摘要
合成了n(Al)/n(Fe)和碱化度不同的45个聚合氯化铝铁(PAFC)样品,进行了光谱分析,结果显示光吸收边蓝移或红移以及Fe(Ⅲ)羟基氧化物和Al-Fe共聚体纳米胶体颗粒大小分布与溶液的Al/Fe比和碱化度(B=[OH]/[Al+Fe])密切相关。电镜观察和电子衍射分析表明:Al(Ⅲ)的加入使Fe(Ⅲ)羟基氧化物和Al-Fe共聚体纳米胶体颗粒变小、有序度降低是造成PAFC光吸收边蓝移和保持胶体颗粒在亚稳定状态下存在的重要原因。当n(Al)/n(Fe)>8∶2后,PAFC溶液中Fe(Ⅲ)羟基氧化物和Al-Fe共聚体胶体主要以<10nm的纳米颗粒形态存在,对应的光谱能级提高到26000cm-1以上,且各种B值下Fe3+的光谱能级趋于一致。这表明,在大量A1(Ⅲ)存在条件下,PAFC中Fe3+的所处的化学环境相似。点能谱分析显示,n(Al)/n(Fe)=4∶6的样品中颗粒物的化学计量比最接近AlOOH,FeOOH,溶液的稳定性最差。
Blue and red shifts of the absorption edges of 45 samples of polyaluminum ferric chloride（PAFC） are closely related with nano-colloidal particle size alteration of Fe（m）hydroxyl polymer and A1-Fe co-aggregate and with AI/Fe molar ratio and basicities （B = [OH]/[A1 ＋ Fe]） in PAFC solutions. Observations under a high resolution wansmitted electron microscope and electron diffraction analysis of crystal structure showed that the addition of Al（Ⅲ） in PAFC is a dominantfactor causing colloidal particle size to decrease and long-range disorder of ferric oxide hydroxyl polymer and A1-Fe coaggregate and this is an important cause for the blue shift of absorption edges and the particles being kept in sub-stability state. In the case of A1/Fe molar ratio 〉 8 ： 2, the principal colloidal particles of Fe（ Ⅲ ） oxide hydroxyl polymer and A1-Fe co-aggregate in PAFC solutions are 〈 10 nm ,the energy scales of electron transition of Fe^3＋ in PAFC solutions are over26000 cm^-1 and tend to be unanimous at variable B ,which displays that the chemical surroundings of Fe^3＋ are the same as in PAFC solutions with the presence of larger quantities of Al （ Ⅲ ） oxide hydroxyl polymer. Compositional analysis of nmlevel area and microanalysis of element distribution using EDS showed that the stoichiometry of particles in Al/Fe molar ratio 4：6 PAFC solution is nearest those of AlOOH and FeOOH, so the stability of the solution is poor.
出处
《矿物学报》
CAS
CSCD
北大核心
2005年第2期158-164,共7页
Acta Mineralogica Sinica
基金
四川省重点学科资助项目(SZD0407)
关键词
聚合氯化铝铁
纳米级胶体颗粒
光吸收边蓝移
量子尺寸效应
表面效应
畸变八面体
polyaluminum ferric chloride solution
nano-colloidal particle
blue shift of absorption edge
quantum size effect
surface effect
distorted oetahedron
