从含银溶液回收银提供了一种新思路。本论文主要进行了以下三个方面的研究:(1)合成了磺乙基改性的纳米二氧化硅。磺乙基改性二氧化硅能够选择性吸附银离子,最大吸附量为21.9mg/g,吸附平衡时间为60min,最佳吸附pH值为6,吸附过程符合Langmuir等温吸附模型和准二级吸附动力学模型,表明吸附过程主要为单层吸附,速率控制步骤为化学吸附,吸附剂对银离子有较好的选择性,红外光谱(FT-IR)和X射线光电子能谱(XPS)表明吸附机理为氨基、磺酸基与银离子产生络合作用。(2)羧甲基-二硫代氨基甲酸酯改性二氧化硅对银离子的吸附研究。羧甲基-二硫代氨基甲酸酯改性纳米二氧化硅对银离子的最佳吸附pH为6,吸附过程大约在120 min达到平衡,最大吸附量为25.8 mg/g,吸附过程符合Langmuir等温吸附模型和准二级吸附动力学模型,表明吸附过程主要为单层吸附,速率控制步骤为化学吸附,并且吸附剂对银离子有较好的的选择性。(3)三聚硫氰酸改性二氧化硅选择性吸附银离子的研究。三聚硫氰酸改性二氧化硅能够选择性吸附银离子,最大吸附量为80.0mg/g,吸附平衡时间为30min,最佳吸附pH值为6,吸附过程符合Langmuir吸附等温线模型和准二级动力学模型,吸附剂经5次重复使用后吸附效率无明显降低。研究表明银离子的吸附机理主要是银离子与巯基之间发生的络合作用。
[Abstract]:The extensive application of silver and silver-containing products in the fields of electronic electroplating, photosensitive materials, chemical industry and scientific research has not only caused serious environmental pollution, but also made a large amount of waste of silver resources. The recovery of silver from the waste liquid containing silver ions is of great significance in research and practice. In this paper, organic functional molecules with different structures and properties are grafted onto the surface of nano-silica. Three kinds of materials with selective adsorption of silver ions were prepared. This paper provides a new way to recover silver from silver solution. The nanometer silica modified by sulfonethyl was synthesized. The modified silica can selectively adsorb silver ions. The maximum adsorption capacity is 21.9 mg / g, the adsorption equilibrium time is 60 min, the optimum adsorption pH is 6, and the adsorption process accords with the Langmuir isothermal adsorption model and the quasi-second-order adsorption kinetic model. The results show that the adsorption process is mainly monolayer adsorption, the rate control step is chemical adsorption, and the adsorbent has good selectivity for silver ions. FT-IR) and X-ray photoelectron spectroscopy (XPS) show that the adsorption mechanism is amino. Complexation of sulfonic groups with silver ions. The adsorption of silver ions on silica modified by carboxymethyl-dithiocarbamate was studied. The optimum pH for the adsorption of silver ions on nano-silica modified by carboxymethyl dithiocarbamate was 6. The adsorption process reached equilibrium at about 120 min and the maximum adsorption capacity was 25.8 mg / g. The adsorption process was in accordance with the Langmuir isothermal adsorption model and the quasi-second-order adsorption kinetic model. The results show that the adsorption process is mainly monolayer adsorption and the rate control step is chemical adsorption. And the adsorbent has good selectivity for silver ion.) the silica modified by thiocyanate can selectively adsorb silver ion. The maximum adsorption capacity is 80.0 mg / g, the adsorption equilibrium time is 30 min, the optimum adsorption pH is 6, and the adsorption process accords with the Langmuir adsorption isotherm model and the quasi-second-order kinetic model. The adsorption efficiency of the adsorbent was not significantly decreased after repeated use for 5 times. It was found that the mechanism of silver ion adsorption was mainly the complexation between silver ion and sulfhydryl group.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TF832;TB383.1

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