纳米硫化锌的生物还原-化学沉淀耦合制备及其性能表征

Nano Sized ZnS Particles: Optical Properties and Preparation by Coupling of Biological Reduction and Chemical Precipitation Mediated with EDTA

生物还原-化学沉淀耦合反应法制备了纳米硫化锌,采用XRD、SEM、TEM、EDS、PL、FTIR等测试手段对产物进行了结构形貌性能表征。结果表明,在加入与Zn2+等物质的量浓度的EDTA后,Zn2+对硫酸盐还原菌(SRB)的毒性消除,SRB的较快生长和SO42-的高效还原得以实现,EDTA修饰的生物转化-化学沉淀耦合系统可制备出高纯的纳米硫化锌晶体。制备的纳米ZnS实心微球体形状规则、分散均匀、大小一致,一次粒子直径10～15nm,二次粒子直径400nm左右。光致荧光光谱和红外光谱分析显示,ZnS纳米粒子在396nm处出现荧光发射峰,在465nm处出现缺陷发光峰,而且具有良好的红外透过性。分散剂聚丙烯酰胺(polyacrylamide)的加入导致产物ZnS的形貌和粒度改变,二次粒子的平均直径减至100nm以下,其荧光发射峰强度增强,红外透过性提高。

High-purity nano ZnS particles were synthesized using a coupling reaction of biological reduction and chemical precipitation mediated with EDTA（CRBRCP-EDTA process）. The results showed that the addition of EDTA with equal molar concentration to Zn^2＋ eliminated the toxicity of Zn^2＋ to sulfate reducing bacteria（SRB）, leading to growth of SRB, reduction of SO4^2- and ZnS production. The characterization by XRD, EDS, SEM and TEM demonstrated that the obtained ZnS particles were highly pure and well-distributed solid spheres with diameter about 10～15 nm for primary particles and around 400 nm for secondary particles. When polyacrylamide（PAM）was incorporated in CRBRCP-EDTA process, the secondary particles diameter was reduced to less than 100 nm. PL studies further proved that the nanoparticles with smaller size exhibited strong quantum size effect and highly intense PL characteristics compared to that without EDTA-mediated ones. The FTIR studies confirmed the ZnS nanoparticles had no IR absorption.