胞外多聚物在废旧锌锰电池生物浸提中的作用机制

The reaction mechanism of extracellular polymeric substances in bioleaching of spent Zn Mn batteries

以A.thiooxidans和L.ferrooxidans为浸提菌株,研究其胞外多聚物(EPS)在废旧锌锰电池生物浸提中的作用.通过三维荧光获取了生物浸提中EPS的组成及特征变化,并利用半透膜包覆生物淋滤实验和扫描电镜(SEM)、透射电镜(TEM)等手段探讨了菌株及其EPS与电极材料的界面行为.结果表明:EPS促进了菌株与材料的接触,强化了Fe^(3+)/Fe^(2+)的生物循环;EPS总荧光区域积分标准体积(ΦT,n)与锌、锰的溶出效率之间拟合的决定系数分别为0.942和0.981,EPS保有量显著提升了锌、锰浸提效率;废旧锌锰电池溶释是菌株EPS参与下的直接接触浸提及其代谢产物间接浸提的共同结果.

The function of extracellular polymeric substances（ EPS） in bioleaching process of the spent Zn-Mn batteries have been examined with A.thiooxidans and L. ferriphilum as leaching strains. The composition and characteristics of ESP varied during bioleaching pocess have been studied by using three-dimension fluorescence spectra. The interface behavior among bacteria,EPS and electrode materials have been discussed by the experiment of bioleaching with semi-permeable membrane bag,scanning electron microscopy（ SEM） and transmission electron microscopy（ TEM）. The results have shown that EPS has promoted the contact between bacteria and battery materials and a cycle reaction of Fe^3＋/Fe^2＋. The determination coefficients of the dissolution efficiency of Zn/Mn and excitation-emission area volumes（ Φ（T,n）） were 0.942 and 0.981 respectively,and the efficiency of bioleaching of zinc and manganese have been enhanced by the amount of EPS. The spent Zn-Mn batteries dissolution is the result from interactions among direct leaching of bacteria ESP and indirect leaching of its metabolites.