Exploring key physicochemical sediment properties influencing bioleaching of heavy metals

• Published in: Journal of hazardous materials 2023-03, Vol.445, p.130506, Article 130506
• Main Authors: Wu, Chuncheng, Hu, Xinyi, Wang, Haizhen, Lin, Qi, Shen, Chaofeng, Lou, Liping
• Format: Article
• Language: English
• Subjects: Bacteria - metabolism; Bioleaching; Bioleaching process improvement; Geologic Sediments - chemistry; Heavy metal pollution; Mechanism; Metals, Heavy - analysis; Physicochemical property; Sediment; Sulfur - chemistry
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130506

Bioleaching is a promising technology to remediate sediments contaminated by heavy metals. However, the complex heterogeneities of the sediments can reduce the acidification efficiency and the heavy metal removal rate, thus hindering the practical application of sediment bioleaching. This experiment conducted comparative bioleaching experiments between the inoculated group (average leaching percentages: Cu 67.64%; Zn 54.44%; Ni 29.59%) and the non-inoculated control group (Cu 37.10%; Zn 41.04%; Ni 19.89%) on 28 sediments characterized by different physicochemical properties to explore the key factors influencing bioleaching. The results indicated that the bioleaching process was predominated by the indigenous bioleaching bacteria and the bioleaching inoculum, respectively. The ACCpH=4 (acid-consuming capacity), TOC (total organic carbon), and TN (total nitrogen) of the sediments played an essential role in influencing the microbial community structure and bioleaching performance: the ACCpH=4, as the inhibitive factor, could influence the succession growth of the indigenous bioleaching bacteria and the inoculum during the bioleaching process, while the TOC and TN, as the contributing factor, could influence the metabolism of the indigenous bioleaching bacteria. Based on these results, the bioleaching process was improved with the classification and pretreatments of sediment to realize successful bioleaching of all types of the sediments examined in this research. [Display omitted] •Bioleaching process predominated by indigenous bacteria and inoculum respectively.•Acid-consuming substance influences the change of microbial community structure.•Nutrient content influences the growth of the indigenous bioleaching bacteria.•Pre-treatments can be conducted to promise the success of sediment bioleaching.