Spent petroleum catalyst as a repository of several toxic metals is recommended for metal removal before safe disposal. To evaluate an effective biotechnological approach for metal removal, a comparative study between sequential-aerobic and sequential-anaerobic bioleaching processes was conducted for the removal of metals from crushed-acetone-pretreated spent petroleum catalyst. The SEM–EDX and XPS analysis confirmed the presence of Ni, Al, Mo and V in their oxidic and sulphidic forms in spent catalyst. The bioleaching experiments were performed in stirred tank batch reactors (2.5 L), temperature 30 °C, pH 1.4 and stirring speed 250 rpm for the period of 160 h. Sulfuric acid acted as lechant for both sequential-aerobic (Acidithiobacillus ferrooxidans oxidised sulfur to sulfuric acid aerobically) and sequential-anaerobic (Acidithiobacillus ferrooxidans oxidised sulphur to sulfuric acid coupled with the ferric reduction to ferrous anaerobically) bioleaching studies. The higher Ni and V extractions compared to Al and Mo for all the studies were due to increased solubility of Ni and V, and supported by XPS which showed marginal signs of Ni and V peaks in leach residues compared to feed spent catalyst. At the end (320 h), sequential-aerobic bioleaching was resulted to 99% Ni, 65% Al, 90% Mo and 99% V extraction quite more effective than sequential-anaerobic bioleaching (88% Ni, 28% Al, 33% Mo and 77% V) and sequential-control leaching (94% Ni, 20% Al, 40% Mo and 57% V). Although anaerobic bioleaching a possible approach, aerobic condition was found to be more suitable for sulfuric acid generation by A. ferrooxidans and high yield. So aerobic bioleaching is recommended to be favourable approach compared to anaerobic counterpart for future study and extrapolation.

废石油催化剂作为多种有毒金属的储存库，建议在安全处置前去除金属。为了评估一种有效的金属去除生物技术方法，对顺序好氧和顺序厌氧生物浸出工艺进行了比较研究，以从压碎丙酮预处理的废石油催化剂中去除金属。SEM–EDX 和 XPS 分析证实，废催化剂中存在氧化态和硫化态的 Ni、Al、Mo 和 V。生物浸出实验在搅拌釜间歇式反应器 (2.5 L) 中进行，温度为 30 °C，pH 值为 1.4，搅拌速度为 250 rpm，持续时间为 160 小时。硫酸对顺序好氧（Acidithiobacillus ferrooxidans氧化硫在好氧条件下生成硫酸）和顺序厌氧条件下（Acidithiobacillus ferrooxidans氧化硫到硫酸加上铁在厌氧条件下还原成亚铁）生物浸出研究。在所有研究中，与 Al 和 Mo 相比，Ni 和 V 的萃取率更高是由于 Ni 和 V 的溶解度增加，并且得到 XPS 的支持，与进料废催化剂相比，XPS 在浸出残留物中显示出 Ni 和 V 峰的边缘迹象。最后（320 小时），顺序好氧生物浸出 99% Ni、65% Al、90% Mo 和 99% V 的提取比顺序厌氧生物浸出（88% Ni、28% Al、33% Mo 和 77% V）和顺序控制浸出（94% Ni、20% Al、40% Mo 和 57% V）。虽然厌氧生物浸出是一种可能的方法，但发现有氧条件更适合A. ferrooxidans产生硫酸和高产。因此，与厌氧对应物相比，好氧生物浸出被推荐为有利的方法，用于未来的研究和外推。