粒状载银活性炭微结构及对有机物的吸附性

Microstructure of granular silver-loaded activated carbon and its adsorption properties for organic matter

为了探讨载银对活性炭吸附有机物性能的影响,采用硼氢化钠还原法制备粒状载银活性炭。通过X射线衍射、扫描电子显微镜、红外光谱以及比表面积测定等方法对载银活性炭的微结构进行分析表征,考察AgNO3浓度对粒状活性炭微结构和有机物吸附性能的影响,同时研究载银活性炭吸附有机物的动力学特性。结果表明,银以单质形式负载在活性炭上,活性炭的比表面积、银颗粒的粒径及分布与AgNO3溶液浓度密切相关。红外光谱证实载银活性炭表面有羰基、羧基、羟基等氧化性基团存在。载银活性炭对苯酚等4种有机物的吸附去除率比普通活性炭增大了约10%,这些吸附属于优惠吸附,可以很好地用Freundlich吸附等温线模型来描述其吸附平衡过程。载银活性炭具有较普通活性炭更大的有机物吸附性能。

To investigate the effect of silver loading on the adsorption of organic compounds by activated carbon,granular silver-loaded activated carbon was prepared by NaBH 4 reduction method.The obtained silver-loaded activated carbon was characterized by X-ray diffraction,scanning electron spectroscopy,Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface area methods.The effects of AgNO 3 concentration on the microstructure and organic adsorption properties of silver-loaded activated carbon were discussed.The adsorption kinetics of silver-loaded activated carbon on organic matter was studied.The results show that the silver is deposited on the silver-loaded activated carbon in the state of Ag 0.The specific surface area,particle size and distribution of the generated silver particles are determined by the concentration of the aqueous solution of AgNO 3.FTIR spectra confirmed the presence of oxidizing groups such as carbonyl,carboxyl and hydroxyl groups on the surface of silver-loaded activated carbon.The adsorption removal rate of four organic substances such as phenol by the silver-loaded activated carbon increases by about 10%compared with the ordinary activated carbon without silver-loading.The substance having a relatively large molecular weight is more easily adsorbed.These organics adsorption belongs to preferential adsorption,which can be well described by Freundlich adsorption isotherm model.The silver-loaded activated carbon has a higher adsorption capacity than the ordinary activated carbon.