活性碳纤维对银离子还原吸附能力的改进  

STUDY ON THE IMPROVEMENT OF THE REDUCTION AND ADSORPTION CAPACITY OF Ag+ ACTIVATED CARBON FIBERS

作　　者：陈水挟[1] 曾汉民[1] 

机构地区：[1]聚合物复合材料及功能材料教育部重点实验室,中山大学材料科学研究所,广州510275

出　　处：《离子交换与吸附》2001年第5期316-323,共8页Ion Exchange and Adsorption

基　　金：国家"863"基金 (863-715-004-024) ;教育部博士点基金

摘　　要：活性碳纤维不仅对有机物有高的吸附容量,对贵金属离子也具有强的还原吸附能力,可将Pd(II), Ag(I), Au(III)等离子还原为金属单质。因而可用于提取矿液或回收废液中的贵金属。由此,提高或改善贵金属在活性碳纤维上的还原吸附容量或分布形态,显得非常重要。本文研究了活性碳纤维制备条件、表面氧化改性、以及负载有机物等对活性碳纤维还原能力的影响。结果表明,(1)制备条件对剑麻基活性碳纤维的还原能力有很大的影响。用H3PO4或ZnCl2活化的活性碳纤维对银离子具有更高的还原吸附容量,分别可达250和700mg/g,约为水蒸汽活化剑麻基活性碳纤维对银离子还原吸附容量的2倍和5倍。(2)过氧化氢、高锰酸钾、或硝酸等无机氧化剂对活性碳纤维进行表面改性,也能提高活性碳纤维的还原能力。结果表明,虽然改性活性碳纤维的比表面积和孔体积下降10～20%左右,但其表面含氧量及含氧基团的种类发生了改变。这些改性活性碳纤维对Ag(NH3)2+的还原吸附量大幅度提高,可达550mg/g 以上。推断表面改性在活性碳纤维表面创造了更多有利于碱性条件下发生氧化还原的活性点。(3)在活性碳纤维表面负载适当的有机物如亚甲基蓝、苯胺或对硝基苯酚,也能显著提高活性碳纤维对Ag(NH3)2+的还原吸附能力。The reduction property of activated carbon fibers(ACF) enable them to be used in the recovery of noble metal from wastewater, or in the extraction of gold or silver from ore leaching solution. In order to effectively recover or extract noble metals, it is important to enhance the reduction capacity of activated carbon fiber and to improve the particle form of noble metal reduced and adsorbed on the surface of activated carbon fibers. In this paper, the reduction capacity of ACF is improved through three aspects. The study results show that: (1) the preparation methods of activated carbon fibers has significant influence on the reduction-adsorption capacities of ACF for silver ion in solution, those ACFs activated with phosphoric acid or zinc chloride have much higher reduction capacities. (2) The surface modification of ACF with some inorganic oxidants such as nitric acid, potassium permanganate, or hydrogen peroxide, though result in somewhat decrease of specific surface area or pore volume, will enhance the reduction capacity of oxidized ACFs for silver ion. And (3) methylene blue, aniline, or p-nitrophenol present in solution or adsorbed on ACFs significantly increase the reduction capacities of sisal based ACF for silver ion.

关 键 词：活性碳纤维 还原吸附 银离子 表面改性 吸附能力 

分 类 号：O614.122[理学—无机化学] O647.3[理学—化学]