基于毛竹半纤维素的银纳米粒子的绿色合成

直接以碱溶性毛竹半纤维素为稳定剂、葡萄糖为还原剂,在水介质中绿色合成银纳米粒子,讨论了合成条件对银纳米粒子的形成和储存稳定性的影响,表征了银纳米粒子-半纤维素复合物经热处理后获得的Ag-C复合物的物理化学特性,并讨论了银纳米粒子的可能形成机理。在恒定其他反应条件下,延长反应时间会有更多银纳米粒子生成,但过度延长反应时间会使银纳米粒子发生团聚而生成大颗粒的粒子;高的葡萄糖浓度、反应温度和初始半纤维素用量会加快银纳米粒子的生成。银纳米粒子的平均粒径和粒径分布范围均随半纤维素用量的增大而减小,而银纳米粒子在4℃的储存稳定性随半纤维素用量的增大而增强。银纳米粒子-半纤维素复合物在空气气氛中300℃热处理1h后获得的Ag-C复合物中同时存在金属态的银和氧化态的银。半纤维素中呈电负性的大量自由羟基和少量羧基可能对银纳米粒子的形成起至关重要的作用。

Green Synthesis of Silver Nanoparticles Based on Bamboo Hemicellulose

Silver nanoparticles were green synthesized in aqueous medium using alkali bamboo ( Phyllostachys pubescens Mazel) hemicellulose as stabilizer and glucose as reducing agent .The effect of reaction factors on the formation and storage stability of silver nanoparticles were discussed . The Ag-C compound formed after thermal treatment of silver nanoparticles-hemicellulose compound was characterized .When the other reaction factors were kept as constants ,longer reaction time could result in the formation of more silver nanoparticles .However ,much long reaction time could stimulate aggregation of silver nanoparticles to form large particles .High concentrations of glucose and hemicellulose ,and also high reaction temperature accelerated the formation rate of silver nanoparticles . High amount of hemicellulose resulted in smaller average particle size and narrower range of particle size distribution .The storage stability of silver nanoparticles at 4 ℃ became stronger when higher amount of hemicellulose was added . The metallic silver and oxided silver coexisted in the Ag-C compound formed after silver nanoparticles-hemicellulose compound was treated at 300 ℃ for 1 h under air atmosphere .The electronegative groups including a large number of free hydroxyl groups and a small number of carboxyl groups in the hemicellulose may play an important role in the formation of silver nanoparticles .