The vital functions of extracellular polymeric substances (EPS) have been well recognized in bioleaching of sulfide ores. However, no report is available about the role of EPS in bioleaching of spent catalyst. To completely and deeply understand the functions of EPS in bioleaching of spent catalyst, the generation behavior of EPS at various pulp densities during bioleaching was characterized by three-dimensional excitation-emission matrix (3DEEM), and its relevance with bioleaching performance and process parameters were analyzed using mathematical means. The results showed that the EPS contain humus-like substances as main component (>70%) and protein-like substances as minor component (<30%). Both total EPS and humus-like substances mainly keep growing over the whole duration of bioleaching at low pulp density of 5.0% or lower; whereas total EPS and humus-like fraction keep declining at high pulp density of 7.5% or higher. Among the total EPS and its components, humus-like substances only have a positive significant correlation with bioleaching efficiencies of both Co and Mo and affect bioleaching process more greatly due to greater correlation coefficient. Biofilm appears at the spent catalyst surface under 2.5% of pulp density mediated by EPS while no biofilm occurs at 10% of pulp density due to shortage of EPS, accounting for the great difference in bioleaching efficiencies between high and low pulp densities which are 48.3% for Mo and 50.0% for Co at 10% of pulp density as well as 75.9% for Mo and 78.8% for Co at 2.5% of pulp density, respectively.

中文翻译：

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废石油催化剂生物浸出过程中细胞外聚合物物质的生成行为及其与有价金属提取效率和工艺参数变化的相关性


细胞外聚合物物质 （EPS） 的重要功能在硫化物矿石的生物浸出中已得到充分认可。然而，没有关于 EPS 在废催化剂生物浸出中的作用的报告。为全面深入地了解 EPS 在废催化剂生物浸出中的作用，采用三维激发-发射矩阵 （3DEEM） 对生物浸出过程中不同矿浆密度的 EPS 生成行为进行了表征，并采用数学手段分析了其与生物浸出性能和工艺参数的相关性。结果表明，EPS 以腐殖质样物质为主 （>70%），以蛋白质样物质为主 （<30%）。总 EPS 和腐殖质样物质主要在整个生物浸出过程中以 5.0% 或更低的低髓密度保持生长;而总 EPS 和腐殖质样馏分在 7.5% 或更高的纸浆密度下继续下降。在总 EPS 及其成分中，腐殖质样物质仅与 Co 和 Mo 的生物浸出效率呈正显著相关，并且由于相关系数较大，对生物浸出过程的影响更大。在 EPS 介导的 2.5% 纸浆密度下，生物膜出现在废催化剂表面，而由于 EPS 短缺，在 10% 的纸浆密度下没有生物膜，这是高低纸浆密度之间生物浸出效率的巨大差异，在 10% 的纸浆密度下，Mo 为 48.3%，Co 为 50.0%，Mo 为 75.9%，Co 为 78.8%，在纸浆密度的 2.5% 时为 78.8%， 分别。